低渗透砂岩油藏暂堵重复压裂技术研究

STUDY OF REFRACTURING TECHNOLOGY IN LOW-PERMEABILITY SANDSTONE RESERVOIR

谈士海

Tan Shihai

中国科学院, 地质与地球物理研究所, 北京, 100029 2. 西北大学, 西安, 710069 3. 中国石化, 华东分公司采油厂, 江苏, 泰州, 225300

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2. Northwest University, Xi'an, Shanxi 710069, China 3. The Production of Huadong Company, SINOPEC, Taizhou, Jiangsu 225300, China

初次水力压裂后产生的支撑裂缝周围会形成诱导应力场,进而改变原始地应力场,从而导致重复压裂时启裂改向,其延伸方向依然取决于地应力状态。通过改变围压条件进行的水力压裂模拟实验,证实了重复压裂造新缝的可能性。鄂尔多斯盆地安塞油田采用了暂堵重复压裂工艺技术:在老裂缝重张过程中加入暂堵剂进行封堵形成高压环境,产生新裂缝并沟通部分天然微裂缝,随后加入支撑剂构建新的高导流裂缝体系,使泄油面积大大增加。现场试验的裂缝监测和效果分析资料证实产生了新裂缝。

The propped fracture generated during primary fracturing induces a stress field that changes original stress field and further reorients new fracture during refracturing,the extension direction is still controlled by stress status.By means of altering confining pressure,hydraulic fracturing simulation experiment proves the possibility of new fracture generation during refracturing.Temporarily blocked refracturing is applied in the Ansai oilfield of the Ordos Basin: a temporary blocking agent is injected during old fractures reopening to form a high-pressure environment and newly generated fracture connects the natural micro fractures which establishes new high-conduction fracture system with later added proppant and enlarges the oil-draining area.Pilot fracture monitor and effect analysis prove the generation of new fractures during refracturing.

https://doi.org/10.11781/sysydz200603307