后效复合射孔技术在海上低孔渗油气藏的探索应用

Exploration and Application of Aftereffect Compound Perforation Technique in Low-porosity & Low-permeability Reservoirs in Offshore Fields

海上低孔渗油气藏对射孔工艺要求高,常规聚能射孔普遍存在压实损害带,导致渗流阻力大、产能降低,对探井测试产能的准确分析造成较大影响。后效复合射孔技术通过常规射孔弹+后效体的复合结构,两级做功改善孔道几何形态,室内进行了射孔流动效率实验、地面混凝土靶射孔实验,相比常规射孔流动效率提高38%,穿深提高17%,入口直径增大22%,孔容提高45%,孔道周围形成明显的网状微裂缝,有效恢复储层渗透率。射孔施工时采用井下动态监测技术测量井筒压力、温度及管柱横向、纵向冲击力,为射孔参数优化、管柱安全性、井筒完整性评价提供依据。该技术在海上M1井的测试作业及射孔完井作业中得到成功应用,对提高深部低孔渗油气藏的评价测试效果显著。

The requirements of low-porosity and low-permeability reservoirs to perforating technology are high in offshore fields.Conventional perforation technique has damage zone near the bore,which leads to increase flow resistance,decrease productivity and influence the exact analysis of formation testing in exploration wells.The aftereffect compound perforation technique combines conventional perforation and aftereffect body,which produces two-stage work to improve hole geometric shape.Perforating flow efficiency test and ground concrete target perforating test are carried out.Compared with conventional perforation technique,the flow efficiency of aftereffect compound perforationis increased by 38%,penetration depth increased by 17%,diameters increased by 22%,pore volume increased by 45%.There are obvious network-like micro-cracks formed around the pores which could recover formation permeability.The downhole dynamic test is used in the perforation to measure pressure,temperature,horizontal and vertical impact force.The result will supply the reliable assurance for the evaluation of perforating parameters optimization,string safety and wellbore integrity evaluation.The technique has been successfully applied in formation testing and completion of well M1.Notable effect of well evaluation and testing in low-porosity and low-permeability reservoirs has been obtained.