In oil-gas exploration and development, the space for innovation in exploration and development technology relying on existing models is becoming increasingly limited, the existing information and digitization achievements are no longer able to support the new demand for increasing oil-gas reserves and production, reducing costs and increasing efficiency. Years of exploratory practice in the domestic oil and gas exploration field has shown that implementing geology-engineering integration is the only way to reverse the trend of declining oil-gas reserves and achieve high-quality exploration and development. To this end, a set of application scheme integrated engineering implementation and geological research is proposed. On the basis of integrating existing oil-gas exploration and development information system resources and application modules, and solving various technical defects and application problems in the existing system, a multi-professional integrated collaborative decision-making platform of geology and engineering with big data and core business system integration of oil-gas exploration and development is constructed. The platform adopts a standardized four-layer structure model, including data acquisition layer, network support layer, data storage layer and data application layer. It is composed of 7 core modules, such as mud logging data acquisition, processing and interpretation, and mud logging geological big data application. It can provide integrated service support for digitization innovation of oil-gas exploration and development, covering mud logging data acquisition, interpretation and evaluation, drilling engineering construction, geological synthesis study and other businesses. The construction and application of this platform have achieved good economic and social benefits, becoming an important driving force for expanding business, improving quality and efficiency, and continuously promoting the comprehensive transformation of various majors in oil-gas exploration and development from digitization to intellectualization.

With the development of unconventional reservoirs in recent years, the complexities of oil and gas exploration have risen significantly, and subsurface fluid relations have become more and more complex. The demand for rapid and accurate evaluation of formation fluids, discovery of thin, fracture-type, and weakly show of oil and gas layers, and provision of decision-making basis for exploration and development has become more urgent. Aiming at the difficulties of identifying thin interlayers in complex reservoirs and recognizing the nature of unconventional oil and gas fluids, we have carried out research on infrared spectrum logging featured technology based on the spectroscopic principle of gas molecular. This technology has an analysis period of ≤8 s, and is not easy to leak oil and gas layers under rapid drilling conditions. In particular, it has more technical advantages in fluid evaluation of oil, gas and water layers while drilling, identification of fractured/thin hydrocarbon reservoirs, fine classfication of reservoirs and boundary determination. Based on the infrared spectrum gas logging technology, the reservoir energy level spectrogram evaluation model and the evaluation standard of reservoir fluid properties are established. The practical application of this method in the well site has achieved good results and effectively solved the problem of reservoir fluid identification and evaluation under rapid drilling conditions.

Accurate identification of site lithology plays an important role in oil and gas exploration and development. As the difficulty of exploration increases, the difficulty of lithology identification on site also increases accordingly. An intelligent identification method of lithology based on data while drilling is proposed to solve the problem of on-site stratigraphic lithology identification while drilling. This method analyzes the formation elements and parameters while drilling, extracts the eigenvectors, establishes the multiple-feature collection library of different lithology, and realizes the lithology intelligent identification based on data while drilling by using the generalized regression neural network model of the Max-Min Ant System optimization algorithm.This method is applied to actual lithology identification while drilling, and the MMAS-GRNN model constructed from non-feature extraction data and feature extraction fusion data is compared.The experimental results show that the accuracy rate of stratigraphic lithology identification of MMAS-GRNN model based on multi-source information feature extraction fusion data reaches 90.71%, which is 4.76% higher than that of non-feature extraction data model, showing the superiority of multi-source data after feature extraction fusion in stratigraphic lithology identification effect.

The south bank of Tarim river is one of the main areas for exploration and development of the Tarim Oilfield to increase reserves and production, with deep and ultra-deep layers as the main exploration targets. However, due to the development of Permian igneous rocks, frequent incidents of lost circulation and stuck occur during the drilling process, which seriously restrict the drilling speed. To this end, in the drilling and completion stages, the complexity early warning of downhole accidents is carried out in advance through the geology-engineering integration technology, so as to reduce the complexity of engineering accidents in the drilling process. That is, before drilling, seismic, well logging and mud logging identification methods are used to summarize the distribution of igneous rocks and the combination of igneous rock facies, to predict the lithology of a single well, to establish a geological risk prediction template, to guide the selection of drill bits, and to formulate lost circulation prevention measures in advance. During drilling, the combination of mud logging technologies such as elements, whole rock, rock thin section identification, and scanning electron microscope is used to identify igneous rock lithology from the perspective of "chemical composition + microstructure", establish igneous rock identification criteria, carry out igneous rock lithology identification, and achieve accurate site layer determination, fracture identification, drillability evaluation, so as to conduct real-time risk early warning. Post drilling, the construction experience is summarized, and the penetration rate improvement template for safe drilling in Permian igneous rock sections is perfected, which provides guidance for subsequent drilling. The geology-engineering integration technology provides technical support of the geology for the optimization of drilling construction in igneous rock development area, effectively reduces the regional accident complexity rate, and improves time efficiency of drilling.

Making abnormal high pressure prediction while drilling in carbonate reservoirs is the key to reduce the probability of overflow and lost circulation risks. In view of the prediction problem of abnormal high pressure in Yijianfang Formation-Yingshan Formation carbonate reservoirs of Fuman area, Tarim Basin, the porosity and fracture number related to abnormal high pressure in fault-controlled fracture-cavity carbonate reservoirs are obtained through rock and mineral scanning logging technology, the fracture complexity index reflecting the complexities of fractures is introduced, and the porosity and fracture complexity index chart is established to identify and predict the abnormal high pressure in Yijianfang Formation-Yingshan Formation carbonate reservoirs of Fuman area, Tarim Basin. Taking well FD 1 in Fuman area of Tarim Basin as an example, the application of porosity and fracture complexity index chart can effectively characterize abnormal high pressure sections of carbonate reservoirs, providing a new method for the study and prediction of abnormal high pressure of carbonate reservoirs in this area, and also providing technical support for further exploration and development to take engineering measures in advance to reduce the probability of overflow and lost circulation risks.

