砂岩油藏特高含水期的水驱特征  

Water displacement rules of sandstone reservoirs at extra-high water-cut stage

作　　者：李传亮 王凤兰[2] 杜庆龙[2] 由春梅[2] 单高军[2] 李斌会[2] 朱苏阳 LI Chuanliang;WANG Fenglan;DU Qinglong;YOU Chunmei;SHAN Gaojun;LI Binhui;ZHU Suyang(School of Petroleum Engineering,Southwest Petroleum University,Chengdu 610599,China;Research Institute of Exploration&Development,PetroChina Daqing Oilfield Company Limited,Daqing 163712,Heilongjiang,China)

机构地区：[1]西南石油大学石油与天然气工程学院,成都610599 [2]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《岩性油气藏》2021年第5期163-171,共9页Lithologic Reservoirs

基　　金：国家科技重大专项“大庆长垣特高含水油田提高采收率示范工程”(编号:2016ZX05054);西南石油大学“专创融合”项目联合资助。

摘　　要：注水开发砂岩油藏进入特高含水期后,其生产特征和水驱规律都与高含水阶段有所不同,高含水阶段的水驱规律不能用于指导特高含水期的生产实践。为了做好特高含水期的油藏开发管理工作,基于DT油藏的生产数据,从生产特征和驱油机理出发,研究了特高含水期的水驱规律,取得了以下主要认识。特高含水期油藏呈现出了“一高两低”的生产特征,即高含水、低产量、低采出程度。产量递减率和含水上升速度也都较低。地下存在大量的剩余油可以挖潜。油藏存在水驱采油和水洗采油两个基本的开采机理,水驱采油的对象为连续型剩余油,开采效果较好;水洗采油的对象为离散型剩余油,开采效果较差。油藏开发初期以水驱采油为主,然后转变为开发后期以水洗采油为主的开发过程。高含水阶段的水驱曲线和水油比曲线近似为一直线,特高含水期的水驱曲线和水油比曲线出现上翘,表明水驱采油向水洗采油过程的转变,开采效果变差。用高含水阶段水驱规律预测的油藏采收率比用特高含水期水驱规律预测的采收率高,DT油藏平均高了5.24%。提高采收率的方法都是通过提高采出程度来实现的,具体包括3个方面:扩大波及、加深水洗、提高驱油效率。长期水洗也可以提高油藏采出程度。特高含水期的油藏开发仍应以扩大波及为主,并带动驱油效率一起提高。Water-flooded sandstone reservoirs showed quite different production characteristics and water displacement rules at the extra-high water-cut stage from the high water-cut stage.The theoretical models of reservoirs at high water-cut stage cannot be applied to the production practice of reservoirs at the extra-high water-cut stage.In order to manage the reservoir production at the extra-high water-cut stage properly,a study was carried out based on the production data of reservoir DT to find out the water displacement rules and displacement mechanism.There are some conclusions as following.The reservoirs at extra-high water-cut stage showed the main aspects of“one high and two lows”,i.e.high water-cut,low production rate and low recovery factor.The decline ratio of production rate and the rising rate of water-cut are also quite low.There is tremendous remaining oil underground being worth recovering.Reservoir oil is displaced through two basic mechanisms,one is water-driving recovery and the other is water-flooding recovery.The continuous oil is produced by water-driving recovery with high efficiency,and the discrete oil is produced by water-flooding recovery with low efficiency.At the early stage of development,reservoirs are produced mainly through water-driving recovery,while in the late stage mainly through water-flooding recovery which is converted from the water-driving recovery in the early stage.The water drive curve and the water-oil ratio curve are approximate straight lines at high water-cut stage.However,the lines are up warding at extra-high water-cut stage from high water-cut stage,which means that the recovery mechanism is converting from the water-driving to the water-flooding with the recovery efficiency changing worse.The efficiency of oil recovery predicted by the displacement rules of high water-cut stage is higher than that predicted by the displacement rules of extra-high water-cut stage,for example it is 5.24 percent points for reservoir DT.The recovery efficiency enhancement of reservoi

关 键 词：砂岩油藏 水驱 水洗 含水率 特高含水 采收率 水油比 水驱曲线 波及系数 

分 类 号：TE341[石油与天然气工程—油气田开发工程]