微米网凝胶暂堵技术在储气库的应用  

Micro-net gel temporary plugging and its application to UGSs

作　　者：张毅 杨东 张敏[1] 马越 陈立森 石小龙 ZHANG Yi;YANG Dong;ZHANG Min;MA Yue;CHEN Lisen;SHI Xiaolong(CNPC Bohai Drilling Engineering Company Limited,Tianjin 300450,China)

机构地区：[1]中国石油渤海钻探工程有限公司

出　　处：《天然气勘探与开发》2023年第3期77-83,共7页Natural Gas Exploration and Development

基　　金：中国石油渤海钻探工程公司重大专项“储气库可降解三元复合暂堵技术研究”(编号:2019ZD09K-03)。

摘　　要：储气库井进行各种施工前,为保证安全,必须对储层进行暂堵并经循环脱气、保证井内无气体后方可作业。油气井的暂堵方式有很多种,针对目前行业内较为先进的微米网凝胶暂堵技术,研究该项技术在储气库井的应用,主要解决储气库井暂堵后由于地层稳定性不强而导致的降解物返排效果差、渗透率恢复困难的难题。研究要点为:①在普通凝胶的基础上,通过与具有特殊结构的交联剂融合,最终形成对水分子存在显著空间位阻效应的微米网结构聚合物,从而提高凝胶体系的强度和稳定性。②在聚合物水溶液中加入六亚甲基四胺、双酚基丙烷、延缓交联剂和稳定剂,通过室内试验验证在90~170℃环境温度下恒温候凝3~70 h后,即能形成微米网凝胶。③通过试验室对微米网凝胶进行耐温、渗透率以及破胶3项性能试验,结果显示其性能满足储气库井暂堵、返排的要求。④对华北油田储气库苏49K-2X井应用微米网凝胶暂堵技术,作业完成后破胶的降解物实现顺利返排,保证了该井快速投入正常注采。研究结果表明:①微米网凝胶具有封堵有效期长、耐高温、破胶后液黏度较低、无残渣、破胶彻底、不会堵塞污染地层、不影响原始储层渗透率等诸多优点,微米网凝胶暂堵技术是一项适用于埋藏较深、高温枯竭型油气藏储气库的新型绿色封堵技术。②微米网凝胶暂堵施工前,应测定井温、开展试注,以防产生气侵而影响暂堵效果,且泵注排量设计冗余量,防止低分子溶液不能按时到达井中设计位置、在井中其他位置形成固体胶塞而影响暂堵效果。For a gas storage well,to temporarily plug reservoirs is needed before all its construction and ensure its gas free through cyclic degassing for safety reasons.There exist numerous modes of temporary plugging used in oil and gas wells.Among them,one technology of micro-net gel temporary plugging is more advanced.It has been applied to gas storage wells and can solve two problems on poor flowback of degradation products and difficult permeability recovery inferred from insufficiently stable formation after tem-porary plugging.In this study,conventional gel is blended with a crosslinking agent with special structure to form a micro-net polymer with a significant steric-hindrance effect on water molecules,thereby enhancing both intensity and stability of this gel system.Labora-tory experiments have proved that polymer solution can be added with hexamethylenetetramine,diphenylpropane,delayed crosslinking agent and stabilizer,and then held at constant temperature of 90°C–170°C for 3–70 h to ultimately form the micro-net gel.Experimen-tal tests demonstrate that the temperature resistance,permeability,and gel-breaking performance of this gel meet the requirements for temporary plugging and flowback in those gas storage wells.This technology of micro-net gel temporary plugging was applied to a gas storage well of Su49K-2X in Huabei oilfield.After that,degradation products generated after gel-breaking flowed back in success,en-abling this well fast putting into normal injection and production very well.Results show that(i)this kind of gel enjoys long effective plugging period,high-temperature resistance,low post-gel-breaking viscosity,no residue,complete gel-breaking,no formation clog-ging or contamination,and no impact on original reservoir permeability.The micro-net gel temporary plugging technology is a new environmental-friendly plugging option for deep and high-temperature UGSs rebuilt from depleted reservoirs;and(ii)before using this plugging,it is essential to measure well temperature and conduct trial inject

关 键 词：暂堵剂 凝胶 微米网 储气库 储层 渗透率 

分 类 号：TE972[石油与天然气工程—石油机械设备]