天然气工业2023，Vol.43Issue(12)：55-62,8.DOI:10.3787/j.issn.1000-0976.2023.12.006
柴达木盆地涩北气田水淹后注CO2驱提高采收率实验分析
An experimental study on recovery factor of watered gas reservoirs by CO2 EOR in the Sebei Gas Field of the Qaidam Basin
摘要
Abstract
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 CO2 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 CO2 flooding.In addition,a target area is selected,and the production performance of CO2 flooding is predicted.And the following research results are obtained.First,the injection of CO2 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 CO2 injection,the average pressure of the gas reservoir under the same degree of reserve recovery is significantly increased.Second,CO2 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 CO2 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 CO2 in the produced gas at the outlet,the increment of gas recovery by CO2 flooding is larger,but the increase amplitude decrease.Fourth,gas production rate,CO2 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 engineering,the uniform advance distance of CO2 injection in a single well is 161-400 meters under different injection/production ratios during 1-year period.In conclusion,CO2 flooding can effectively improve gas recovery of watered gas reservoirs.The experimental results support the feasibility of CO2 injection to improve gas recovery in watered gas reservoirs,and provides a new technical route for efficient development of watered gas reservoirs.关键词
水淹气藏/注CO2驱/采收率/气藏能量/气体置换/水侵速度/采气速度/水体倍数Key words
Watered gas reservoir/CO2 flooding/Recovery factor/Gas reservoir energy/Gas replacement/Water invasion rate/Gas production rate/Water body multiple引用本文复制引用
高树生,叶礼友,刘华勋,朱文卿,程立华,安为国..柴达木盆地涩北气田水淹后注CO2驱提高采收率实验分析[J].天然气工业,2023,43(12):55-62,8.基金项目
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). （编号:2021DJ1705）
