径向井引导水力裂缝扩展机理

Hydraulic crack propagation mechanism of radial well guidance

 李建雄¹ 刘茂林² 郭天魁¹ 刘晓强¹ 李小龙¹

中国石油大学（华东）石油工程学院，山东 青岛 266580 中国石化西北石油分公司石油工程监督中心，新疆 乌鲁木齐 830001）

College of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China Petroleum Engineering Supervision Center, Northwest Petroleum Bureau, SINOPEC, Urumqi 830001, China)

随着低渗、超低渗油藏的深入开发，径向井辅助压裂技术在各大油田进行了先导性试验，但目前对径向井引导裂缝扩展机理的研究尚未见报道。基于ABAQUS有限元软件，建立了径向井储层三维实体仿真模型，研究了径向井井径、井距和孔眼数对裂缝扩展的影响规律。数值模拟结果表明：不同井眼施工参数可以改变径向井周围的应力分布，达到减小储层破裂压力、引导裂缝扩展的作用；径向井井径和孔眼数的增加能够减小轴向压应力，降低储层破裂压力，而井距的增加使轴向压应力变大；直井井壁应力分布受径向井井距和孔眼数的影响明显，压应力随井径的增加而减小，并在径向井方向取得最小值，压应力随孔眼数的增加而增大。

 Along with the development of low permeability and super-low permeability reservoirs, the auxiliary radial well fracturing technology was carried out firstly in several oilfields. But now the mechanism of crack extension of radial well guidance has not yet been reported. Based on the finite element software ABAQUS, a 3D simulation model of radial well, which considers different parameters, including radial well diameters, distance and numbers of radial wells, was established to study the effect on crack propagation. The numerical simulation results show that different borehole parameters can change the circumferential stress distribution of radial well and decrease the reservoir fracture pressure to guide crack extension; the increase of the radial well hole diameter and hole number can reduce the axial compressive stress and fracture pressure; on the other hand, the axial compressive stress will decrease along the growth of well distance; distribution of vertical wellbore stress is affected by the number of radial well distance and radial well diameter, and the compressive stress will decrease with the growth of well distance and radial well diameter and reach the minimum value in the radial direction of radial well.

10.6056/dkyqt201606025