垦东油田固井水泥浆技术

胜利垦东油田地层压力系数低,一般为0.9～1.0,600～700 m井段间还有浅气层,要求水泥浆返至地面,固井面临着封固段长、水泥用量大、易漏失憋泵、地温梯度低、水泥石强度发展慢、施工压力高、油气水易侵入造成窜槽等难题.该区块2003年固井30口(其中5口井经补救合格),合格率为93.3%,优质率为60%,固井质量严重威胁着油田的合理开采和产能建设.经室内实验研究和分析对比,优选出了水泥浆配方,并采取了相应的技术措施.现场应用表明,优选出的水泥添加剂相容性好,配伍性强,浆体性能优良,能防止对油层的污染,延长油井寿命;水泥石的渗透率低、强度高、韧性强,大大提高了固井优质率,现场固井20口,合格率达100%,优质率为80%.

Cement slurry technology for Kendong oilfield

In Kendong block of Shengli oilfield, because of characteristics of low formation pressure factor (generally 0. 9-1. 0) and presence of shallow gas-bearing formation in 600-700 m section, cement slurry is required to return to the surface in cementing job. Thus the cementing problems are involved in long cementing interval, large volume cement slurry to bumped in, easy lost circulation, delayed compressive strength development of cement stone, high operating pressure and easy oil/gas channeling. In 2003, 30 wells were cemented, though five of them were remedied to be qualified, the qualified ratio was only 93. 9%, and the excellent ratio was only 60%, which severely impeded the oilfield reasonable production progress. Based on lab study and comparison analyses, a cement slurry formulation was optimized, as well as the relevant technical measures. Field using indicated that the cement additives determined worked well with each other, the slurry was of excellent performance; the cement stone permeability was low, the compressive strength was high and the toughness was strong. The cement slurry was used in 20 wells, the qualified ratio was 100%, and the excellent ratio was 80%.