25 September 2020, Volume 31 Issue S1
    

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    TECHNOLOGY
  • Practice and discussion on field differentiated service of mud logging application technology
    SONG Qingbin, HE Yuehui, FENG Jianyuan, JIN Juan, QUAN Cheng, SHI Baohai, WANG Jun, CHEN Yong, GAO Xin
    Mud Logging Engineering. 2020, 31(S1): 1-6. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.001
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The mud logging operation is carried out around the drilling site. In the face of different market environment, energy prospecting and development, well shape, well type and drilling development purpose, the application technology of mud logging on site is not the same. As a mud logging service provider, on the basis of understanding and mastering the requirements of the construction party for drilling and development under different conditions, the applicable technology is selected from various mud logging application technologies to implement differentiated on-site mud logging technical services, so as to maximize the benefits of both parties. In the mud logging technology practice, taking the continental shale oil differentiated services of Dagang Oilfield as an example, according to the construction party's exploration and development ideas and needs in different periods, different well shapes, different prospecting and development energy sources and the progress of mud logging technology, the differentiated service has achieved good results.
  • Application of element logging technology in the determination of shale oil wells in Guandong area,Cangdong Sag
    YANG Shaocun, LI Changhong, DONG Feng, WANG Jianwei, ZHANG Yang, YIN Wenrong, SHI Baohai, JIANG Bo, FAN Shiqiang
    Mud Logging Engineering. 2020, 31(S1): 7-12. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.002
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    During the drilling of shale oil wells in Guandong area of Cangdong Sag,Dagang Oilfield,a large number of new drilling techniques accelerated the drilling rate and finely fragmented cuttings,resulting in difficult lithology identification for mud logging and difficulty in formation division. For this reason,element logging technology is applied in on-site mud logging. Based on the drilling propose of shale oil wells in this area,the key target horizons such as the bottom of Ek1-the top of Ek2,and the bottom of C 1-C 2-the top of C 3 were selected for element analysis,and element data statistics,variation law analysis and curve feature identification were performed. The application results of element logging technology in 10 wells show that the logging parameters of the key target horizons in this area change regularly. From the bottom of Ek1 -the top of Ek2,Si element decreases,and the Ca,Mg,Fe,K,S and Mn elements increase to varying degrees. From the bottom of C 1-C 2-the top of C 3,Si,Fe and Al elements first increase and then decrease,and Ca and Mg elements first decrease and then increase. A method for stratigraphic division for element logging in this area was finally formed,providing the basis and reference for stratigraphic division for shale oil wells drilling in Guandong area,Cangdong Sag.
  • Exploration of the comprehensive evaluation method for shale oil logging:A case study of NP 2-SL well in Jidong Oilfield
    MA Qingchun
    Mud Logging Engineering. 2020, 31(S1): 13-18. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.003
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The first ultra deep shale oil well NP 2-SL in Nanpu Sag of Jidong Oilfield obtained industrial oil flow,marking an important breakthrough in shale oil exploration in Jidong Oilfield. Technologies of X-ray diffraction mineral analysis(XRD),X-ray fluorescence element analysis(XRF),gas logging,3D quantitative fluorescence,rock pyrolysis and pyrolysis gas chromatography for mud logging are applied to comprehensively interpret and evaluate NP 2-SL well in mud logging from five aspects of lithology,brittleness,oil bearing,source rock and oil source,and the evaluation conclusion is consistent with the oil test effect. On this basis,the overall evaluation idea of shale oil wells in Jidong Oilfield is determined. The lithology characteristics of the shale oil section are mainly argillaceous with thin sandstone;the overall content of quartz,feldspar,calcite and dolomite are the indexes for brittleness;the main parameters of oil bearing are total hydrocarbons measured by gas logging,comparison grade,liquid hydrocarbons(S1) and total hydrocarbon content(Pg),and that of source rocks are total hydrocarbon content(Pg),TOC and Tmax;and the oil source comparison takes the carbon number distribution,Pr/Ph、Pr/nC17 and Ph/nC18 as the main parameters. An interpretation model of multi-parameter fusion,multi-angle understanding,and multi-directional evaluation of mud logging technologies has been formed. The establishment of evaluation ideas and standards for shale oil reservoirs of NP 2-SL well lays the foundation for future interpretation and development of shale oil reservoirs in the exploration and development in Jidong Oilfield.
