苏东地区气藏水锁机理分析及水锁判识  

Mechanism analysis of the water blocking of gas reservoirs and its identification in eastern Sulige gasfield

作　　者：陈存良 梁艳 刘向前 南学龙 顾聪 CHEN Cunliang;LIANG Yan;LIU Xiangqian;NAN Xuelong;GU Cong(Xi'an Shiyou University,Xi'an Shanxi 710065,China;Gas Field Development Divisionof PetroChina Changqing Oilfield Company,Xi'an Shanxi 710018,China;Gas ProductionPlant 5 of PetroChina Changqing Oilfield Company,Xi'an Shanxi 710018,China)

机构地区：[1]西安石油大学,陕西西安710065 [2]中国石油长庆油田分公司气田开发事业部,陕西西安710018 [3]中国石油长庆油田分公司第五采气厂,陕西西安710018

出　　处：《石油化工应用》2019年第5期54-60,共7页Petrochemical Industry Application

摘　　要：苏东地区属于典型的低渗致密气藏,气田开发面临的突出问题是积液气井的比例不断上升,高液气比条件下水锁伤害更为严重,造成大量的气井产量明显下降甚至停产,严重影响了苏东地区气藏的有效开发。本文在充分调研前人研究的基础之上,深入分析苏东地区水锁产生的机理及模式,以储层特征和采气曲线形态为出发点研究总结气井水锁判识特征,为苏东地区提高气藏采收率,制定最优化的水锁预防及解除措施提供最科学的基础依据,为相似区块水锁判识及相应的水锁防治方案提供经验借鉴。研究结果表明:苏东地区气井水锁的主要原因有3个;根据储层特征及改造方式的不同,苏东气井水锁可总结为两种不同的水锁伤害模式,"上古生界储层水锁模式":以近井筒水相圈闭和储层远端水锁为主要形式,两者之间存在一个水锁堵塞区,"下古生界储层水锁模式":以近井筒水相圈闭与水锁为主要形式,水相圈闭和水锁区域没有明显界限。分析总结苏东地区近1 000口的生产曲线数据,梳理出4种类型的水锁判识特征曲线,提出储层水锁难易程度的判识和气井水锁效应判识(生产曲线特征)密切结合,才能保证气井水锁不漏判,才能为制定最优化的水锁预防及解除措施提供最科学的依据。There are typical low permeability tight gas reservoirs in the eastern Sulige gasfield,Ordos basin.The outstanding problems of gasfield development is that the proportion of gas wells with wellbore fluid is rising continuously.Under the condition of high liquid gas ratio, water blocking damage is more serious, resulting in a large number of gas production decreased or even discontinued.It has seriously affected the effective development of gas reservoirs in the eastern Sulige gasfield,Ordos basin.To provide the most scientific basis for improving the recovery efficiency of gas reservoirs and optimizing water blocking prevention and removal measures in the study area, the water blocking mechanism and models were an alyzed in detail based on the research of previous studies, the identification characteristics of water lock in gas wells are summarized based on reservoir characteristics and gas production curve.It provides experience reference for similar block water lock identification and corresponding water blocking prevention and control program.The results show that there are three main reasons of gas well water blocking in the study area.According to the reservoir characteristics and the transformation of different types, water blocking can be summarized as two different kinds of water blocking damage model."water locking model of Upper Paleozoic reservoir" mainly shows the water phase trapping in the near wellbore area and the water blocking of the distal reservoir, with the tight water blocking zone between them."The water locking model of Lower Paleozoic reservoir" mainly shows the water phase trapping near the wellbore area and water locking, and there is no obvious boundary between them.By analyzing and summarizing the production curve data of nearly 1 000 outlets in the eastern Sulige gasfield,four types of water blocking identification characteristic curves are sorted out.It pointed out that probability prediction of water blocking in reservoir and water blocking identification should be closely combined

关 键 词：苏东地区 致密气藏 水相圈闭 水锁机理 水锁判识 采气曲线特征 

分 类 号：TE311[石油与天然气工程—油气田开发工程]