Analysis method and application of differential enrichment of ultra-deep fault-controlled reservoirs: A case study of the Fuman Oilfield in the Tarim Basin

The fault-controlled fracture-cavity type oil and gas reservoir plays an important role in the exploration and development of oil and gas in the carbonate rocks of the Tarim Basin. Research shows that there are significant differences in the oil and gas development effects in different fractures or different segments of the same fracture in the Fuman Oilfield, leading to unclear oil and gas accumulation characteristics and affecting the efficient development of ultra-deep layers. This paper takes the strata from the Yijianfang Group to the Yingshan Group in the Fuman Oilfield of the Tarim Basin as an example, using drilling data, high-quality 3D seismic data, and production dynamic data to study the control effect of ultra-deep strike-slip faults on the degree of oil and gas accumulation. The results show that: (1)The oil and gas accumulation in the fault zone is mainly controlled by three factors: the contact relationship between the fault and the source rock, the fault’s role as a migration pathway, and the size of the reservoir. (2)By comparing and analyzing the drilling production results, the paper establishes a quantitative relationship between the connectivity of the source, the fault’s guiding role, the scale of the reservoir, and oil and gas accumulation, improving a set of evaluation and calculation methods for the differentiated accumulation degree of ultra-deep fault-controlled oil and gas reservoirs. (3)The source connectivity of deep and large faults is an important factor affecting the accumulation degree of fault-controlled oil and gas reservoirs. The higher the oil and gas accumulation, the better the contact between the fault and the source rock, the better the vertical connectivity of the migration pathway, and the larger the effective reservoir scale.