四川盆地川中地区走滑断裂的分布、类型与成因

近期研究发现四川克拉通盆地内存在大型走滑断裂带，是断控油气藏勘探开发的有利新领域，走滑断裂的分布与成因对油气目标评价具有重要意义。本文在三维结合二维地震资料解释的基础上，分析走滑断裂的分布与成因类型，并探讨走滑断裂的形成机制。结果表明，川中三维地震工区发育北西向走向为主的大型板内走滑断裂系统；走滑断裂呈雁列、斜列的不连续的带状分布，断裂发育成熟度低，具有断裂样式的多样性与分层分布的差异性；四川盆地存在川中克拉通内走滑断层、川东南帚状走滑构造、川东调节走滑带、川东北楔入走滑带、川西北斜向冲断走滑带等5个地区发育5种类型走滑断裂带；走滑断裂形成于震旦系灯影组沉积晚期，受控于原特提斯洋俯冲背景下的斜向伸展作用，基底北西向先存断裂构造复活，形成了调节斜向伸展裂陷槽的川中板内走滑断裂系统。结果揭示克拉通盆地可能发育大型的板内走滑断裂系统，不同于常规的板缘与板内调节走滑断裂系统。

The distribution, type and origin of the strike- slip faults in the central Sichuan basin

Recently, it has found that there are large scale strike-slip fault zones in the Sichuan cratonic basin, which is a new favorable frontier for the exploration and development of fault-controlled hydrocarbon reservoirs. Due to none case study this kind strike-slip fault system, the distribution and origin of strike-slip faults are of great significance to the evaluation of hydrocarbon targets in the Sichuan Basin. Based on the interpretation of 3D and 2D seismic data, this paper analyzes the distribution and genetic types of the strike-slip faults, and discusses the origin mechanism of the strike-slip faults. The results show that large scale intracontinental strike-slip fault system developed in the central Sichuan Basin. The strike-slip faults present isolated en echelon or oblique segments with low fault maturity, and show diversity in fault styles and variation in strata distribution. There are five types strike-slip fault systems in five area in the Sichuan Basin: central intracratonic strike-slip fault zones, southeastern brush structures, eastern accommodation strike-slip belts, northeastern indent-linked strike-slip zones, northwestern transprssional belts. The strike-slip fault system in the central basin initiated in the late deposit period of the Sinian Dengying Formation. It was controlled by the oblique extension setting by the Proto-Tethyan subduction process, and influenced by the reactivation of the NW-trending fracture structure in the basement weaken zones, forming the intracontinental strike-slip fault system in the central craton to adjust the oblique extensional trough in the Sinian System. The results indicate that large intracontinental strike-slip fault system may occur in the intracratonic basin, which are different from the conventional strike-slip fault systems with adjustment effect at the plate margin and intraplate.