川西坳陷孝泉-新场地区须家河组二—四段构造应力场模拟及裂缝发育区带预测

Tectonic stress field modeling and fracture prediction in Tχ strata in Xiaoquan-Xinchang area, western Sichuan depression

张守仁 万天丰 陈建平

Zhang Shouren Wan Tianfeng Chen Jianping

弹-塑性增量法应力场模拟,就是用若干个直线段去逼近抛物线型应力应变曲线,在每个直线段中按有限元法进行弹性模拟计算。运用该方法对孝泉-新场地区须家河组二—四段构造应力场进行了精细数值模拟。结果显示孝泉-新场地区为一构造裂缝不发育地区,仅断裂带附近区域构造裂缝较发育。经地震剖面解释及构造演化分析,该区主要断裂带是油气运移的良好通道,且不存在油气的严重漏失。因此,断裂带附近区域是天然气勘探最有利区域,特别是近东西向断裂与现今主应力方向平行,表现为开启性,对天然气的导通作用更为明显。

Elastic-plastic incremental modeling of tectonic stress field is to approximate parabolic stress-strain curves with several linear portions and perform elastic modeling with finite element method in each linear portion. It is applied to perform numerical simulation of the tectonic stress field in Tx strata in Xiaoquan-Xinchang area.Modeling results show that structural fractures are poorly developed in this area,except in the near-fault regions where regional structural fractures are relatively well developed. Seismic section interpretation and structural evolution analysis reveal that the main fractured zones are good hydrocarbon migration pathways and no serious leakage of hydrocarbons exists.Therefore,favorable regions for gas exploration are those neighboring faults,especially the near E-W trending faults which are parallel with the current major stress and in open state can more effectively conduct gas.

10.11743/ogg20040113