INTERPRETATION & EVALUATION
FU Dawei, GONG Liyuan, HU Desheng, ZHANG Shuai, CHEN Kui
In view of large differences in crude oil quality, high fluorescence drilling fluids are used for drilling construction of some wells in Wushi Sag, which makes it difficult for conventional mud logging to effectively identify true or false oil and gas shows and judge the properties of reservoir fluids. This paper uses 3D quantitative fluorescence logging technology to obtain the best excitation wavelength, emission wavelength and oiliness index of crude oil samples of different quality in this area, and establishes the identification standards for crude oil with different qualities. The 3D quantitative fluorescence parameters such as oiliness index, equivalent oil content, and contrast level are combined with gas logging data to establish a discrimination chart of reservoir fluid properties. In application, it can quickly judge the quality of crude oil, and effectively identify true or false oil and gas and weak oil and gas shows. The coincidence rate between the results of reservoir fluid properties interpreted by the chart method and the results of actual tests and samplings is 92%, effectively improving the rapid judgment ability of mud logging for oil and gas layers.