柴达木盆地涩北气田水淹后注CO_(2)驱提高采收率实验分析  

An experimental study on recovery factor of watered gas reservoirs by CO_(2) EOR in the Sebei Gas Field of the Qaidam Basin

作　　者：高树生[1,2] 叶礼友 刘华勋[1] 朱文卿 程立华[1] 安为国[1] GAO Shusheng;YE Liyou;LIU Huaxun;ZHU Wenqing;CHENG Lihua;AN Weiguo(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国石油勘探开发研究院 [2]中国科学院大学

出　　处：《天然气工业》2023年第12期55-62,共8页Natural Gas Industry

基　　金：中国石油天然气股份有限公司科学研究与技术开发项目“疏松砂岩气藏提高采收率技术研究与试验”(编号:2021DJ1705)。

摘　　要：青海涩北疏松砂岩气藏埋藏浅、储层疏松、渗透率高、孔隙度大、边水发育,开发初期产量高,见水时间早,气水同产严重,降低了气井产能和气藏采收率。为了提高水淹气藏采收率,根据气藏转变开发方式提高采收率思路,设计了气井见水后注入CO_(2)提高采收率实验流程与方法,开展了水淹气藏注CO_(2)驱提高采收率物理模拟实验,优选了目标区、预测了注CO_(2)生产动态。研究结果表明:①水淹气藏生产过程中注CO_(2)可以有效提高气藏能量,增加渗流能力,驱替、置换采出更多的CH4气体,相比于注气前的生产动态,在相同采出程度下气藏平均压力明显提高;②能够降低水侵速度2.4~6.5倍,有效减小水侵对气井产能的影响,解放储层中大量的水封气;③当CO_(2)在岩样出口突破时,相较见水时采收率可以提高30%左右,随着出口产气中CO_(2)体积占比增加,气驱采收率增值会更高,但增加幅度变缓;④采气速度、CO_(2)注入能量、水体倍数、原始含水饱和度对采收率都有一定影响;⑤气藏工程等效计算目标气藏在不同注采比下,1年期单井注CO_(2)前缘均匀推进距离161~340 m。结论认为,气藏水淹后注CO_(2)可有效提高天然气采收率,实验结果支持了水驱气藏转变开发方式注CO_(2)提高采收率技术的可行性,为水淹气藏的高效开发提供了新的技术路线。The unconsolidated sandstone gas reservoirs in Sebei of Qinghai Province are characterized by shallow burial,unconsolidated reservoir,high permeability,high porosity and developed edge water,and it has a high production rate at the initial stage of development and early water breakthrough,which lead to serious gas and water co-production,seriously reducing gas well productivity and gas reservoir recovery.In order to enhance the recovery factor of watered gas reservoirs,this paper designs an experimental process and method of CO_(2) EOR after water breakthrough in a gas well according to the idea of transforming the gas reservoir development mode based on its characteristics,and then carries out a physical simulation experiment of CO_(2) flooding.In addition,a target area is selected,and the production performance of CO_(2) flooding is predicted.And the following research results are obtained.First,the injection of CO_(2) in the production process of watered gas reservoirs can effectively increase the energy and seepage capacity of the gas reservoirs,and displace and replace more methane gas.Compared with the production performance before CO_(2) injection,the average pressure of the gas reservoir under the same degree of reserve recovery is significantly increased.Second,CO_(2) injection can reduce the water invasion rate by 2.4-6.5 times,effectively reduce the impact of water invasion on the productivity of gas wells,and release a large amount of water sealed gas in the reservoir.Third,when CO_(2) breaks through at the outlet of the sample,the gas recovery can be about 30%higher than that when water breaks through.With the increase of the volume proportion of CO_(2) in the produced gas at the outlet,the increment of gas recovery by CO_(2) flooding is larger,but the increase amplitude decrease.Fourth,gas production rate,CO_(2) injection energy,water body multiple and original water saturation all have certain effects on recovery factor.Fifth,in the target gas reservoir equivalent calculation of gas reservoir engin

关 键 词：水淹气藏 注CO_(2)驱 采收率 气藏能量 气体置换 水侵速度 采气速度 水体倍数 

分 类 号：TE377[石油与天然气工程—油气田开发工程]