In oil and gas exploration, it is of great significance to identify the genetic type of natural gas while drilling, it can reflect important oil & gas geological information in real time. At present, there are few methods to identify the genetic types of natural gas while drilling. In view of the diversity of identification methods, Baiyun Sag is chosen as the study area, using FLAIR mud logging technology. The genetic types of natural gas identified by ethane carbon isotope and corresponding three FLAIR mud logging sensitive parameters C₇H₁₄, nC₇ and C₇H₈ are studied. The identification method of C₇ light hydrocarbon system triangular plot is used for reference to establish a new method for identifying natural gas genetic types in Baiyun Sag. The results show that FLAIR sensitive parameters closely related to the genetic type of natural gas are used, a new triangular plot identification method for C₇ light hydrocarbon system is set up, oil type gas and coal-related gas can be accurately identified, it obtains good application effects in identification while drilling, provides important data basis for the study on oil and gas reservoir forming characteristics and migration and accumulation distribution system, and is of popularization value.

Total hydrocarbon data is an important parameter in the interpretation and evaluation. Because the form evaluation of total hydrocarbon shape mainly depends on visual identification, and the subjective factors account for a large proportion, which cause certain limitations to its application effect. In order to realize the quantitative evaluation of the forms of total hydrocarbon peak shapes, the absolute area of total hydrocarbon peak shape is calculated by trapezoidal segmentation based on the basic principle of total hydrocarbon curve. Then the calculation method of total hydrocarbon peak shape relative area is proposed by the ratio of the absolute area and the rectangular area. The interpretation and evaluation charts are established based on absolute area and relative area of total hydrocarbon peak shapes, the maximum value of total hydrocarbons and the relative percentage content of methane, and the charts have a good effect on distinguishing fluid properties. The method has been applied and verified in Chaheji oilfield of Baxian sag, with a coincidence rate of 77.3%, which can meet the production demand and provide a new method for quantitative evaluation of the forms of total hydrocarbon peak shapes.

Natural gamma energy spectrum logging technology plays an important role in lithology identification, stratigraphic division, reservoir identification and other aspects. However, operational differences among operators, drilling coring during the drilling process and insufficient cuttings caused by drilling complexities such as lost circulation can all lead to measurement data deviations. By conducting experiments on influence factors of natural gamma energy spectrum data, the influence degree of the sensing time, cuttings sample filling pattern, the coarse or fine of the cuttings grains,the dry or wet degree of the samples, and sample mass on measurement data were analyzed. It is considered that sample mass is the most important factor influencing natural gamma energy spectrum logging, and the total dose rate of its radiation has a linear relationship with cuttings mass. Based on the experimental conclusions, a set of standardized operations suitable for the field has been formed. When the sampling conditions are limited and the sample mass is insufficient, parameter correction can be performed using the linear relationship between the total dose rate of the radiation gamma and the sample mass.

With the continuous breakthroughs in shale oil and gas exploration and development, the "Well Factory" model came into being in order to meet the needs of the shale oil and gas drilling factory construction model and the integrated construction of drilling, well logging, mud logging, and directional well. However,in many aspects such as well site construction, rear management and data application, the profession of drilling, well logging, mud logging, and directional well operates independently and lacks coordination and management methods. Therefore, business operations are scattered, software is difficult to integrate, data is difficult to share, and there is a lack of a unified comprehensive application platform to meet the need of "Well Factory" model. With the help of the "Well Factory" model, a cross-professional, cross-regional, and cross-organizational integrated decision support platform has been built, which can realize the organic fusion of various professional technologies, real-time sharing, and collaborative linkage among multiple parties. The platform meets the needs of integrated geological engineering construction and has reference significance for the construction and development of intelligent oil and gas fields.

Due to the significant heterogeneity and intricate gas-water relation of the tight sandstone gas reservoirs in Sulige Gas Field, there is a limited distinction in fluid logging response characteristics. Consequently, this leads to a low coincidence rate in identifying the reservoir fluid properties for the conventional logging parameters cross-plot interpretation methods, making it challenge to effectively identify gas layers. A new gas-water identification method for tight sandstone reservoirs is established based on grey relational and principal component analysis methods. 112 gas test reservoirs from 30 wells in the southwestern part of Su 20 block are selected as analysis samples. First, the grey relational method is used to select 5 logging response parameters, which are the most sensitive to the change of reservoir fluid properties, namely interval transit time, compensated density, compensated neutron, porosity and the difference（A₁） in amplitude between internal transit time and compensated neutron curves. On this basis, principal component variables from Y₁ to Y₅ independent from each other are constructed based on the principal component analysis method, and principal components Y₁ and Y₂, with a cumulative variance contribution rate of 86.99%, are selected to synthesize the raw information reflecting the multidimensional logging variables. Finally, Fisher linear discriminant method is used to establish a gas-water quantitative interpretation model. The new method recognizes the reservoir fluid properties by integrating the information of multiple logging sensitive parameters, the overall interpretation compliance rate is 86.6%, and the gas layer interpretation compliance rate reaches 92.3%, which is an obvious improvement in the recognition efficiency compared with the conventional crossplot chart method. At the same time, the new method is effective in practical application on Member 8 of Shihezi Formation, which further indicates that the new method can provide effective technical support for the efficient development of tight gas reservoirs in the study area.

The improvement and breakthrough of the exploration technology of buried hill oil-gas pool in marine exploration put forward higher requirements for mud logging in reservoir effectiveness evaluation, that is, the buried hill reservoir interpretation and evaluation are fine and quantified. The geological logging interpretation and evaluation of buried hill reservoirs also faces the problem of increasing the difficulty of qualitative evaluation due to the diversity of data. Currently, reservoir reliability assessment methods cannot achieve dimensionality reduction of multiple geological logging data.The fuzzy matter-element analysis method is used to conduct fusion evaluation of multiple parameters from gas logging, three-dimensional quantitative fluorescence logging, element logging, diffraction logging, etc., which can reduce the multidimensional to the one-dimensional and comprehensively evaluate the physical properties and oil-gas potential of the reservoirs. According to the mechanical specific energy and mechanical specific energy base values of engineering logging parameters, the vuggy-fracture index is introduced to characterize the physical properties of buried hill reservoirs. Finally, the standards of reservoir effectiveness are quantified by intersecting the comprehensive evaluation indicator of the fuzzy matter-element and the vuggy-fracture index, which provides a new method for reservoir effectiveness evaluation in buried hills. The application of this evaluation method in new drilling wells in a certain block has obtained good results.

