赤水地区官南构造须4段气藏裂缝预测

从贵州赤水地区官南构造现今构造形迹特征入手，利用数值分析技术，模拟计算该地区须4段气藏岩体的古构造应力场和破裂接近程度系数（η）；将η与实际资料和野外观测结果对比，确定不同裂缝发育级别及其对应的η值；文章利用此标准，结合岩石力学与构造地质学理论、野外裂缝观测结果、以及实际生产资料，对官南构造裂缝发育程度、裂缝类型及产状进行综合预测。结果表明：须四段裂缝较发育，主要分布在官南构造翼部高陡带、长轴、鞍部、鼻突及断裂带区域裂缝共有2期5组；裂缝的主要方位为东西向、北东向和北西向；裂缝类型以高角度共轭剪切缝和张性缝为主；晚期裂缝较早期更加发育。

PREDICTION OF FRACTURES IN GAS RESERVOIRS IN 4TH MEMBER OF XUJIAHE FORMATION OF GUANNAN STRUCTURE IN CHISHUI, GUIZHOU

Beginning with the present structural features of Guannan structure, numerical analysis technique is used to calculate the paleotectonic stress field and fracturing proximity coefficient of gas reservoirs in the 4th member of Xujiahe Formation in Chishui, Guizhou. Fracture development degrees and the corresponding η values are determined through correlation of η with real data and field observation. The development degrees, types and occurrence of fractures are comprehensively predicted by using these criteria and in combination with rock mechanics, theories of structural geology, field observation of fractures and real production data. Fractures are relatively well developed in the 4th member of Xujiahe Formation and are mainly distributed in the highly steep zone of the flank, long axis, structural low, structural nose and faulted zone in Guannan structure. There are 5 regional fracture groups formed in 2 stages. The fracture azimuths are mainly E W, N E and N W and the types of fractures are dominated by high angle conjugated shear fractures and extensional fractures. Fractures are more developed in the late stage than in the early stage.