RESEARCH ON THE INTERNAL STRUCTURES AND DIFFERENCES OF ITS OPENING OR SEALING OF STRIKE-SLIP FAULT ZONE IN CARBONATE REGION: A CASE STUDY OF TARIM BASIN

Carbonate rocks are rich in oil and gas resources and have become one of the core strata for deep oil and gas exploration in China. Studies show that strike-slip faults control the development of deep carbonate reservoirs and oil-gas migration pathways and determine hydrocarbon accumulation areas in Tarim Basin. Due to the complexity of stress mechanism, the strike-slip fault is characterized by sectional stratification and planar segmentation. It is proved by exploration that there are great differences of hydrocarbon enrichment in different positions along the fault dip or strike. At the same time, because of the brittleness and fragility of carbonate rocks, the developed strike-slip fault zone has a complex three-dimensional spatial structure, which varies greatly along the fault strike and dip. The reservoir-controlling mechanism of the strike-slip fault zone is extremely complex. The key to reveal the reservoir-controlling mechanism is that what kind of unique structural mode does the strike-slip fault belt have, when to transport and how to transport, when to seal and how to seal. The study aims at the strike-slip faults developed in carbonate rocks in Keping-Bachu outcrop area and coverage area in Tabei-Tazhong of Tarim Basin. By means of geophysics processing and interpretive technique, field outcrops and core fine characterization technology, using the physical simulation, cement dating and other methods of analysis and testing, the structural characteristics of strike-slip fault zone in carbonate rock area were fined analyzed, the spatial differences and causes were revealed, the structural models were established, the mechanism of oil and gas transportation were clarified, and the evaluation method of fault sealing were innovated. The results have effectively guide the deep hydrocarbon exploration in China.

Acknowledgments

This research was supported by the National Natural Science Foundation of China (No. 42272155), the National Science-Technology Major Projects (No. 2017ZX05001003).