我国水平井完井技术现状与发展建议

经过几十年的发展,我国各种岩性的油气藏都有水平井钻成,且采取的水平井完井方法多种多样。但是,我国的水平井完井技术尚有2个难点,即水平井如何均衡排液并提高开发效益、低渗透砂岩油气藏水平井如何进行多段压裂改造。详细介绍了我国底水油藏延缓和控制底水脊进的技术现状,现有技术有采水采气联合控制水气脊进、射孔井分段控水完井、裸眼井分段控水完井、水平井井下智能找堵水及分层开采完井、水平井均衡排液完井等。其中,均衡排液完井属于系列技术,包括变盲筛比例筛管控水完井、梯级筛管完井、梯级筛管与变盲筛比例筛管复合、中心控压控水完井等。分析介绍了低渗地层水平井分段压裂完井技术现状,该类技术包括水力喷射分段压裂、双卡上提压裂多段技术、分段环空压裂、液体胶塞隔离分段压裂、机械桥塞隔离分段压裂、水平井限流压裂等;研究了水平井分段压裂合理段数的设计,指出:应根据地层特点确定合理的分段压裂段数,以避免因裂缝间距太小相互干扰或因裂缝间距太大造成死油区很大。最后,针对我国水平井完井技术现状,预测了发展趋势,提出了发展建议。 

Present Status and Development Comments on Horizontal Well Completion Techniques in China

Horizontal wells were drilled and completed in almost all kinds of reservoirs through decades of development,and many kinds of well completion method are available.However,two difficulties still exist in horizontal well completion in China,i.e.equilibrium drainage along horizontal wellbore in order to improve development efficiency,multi-stage fracturing in low permeability sandstone reservoirs.The technology to delay and control bottom water cresting in oil reservoirs with bottom water in China were described in detail.Those technologies included: combination control of water and gas cresting by water and gas production,selective well completion to control water cresting in perforated and open hole wells,intelligent water identification/plugging in horizontal wells and separated recovery and completion and equilibrium drainage techniques in horizontal wells.Equilibrium drainage completion techniques were introduced as a series,i.e.screen pipe water-control completion with variable blind-screen ratio,step screen pipe completion,combination of step screen pipe and screen pipe with variable blind-screen ratio,center water and pressure controlling completion.Current situation of multi-stage fracturing technologies in low-permeability formation was introduced,which included staged fracturing by hydraulic jetting,double sticking lifting,annular staged fracturing,liquid plug isolation,mechanical bridge isolation and horizontal well limited-entry fracturing.Optimal fracturing stage number was studied and it was shown that,reasonable fracturing stage number shall be determined according to the reservoir characteristics,to avoid mutual interference between fractures because of dense spacing or avoid large dead oil area because of sparse spacing.Finally,the development trend and suggestions were presented considering the development status of horizontal well completion technology in China.