The shallow lithologic oil pool in Bohai Sea has the characteristics of thin target beds, rapid longitudinal and transverse change of sand body, complex sand body configuration, etc. Adopting the "stabilizing hole-deviation angle to explore the top of the target bed" method commonly used for thin reservoir geosteering often results in drilling through the target bed during landing, which brings great difficulties and challenges to the accurate landing of horizontal wells. By summarizing relevant data and analyzing and improving the applicability of conventional landing methods for horizontal wells, a low hole-deviation landing geosteering method for thin reservoir horizontal wells is proposed, that is, once the target layer is found by stabilizing hole-deviation angle, land immediately, and the remaining deflection section is implemented in the horizontal section. The successful application of this method in well H has confirmed that it effectively improves the landing success rate of thin reservoir horizontal well, and can provide reference for similar thin reservoir horizontal well landing geosteering.

Traditional geochemical pyrolysis technology has the problem of the easy loss of light components of hydrocarbons during the analysis process, resulting in the distortion of the geochemical pyrolysis parameter S₀, and the loss process of light hydrocarbons is affected by various factors. The current pyrolysis correction and restoration methods still cannot accurately restore the actual hydrocarbon content of the sample, which have constrained the accurate evaluation and application of traditional geochemical pyrolysis technology to shale oil mobility. In response to the above problems, a method of applying the four-temperature-step sealed pyrolysis logging technology to evaluating the mobility of shale oil in the Weixinan sag is proposed. The sum of S_g and S₀₁ values obtained by this method is defined as the S₀ of the four-temperature-step sealed pyrolysis,which is 35.7 times higher than the S₀ of on-site rock pyrolysis, and the gradient analysis of the full-component hydrocarbons is realized. Obtained from the four-temperature-step sealed pyrolysis and on-site pyrolysis TOC for the cored intervals of well WYX 1 of Weizhou X structure, the average oil saturation index （OSI） is 258 mg/g, the average gaseous hydrocarbon index is 0.085, and the average ratio of light hydrocarbon to heavy hydrocarbon ratio is 0.35, indicating that the shale oil in the study area has good mobility and potential for exploitation. The four-temperature-step sealed pyrolysis logging technology can effectively avoid the loss of light hydrocarbon, realize the accurate determination of gaseous hydrocarbon and free hydrocarbon content, reduce the real hydrocarbon content of shale, and provide a reliable method for evaluating the mobility of offshore shale oil.

With the deepening of exploration and development, the continuous increase in reserves and production of K oilfield in Bohai Sea has encountered a bottleneck, and low-resistivity oil layer has gradually become an important exploration target. However, the controlled factors of Guantao Formation in K oilfield of Bohai Sea are complicated and changeable, and the conventional mud logging and well logging evaluation methods cannot effectively and rapidly identify the low-resistivity reservoirs while drilling. For the reservoirs of Guantao Formation in K oilfield of Bohai Sea, by deeply mining the correlation of resistivity controlled factors, mud logging parameters, and hydrocarbon abundance, the characteristic parameters of gas logging, geochemical logging, and three-dimensional quantitative fluorescence logging were optimized. Combined with the resistivity, the multivariate parameter interpretation and evaluation method for formation fluid was established. This method can effectively identify the low-resistivity oil layers while drilling, increase the formation fluid interpretation coincidence rate to more than 88%, and provide an effective means for increasing reserves and production in K oilfield of Bohai Sea.

The drilling fluid level in the buffer tank at the mud logging site often fluctuates up and down with the changes of pump displacement and bottom-hole complex situations, and the influence of some human factors. In order to stabilize degassing, the degasser needs to be manually regulated according to the changes of drilling fluid level. Otherwise, if the drilling fluid level is too high, it may cause the pumping drilling fluid to block the gas pipeline and burn the motor.If the drilling fluid level is too low to degas the drilling fluid, resulting in the loss of gas logging data. In order to save manpower and ensure the accuracy and timeliness of gas logging data, the full automatic level self-regulating degasser has been researched and developed, which can measure the level height through the ultrasonic liquid level sensor, then drive the motor to regulate the liquid intake height of the degasser up and down, and automatically deal with the complex situations such as level heave and excessive drilling fluid bubbles in the buffer tank. Compared with the traditional degassers, the full automatic level self-regulating degasser changes the regulation drive mode, realizes automatic regulation for the liquid intake height of the degasser, thereby reducing labor intensity, improving equipment operation reliability and inherent safety, and enhancing the quality of gas logging data.

Mud logging technology evaluation is determined in this paper from 3 aspects to solve geological and engineering characteristics and technical difficulties in drilling and exploration process of compressed air energy storage injection-production wells. The evaluation method for halite, gypsum and mirabilite has been established by saturated brine experiment based on XRD & XRF technology. Based on comprehensive mud logging engineering parameters, the forecasting standards for abnormal engineering situation have been built with the combination of 5 stages in determining horizons of entering cavity of injection-production wells. Relying on geological data and combining with engineering requirements, the horizon determination method of compressed air energy storage injection-production wells has been set up. There are 18 abnormal situation alarms in the verification of 7 wells on the site, the accuracy rate is 100%, and the accuracy rate of finding the top of the salt cavity is 100% after midway completion, which fully verifies the effectiveness of the above evaluation methods, and provides reference methods and standards for the later drilling of compressed air energy storage injection-production wells.

The oil and gas resources in northern Shaanxi area of the Ordos Basin have the characteristics of wide distribution and are the key area of oil and gas exploration. The systematic scientific study of the accumulation time and accumulation period of the Chang 2 and Chang 6 reservoirs in the Zhidan area of northern Shaanxi is not only conducive to the fine exploration of the oilfield, but also improves the understanding of the Triassic oil and gas accumulation in the Ordos Basin. The characteristics of inclusions are observed under microscope and fluorescence, and the hydrocarbon accumulation period of the reservoir fluid inclusions is divided by the inclusion homogenization temperature experiment and freeze point experiment. The results show that there are three main types of inclusions of Chang 2 and Chang 6 reservoirs of Yanchang Formation in the Zhidan area of northern Shaanxi, namely brine inclusions, liquid-containing hydrocarbon inclusions and liquid hydrocarbon inclusions, and liquid hydrocarbon inclusions are mostly yellowish-green and orange-yellow under fluorescence irradiation, which indicates that the maturity of organic matter in the Chang 2 and Chang 6 reservoirs reaches a medium level. The fluid inclusions of the Chang 2 and Chang 6 reservoirs are mainly distributed in the quartz overgrowth and quartz healing microfissures, and the homogenization temperature distribution continuously indicates that the Chang 2 and Chang 6 reservoirs are one-stage charging. The homogenization temperature is mainly distributed the rage of 85-130 °C, the peak is the range of 90-110 °C, and the brine inclusions have the characteristics of high temperature, medium salinity and medium-high density, which are derived from the oil and gas fluids formed during the thermal evolution of organic matter, the accumulation time is during 111-100 Ma, and the accumulation time is the late Early Cretaceous.

