定向射孔对水力压裂多裂缝形态的影响实验  

Experiments of the oriented perforating impact on the multi-fracture pattern of hydraulic fracturing treatment

作　　者：姜浒 刘书杰 何保生 陈勉 张广清 

机构地区：[1]中海油研究总院 [2]"油气资源与探测"国家重点实验室.中国石油大学

出　　处：《天然气工业》2014年第2期66-70,共5页Natural Gas Industry

摘　　要：定向射孔广泛应用于油气井完井措施,其对水力压裂的人工水力裂缝形态有很大影响,定向射孔方向与最大水平地应力方向的夹角、远场水平地应力的差值都会影响到裂缝的起裂部位和整体形态。为此,采用大型(试件尺寸300mm×300mm×300mm)真三轴水力压裂物理模拟实验系统,研究了定向射孔水力压裂人工水力裂缝起裂和形态的影响因素。结果表明:定向射孔方位角和水平地应力差影响很大;定向射孔水力压裂形成的人工水力裂缝可能不是理想的平直双翼裂缝,而是双翼弯曲裂缝,在水平应力差和定向射孔方位角较大的情况下,容易形成由定向射孔方向和最大水平地应力方向多点同时起裂的非对称多裂缝系统或穿过微环面的双翼裂缝;提高原场地应力测量的精度和定向射孔的定向精度,将定向射孔方位角控制在较小角度,有利于避免产生形态复杂的人工水力裂缝,降低压裂施工难度和砂堵风险,从而达到改进压裂增产效果的目的。最后,还对完井和压裂施工提出了建议。Oriented perforating has been widely applied in oil and gas well completion measures, which greatly influences the artificial hydraulic fracture pattern of hydraulic fracturing treatment. The initial fracture location and overall pattern are affected by the angle between the oriented perforating direction and the direction of the biggest horizontal crustal stress as well as the difference value of the far field horizontal crustal stresses. Therefore, the influencing factors on the initial fracture position and pattern of artificial hy- draulic fracturing with oriented perforating were studied with the large-scale real triaxial hydraulic fracturing physical simulation ex periment system （the test piece is of 300 mm ）〈 300 mm X 300 mm）. The research results indicated that the oriented perforating azimuth angle and the horizontal crustal stress difference generate greater influences; the artificial hydraulic fracture formed by the hydraulic fracturing with oriented perforating may be an unsatisfactory straight dual wing fracture, instead, it may be a bent dual wing crack; when the horizontal stress difference and the oriented perforating azimuth angle are comparatively large, it is easy to generate asymmetric multiple fractures at multiple points in the direction of oriented perforating and the biggest horizontal crustal stress or result in dual wing fractures that pass through mini-circle surface. For improving the precision of the crustal stress meas urement on the original site and the oriented precision of the oriented perforating, the azimuth angle of the oriented perforating is controlled to be small, which avoids the generation of artificial hydraulic fractures in complicated patterns and decreases sand-plug- ging risk and the difficulties in fracturing operation, thus realizes the improvement of fracturing stimulation. Finally, positive pro- posals on well completion and fracturing were also presented in this paper.

关 键 词：水力压裂 定向射孔 裂缝(岩石) 形态 非对称性 水平应力差 射孔方位角 改进压裂增产效果 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]