黏弹性聚合物钻井液技术

Viscoelastic Polymer Drilling Fluid Technology

以自制的性能优良的黏弹性聚合物MVPP为基础,通过优选出配套的抗温降滤失剂,开发出了系列的无黏土、低黏土和中等含量黏土黏弹性聚合物钻井液体系。该体系具有优异的抗剪切稀释性和抗温抗盐性、良好的抑制性和润滑性,无黏土和低黏土体系抗温达180℃,中等含量黏土体系抗温达200℃;150℃的页岩回收率大于90%,8 h页岩膨胀高度不大于0.8 mm;润滑系数不大于0.10,泥饼黏附系数不大于0.016;API滤失量不大于5 mL。该黏弹性聚合物钻井液技术在胜利油田、川东北和新疆区块进行了30余口井的现场试验,该技术以抗温、抗盐、高密度、无黏土和低黏土为特色,可提高机械钻速,减少钻井液滤液对油层的侵害,保护油气层,降低钻井综合成本,实现安全、快速及高效钻井。

A clay-free, a low clay content and a medium clay content drilling fluids were formulated in laboratory with a new viscoelastic polymer MVPP and a high temperature filter loss reducer. The formulated drilling fluids have excellent shear thinning property, high temperature stability, salinity tolerance, and good inhibitive capacity and lubricity. The clay-free and low clay drilling fluids can be used at temperatures of 180 ℃, and the medium clay drilling fluid can be used at temperatures of 200 ℃. Tested at 150 ℃, the percent recovery of shale in a hot rolling test is greater than 90%. The length of shale cores increased by less than 0.8mm in 8 hours in swelling test. The friction coefficient of the formulated muds is not greater than 0.10. The sticking coefficient of the mud cake is not greater than 0.016. And API filter loss is not greater than 5 mL. The viscoelastic polymer drilling fluid has been used in more than 30 wells in Shengli, northeast Sichuan and Xinjiang. The mud is characteristic of high temperature stability, high salt tolerance, high density, no or low clay content, and is capable of increasing ROP and minimizing impairment of reservoirs by mud filtrates. It helps drill safely, fast and efficiently, and reduce the overall drilling cost.