东濮凹陷三叠系砂岩储层构造裂缝特征及形成期次

根据露头、 岩心、 薄片、 古地磁、 成像测井、 岩石力学实验等资料；对东濮凹陷北部三叠系砂岩储层构造裂缝特征及形成期次进行分析。东濮凹陷三叠系砂岩储层主要发育北北东、 北东和近东西向3组高角度构造裂缝；裂缝走向近于平行或垂直主断层；倾向为北西和南东。二马营组裂缝较为发育；和尚沟组和刘家沟组裂缝相对不发育。储层裂缝为3期；分别为燕山早期的北西向扩张裂缝和北北西、 北西西向剪切裂缝；燕山晚期形成北东向拉张裂缝；喜马拉雅期形成北北东、 北东向拉张裂缝、 北北东向剪切裂缝和东西向扩张裂缝。古、 今构造应力场和岩石力学性质的各向异性分析表明；现今构造应力场最大水平主应力和岩石抗压强度的各向异性均影响燕山早期北西向裂缝的张开度及有效性。储层裂缝表现为两期；分别为燕山晚期的北东向拉张裂缝、 喜马拉雅期的北北东、 北东向拉张裂缝；北北东向剪切裂缝和东西向扩张裂缝。研究结果阐明了东濮凹陷北部三叠系砂岩储层构造裂缝特征及发育规律。

Characteristics and periods of the fracture of Triassic sandstone reservoirs in Dongpu sag

According to the outcrops,cores,slices,paleomagnetism,imaging logging and the experiment of the rock mechanical properties,the characteristics and periods of the tectonic fractures of Triassic sandstone reservoirs in the north of Dongpu sag are analyzed. It is concluded that there were NNE,NE and EW high angle tectonic fractures developed,the fracture were mostly parallel to or plumb to the main fault,the tendency was NW and SE. There were mainly developed fracture in Ermaying Formation,and rarely developed fracture in Heshanggou and Liujiagou Formation. Three periods of fracture developed. These fractures were NW extension,NNW and NWW shear crack in the Early Yanshanian,NE tension in the Late Yanshanian,NNE and NE tension,NNE shear,EW extension in the Himalayan. The analysis of the ancient-present tectonic stress field and the anisotropy of mechanical properties of rock shows that the direction of maximum principal stress of the recent tectonic stress filed and the anisotropy of rock mechanics property influenced the NW fracture of the Early Yanshanian. There were two stages fracture which were NE tension in the Late Yanshanian,NNE and NE tension,NNE shear,EW extension in the Himalayan. The results illustrate the triassic sandstone reservoir fracture characteristics and the development law.