  • Supporting techniques for horizontal well drilling in Chenghai Oilfield in Dagang exploration area
    WANG Jianfu, LIU Wenyu, ZHANG Jinglei, WANG Dong, JIANG Chengcheng, MU Xiaohui, LI Qian, ZHOU Lianmin
    Mud Logging Engineering. 2020, 31(S1): 19-23. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.004
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Chenghai Oilfield is located in Tanhai in the southern Dagang of the depth of 4m. With the deepening of the exploration and development of producing marine oil using land drilling,major breakthroughs have been made in horizontal well development and drilling. On the basis of the optimization technique for geological well design based on reservoir prediction,inclination prediction and target optimization,by applying supporting techniques for drilling engineering design such as anti-collision technique for dense cluster wells,single-bore dual-well drilling technique and supporting techniques for drilling speed increase,PeriScope logging technology for limit testing while drilling was introduced to improve horizontal trajectory control,and techniques such as precise entrance and formation sticking,recognition of formation dip and well inclination matching,and recognition of center symmetry of upper and lower gamma curves while drilling were summarized. The implement success rate for horizontal wells reached 100%,which indicated that the geological engineering integration is the basis for the successful implementation of horizontal wells. Supporting techniques for drilling have played an important role in the exploration and evaluation of Chenghai Oilfield in Dagang exploration area,and provided important technical guarantee for the high-quality and efficient development of oilfields in tidal-flat area in Dagang,and technical reference for the construction and development of similar oilfields.
  • Application of digitization of pyrolysis gas chromatogram forms in Binhai Area
    JIAO Xiangting, LI Dengyue, SUN Weiyong, WANG Xiaocheng, ZHAO Huixia, YUE Ying, ZHANG Chao
    Mud Logging Engineering. 2020, 31(S1): 24-28. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.005
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Pyrolysis gas chromatography has unique advantages in the evaluation of source rocks and reservoirs. The pyrolysis gas chromatogram can reveal the full view of the hydrocarbons in rock samples through its distribution curve,reflecting the abundance of organic matter and its evolution degree. In the past,most of the evaluation of spectrogram forms used visual qualitative methods,which were affected by human factors,and there were no quantitative parameters,increasing the difficulty of intelligent evaluation. By processing the original data,the fitting method was used to give quantitative morphological factors and digitize the spectrum. With the combination of spectrum form factors and the total peak area of pyrolysis gas chromatographic parameters and the rock pyrolysis parameters,an interpretation chart of Binhai Area was established. The effect was remarkable in actual well application with the interpretation coincidence rate increased from 78.85% to 82.69%.
  • Analysis and research on the influence of brine drilling fluid on logging
    HUANG Wanguo, WANG Changzai, LI Yawen, ZHANG Huimin, CHEN He, YU Qianzi
    Mud Logging Engineering. 2020, 31(S1): 29-36. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.006
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Aiming at the brine drilling fluid widely used in deep and horizontal wells,the influence of brine drilling fluid invasion on electrical characteristics was analyzed,and the influence of brine drilling fluid on logging analysis results was studied through experiments before and after brine drilling fluid invasion. Experiments showed that due to the short immersion time of cutting(cores)in the wellbore and little influence from brine drilling fluid,logging data can accurately restore the true characteristics of formation lithology and hydrocarbon bearing. It was proved that the advantages of logging technology can be fully utilized when using brine drilling fluid for drilling,which played a significant role in lithology identification,reservoir interpretation and evaluation,and geosteering while drilling,and was conductive to the exploration and development of oil and gas field.
