MTA方法防气窜固井技术在涩北气田的应用  

Application of the MTA method to gas-channeling prevention in well cementing in the Sebei Gas Field,Qaidam Basin

作　　者：顾军[1] 何吉标[1] 谯世均[2] 蒲继才 周福 张文平[1] 

机构地区：[1]中国地质大学(武汉)资源学院 [2]中国石油青海油田公司钻采工艺研究院 [3]中国石油青海油田公司监督监理公司 [4]中国石油西部钻探工程公司青海钻井公司

出　　处：《天然气工业》2014年第4期83-89,共7页Natural Gas Industry

基　　金：国家自然科学基金项目"钻井液/水泥浆不变条件下固井二界面泥饼固化机理与交联机制"(编号:51174180);"煤层气井内隔层界面抗剪切强度弱化效应与预测模型研究"(编号:40972103)

摘　　要：柴达木盆地涩北气田为第四系疏松砂岩气藏,气层分布段较长,浅层气窜问题突出,尤其是固井二界面的胶结质量难以保证.为此,拟采用在油井中成功应用的泥饼仿地成凝饼（mud cake to agglomerated cake,简称MTA）方法来解决气层段固井防气窜难题.该方法分为3个步骤：①分别对GM-Ⅱ型泥饼改性剂与钻井液流变性、GA-Ⅲ型凝饼形成剂与水泥浆稠化时间进行了室内评价,观察其对钻井液流变性、固井水泥浆稠化时间的影响;②钻开气层前在钻井液中缓慢加入一定量GM-Ⅱ型泥饼改性剂,并维持此比例至完井;③以GA-Ⅲ型凝饼形成剂为基础配制3 m3前置液,确保它与井壁泥饼的接触时间达到1.5～2 min.开展了6口井施工作业,生产现场固井施工一次成功率达100％,固井质量一次合格率达100％,固井一、二界面胶结质量优质率分别为95.16％～100％,80.01％～98.11％.采用MTA方法防气窜固井技术,可使固井二界面胶结强度大幅度提高6.53～23.21倍,为解决浅层气井固井质量问题提供了新的技术手段.The Quaternary unconsolidated sandstone gas reservoir was found with a long segment of distribution in the Sebei Gas Field,Qaidam Basin.Gas-channeling at the shallow strata is outstanding,especially the cementation quality of cement formation interface is difficult to meet the requirement.To this end,the mud cake to agglomerated cake （MTA） method,having been success-fully applied to the cementing of oil wells,was used for solving the gas-channeling of gas wells in this gas field.First,the effects of GM-Ⅱ type mud cake modifier on the drilling fluid rheology and GA-Ⅲ type agglomerated cake forming agent on the thickening time of cement slurry were evaluated and observed in experiments respectively.Second,a certain amount of GM-Ⅱ was added into the drilling fluid slowly before targeting the pay zone,and this proportion should be maintained until the well completion was implemen-ted.Third,the preflushing fluid （3 m3） is prepared based on the GA-Ⅲ agglomerated cake,and its contact time with the mud cake at sidewall was maintained for 1.5-2 minutes.The application results from six wells in the Sebei Gas Field showed that the one-time success rate of cementing operations reached 100% and the one-time qualified rate of cementing quality was 100%.The high quality rate of cementing quality at casing-cement interface and cement-formation interface reached 95.16 100% and 80.01-98.11%,respectively.By using the MTA method,the cementation strength at cement-formation interface was greatly increased by 6.53-23.21 times.It provides a new technical means for solving the cementing quality problem of shallow gas wells.

关 键 词：柴达木盆地 涩北气田 第四纪 砂岩气藏 固井 MTA方法 防气窜 泥饼改性剂 凝饼形成剂 

分 类 号：TE256[石油与天然气工程—油气井工程]