平面多径向井水射流辅助压裂构造多缝机理

Mechanism of realizing multiple fractures by water jet assisted fracturing for planar multi-radial wells

曲占庆 王涛 郭天魁 李小龙 林强 王晓之

中国石油大学（华东）石油工程学院，山东 青岛 266580

School of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China

常规压裂对天然裂缝不发育或水平地应力差较大的低渗及非常规油气储层难以实现多缝改造，为此创新性地提出了平面多径向井辅助压裂构造复杂多缝的方法。为验证该设想，基于ABAQUS平台建立了平面多径向井辅助压裂的三维数值模型，全面考察了多因素对径向井引导效果的影响，并通过大尺寸真三维水力压裂模拟实验验证了数模结果的正确性。结果表明，较小的径向井方位角、地应力差、弹性模量及较大的孔径、孔长、纵向孔密、泊松比、渗透率、压裂液黏度及排量都会增强孔眼对裂缝的引导。研究成果为平面多径向井引导裂缝定向扩展、构造复杂多缝工艺提供了理论支撑。

In the development of low-permeability and unconventional oil and gas reservoirs with less natural fractures or large horizontal ground stress, it is difficult to realize multi-fracture reformation by conventional fracturing. Therefore, an innovative technique of horizontal multi-radial wells fracturing was proposed to produce complicated multi-cracks. In order to verify this idea, based on Abaqus, a 3D numerical simulation was built to investigate the effects of multiple factors on the crack extension comprehensively. The accuracy of simulation results was verified by big size 3D hydraulic fracturing experiment in the laboratory. The results indicate that: smaller azimuth angle, horizontal ground stress, Young′s modulus and larger hole diameter, well length, vertical perforation density, Poisson′s ratio, permeability, fracturing fluid viscosity and displacement will enhance the guiding effect of the radial well on cracks. This research provides a theory support for water jet assisted fracturing for planar multi-radial wells.

10.6056/dkyqt201903029