  • Application of technical combination for mud logging in the exploration and development of continental shale oil in Dagang
    CHEN He, XIE Wenmin, YUAN Baoqing, ZHANG Huimin, HUANG Wanguo
    Mud Logging Engineering. 2020, 31(S1): 37-41. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.007
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    At present,the exploration and development effect of continental shale oil in Dagang Oilfield is obvious. However,many problems such as the oil-bearing identification of source rocks and analysis of shale brittleness occurred during the construction,which were not encountered in the exploration and development of conventional oil and gas reservoirs. Through the application of cutting-edge mud logging technologies such as geochemistry,elements,3D quantitative fluorescence and geosteering while drilling,technical combination was formed for the guidance of on-site construction,and interpretation and evaluation. It has effectively solved a series of problems such as horizontal well geosteering,favorable spot division of continental shale oil,and the increase of drilling speed in the exploration and development of continental shale oil,and played its role in mud logging technology.
  • Experimental study on the influence of loose sand shale on the blocking of sand control screen
    WANG Ziyu
    Mud Logging Engineering. 2020, 31(S1): 42-47. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.008
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    In order to explore the influence of sand shale formation and clean sand formation on screen plugging,a simulation test device for the evaluation of the plugging of radial flow screen was designed. Under the circumstance of the length of the screen test piece being about 1 m,the plugging process of the screen under simulated clean sand formation and sand shale formation was analyzed by changing the displacement to establish the displacement pressure difference step by step. It showed that the designed test device can establish a displacement pressure difference of more than 4 MPa. The sand shale formation has more serious screen plugging than clean sand formation,and sand shale has a significant impact on screen plugging. The screen plugging of sandstone formation is mainly bridge plugging that is formed due to the fact that formation fluid carries the formation sand into the sand control medium of the screen. The screen plugging in sand shale formation is mainly because the mud in the formation has a certain degree of adhesion and water swellability,so that the mud and sand in the formation form a solid mud cake on the screen surface,which directly blocks the sieve pores outside the scree. During the screen plugging,the initial permeability drops sharply,and after reaching equilibrium,the displacement pressure becomes stable with the change of fluid production.
  • T1-T2 two-dimensional NMR method for detecting oil-bearing property in shale oil reservoirs
    DING Yujiao, LI Junguo, ZHU Weifeng, LIU Aiping, Lü Fangfang, ZHONG Wei
    Mud Logging Engineering. 2020, 31(S1): 48-53. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.009
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The direct detection of pore fluid information by NMR is an important logging suite to evaluate oil-bearing property of shale oil. Since the transverse relaxation time T2 of asphalt, irreducible oil and movable oil in organic pores basically overlaps with that of bound water in inorganic pores, it is difficult to distinguish these information effectively by one-dimensional T2 spectrum. Through the analysis of the fluid compositions' nuclear magnetic characteristics, it is found that the longitudinal relaxation time T1 of different fluids varies greatly, especially the oil-bearing information of shale oil can be effectively evaluated by T1/T2. On this basis, a 4-state T1-T2 two-dimensional NMR method is proposed to detect the oil-bearing property of shale oil. The results show that various fluid compositions have different distribution ranges on T1- T2 two - dimensional spectrogram.By data partitioning of the T1-T2 spectrogram, various fluid composition information is obtained. The model was used to evaluate the shale oil in the third Member of Shahejie Formation in Qikou sag and horizontal wells were deployed. The high yield of 20 t/d is obtained after implementation, and the accuracy of oil-bearing property detection of T1-T2 two-dimensional NMR shale oil reservoir is verified.
  • Influence of the change of water-based drilling fluid density on the component ratio of gas logging while drilling
    WANG Gang, WANG Changzai, SU Peiqiang, WAN Kang, ZHANG Yufeng, ZHAO Tiandong, FU Tian, XIA Yongli
    Mud Logging Engineering. 2020, 31(S1): 54-59. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.010
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Compared with other mud logging data,gas logging while drilling has the advantages of continuous monitoring,little impact from human factors,relatively stable component ratio and reflecting the formation fluid properties,and has been widely applied to discover,identify and evaluate hydrocarbon reservoirs. However,there is no research result at present about the influence of the change of drilling fluid density on the component ratio of gas logging while drilling. To clarify the influence degree on the derived parameters when the density changes,the drilling fluid density is taken as the independent variable,and the component ratio of gas logging while drilling(derived parameters from gas logging)is taken as the dependent variable to study the influence of water based drilling fluid density changes on the component ratio of gas logging while drilling(derived parameters from gas logging). It is found that in terms of impact degree,the isomer ratio<hydrocarbon slope<humidity ratio<triangle size<characteristic ratio<equilibrium ratio<peak-base ratio<weight ratio.According to the research results,the relevant precautions for gas logging interpretation and evaluation are proposed,and the derived parameters of gas logging interpretation are given priority according to the influence degree of each derived parameter.