The problems of little well data, poor seismic data quality, rapid lateral changes of reservoirs, and the large differences in reservoir thickness and structure between different vertical oil formations result in great difficulties in accurate prediction of dominant reservoirs in the early stage of offshore mid-deep hydrocarbon bearing pool development. The first member of Shahejie Formation in D oilfield of Bohai Sea is taken as an example to carry out analysis of the main controlling factors of reservoir distribution. The dominant reservoirs are predicted through palaeogeomorphology restoration, seismic attribute analysis and reservoir cluster analysis. The findings indicate that the early sedimentary reservoirs in D oilfield are controlled by palaeogeomorphology, with dominant reservoir development occurring in gully and slope belt. The middle sedimentary reservoirs are controlled by both palaeogeomorphology and provenance, with dominant reservoirs forming in high positions on the west side of well area 1. The late sedimentary reservoirs are affected by provenace, leading to dominant reservoir development mainly in the southeast block of well area 1. These research results have effectively guided the optimization of well locations and drilling implementation for the D oilfield development plan, achieving successful outcomes that can provide a reference for similar oilfields.

Raoyang sag is a oil-rich sag with the largest buried hill reservoirs in Jizhong depression and high reserves of reservoirs found in the Ordovician, Cambrian, Jixianian and Changchengian Systems. However, there has been no breakthrough in the metamorphic rock reservoirs inside the Archaeozoic buried hills. To solve this problem, the Gaoyuzhuang Formation high-yielding condensate oil/ gas in well NG 1 is taken as a research objective to prove that the oil and gas in well NG 1 come from the dark mudstone and shale of Chuanlinggou Formation. The wells drilled from Hejian buried hill and Liulu buried hill to the Archaean Formation were taken as the research objects, the seismic characteristics of the known buried hill inside seismic profile were analyzed, the study on the regional buried hill inside formation thickness distribution and horizon correlation was strengthened, the faulted structure of the buried hills was analyzed, the faults were finely sorted out, the metamorphic rocks inside Renqiu buried hill were traced and interpreted accurately, and the structural map of the top surface of the metamorphic rocks was completed. At the same time, the exploration potential and direction of the metamorphic rocks inside Renqiu buried hill were analyzed and studied from the aspects of source-reservoir-cap and reservoir-forming model. The results show that the oil and gas of metamorphic rocks inside the buried hills mainly come from the dark mudstone and shale of the Chuanlinggou Formation of the Changchengian System, which have a wide distribution range and large thickness, belonging to medium-good source rocks, and develop high-quality reservoirs such as the Renxi faulted fracture zone and the buried hill top surface weathering crust fracture zone. The seismic facies of the metamorphic rocks inside the buried hills can be divided into discontinuous and chaotic reflection type, leap reflection type, fault plane wave reflection type,and near-straight and near-continuous reflection type. The reservoir-forming model of the condensate reservoirs for the metamorphic rocks inside Renqiu buried hill in Raoyang sag is established, and three types of hydrocarbon reservoirs including faulted fracture zones, top weathering crust fracture zones and the faulted fracture zones inside the buried hills are identified. The favorable target at the R 7 head of Renqiu buried hill is selected by fine comparison, which points out the direction for exploration of condensate reservoirs. If the drilling of the metamorphic rock condensate reservoirs inside Renqiu buried hill is successful, it can open up a new situation for the exploration of the Archaean field in Huabei Oilfield.

ZY 1 is a risk exploratory well in Nanyang Depression aiming to drill matrix shale oil. The original research believed that the sub-depression where Well ZY 1 is located is the most favorable area for matrix shale oil exploration. It is predicted that Well ZY 1 will drill into four sets of high-quality shale layers, but finally only drill into a relatively high-quality shale layer with a thickness of 85.0 meter of the strata of upper E₂h₂Ⅲ, while the strata of middle E₂h₂Ⅲ and E₂h₃Ⅱ drill into thick sandstone layers, which is quite different from the original prediction. In the absence of multi-well element data comparison, by analyzing the content changes of vertical easily migrating elements and argillaceous rock elements, combined with core logging data and regional geological data, the reason for the large difference between actual drilling and original prediction has been found out. The strata drilled by the well comes from two sources： the source of middle E₂h₂Ⅱ and upper E₂h₂Ⅲ strata comes from the northern delta, which is consistent with the original prediction; the source of middle E₂h₂Ⅲ and upper E₂h₃Ⅱ strata comes from the small sand body of the fault near the southern boundary. The impact of the actual drilling results of Well ZY 1 on oil and gas exploration is as follows： on the one hand, the area of source rocks has decreased, which has affected the calculation and evaluation of resources amount; on the other hand, it has provided new exploration areas. Based on element logging data and other exploration results, corresponding suggestions for oil and gas exploration in this area are put forward.

Drilling engineering data is of great value to drilling enterprises, and the implementation of digital transformation strategies in enterprises puts higher demands on data quality. However, due to multiple factors such as system planning, management requirements, and personnel operation levels, drilling enterprises often encounter problems such as low data quality, multiple sources of data, and time-lagged data in the process of oil exploration and development. In response to these problems, this paper summarizes and analyzes the types and causes of the problems, proposes a data governance plan suitable for drilling enterprises, combines the concept of data life cycle management with the data governance process, and designs technical and management measures focusing on four aspects： on-site data acquisition, data verification, assessment supervision, and data sharing. It elaborates on the specific implementation content of software upgrades at the acquisition software, development of web-based verification functions, and development of data synchronization and interface services. Meanwhile, it introduces the achievements made in drilling engineering data governance work. The implementation of the data governance plan not only meets the needs of drilling enterprises in production management, but also lays a foundation for the construction of fupper analysis and early warning applications.

