浅层致密砂岩油藏直井水平缝压裂参数优化研究

Study on optimization of vertical well fracturing horizontal fracture in shallow tight sandstone reservoir

延长油田长6储层岩性主要为中-细粒长石砂岩,埋深550~800 m,孔隙结构复杂,喉道细,分选差。平均渗透率11.76~100.00 mD,孔隙度主要分布在19%以下,属低渗透储层。浅层油藏水力压裂后,存在水平裂缝形态。依据渗流阻力原理,建立了直井压裂水平裂缝参数优化设计方法。以长6储层为例,优化了直井压裂水平缝压裂参数,采用反九点井网开采,井距200×200 m,储层厚5 m,渗透率范围为(5.5~9.5)×10^(-3)μm^(2),优化后的裂缝长度为80 m,支撑裂缝宽度为1.3~1.6 mm。基于渗流阻力理论的直井压裂水平缝压裂参数优化方法,为提高低渗砂岩油藏单井产量提供了理论依据。

Chang 6 reservoir in Yanchang oilfield is mainly composed of medium fine-grained arkose with burial depth of 550~800 m.The pore structure of reservoir space is complex,the throat is fine and the sorting is poor.The average permeability of the reservoir is11.76~100.00 mD,and the porosity is generally less than 19%.It is a low permeability reservoir.There are horizontal fractures after hydraulic fracturing in shallow reservoirs.According to the principle of seepage resistan ce,the optimization design method of horizontal fracture parameters of vertical well fracturing is established.Taking Chang 6 reservoir as an example,the vertical well fracturing and horizontal fracture fracturing parameters are optimized,and the reverse nine point well pattern is used for production,well spacing 200×200 m,the reservoir thickness is 5 m,and the reservoir permeability range is(5.5~9.5)×10^(-3)μm^(2).The optimized crack length is 80 m and the support crack width is 1.3~1.6 mm,the optimization method of vertical well fracturing and horizontal fracture fracturing parameters based on seepage resistance theory provides a theoretical basis for improving the production of single well in low permeability sandstone reservoir.