  • Establishment and application of periodic dynamic monitoring system for gas storage group of gas reservoir type
    YE Ping
    Mud Logging Engineering. 2020, 31(S1): 60-65. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.011
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Dynamic monitoring is an important task that runs through the production and operation of the gas storage group. To ensure the safe,efficient,scientific and reasonable operation of underground gas storage group,a monitoring system mainly for pressure field,fluid field,production capacity of injection and production wells and fluid composition was established by Dagang Oilfield X gas storage group of gas reservoir type. It has realized all-round and three dimensional monitoring of gas storage group and provided scientific basis for the operation,management,safety evaluation and dynamic analysis of gas storage group. The establishment and application of the monitoring system not only realized the multi-period safe and stable production of X gas storage group,but also guided the adjustment and optimization of the later expansion and production plan of X gas storage group by combining the actual injection and production characteristics and production conditions of each gas storage,which ensured safe,efficient,scientific and reasonable operation.
  • Experimental research on joint development of low pressure condensate gas reservoir with CO2 gas reservoir
    HAN Shiqing, LI Dening, YE Ping
    Mud Logging Engineering. 2020, 31(S1): 66-71. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.012
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Aiming at the problem of low condensate oil recovery during the depletion development of small fault-block condensate gas reservoirs rich in condensate oil,combined with the distribution characteristics of condensate oil and gas and CO2 resources in the research area,the idea of joint development of low-pressure condensate gas reservoirs and gas reservoirs with rich CO2 was put forward. Low-pressure condensate gas reservoir A and high CO2 content gas reservoir B in the research area were selected to conduct simulation tests of joint development. Through numerical simulation analysis,comparative studies on the recovery degree of condensate oil under different development programs,such as the optimization of gas injection and production well patterns,injected gas component design and the optimization of gas injection speed indicators were carried out. It is showed that the joint development has remarkable effect in increasing the expected condensate oil recovery by 20.46% on the basis of the original recovery level. The design concept not only solves the problem of temporary closure of gas reservoirs with rich CO2 that cannot be developed and utilized due to environmental protection requirements,but also provides a technical method for improving the condensate oil recovery of the low-pressure condensate reservoir after depletion development.
    • GEOLOGICAL RESEARCH
  • Mesozoic tectonic evolution and basin prototype restoration in Chenghai area of Qikou sag
    LOU Da, PEI Yanlu, LI Xiaoxiang, ZHOU Shuhui, ZHU Guijuan, MI Xingduo
    Mud Logging Engineering. 2020, 31(S1): 72-78. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.013
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Dagang Chenghai area is located in the south margin of Qikou sag. It is a region with severe structural deformation at the basin margin. Due to the superposition of Cenozoic stepped fault depressions, the Mesozoic structural pattern becomes extremely complex. For a long time, the cognition of Mesozoic structure outline and evolution process in Chenghai area are not clear, which limits the understanding of Mesozoic reservoir distribution. In this paper, the Mesozoic deformation in Chenghai area is studied by using the new high-precision 3D seismic data and drilling data, the balanced section and the basin prototype recovery technique, and the distribution points of the Mesozoic residual strata are defined. The formation and evolution of basin archetype are discussed by analyzing the evolution process of paleostructure. Studies have shown that the formation and collapse of paleo-eastern plateau of the north China craton during the Mesozoic era had a decisive influence on the distribution of Mesozoic in Chenghai area. Based on the results of structural deformation analysis, the oil and gas exploration direction of Jurassic clastic rock buried hill in Chenghai area was preliminarily defined.
