大尺寸砂岩靶射孔孔道损伤评价  

Quantitative evaluation of perforation damage in large-sized sandstone targets

作　　者：郭书生 梁豪 崔佳莉 GUO Shusheng;IANG Hao;CUI Jiali(CNOOCChina Limited,Hainan Branch,Haikou,Hainan 570300,China;CNOOC Energy Development Engineering Technology Corp,Zhanjiang Branch,Zhanjiang,Guangdong 524057,China)

机构地区：[1]中海石油(中国)有限公司海南分公司,海南海口570300 [2]中海油能源发展工程技术公司湛江分公司,广东湛江524057

出　　处：《中国海上油气》2024年第1期134-142,共9页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司重大生产科研项目“南海大中型天然气田形成条件、勘探潜力与突破方向(编号:KJZH-2021-0003-00)”部分研究成果。

摘　　要：射孔高速金属射流穿透油气层的同时也在孔眼附近形成压实带,造成油气层的孔隙度和渗透率损伤,严重影响油气井产能。当前对于射孔效果的检验主要基于地面水泥靶、钢靶或小尺寸砂岩靶进行实验,无法真实评价原位地层条件下的射孔效果、流动效率,对于射孔孔道压实损伤机理认识不足,缺乏定量评价手段。针对上述问题,研发了模拟原位地层条件下的大型射孔物理模拟装置及实验技术,基于稳态气流注入技术的岩心自动扫描系统点测砂岩靶上任意点的渗透率以及纵、横波速,结合微CT、扫描电镜等手段实现对射孔砂岩损伤程度定量评价。结果表明:对比混凝土靶的射孔数据,砂岩靶穿深急剧下降且不存在明显的裂纹,不同弹型射孔穿深下降幅度为17%~40%,温度对射孔深度无明显影响;射孔孔道径向表现为破碎带、过渡带、压实带及原状带等4个区域,平均压实带厚度17.10~79.95 mm,压实损伤率12%~63%;孔道内壁受剪胀作用,孔隙度、渗透率增加,压实区域受塑性挤压,大幅降低喉道直径,导致孔隙度、渗透率显著下降。本文研究成果对于明确射孔孔道损伤机理、指导射孔参数设计优化具有借鉴意义。The high-speed metal jet of perforation penetrates the oil and gas layer while forming a compaction zone near the perforation hole,which causes damage to the porosity and permeability of the oil and gas layer and seriously affects the production capacity of oil and gas wells.Currently,the testing of perforation effect mainly involves experiments on cement targets,steel targets,or small sandstone targets under ground conditions,which is insufficient to evaluate the perforation effect and flow efficiency under in-situ formation conditions.This leads to a lack of understanding of the mechanism and quantitative evaluation methods for the compaction damage in perforation channels.Therefore,a large physical simulation device and experimental technology for simulating the in-situ formation conditions were developed.Based on the steady-state airflow injection technology,an automatic scanning system of cores was used to measure the permeability at arbitrary points and the longitudinal and transverse wave velocities of sandstone targets.Furthermore,by combining micro-CT and scanning electron microscopy techniques,a quantitative evaluation of the damage degree of perforated sandstone was realized.The results shows that there was no obvious crack in sandstone targets.Compared with the perforation data on concrete target,the penetration depth of sandstone target is smaller,with a range of 17%to 40%for different bullet types.Temperature has no significant effect on perforation depth.The radial direction of the perforation channel could be characterized by four regions:broken zone,transition zone,compaction zone and original zone.The average thickness of the compaction zone is 17.10 mm to 79.95 mm,and the compaction damage rate is 12%to 63%.The inner wall of the hole is subject to shear expansion,resulting in increase of porosity and permeability.The compaction zone is subject to plastic extrusion,which reduces the throat diameter significantly.The research results of this paper have reference significance for clarifying the da

关 键 词：砂岩靶 射孔损伤 岩心扫描 渗透率 压实 

分 类 号：TE58[石油与天然气工程—油气田开发工程]