南部探区致密油藏体积压裂参数优化

Optimization of Volumetric Fracturing Parameters for Tight Oil Reservoirs in Southern Exploration Area

致密油气藏的开发一般是通过水力压裂技术进行储层改造,而南部探区致密油藏存在低孔、低渗、低压等特点,此类油藏流体由基质向裂缝的流动能力差,常规压裂技术很难取得较好的增产效果,只能采取体积压裂的增产措施。为了实现南部探区致密油藏的增产,探索南部探区致密油藏体积压裂参数优化具有十分重要的意义。本文基于工区储层物性特征、声波时差实验、电阻率特征提出了南部探区压裂选井选层的地质依据。研究表明长7层位选井选层依据为Δt>223、RT>52、孔隙度>6.6%、渗透率>0.18、含油饱和度>30%;南部探区射孔参数优化结果为射孔方位角小于60°、射孔孔数为13孔/m、射孔孔眼直径为12~14 mm、射孔深度为0.8~1 m。优化的南部探区体积压裂施工排量为8~10 m3/min、压裂液规模为500~700 m3、滑溜水百分比为32%~36%、胍胶压裂液比例为32%~40%、平均砂液比13%~14%。以上研究成果为南部探区致密油藏各体积压裂井的压裂施工提供了一定的指导。

Fracturing technology must be adopted to transform the tight oil and gas reservoir to achieve high efficiency and commercial development.In some certain case,such as low porosity,low permeability and low pressure,conventional fracturing technology can hardly achieve excepted effects owning to the poor fluid supply capacity of reservoir matrix to fractures,so it is important to study the optimization of volume fracturing parameters of tight reservoirs in the southern exploration area.This paper established the discriminant basis of the selection of wells and layers in the southern exploration area by defining the petrological characteristics,pore structure characteristics,reservoir sensitivity,fracture characteristics and other geological conditions in the study area.The research shows that the basis of well selection in Chang 7 layer isΔt>223,RT>52,porosity>6.6%,permeability>0.18,oil saturation>30%;The optimization results of perforation parameters in the southern exploration area are that the perforation azimuth angle is less than 60°,the perforation number is 13 holes/m,the perforation diameter is 12~14 mm,and the perforation depth is 0.8~1 m.The optimized volumetric fracturing construction displacement in the southern exploration area is 8~10 m3/min,the scale of fracturing fluid is 500~700 m3,the percentage of slippery water is 32%~40%,and the proportion of guar gum fracturing fluid is 13%~14%.The above research results provide certain guidance for the fracturing operation of each volume of fracturing wells in tight oil reservoirs in the southern exploration area.