关键词: 和田河走滑断裂带, 差异活动, 断裂演化, 控储效应, 塔西南地区

Abstract: In recent years, the intraplate small-displacement strike-slip fault zone is the focus and hotspot of oil-gas exploration and development in Tarim Basin, where a series of oil-gas enrichment zones such as Shunbei and Fuman have been discovered successively. The latest studies indicate the development of similar intraplate small-displacement strike-slip fault zones in southwest Tarim Basin. Based on the fine interpretation of three-dimensional seismic data of Hetianhe strike-slip fault zone in southwest Tarim Basin, in combination with previous research results and oil-gas exploration practices, this paper discusses the fault distribution, differential activity mechanism, genetic evolution and reservoir-controlling effect of Hetianhe strike-slip fault zone, so as to clarify the development characteristics and petroleum geological significance of the study area. The research results show as follows. (1)As a large dextral strike-slip fault zone mainly developed in the Lower Paleozoic of Tarim Basin, Hetianhe strike-slip fault zone shows a northeast-striking arc distribution and stratified differences, which was distributed linearly in the Cambrian and obliquely or laterally in the Ordovician. The faults develop negative flower, positive flower, and upright structures in the section. (2)Under the lateral connection or buckling effect of dextral right stepping and dextral left stepping, Hetianhe strike-slip fault zone shows the obvious characteristic of segmented differential activity, and the study area can be divided into 3 types of faults (transtensional, transpressional, and transcurrent faults), including 8 fault segments. (3)Hetianhe strike-slip fault zone has undergone multiple stages of tectonic evolution, especially the key activity periods in Episode Ⅰ and Episode Ⅲ of the Mid-Caledonian, and the Late Caledonian to Early Hercynian, and then experienced the deep burial stage, in which the tectonic structure was relatively stable and the fault activity terminated. (4)The segmented differential activities of Hetianhe strike-slip fault zone cause significant differences in the development degree of fault-karst in different fault segments. The development degree of fault-controlling reservoirs in transtensional and transpressional fault segments is significantly higher than that in transcurrent fault segment, demonstrating that the former is a favorable target for Lower Paleozoic oil-gas exploration along the large-scale strike-slip fault zone in southwest Tarim Basin.

Key words: Hetianhe strike-slip fault zone, differential activity, fault evolution, reservoir-controlling effect, southwest Tarim Basin