  • Hydrodynamic characteristics of Paleogene and hydrocarbon accumulation in Qikou Sag
    WANG Na, Lǚ Fangfang, SUN Chaonan, GUO Zhiqiao, ZHONG Wei, DONG Xiongying, LI Haodong, WANG Guan
    Mud Logging Engineering. 2020, 31(S1): 79-85. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.014
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    As an important part of sedimentary basins,the formation and the law of movement of fluid are closely related to the generation,migration and accumulation of hydrocarbon,and the formation,preservation and destruction of hydrocarbon reservoirs. Taking the Paleogene hydrodynamic research in Qikou Sag of Dagang exploration area as an example,through a large amount of measured data,the relationships between hydrodynamic characteristics,genesis and evolution process,and hydrodynamic and hydrocarbon accumulation are discussed separately. It is showed that the Paleogene abnormally high pressure in Qikou Sag generally develops in deep layers and that undercompaction,clay mineral dehydration,hydrocarbon generation,and hydrothermal pressurization are the factors leading to the abnormal pressure in the area. Under the abnormally high pressure,the last stage of accumulation of deep source rocks is later than that of the upper source rocks. Through the study of Paleogene hydrodynamic in Qikou Sag,it is clear that the pressure transition zone is the focus of hydrocarbon exploration,and the scope of hydrocarbon exploration has been expanded,which is of great significance for strengthening mid-deep formation exploration and finding hydrocarbon enrichment areas.
  • Porosity evolution and quality prediction of sand bodies of gravity flow channel: Study of sand bodies in the middle Member 1 of Shahejie Formation in Qinan slope,Qikou sag
    MU Liangang, ZHAO Liang, QU Yanling, WANG Na, ZHOU Fengchun, LIU Huifang
    Mud Logging Engineering. 2020, 31(S1): 86-94. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.015
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Gravity flow sedimentary sand bodies always have characteristics of heterogeneous type and the distribution of high quality reservoirs is the core research content. Taking the gravity flow sedimentary sand bodies of the middle Member 1 of Shahejie Formation in Qinan slope area of Qikou sag as the research object, based on the existing knowledge, the seismic sedimentology and the numerical simulation method of diagenesis is used to construct the prediction model of sedimentary and diagenetic integrated porosity under the tectonic setting. In this paper, the conclusion provided the basis for the quality evaluation and prediction of gravity sandstone reservoir.There are three sedimentary microfacies in the middle Member 1 of Shahejie Formation of the study area: the center of the waterway, the edge of the waterway and the overflow of the water. Research of sedimentology shows that the physical properties of reservoirs are controlled by sedimentation and diagenesis. In terms of the original reservoir physical properties, the property of gravity flow channel central reservoir is the best, the waterway edge is the second, and the waterway overflows is the worst. In plane, at the middle Member 1 of Shahejie Formation, there are two secondary porosity developmental areas in the north and south.In the low slope area of the main waterway phase region, the buried depth is large, the dissolution is strong, late cementation is weak, and the porosity can reach more than 12%. The pore evolution of the gravity flow channel is inseparable from the hydrocarbon accumulation process, and the center of gravity flow channel in the hydrocarbon generation center is the main target of increasing production and storage.
  • Lithology and lithofacies characteristics of tight oil from the Second Member of Funing Formation in Qutang sub-sag,Northern Jiangsu
    ZHANG Shaohui, YANG Ziyu, DUAN Runmei, MI Xingduo, LI Yuqin, BAI Pengzhu, WANG Yanli
    Mud Logging Engineering. 2020, 31(S1): 95-99. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.016
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    As a new exploration and development field of unconventional oil and gas resources,the tight oil from the Second Member of Funing Formation in Qutang sub-sag has few understanding or research on reservoir lithology and lithofacies. Based on a large amount of core and laboratory analysis data,through research on the longitudinal combination characteristics of reservoir lithology and lithofacies of the Second Member of Funing Formation in Qutang sub-sag,it is clarified that the rock types of the Second Member of Funing Formation can be divided into four types,clay rock,carbonate rock,felsic sedimentary rock and fine-grained mixed sedimentary rock,and that dolomite is the dominant reservoir. There are six lithofacies in the Second Member of Funing Formation from bottom to top,among which the lithofacies of LF③ from the second submember of the Second Member of Funing Formation and the LF⑤ from the third submember of the Second Member of Funing Formation are source-reservoir adjacent structure,and LF④ from the second submember of the Second Member of Funing Formation is source-reservoir integrated structure. These three lithofacies are the most favorable longitudinal combination of the Second Member of Funing Formation in Qutang sub-sag,based on which the two indexes of thickness and brittleness are used to study the plane changes and distribution of the lithofacies of the Second Member of Funing Formation,providing geological support for the oil and gas exploration breakthroughs in the tight oil from the Second Member of Funing Formation in Qutang sub-sag.
