摘要
柴达木盆地台南气田水平井出水已成为制约该气田稳产的主要因素。为破解上述难题,基于核磁共振测井解释技术,对储层束缚水饱和度分布特征进行研究,并结合该气田水平井投产初期的生产情况,确定投产即产出层内水的储层特征参数;通过岩心气驱水实验对束缚水产出的影响因素进行研究,通过隔夹层击穿实验开展隔夹层封隔能力的影响因素研究;采用数值模拟技术研究水平井在不同日产气量下,水平段长度对井底压力的影响;在此基础上,提出了该气田水平井出水防控对策。研究结果表明:①钻遇可动水饱和度大于7.2%、含气饱和度小于63.5%储层的水平井投产初期即会产出地层水;②泥质含量越低、生产压差越大越有利于束缚水的采出,平面非均质性较强的储层束缚水的产出是一个持续的过程;③隔夹层的封隔能力随夹层的垂向渗透率、含水饱和度减小而增强,随泥质含量、夹层厚度增大而增强;④泥质含量大于90%的Ⅰ类泥岩的突破压力约为4 MPa,泥质含量介于80%～90%的Ⅱ类泥岩的突破压力约为2MPa,泥质含量介于60%～80%的Ⅲ类泥岩的突破压力约为1.5MPa。结论认为,通过增加水平段长度和控制生产压差可以延缓边水侵入,延长气井无水采气期;水平井生产初期应均衡采气,生产过程中应加强动态监测,出水后应及时排水,以提高气井的累计产气量。
Water breakthrough in horizontal wells is now the main factor restricting the stable production of the Tainan Gas Field in the Qaidam Basin.In view of this problem,the distribution characteristics of irreducible water saturation were investigated by using the nuclear magnetic resonance logging interpretation technology.And combined with the production situations of the horizontal wells in Tainan Gas Field in the initial stage of their production,the characteristic parameters of the reservoir which produced the intrastratal water as soon as it was put into production were determined.Then,the factors influencing the production of irreducible water were studied by means of gas drive water core experiments,and the factors influencing the sealing ability of the interbeds were researched by conducting mudstone breakdown tests.What’s more,the effects on the bottom hole pressure by the length of horizontal section at different daily gas productions were investigated through numerical simulation.Finally,the prevention&control countermeasures for water breakthrough in horizontal wells were proposed.And the following research results were obtained.First,the horizontal well which drills into the reservoir with mobile water saturation higher than 7.2%and gas saturation lower than 63.5%produces formation water in its initial stage of production.Second,the lower the shale content is and the greater the production pressure difference is,the more favorable it is for the production of irreducible water.The production of irreducible water in the reservoirs with stronger areal heterogeneity is a continuous process.Third,the sealing capacity of the interbed increases with the decrease of its vertical permeability and water saturation and with the increase of its shale content and thickness.Fourth,the breakthrough pressure of typeⅠmudstone(shale content>90%)is about 4 MPa,that of typeⅡmudstone(80%<shale content<90%)is about 2 MPa,and that of typeⅢmudstone(60%<shale content<80%)is about 1.5 MPa.In conclusion,the edge water encroachment can be delayed and the water-free gas production period of gas well can be extended by increasing the length of horizontal section and controlling the production pressure difference.It is recommended to carry out balanced gas production in horizontal wells in the initial stage of production,enhance dynamic monitoring in the process of production,and drain the water in time in the case of water breakthrough so as to increase its cumulative gas production.
作者
杨云
顾端阳
连运晓
刘国良
韩生梅
常琳
马元琨
张勇年
Yang Yun;Gu Duanyang;Lian Yunxiao;Liu Guoliang;Han Shengmei;Chang Lin;Ma Yuankun;Zhang Yongnian(Exploration and Development Research Institute,PetroChina Qinghai Oilfield Company,Dunhuang,Gansu 736202,China;No.1 Gas Production Plant,PetroChina Qinghai Oilfield Company,Dunhuang,Gansu 736202,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2019年第5期85-92,共8页
Natural Gas Industry
基金
国家科技重大专项"疏松砂岩气藏长期稳产技术"(编号:2016ZX05015-004)
中国石油天然气股份有限公司科技重大专项"柴达木盆地老气区控水稳气及新气区高效开发技术研究"(编号:2016E-0106GF)
关键词
水平井
出水机理
束缚水饱和度
隔夹层
渗透率
非均质储集层
突破压力
柴达木盆地
台南气田
Horizontal well
Water breakthrough mechanism
Irreducible water saturation
Interbed
Permeability
Heterogeneous reservoir
Breakthrough pressure
Qaidam Basin
Tainan Gas Field
