鄯善油田裂缝特征及构造应力场

通过野外节理裂缝的观测,钻井岩心裂缝的古地磁定向与倾角测井裂缝解释,分析了鄯善油田构造应力场,得出鄯善油田储层构造裂缝发育方位主要为N30°-40°E,N30°-50°W,为一对NE、NW向共轭断裂.高角度缝和垂直缝为主.鄯善构造带是近南北挤压作用下形成的,侏罗纪末期燕山期构造运动为近SN向的主压应力模式,形成油田内一系列近SN向正断层,以及测量的NE、NW向共轭断裂.鄯善油田储层断裂是侏罗纪末期燕山期构造运动形成的.通过倾角测井椭圆井径曲线分析等方法判别的鄯善油田现今最大水平主应力方向约140°.人工压裂的裂缝方位理论上当为140°,它与320°方位的构造缝如果匹配,可能对压裂产生影响.

THE FRACTURES PATTERNS AND TECTONIC STRESS FIELDS IN SHANSHAN OIL FIELD, XINGJIANG

Based on the investigation of field joints and cracks in the field paleomagnetic orientation of cracks in cores, and identification of cracks in dip logging curve, we have analyzed the tectonic stress field in Shanshan oil field.Xinjiang N30-40E-and N30-50 Wtrending conjugate shear fractures are well developed in the reservoir rocks.And high-angle, especially vertical fractures are predominant.
The structures in the Shanshan oil field were formed by a nearly N-S compression at the Yanshanian movement in Late Jurassic.The structures comprise the N-S-trending normal faults and the NE-NW conjugate fractures.
The present maximum horizontal principal stress determined from an analysis of the changes of the diameter of the drilling holes by dip logging is about 140° which is consistent with equivalent to the direction of fractures that would be artificially produced in the oil field.