触变早凝膨胀水泥浆体系在厄瓜多尔TAMBOCOCHA区块尾管固井中的应用

Application of Thixotropic Early-setting Expanding Cement Slurry in Cementing Liner String in Block TAMBOCOCHA, Ecuador

Tambococha区块位于厄瓜多尔亚马逊热带雨林腹地,是著名的“ITT”项目的重要组成部分,主力油层NAPOM1属于高孔高渗油气藏,油藏埋深在1500 m左右。针对前期尾管固井存在的油层封固质量差的问题,通过及时调整领浆密度、水泥浆稠度、减少降失水剂加量、减少胶乳的加量、引入早强触变剂等措施调整水泥浆配方,调整后的触变早凝膨胀水泥浆体系稠化时间、初终凝时间有所缩短,胶凝强度增大,胶凝强度发展速度加快。对调整后的水泥浆体系进行了8井次的现场应用,油层优质率为100%,尾管全井段优质率为95%以上,解决了该区块尾管固井存在的原始地层油水活跃、油层位置高的难题,为该项目后续尾管固井施工提供了技术支撑。

Block Tambococha,as an important part of the famous“ITT”project,is located near the center of the Amazon tropical rainforest in Ecuador.The major reservoir NAPOM1 is a high porosity high permeability reservoir with buried depth of about 1500 m.Poor liner cementing job quality has been met previously.To resolve this problem,the composition of the cement slurry was modified by changing the density of lead slurry and the consistency of the cement slurry,reducing the concentration of filter loss reducers and latex,and adding early strength thixotropic additives into the slurry.The cement slurry with modified composition had its thickening time,initial and final gelling time slightly shortened,while the gel strength was increased,and the gel strength of the cement slurry developed faster than the gel strength of the cement slurry prior to modification.Eight times/wells of application of this improved cement slurry gave 100%success rate of cementing job,more than 95%of the liner cementing job had high quality.The use of the cement slurry with modified composition resolved the problems encountered during cementing operation,such as active in-situ oil and water in the reservoirs and shallow oil bearing zones,providing a sound technical support to subsequent liner cementing operation.