应用滑动准则判断断层稳定性

Study on fault stability with sliding criterion

胡光义¹ 范廷恩¹ 宋来明¹ 侯亚伟²

中海油研究总院，北京 100027 中海石油（中国）有限公司天津分公司渤海油田勘探开发研究院，天津 300452

CNOOC Research Institute, Beijing 100027, China Research Institute of Exploration and Development of Bohai Oilfield, Tianjin Branch of CNOOC Ltd., Tianjin 300452, China

中国海上某油田钻井少，缺乏足够的毛管压力数据，无断层岩样品，浅层断层多处于未胶结成岩状态，应用目前常用的SGR方法和断层岩排替压力方法判断断层封闭性具有一定的局限性。为此，文中采用Byerlee滑动准则，从三轴应力的角度计算了断层临界失稳压力。研究认为，在类似断裂带填充物饱含水、未成岩的状况下，用Byerlee滑动准则判断断层稳定性时，摩擦系数的选取应该不同于其常规工业取值范围（0.6～1.0），在本油田推荐取值为0.4～0.5，相应断层临界失稳压力为2.74～4.26 MPa。计算结果对工区油田注水开采具有重要的借鉴意义。

There are few drilling, insufficient capillary pressure data and no fault rock sample in an offshore oilfield in china. And the shallow faults mostly present the uncemented diagenetic state. There are great limitations to study the fault sealing with the methods of SGR and displacement pressure of fault rock. Therefore the critical unstable pressure is calculated with Byerlee sliding criteria from the angle of triaxial stress. It is believed that the selection of frictional coefficient should be different from the conventional industry span(0.6-1.0) when Byerlee sliding criterion is adopted to judge the fault stability, with infill water saturated and no lithogeneous condition in similar fault zone. Recommended frictional coefficient is 0.4-0.5 in this oilfield and relevant critical unstable pressure of fault is 2.74-4.26 MPa. The calculated result provides an important reference for flooding development of oilfield.

10.6056/dkyqt201204011