The distribution of high-quality reservoirs of tight volcanic rocks in northern Songliao Basin is not clear. Based on the geological data such as thin section under microscope, scanning electron microscope, high pressure mercury injection and NMR, this paper clarifies the fractal characteristics of volcanic reservoirs and their relationship with physical properties, and also classifies and evaluates the volcanic reservoirs of the third member of the Yingcheng Formation by fractal dimension Q-type clustering method. The results show that the pores of the volcanic reservoir of the third member of the Yingcheng Formation have fractal characteristics, more tiny pores can be reflected by NMR, and the fractal dimension D₂ reflected by NMR is slightly larger than the fractal dimension D₁ of high pressure mercury injection as a whole. There is a significant positive correlation between fractal dimension and reservoir physical properties and pore structure parameters, and there are some differences in fractal dimension of reservoirs with different lithology and lithofacies. According to fractal dimension Q-type clustering and pore structure characteristics, the tight volcanic rock reservoirs are divided into four types, among which the pore-fracture combination of type Ⅰ reservoir is mainly "primary pores + dissolved pores + structural fractures", the fractal dimension is mainly distributed between 2.06 and 2.34, the average displacement pressure is 4.79 MPa, the average pore throat radius and relative sorting coefficient are 2.40 μm and 34.37, and the reservoir performance is good. Type Ⅱreservoir is mainly "amygdaloid pores+structural fractures". The fractal dimension is 2.24-2.62, the average displacement pressure is 9.64 MPa, the average pore throat radius and relative sorting coefficient are 0.69 μm and 46.64, and the reservoir performance is good. The pore-fracture combination of type Ⅲ reservoir is mainly "micro-pore+micro-fracture", the fractal dimension ranges from 2.43 to 2.86, the average displacement pressure is 9.98 MPa, the average pore throat radius and relative sorting coefficient are 0.25 μm and 63.78, and the reservoir performance is relatively poor. The pore-fracture combination of type Ⅳ reservoir is mainly composed of "inter-pyroclastic matrix micro-pores and devitrified micro-pores ", with fractal dimension generally>2.8, the average displacement pressure of 13.99 MPa, the average pore throat radius and relative sorting coefficient of 0.09 μm and 70.47, which basically have no reservoir performance. On the whole, the study area is dominated by type Ⅱ and Ⅲ reservoirs, and there are significant differences in pore types and pore structures among different types of reservoirs.

In the Qikou Sag of Bohai Bay Basin, the hybrid shale layer is developed, and the pore structure is mainly microporous and mesoporous, among which the pore structure of the calcareous hybrid shale is the most developed, and the oil content is mainly heavy crude oil. After the reconstruction of measures, the oil wells generally reach the industrial oil flow, but the geological factors influencing the productivity are not clear, so it is necessary to carry out relevant research in this area to guide the stimulation of similar oil wells. According to the data of rock physical property, rock lithology and fracture development degree, formation pressure and fracture scale, structural morphology and curvature, electrical parameters, etc., the corresponding geological characteristics of "natural productive wells" "acidizing effective wells" "fracturing effective wells" and "acid fracturing effective wells" are summarized to guide the selection of transformation methods. The results are obtained in four aspects. First, shale layers with porosity lower than 15% and permeability lower than 0.41 mD in this area need to be reformed to improve production. Second, "natural productive wells" are dominated by gray mixed shales and felsic shales with relatively developed adjacent faults and fractures. The D value （ratio of the distance from well to fault to vertical fault distance） is generally less than 1, and the influence of faults is obvious and the structural curvature is large. Third, acidizing effective wells are mainly composed of calcareous hybrid shale and dolomitic hybrid shale, with high calcareous content in general, D value of 2.8-7.9, weak degree of formation transformation by faults, medium structural curvature, and electrical parameter ΔGR generally greater than 20 API. Fourth, when the D value of "fracturing effective wells" is 1.2-5.2,dolomitic hybrid shale and felsic shale with poor fracture development are the main ones. When D value is greater than 16, the influence of faults is very weak, and the calcareous hybrid shale without fractures is the main one. The structural curvature corresponding to the well with effective fracturing is small, and the electrical parameter ΔGR is generally less than 20 API. According to the analysis of geological factors of different productive wells, the geological environment suitable for "natural productive wells" "acidizing effective wells" "fracturing effective wells" and "acid fracturing effective wells" is put forward to guide the newly completed drilling in the area to take stimulation treatment, and after the transformation, the industrial oil flow standard is reached, and the oil and gas production is effectively increased, which has a positive effect on the production of shale layers in the oilfield.

Complex structural model is built by conventional geological modeling methodology with approximation treatment of fault model, which usually decreases the precision between fault model and structural interpretation results, and affects model accuracy. Therefore, Petrel modeling software and its method module is chosen. Based on an interactive approach of integrating both corner point gridding and structural framework modeling methods, with the determination of connectionship for each pair of truncate faults, intersecting treatment is done on fault model combination, meanwhile crucial parameters for each fault plane are optimized. Finally, the high accuracy 3D complex fault model is built. The method adopted for A oilfield in Central Asia accomplishes the optimization of fault model for the whole block, shows remarkable improvement, and provides a high accuracy structural modeling method for various complex fault oilfields.

The Ordos Basin has stable structure, relatively simple transport system, and underdeveloped transport systems such as faults and unconformities. However, as a "bridge and link" between source rock and trap, the transport system is very important in the study of gas reservoir enrichment law. In this paper, the Upper Paleozoic transport system of Su 76 block in Sulige Gas Field is studied. The results show that the transport system mainly composed of pores is developed in the study area, and the transport system mainly composed of fractures is developed. Based on the analysis of cast thin sections and lithology data, the transport system dominated by pores plays a leading role in the migration of parallel layer gas reservoir, while the transport system dominated by fractures plays a leading role in the migration of vertical layer gas reservoir. The structural curvature method and R/S analysis method are used to identify the fractures in the study area. Both methods have a high coupling degree with the fracture development area, and the development degree is positively correlated with the production situation. The more developed the fractures, the more beneficial to improve the transport performance of tight reservoirs. The identification and prediction of fractures is of great guiding significance to the gas reservoir development in Su 76 block.

