盐沉析技术堵气窜实验  

An experimental study on gas-channeling blocking by salt precipitation

作　　者：金发扬[1] 田园媛[1] 蒲万芬[1] 袁成东[1] 郭勇 刘哲知[1] 

机构地区：[1]西南石油大学石油工程学院 [2]中海油服油田生产研究院

出　　处：《天然气工业》2013年第9期74-78,共5页Natural Gas Industry

基　　金：国家科技重大专项课题(编号:2011ZX05049-004-004);中央财政支持地方高校发展专项资金"石油与天然气工程国家一级学科"项目

摘　　要：注入气在地层中气窜是长期困扰注气开发油气田的技术难题，特别在高温（≥120℃）高盐（≥20×10^4mg／L）条件下，因凝胶、泡沫等堵气窜技术不满足恶劣的油藏条件，使得堵气窜变得更加困难。基于盐沉析理论和堵气窜提高波及体积原理，提出了盐沉析堵气窜技术。采用电镜扫描研究了盐结晶颗粒的微观结构，用单岩心和并联岩心流动实验，研究了盐沉析对气窜的封堵能力，并与水气交替和泡沫的堵气窜能力进行了对比，同时开展了盐沉析后的耐冲刷实验和解堵实验。结果表明：多层堆积的盐结晶颗粒使盐沉析对不同渗透率气窜层均有较好封堵能力，封堵率介于55．18％～68．34％，且盐沉析对气窜的封堵率分别比水气交替和泡沫高21．06％和19．27％；盐沉析具有良好的耐冲刷性、较好的选择性封堵能力和可解堵性，累积注入气20PV时封堵率仍大于50％，解堵后封堵率可降至3％。盐沉析堵气窜技术有良好的耐温、耐盐性和完善的堵气窜提高气驱波及体积优势，对解决恶劣油气田的气窜问题具有重要意义。Gas channeling of injected gas in the strata has been a bottlenecking problem in injecting gas and developing oil and gas fields. Gas channeling blocking is made more difficult due to the failures of gel, foam and other blocking means unable to meet unfavorable oil reservoir conditions, especially at high temperatures （≥120℃） and high salt contents （≥20× 10^4 mg/L）.To this end, gas-channeling blocking by salt precipitation was proposed based on the salt precipitation theory and the theory of improving swept volume by gas channeling blocking. A research was then made on the microstructure of salt grains by means of scanning electron mi croscope. Moreover, single core and double-parallel core flow experiments were conducted to investigate the shutoff ability of salt precipitation to gas. Additionally, comparisons, among salt precipitation, water-gas alternation injection and foam injection, were made to evaluate the gas blocking effect of salt precipitation. Subsequent experiments were carried out to access the washing resist ance and blocking removal after salt precipitation. The results demonstrated that salt grain precipitated can provide a good blocking rate （55.18 % - 68.34% ） for gas channeling of different permeability zones, which is 21.06 % and 19.27 % higher than water alternate gas injection and foam injection respectively. Salt precipitation is featured by good washing resistance as well as good selective blocking capacity and blocking removal capacity. Even when the injected gas volume reaches up to 20 PV, the blocking rate is over 50% and the blocking rate can be reduced to 3 % after the blocking solved. Also, salt precipitation has a complete capacity of improving the gas-driven swept volume of gas channeling blocking. Besides, salt precipitation can be applied to those reservoirs with high temperature and high salinity and is of great significance to serious gas channeling in oil and gas fields.

关 键 词：盐沉析 气窜 封堵 物模实验 注气 波及体积 机理 

分 类 号：TE358[石油与天然气工程—油气田开发工程]