表面接枝C—S—H的岩沥青对高温油井水泥石力学性能的影响  

Effects of Rock Asphalt with Surface Grafted C—S—H on Mechanical Properties of Set Cement in High Temperature Wells

作　　者：王佳[1] 张春梅[1] 张晔 程小伟[1] 梅开元[1] WANG Jia;ZHANG Chunmei;ZHANG Ye;CHENG Xiaowei;MEI Kaiyuan(School of New Energy and Materials,Southwest Petroleum University,Chengdu,SiChuan,610500;No.1 Cementing Branch of Bohai Drilling Engineering Co.,Ltd.of CNPC,Renqiu,Hebei,062552)

机构地区：[1]西南石油大学新能源与材料学院,成都610500 [2]中国石油集团渤海钻探工程有限公司第一固井分公司,河北任丘062552

出　　处：《钻井液与完井液》2023年第6期806-814,共9页Drilling Fluid & Completion Fluid

基　　金：四川省科技计划省院省校合作项目“页岩气固井用天然岩沥青韧性油井水泥的研发及应用”(2021YFSY0056)。

摘　　要：研究了表面接枝C—S—H的岩沥青对高温油井水泥石力学性能和微观结构的影响,采用压力试验机及XRD、TG、SEM和EDS对油井水泥石的力学性能和微观结构进行了测试和表征。研究结果表明,与纯水泥石相比,掺入1%未改性岩沥青的水泥石3 d抗压强度下降了2.98%,而掺入1%表面接枝C—S—H岩沥青的水泥石3 d抗压强度提高了4.26%。物相分析和热重实验表明,表面接枝C—S—H岩沥青的加入不会引起水化产物类型的变化,而掺量为3%表面接枝C—S—H的岩沥青水泥石养护3 d的失重量比纯水泥石高1.01%,说明表面接枝C—S—H的岩沥青可以促进水泥的水化。水泥石的微观形貌和元素分析表明,未改性岩沥青在180℃下热解导致沥青颗粒破碎,而接枝C—S—H的岩沥青表面形成的富Si层可以避免沥青颗粒因气孔而引起破碎,使得未改性岩沥青水泥石界面处的C元素含量较接枝C—S—H的岩沥青水泥石高29.14%,未改性岩沥青水泥石基体中C元素含量较接枝C—S—H的岩沥青水泥石高13.76%。This paper discusses the studies conducted on the effects of rock asphalt with surface grafted C—S—H on the mechanical property and microstructure of set cement used to seal high temperature oil wells.Measurement of the mechanical property and characterization of the microstructure of set cement samples were done with pressure testing machine and XRD,TG,SEM and EDS,respectively.Study results obtained in laboratory experiments show that compared with pure set cement,the set cement containing 1%nonmodified rock asphalt had its 3-day compressive strength reduced by 2.98%,while the set cement containing 1%rock asphalt which surface grafted C—S—H had its 3-day compressive strength increased by 4.26%.Phase analysis and TGA experiment results show that the addition of the rock asphalt with surface grafted C—S—H into the cement slurry does not cause change of the type of the hydrational products.The weight loss of a set cement containing 3%rock asphalt with surface grafted C—S—H is 1.01%higher than the weight loss of the pure set cement after aging for 3 days,indicating that rock asphalt with surface grafted C—S—H has accelerated the hydration process of the cement.Analyses of the micromorphology and element composition of the set cement indicate that the nonmodified rock asphalt thermally disintegrated at 180℃and the particles of the asphalt were broken into pieces,while the rock asphalt with surface grafted C—S—H has formed an Si-rich layer around its surface,protecting the rock asphalt from generating air holes inside it and the asphalt particles are therefore not easy to break down.Furthermore,comparing the set cement containing nonmodified rock asphalt and the set cement containing rock asphalt with surface grafted C—S—H,it is found that the C element content at the interfaces of the former is 29.14%higher than that of the latter,and the C element content in the body of the former is 13.76%higher than that of the latter.

关 键 词：岩沥青 C—S—H晶种 化学接枝 油井水泥 高温固井 

分 类 号：TE256[石油与天然气工程—油气井工程]