Xihu sag is one of the most important hydrocarbon bearing sags nearshore China. A set of extremely thick coal measure strata is developed at the end of the fault depression period of the sag, it is the main source rock series of Xihu sag. Due to the influence of multiple solutions, it is difficult to explain the depositional setting and hydrodynamic characteristics of the study area in detail through the macrofeatures such as lithological combination and sedimentary structure. This paper attempts to analyze the sedimentary environment and hydrodynamic characteristics of the Pinghu Formation coal measure strata in Z area of Xihu sag through kerogen macerals and micropetrological characteristics of coal measure strata. The study shows that there are great differences in the kerogen macerals of different regions in Z area, and the core exhibits four morphologic characteristics: cross laminated, banded, horizontally-laminated and nodular siderite. Both indicate that there are great differences in the depositional setting and hydrodynamic characteristics of coal measure strata in the plane and vertical directions of Z area. The depositional stage of A region in low uplift is dominated by weak oxidation-reduction sedimentary environment with the shallow water and intermittent exposure to the water surface, and natural levee and bottom land can be developed on it, which is conducive to the development of water channel. B region of the sag is a semi-enclosed lagoon formed by the barrier of the low uplift on the outer edge, and the whole is in a reducing depositional setting. During the spring tide, the tidal current can pass over the low uplift and transport the debris from the upwarped district and outside the upwarped district to the depressed area to form a washover fan. C region of the low uplift has been located above the water surface for a long time and is in an oxidizing environment. It is covered by water body under the influence of intermittent tides in middle Pinghu period, thus forming a shallow swamp. D region of the sag is a depositional setting that the water body is relatively deep and a favorable place for delta front deposition. In general, the sedimentary environment and hydrodynamic characteristics of Pinghu Formation in Z area differ greatly from south to north due to geomorphic impacts. The A and C regions of low uplift, due to long-term exposure to the surface, their overall performance is oxidized. The environment is dominated by rivers and intermittently affected by tidal current. The B and D regions of the sag are overall in a reducing sedimentary environment and are greatly affected by tides. The deepening understanding of the depositional setting and hydrodynamic characteristics in the Z area of the Xihu sag provides important theoretical support for the exploration and deployment in this area.

As exploration and development progress, deep coal-rock gas has gradually become one of the main targets for exploration. The deep coal-rock gas in the Wumaying coal accumulation belt of the Huanghua Depression may become an important region for sustaining production capacity in the Dagang Oilfield in the future. However, there is no existing experience in mud logging technology for coal-rock exploration in this region, the evaluation of mud logging while drilling is still blind area. Therefore, by analyzing the data of the multiple mud logging techniques of the Shanxi Formation and Taiyuan Formation coal measure strata from 7 wells in the Wumaying coal accumulation belt of Huanghua Depression, and summarizing the technical characteristics, the method of evaluation while drilling for coal-rock quality, gas bearing quality, characteristics of source rocks and fluorescence was initially formed. The method is well characterized in the comprehensive evaluation of Carboniferous-Permian coal measure strata in the study region, which provides favorable geological basis for the next exploration and deployment of deep coal-rock gas in Huanghua Depression.

With the organizational restructuring of China Petroleum and vigorous widespread of teams of private petroleum enterprises,mud logging operations are currently undertaken by personnel without a geology（logging） background or young engineers,who lack of work experience and complete professional knowledge,and this leads to an increase in misoperations,false alarms and omissions,which results in growing risks to drilling well-control and brings a threat to production safety that cannot be ignored. An intelligent mud logging platform is proposed focused on MapReduce technology,which includes a series of core functional modules such as automatic generation of mud logging assignment, real-time warning of geological anomalies and comprehensive geological assessment. The construction of these functional modules has greatly improved the intelligent level of logging operations. After being applied in 98 mud logging teams and over 700 wells in the Chuanyu and Changqing regions,the digital mud logging operation model has effectively reduced misjudgments and oversights and provided strong technological support and safety assurance for improving drilling speed, efficiency and quality.

Adhesive suction and sand settling are the common and frequent accidents for drill pipe sticking. The main reason for such accidents is that after the circulation is stopped or the drilling fluid is static, the drill tools are close to the borehole wall and lost the drilling fluid lubrication, and the horizontal positive pressure of the liquid column squeezes the drill tools to the borehole wall and compresses them tightly, resulting in the drill tools to tightly adhere to the borehole wall and bond with the mud cake. At the same time, the cuttings sinks, wrapping and plugging the down-hole drilling tools. A set of anti-sticking device with rotating circulation at the wellhead was developed by using the three-way technology of cycle seal, SIT function merging and rotation principle of high pressure washing pipe, which was used in 29 wells of Tuha,Santanghu and other oil and gas fields. When the drilling lifting system, rotating system or drilling fluid circulation system fails, the rotating circulation anti-sticking device is installed to realize the function of rotating drill tools and independent circulation, solving the problem of ineffective prevention of drill pipe sticking accidents of adhesive suction and sand settling caused by drilling lifting system, rotating system or drilling fluid circulation system failures in drilling sites. It provides technical support for optimal fast drilling and safe drilling.

As mud logging technology advances, carbon isotope logging has emerged as a prevalent technique in oil and gas exploration. The carbon isotope logging carried out around the shale oil zone in Weixinan Sag aims to effectively assess the maturity and origin of shale oil and gas in different horizons. Carbon isotope logging is used to obtain the isotopic composition of drilling fluid gas, and the carbon isotope logging characteristics from exploration wells at diverse structural positions are compared and analyzed. Meanwhile, by monitoring the isotopic fractionation characteristics of the cuttings headspace gas and volume changes in gas released from cuttings, the pore abundance and the characteristics of oil-gas potential for the shale are assessed. The carbon isotopes being a heavy trend within intercalated beds and interbeds for the oil shale in Weixinan Sag could be attributed to the charging of hydrocarbon generation products from deeply buried and highly evolved oil shale. The above results have identified the favorable reservoir horizons for oil and gas in Weixinan of Beibu Bay Basin, providing practical guidance for the deployment of follow-up oil and gas exploration.

