苏北复杂小断块油田提高采收率技术应用研究

苏北油田为一复杂断块区,具有＂低＂、＂薄＂、＂窄＂、＂深＂、＂多＂的地质特点。共探明油藏20个,探明总储量达4200.39×104t,开发油藏17个共30个区块单元,动用储量2856.64×104t,可采储量630.42×104t。＂十一五＂以前,主要以试采为主,多数单元采用弹性水驱和试注水开发,由于构造破碎,储层横向变化大,注采连通性差,多数单元采收率小于15%。近年来,应用水驱、化学驱以及气驱等技术,重点开展提高储量动用程度和提高采收率攻关研究工作。其中,水驱以井网加密、油井转注、补开注采对应层等完善注采井网为重点;化学驱以开展化学调驱室内评价研究、矿场调剖试验为主;气驱以二氧化碳驱油提高采收率为主。从经济角度评价,受断块小及储量规模控制,水驱是现今提高复杂小断块油藏采收率的主要技术。而二氧化碳驱油技术及化学驱油技术,成本高、投资大,在绝大部分小断块中推广应用,不具备经济和技术优势。

Application and Research of EOR in Small Complex Fault Block of North Jiangsu Oilfield

North Jiangsu oilfield is a region of complex fault block with the geological features of ＂low＂,＂thin＂,＂narrow＂,＂deep＂ and ＂more＂.There are 20 oil reservoirs proved with total proven reserves of being up to 4200.39×104t.Seventeen oil reservoirs and 30 blocks or units are developed with 2856.64 ×104t of produced reserves and 630.42×104t of recoverable reserves.Before ＂Eleven Five＂,production test is the main way of development,and large number of units developed by elastic water drive and pre-water flood.Their recovery efficiency is lower than 15% for breaking structure,great lateral variance of reservoirs and weak injection-production communication.In recent years,water flood,chemical flood and gas drive are applied to the research on enhancing produced degree of reserves and recovery efficiency.For the water flood,flood pattern should be improved through well pattern thickening,oil well converting to injection well,corresponding injection-production layers producing.For the chemical flood,laboratory evaluation research and field profile control experiment should be made.For the gas drive,EOR by CO2 drive is the main job.In the economics,the water flood is the main EOR for the small complex fault blocks for controlling by small fault block and reserve scale.Oth erwise,the CO2 drive and the chemical flood has no advantages on economy and technology for the most small fault blocks because of high cost and large investment.