  • The composition of maceral and the hydrocarbon-generation characteristics of upper Paleozoic coal-bearing source rocks: Taking Carboniferous-Permian source rocks in Bohai Bay Basin as an example
    WANG Na, MU Liangang, DONG Xiongying, BAI Jing, LIN Changmei, ZHOU Jing, HE Chuan, LIU Huifang, LI Haodong
    Mud Logging Engineering. 2020, 31(S1): 100-107. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.017
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    The coal-bearing source rocks of upper Paleozoic are widely developed in the Bohai Bay Basin, which is one of the major contributors to deep oil and gas in eastern China. Based on the previous research results on the distribution, the geochemical characteristics and the hydrocarbon generation evolution characteristics of this set of source rocks, the analysis of chemical components and chemical structure differences about different organic maceral was carried out by using the test data from Micro-FTIR, laser pyrolysis-gas chromatography and NMR, the relationship between the organic maceral with the oil-prone and gas-prone of coal measure strata is discussed. According to the comprehensive analysis about the characteristics of coal-bearing source rocks and organic maceral in many areas, the hydrocarbon-generation potential of coal-bearing source rocks of upper Paleozoic in different areas of Huanghua depression is determined, it provides a reference for the reasonable evaluation about the prospect of oil and gas exploration of upper Paleozoic coal measure strata in the study. The results indicated that the coal-bearing source rocks of the upper Paleozoic in the Bohai Bay Basin are thick. The organic maceral was dominated by the vitrinite, the content of the rich hydrogen is higher,the percentage of exinite+sapropelinite is 2.8%-54%,the percentage of the desmocollinite is 2.68%-32.4%, the most powerful component of oil-generation is the cutinite, resinite and sporophyte. Due to the frequent and different regional tectonic activities,there are complex and diverse history of tectonic-thermal evolution and many kinds of thermal-evolution and hydrocarbon generation history,the continuous deep burial type and stable buried type are the main hydrocarbon generation evolution history types in the exploration area,it is beneficial to the formation of secondary hydrocarbon generation and the preservation of oil and gas. The belts of Kongxi-Wang Guantun, Wu Maying and Qibei -Zhang Juhe become the favorable areas to find the coal-formed oil (gas) of the upper Paleozoic within the region.
  • Application of attribute optimization in prediction for igneous reservoirs in Dongguan,Dagang
    ZHAO Liang, ZENG Fanping, XU Tian
    Mud Logging Engineering. 2020, 31(S1): 108-112. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.018
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    The Mesozoic igneous rock reservoir in Dongguan,Dagang is a fracture-porous type dual-medium complex reservoir. Its lithofacies change rapidly and the rock masses are spatially overlapped,making it difficult to apply conventional event tracking and seismic attribute plane prediction. To accurately predict the plane distribution of igneous rock reservoirs,the thickness of igneous rock reservoirs in joint wells was picked to establish correlation with 52 sample sets of seismic attributes along layers of two-dimensional joint well profiles,and 10 seismic attributes with high correlation coefficients were selected by calculations as the spatial sample set. Based on the optimal seismic attribute sample set,igneous rock reservoirs thickness was predicted by using well-supervised neural network attribute pattern recognition. The results are in good agreement with actual drilling. This method effectively reduces the multiplicity of a single attribute in reservoir prediction,well predicts the plane distribution characteristics of igneous rocks,and improves the accuracy of reservoir prediction.
