摘要
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 oilfieht.