浅部地层自由套管外二次置换固井水泥浆体系研究  

Study on a Cement Slurry for Cementing Uncemented Shallow Section of Old Casing String by Secondary Displacement

作　　者：殷慧 柳华杰 崔洁[3] 张红卫 张洪旭 步玉环 柴德民 YIN Hui;LIU Huajie;CUI Jie;ZHANG Hongwei;ZHANG Hongxu;BU Yuhuan;CHAI Demin(Key Laboratory of Unconventional Oil&Gas Development,Ministry of Education,Qingdao,Shandong 266580;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580;Shengli Oil Production Plant of SINOPEC Shengli Oilfield Branch,Dongying,Shandong 257100;Engineering Technology Management Department of SINOPEC Northwest China Petroleum Bureau,Urumqi,Xinjiang 830011)

机构地区：[1]非常规油气开发教育部重点实验室(中国石油大学(华东)),山东青岛266580 [2]中国石油大学(华东)石油工程学院,山东青岛266580 [3]中石化胜利油田分公司胜利采油厂,山东东营257100 [4]中石化西北油田分公司工程技术管理部,乌鲁木齐830011

出　　处：《钻井液与完井液》2023年第2期216-221,共6页Drilling Fluid & Completion Fluid

基　　金：国家青年基金“水合物层固井水泥热能存储剂载体研制及承载机理研究”(51804332);国家面上基金“深水油气井固井水泥传质传热过程中浅层水合物稳定机理”(51974355)。

摘　　要：胜利油田经过了二十多年的开发,早期的开发井油层套管水泥面以上的套管腐蚀破坏严重,严重干扰正常生产。为此,拟对浅部地层自由套管段进行二次固井,可在修复套管密封失效的同时防止套管进一步腐蚀。针对环空二次固井注浆施工工艺特点,结合浅部地层松软的特点,在明确浅部地层自由套管外二次固井性能需求的基础上,对水泥浆体系进行开发。通过对胶凝材料体系、低黏触变剂、降失水剂和缓凝剂的研选,构建出一种低密度-低黏度-强触变-长稠化时间的固井水泥浆体系,其配方为:40%G级油井水泥+30%粉煤灰+30%矿渣+(20%~25%)低黏触变剂L-TA+2.5%聚乙烯醇降失水剂+(0.16%~0.32%)氧化锌+1%分散剂+0.5%消泡剂,水固比为0.56,水泥浆密度低至1.5~1.6 g/cm^(3),黏度小于50 mPa·s,稠化时间大于15 h,平均静切力差值为17.885 N/m2、且触变具有可重复性,满足东部老区浅部地层自由套管外二次固井作业的要求。In Shengli Oilfield,after more than 20 years’development,the production casing strings above the top of the set cement in some early development wells have been seriously damaged by corrosion,and this badly hinders the normal production of the oil and gas wells.To deal with this problem,it was proposed to conduct secondary well cementing to the free section of the production casing string in the shallow formations.This secondary well cementing not only repairs the integrity of the casing string,it also protects the casing string from further corrosion.Several factors were considered in developing the required cement slurry,such as the technical characteristics of cement slurry injection into the annulus,the nature of the shallow formations being soft,and the requirements of the secondary cementing operation outside the free section of the production casing string.A low-density low-viscosity strong-thixotropy long-thickening time cement slurry was formulated with carefully selected gel agent,low-viscosity thixotropic agent,fluid loss additive and retarder.The composition of the cement slurry is as follows:40%class G oil well cement+30%fly ash+30%slag+(20%-25%)low-viscosity thixotropic agent L-TA+2.5%polyvinyl alcohol fluid loss additive+(0.16%-0.32%)ZnO+1%dispersant+0.5%defoamer.Water/solids ratio of this cement slurry is 0.56.This cement slurry has a density that is as low as 1.5-1.6 g/cm^(3),viscosity of less than 50 mPa∙s,thickening time of longer than 15 h,difference of average gel strengths of 17.885 N/m2,as well as repeatable thixotropy.Field application proved that this cement slurry satisfied the requirements of the secondary cementing outside the free section of the casing string in the shallow formations in Shengli Oilfield.

关 键 词：自由套管外二次固井 水泥浆 低黏触变剂 降失水剂 缓凝剂 

分 类 号：TE256.6[石油与天然气工程—油气井工程]