  • Application of high-resolution seismic processing and interpretation technology in the exploration of Chengbei low step fault block lithologic reservoirs
    GUO Shuwen, DONG Xiaowei, ZHU Weifeng, ZENG Tianjiu, MENG Wen, HE Zhaoquan, WANG Wentao, XING Xing
    Mud Logging Engineering. 2020, 31(S1): 113-119. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.019
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    Chengbei low step fault block lies in the tidal-flat area,within which fault developed,sand body has great lateral variation and overlaps vertically. Affected by shallow water surface acquisition and underground complex geological conditions,the quality of conventionally processed seismic data and the accuracy of reservoir prediction cannot meet the fine prediction of overlapped reservoirs of lithologic reservoirs. To this end,the research on high-resolution processing and interpretation technology of seismic data in tidal-flat area was carried out. Shallow water singing and reverberation full-spectrum band suppression technology was used to suppress high-frequency noise and highlight the low-frequency characteristics of seismic data,increasing the bandwidth of seismic data. Half bin processing technology of five-dimensional spatial reconstruction to increase spatial sampling rate,strengthen effective signals,and improve seismic imaging accuracy. Based on high-resolution seismic data,facies-controlled geostatistics inversion was carried out to improve the accuracy of reservoir prediction,and to achieve quantitative characterization of the main single sand body of five-level sequence. The actual application effect in the Second Member of Shahejie Formation in Chengbei low step fault block showed that high-resolution processed seismic profile can identify and track 10 five-level sequence interfaces. According to the facies-controlled inversion results,the spatial distribution variation of 3 sand body belts can be clearly identified,and the reservoir prediction coincidence rate reached 85%,which can meet the geological needs of high-resolution fine prediction and reserves utilization in the area.
  • Accumulation law of unconformable screened reservoir in Shahejie Formation of Gangbei area
    LIANG Bin, WANG Ximei, CHENG Qi, WANG Quanguo, JIA Guolong, WEI Yuhong
    Mud Logging Engineering. 2020, 31(S1): 120-124. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.020
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    Unconformable screened hydrocarbon reservoir is a special type of hydrocarbon reservoirs whose accumulation process is affected by many factors such as faults,unconformities,and the lithology of the upper and lower layers of the unconformities. Compared with structural hydrocarbon reservoirs,its research and understanding in reservoir interpretation and description methods and formation law are not enough. In this paper,the seismic response characteristics of different lithologic joints above and below the unconformity are simulated by forward modeling of the unconformable screened reservoir,the denuded unconformable belt is identified by seismic inversion,and the distribution characteristics of different sand body belts are characterized by the comparison and calibration of known wells,and the seismic in-phase axis tracking interpretation. Furthermore,according to the genesis of hydrocarbon reservoirs,this type of reservoir can be divided into two types,veneer accumulation and internal accumulation,and the accumulation conditions of binary and ternary are proposed correspondingly. The research results have important guiding significance for the fine description of unconformable screened reservoirs,the study on hydrocarbon accumulation law,and the exploration and development deployment.
  • Controlling factors of geothermal field and potential of geothermal resources in Huanghua Depression
    WANG Xiaomin, SHAO Huifa, WANG Yongkai, ZHOU Fengchun, GAO Lijin
    Mud Logging Engineering. 2020, 31(S1): 125-129. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.021
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    Huanghua Depression has a moderate geothermal gradient,and multiple thermal anomalies developed in the middle and shallow layers,which are favorable conditions for the formation of geothermal field. In order to understand the basic characteristics of the geothermal reservoirs of Paleogene and Neogene,a large number of analysis and test data obtained from oil and gas well drilling in the study area are used to analyze the basic characteristics and control factors of the geothermal field in Huanghua Depression,and to implement the geothermal resources potential and favorable regional target. It shows that the deep structure of Huanghua Depression changes regularly from east to west,which is directly related to the tectonic activities since Yanshanian period. On the one hand,the mantle bulges,the crust thins,and the Moho surface rises;on the other had,the fault depression has formed thick Meso-Cenozoic clastic deposit due to the crust subsidence. The deep crustal structure and basement structure are major controlling factors of geothermal field distribution to form the distribution characteristics of southern and northern division,and high upheaval and low depression in Huanghua Depression. The geothermal resources within Dagang exploration area are calculated to be 1 664 × 1018 J using thermal reserve method,mainly distributed in Minghuazhen Formation and Guantao Formation. Geothermal abundance is high in Cangxian uplift,Beitang Sag and Qikou Sag in the northern part of the exploration area,which are the main areas for the development and utilization of geothermal resources.
