高温高压下石英砂粒径对油井水泥石性能的影响  

The Effects of Particle Size of Silica Flour on the Performance of Oil Well Cement at High Temperature and High Pressure

作　　者：张国光[1] 王春雨 代丹[1] 姚晓[2] 陈为行 耿晨梓 胡方[1] ZHANG Guoguang;WANG Chunyu;DAI Dan;YAO Xiao;CHEN Weixing;GENG Chenzi;HU Fang(COSL Oilfield Chemical Research Institute,Yanjiao,Hebei 065201;College of Materials Science and Engineering,Nanjing Tech University,Nanjing,Jiangsu 211816)

机构地区：[1]中海油田服务股份有限公司油田化学研究所,河北燕郊065201 [2]南京工业大学材料科学与工程学院,南京211816

出　　处：《钻井液与完井液》2022年第4期466-471,共6页Drilling Fluid & Completion Fluid

基　　金：中海油田服务有限公司项目“水泥石热衰退规律研究”(G2017A-0521G523)。

摘　　要：在油井水泥中掺入石英砂是防止水泥石在高温高压下强度衰退的常用手段,通过在G级油井水泥中内掺35%不同粒径的石英砂,并在高温高压(240℃×21 MPa)下养护至180 d,来探究石英砂粒径对油井水泥石高温力学性能的影响。实验测试了加入不同粒径石英砂的水泥石的抗压强度和渗透率,分析了水泥石的水化产物和孔隙结构。结果表明,石英砂能够防止水泥石在高温下强度衰退,但是水泥石的抗压强度随石英砂粒径的减小而降低;掺入石英砂可降低水泥石的渗透率,石英砂的粒径越小,水泥石的渗透率越低。掺入较大粒径石英砂的水泥石中,生成的针状硬硅钙石较长,是水泥石具有较高抗压强度的主要原因。以300目35%加砂水泥为基础,复配其他外加剂形成高温高压水泥浆配方,在南海DX-11-2井应用,现场固井施工顺利,24 h时CBL和VDL测井显示固井质量优良。Silica flour is commonly used in oil well cement to prevent the strength retrogression of hardened cement paste at high temperature and high pressure. In this study, a class G cement slurry was mixed with 35% silica flour of different sizes and cured at high temperature and high pressure(240 ℃ and 21 MPa) for 180 d to study the effects of the silica flour particle size on the high temperature mechanical properties of the hardened cement paste. The compressive strength and permeability of the hardened cement paste containing silica flour of different particle sizes were measured, and the hydration products and pore structure were analyzed. It was found that silica flour prevented the strength retrogression of the hardened cement paste at high temperature, and the compressive strength of the hardened cement paste decreased with the decrease of silica flour particle size. Silica flour reduced the permeability of the hardened cement paste. The smaller the particle size of the silica flour, the lower the permeability. The cement slurry mixed with larger particle size silica flour produced longer needle-like xonotlite, which was the main reason why the hardened cemlent paste had high compressive strength. A high temperature and high pressure cement slurry containing 35% 300-mesh silica flour and other additives was used to cement the well DX-11-2 in the Nanhai oilfield. The well cementing operation was smoothly performed, and the 24 h CBL and VDL wireline logging showed that the cementing quality was excellent.

关 键 词：水泥石 石英砂 粒径 高温 高压 固井 固井质量 

分 类 号：TE256.6[石油与天然气工程—油气井工程]