In order to deepen the exploration of sweet spot identification methods and further improve the role of mud logging technology in shale oil exploration, according to the geological characteristics of Chang 7 shale oil in the Ordos Basin, research is carried out on the 100% coverage rate of gas logging technology, the hydrocarbon gases in the wellbore and the influencing factors of infrared spectrum logging are fully analyzed. On the basis of statistics on infrared spectrum logging data collected of Chang 7 shale oil in recent years, first, mathematical methods are used to clean the on-site collected data one after another, and then the oil and gas content in the broken debris in the wellbore is gradually calculated through diffusion gas correction and dilution coefficient correction formulas to represent the information of the real reservoir in the formation. Finally, an infrared spectral correction method suitable for Chang 7 shale oil horizontal wells is established, the wellbore environment correction is completed, and the infrared spectral data is standardized. From the perspective of application results, the revised total hydrocarbon data can more truly reflect the oil and gas information of the reservoirs and has good practical value.

As the first underground gas storage built and put into commercial operation in China, X gas storage of Dagang Oilfield has so far been safely operated for 24 injection and production cycles. In view of the problems exposed during the initial operation of the gas storage, such as poor capacity, production effects, and slow working gas growth rate, adaptability demonstration and optimization adjustment are carried out on the injection-production pattern and structure, operation mode and operating pressure, thus enhancing the gas storage and single well injection and gas production capabilities as well as liquid carrying and drainage capabilities. The expansion effect has been continuously improved, and the peak shaving capacity of the gas storage has increased by 1.17×10⁸ m³, with an increase of 24.2%. These provide mature technical means and practical experience that can be used for optimizing the operation and management of the same type of underground gas storage, and improving their peak shaving capabilities, which have important reference significance for the development of underground gas storage operation and management.

Wellblock B of Huaqing area is located in the southwest of Ordos Basin. Chang 6₃ reservoir is the main horizon of this wellblock, and its sedimentary environment is gravity flow sedimentary system. With the continuous deepening of development in wellblock B, the development contradictions have gradually become prominent. The reservoirs are highly heterogeneous and the connectivity of sand bodies is poor, resulting in poor waterflood development effect and large productivity decline. Therefore, the sedimentary characteristics of gravity flow in this area were studied, and their impacts on oil and gas development were analyzed in combination with dynamic development data. Chang 6₃ reservoir in wellblock B is divided into six layers from top to bottom： Chang 6₃^1-1, Chang 6₃^1-2, Chang 6₃^2-1, Chang 6₃^2-2, Chang 6₃^3-1, and Chang 6₃^3-2. The characteristics of sedimentary petrology and log facies analysis in the study area show parallel bedding, mud boulder, flame structure, flute cast and other sedimentary structures on the cores. Chang 6 reservoir consists of lacustrine and turbidite deposit. The sedimentary microfacies are divided into four types： turbidite channel, turbidite channel flank, semi-deep lacustrine mud, and inter-turbidite channel. The sedimentary microfacies plane analysis shows that the sedimentary evolution of each Chang 6₃ layer is a process of water transgression to water recession. In terms of oil and gas waterflood development,because the sand bodies are controlled by sedimentary microfacies, the connectivity is good and the waterflood development effect is good for the reservoirs of the same stage.The sand body end-to-end connectivity in different stages is poor, and the effectiveness of waterflood development is poor. The study results can provide geological basis for oil and gas waterflood development in Huaqing area.

In view of the low coincidence rate of reservoir interpretation and evaluation caused by the complex fluid properties and the influence of oil-based drilling fluid on field data in Xihu Depression, based on in-depth excavation of geochemical light hydrocarbon spectrogram and data, the complex fluid identification methods based on light hydrocarbon spectrogram shape and derived sensitive parameters are established, and have been verified by application. The results are obtained in three aspects. First, light oil layers and condensate gas layers can be identified based on the differences in light hydrocarbon spectrogram shapes. The former shows that the C₁-C₉ components of normal alkanes are relatively complete, and some isoalkanes, cycloalkanes, and aromatic hydrocarbons have complete and higher peaks. The latter shows that the normal alkanes after C₅ are missing, the detection range for the content of isoalkanes, cycloalkanes, and aromatic hydrocarbons is less, and the peaks are incomplete and the peak values are low. Second, by optimizing I_g（gas index）, I_o（oil index）, ∑（C₁-C₅）（gas-bearing index） and ∑（nC₆-nC₈）（oil-bearing index） that reflect the differences in light hydrocarbon detection components between light oil layers and condensate gas layers, the oil and gas identification chart has been established, which can effectively distinguish light oil layers and condensate gas layers. Third, based on the differences in solubility of different hydrocarbon components in water, the light hydrocarbon parameters of benzene, toluene, cyclohexane, and methylcyclohexane are optimized to establish a water content evaluation chart, which can determine the water content of the reservoirs. The methods are applied to the complex fluid evaluation while drilling of reservoirs in Xihu Depression, and the interpretation coincidence rate can reach more than 88%, which has good prospects for popularization and application.

For the ultra-low-permeability oil reservoirs, water flooding technology is mainly used in conjunction with single well fracturing to improve the development effect. However, in the reservoir development practice, there are some problems, such as low efficiency of single well fracturing measures, poor effect of single sand body stimulation and inability to establish effective driving system between oil and water wells. Therefore, taking the ultra-low-permeability oil reservoirs in the X block of Songliao Basin as examples, the limit driving well spacing of the ultra-low-permeability reservoirs is calculated based on reservoir engineering method. At the same time, combined with the distribution law of sand bodies and remaining oil in the study area, the precise fracturing and stimulation scheme of single sand bodies in ultra-low-permeability oil reservoirs is formulated to ensure that the start-up coefficient between oil and water wells reaches the maximum after fracturing and stimulation, so as to avoid the problems of water breakthrough caused by excessive fracturing scale. And during the oil well fracturing stage, crosswell microseismic monitoring technology is used to track and monitor the scale of fracturing and stimulation of single sand bodies in ultra-low-permeability oil reservoirs. The fracturing scale is controlled by real-time adjusting the fracturing fluid displacement to ensure the precision of the fracturing scale. It is found that for types Ⅲ and Ⅳ reservoirs with the mean permeabilities of 6.5 mD and 3 mD in the study area, after well pattern infilling and single sand body precise fracture network fracturing by single sand body precise fracturing and stimulation technology, the single sand body start-up coefficient of the oil reservoirs and the production after oil well fracturing are significantly increased, indicating that an effective driving system has been established for the single sand bodies in the block, and the remaining oil potential tapping effect is significant.