  • The remaining oil potential of the high water cut and high recovery reservoir in the old waterflooding area of Banqiao Oilfield and its tapping strategies
    HU Zilong, ZHANG Tao, CHE Zhengjia, WANG Shunli, LIU Yonghe, DONG Feng
    Mud Logging Engineering. 2020, 31(S1): 130-134. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.022
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    After more than 30 years of waterflooding development,the old waterflooding area of Banqiao Oilfield has entered the development stage of high water cut,high recovery degree and low oil recovery rate. The recovery degree of recoverable reserves is over 40%,and the distribution of movable remaining oil is so scattered that it is quite difficult to tap remaining oil. In order to resume the production capacity,improve the development effect,and fully tap the remaining oil potential of the high water cut and high recovery reservoir in the old waterflodding area,by carrying out research on reservoir heterogeneity and remaining oil distribution,corresponding measures were adopted for sand bodies of different production degrees. After the implementation of the program,the management effect of high water cut and high recovery reservoirs was outstanding,and the nearly suspended reservoirs were restored to a stable oil production of 80 t/d. The development index has been greatly improved,the reliability of the remaining oil research of single sand body has been verified,and good economic benefits have been achieved.
  • Volume fracturing+imbibition oil production technology and its application in deep low permeability reservoirs in Cangdong Sag
    ZHANG Zhuxin, WU Jiapeng, MENG Wen, ZHAO Yulin, WANG Bin
    Mud Logging Engineering. 2020, 31(S1): 135-139. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.023
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Due to factors such as unsuitable development methods,deteriorating well patterns,and low water-flooding efficiency in the deep low-permeability reservoirs of Dagang Oilfield,the average recovery degree is low,and the overall development effect is poor. In order to revitalize deep low-permeability reservoirs,realize the conversion from reserves to production,and break the technical bottleneck of conventional water injection development in deep low-permeability reservoirs,a new development technology of volume fracturing+imbibition oil production is adopted,which greatly improves the vertical production degree of reservoir through volume transformation. A fracture network with a certain bandwidth is formed,which converts the displacement of pores between water injection wells into displacement between fracture networks,shortens the driving distance,and establishes a plane effective driving system. At the same time,the purpose of water-cut control and production stabilization is achieved on the basis of imbibition and oil recovery by waterflood stimulation,asynchronous injection and production,and oil-water well interchange. This technology has been successfully implemented in the GD 6 block of Cangdong Sag,and good results have been achieved.
  • Study on injection-production flow line regulation mode of complex fault block reservoirs in high water cut period
    ZENG Jichu
    Mud Logging Engineering. 2020, 31(S1): 140-146. https://doi.org/10.3969/j.issn.1672-9803.2020.S1.024
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    After the complex fault block reservoirs enter high water cut development period, its physical properties gradually change with the long-term injection water scouring. Increased permeability and porosity formed a superior flow field, ineffective circulation of injection water caused the development effect to deteriorate year by year. Based on flow field evaluation, the study of flow field regulation means is an effective way to improve reservoir development effect and reservoir utilization degree, which has guiding significance for tapping remaining oil potential in high water cut period. By using fuzzy comprehensive evaluation, various factors affecting flow field intensity such as pore radius, multiple of rinsing, water content and fluid velocity were considered comprehensively. Index evaluation set and weight set between indexes were constructed to evaluate and grade the flow field intensity. According to the grading, regulation mode of flow field was proposed, which points out direction for the study of remaining oil. Through numerical simulation and case analysis, the results of flow field regulation mode are reliable, which is helpful to guide the development and adjustment of complex fault block reservoirs in high water cut period.
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