As one of the key secondary oil-bearing structural belts in the Langgu Sag, Jiuzhou slope belt has not made any new progress in exploration in recent years, with a relatively low level of exploration but abundant remaining resources. Aiming at the problems of unclear understanding of shallow structural features, difficult to accurately control the high points of lithologic trap and insufficient understanding of oil and gas enrichment rules for shallow Jiuzhou slope belt, this paper carried out a comprehensive geological study, and reshaped the regional target tectonic framework through multi-dimensional fault analysis. At the same time, a new accumulation pattern was constructed by evaluating sources-reservoir-cap assemblages, the type of trap, and the coupling development of reservoir sand body and structure and other aspects. The results show that the upper part of the upper sub-member of Sha-3 member in shallow Jiuzhou slope belt is mainly a structural reservoir, and lateral blocking is crucial to its hydrocarbon accumulation. The middle and lower parts of the upper sub-member of Sha-3 member to middle sub-member of Sha-3 member in middle-shallow Jiuzhou slope belt are mainly structural-lithologic reservoirs or lithologic reservoirs, and the development degree and the distribution characteristics of the reservoirs are the key factors for its hydrocarbon accumulation. Based on the comprehensive evaluation, two favorable targets, structural-lithologic trap in wellblock ZH 22 and structural-lithologic trap in southern part of wellblock X 5, were optimized, the resources quantity of the traps was predicted to reach 1 062.1×10⁴ t, both of which could be used to explore multi-layer targets with shallow burial, laying a solid foundation for the new breakthroughs in oil and gas and scale discovery of the reserves in this area.

To investigate the reasons for the production differences between the eastern and western Jurassic hydrocarbon reservoirs and explore the main control factors affecting single well productivity in the southern area of Ansai Oilfield, various methods such as well logging, core test analysis, high-pressure physical property testing of crude oil, and 3D seismic inversion were comprehensively applied to systematically study the effects of sedimentary facies, reservoir physical properties, clay minerals, oil properties, and formation pressure on productivity. The productivity difference between the eastern and western Jurassic hydrocarbon reservoirs in the southern area of Ansai Oilfield is mainly affected by the oil properties and formation pressure, with regional variations in crude oil density and viscosity being key factors. In addition, the direction of production increase technology for the eastern high viscosity and low pressure reservoirs has been proposed. The results point out the direction for the effective development and production and the measures of tapping potential for the Jurassic hydrocarbon reservoirs in Ansai Oilfield, and also provide valuable experiences for the progressive development of similar hydrocarbon reservoirs.

In view of mud logging enterprises' production and operation still using the traditional management modes such as paper documents and Excel tables,there are problems such as file preservation difficulties,limited functions,and inconvenience in cross-specialty statistics,the research on the establishment and application of an integrated management system for production and operation is carried out.In the process of building an integrated management system for production and operation,after in-depth analysis of the management and operation requirements of various departments of the companies,the hierarchical & micro-service architecture and frontier techniques were used to realize efficient data integration,processes optimization and intelligent decision-making. The application of this system can significantly improve management efficiency,reduce costs,and effectively promote digital management innovation in mud logging enterprises.

The prediction of drilling operation cycles is of significant importance for determining the scale of drilling investments, scheduling operations, and achieving exploration and development targets. Currently,the characteristic parameters of the drilling operation cycle prediction models are relatively simple, and the relationship between well sections is not considered, so it is difficult to adjust the predictive results according to the actual operation situation. Addressing these issues, this study focuses on exploratory wells in the Beibu Gulf block, analyzing factors that influence drilling operation time. The characteristic parameters for the model were optimized, and a random forest regression model was utilized to predict drilling operation cycles. The goodness of fit of the prediction models for drilling operations from initial opening to drilling the fourth well section is 0.980,0.947,0.903 and 0.823 respectively, which can meet the practical application requirements. But as the number of drilling different well sections increases, the model performance tends to decline due to the complexity of formation conditions and the extension of operation time. The strategy of pre-drilling prediction and real-time parameter adjustment can be used to continuously supplement the training samples to improve the adaptability of the model to the specific operation characteristics in the study area. Drilling operation cycle prediction is of great significance in the planning and cost assessment of subsequent drilling schemes, and has a certain popularized valve.

In recent years, the importance of engineering sweet spots has become increasingly prominent, but the development of tight oil still focuses on geological sweet spots, which greatly limits the recoverable areas of oil reservoirs. Even though the concept of engineering sweet spots is considered in the development of tight oil, how to organically combine geological sweet spots with engineering sweet spots and conduct integrated evaluation is still a difficult problem. In order to evaluate the geological and engineering double sweet spots of tight oil, an indicator system including geological and engineering double sweet spot evaluation indices is first constructed. Then, the analytic hierarchy process is applied to determining the weight of each indicator in the indicator system and calculating the evaluation indices of the geological and engineering double sweet spots based on the indicator weights. Taking Jilin Oilfield as an application example, this paper presents how to use analytic hierarchy process to construct the evaluation indices of the geological and engineering double sweet spots for the target beds corresponding to each well position. By drawing the evaluation index plans of geological sweet spots, engineering sweet spots and geological and engineering double sweet spots, the new recoverable areas for sweet spots are found. At the same time, this paper introduces how to construct and calculate the evaluation indices of the geological and engineering double sweet spots for the tight oil horizontal wells, and presents the prominent role of the evaluation indices of the geological and engineering double sweet spots on regulating the well track during drilling and effectively tracing the oil layer sweet spots with the example. The actual drilling application validations at the well site show that the evaluation indices of tight oil geological and engineering double sweet spots based on the analytic hierarchy process can provide comprehensive and accurate guidance for oil & gas exploration and development, proving their practicability and effectiveness in geological and engineering evaluation.