一种深水水基无黏土恒流变钻井液体系

Research on Constant Rheology Deepwater Drilling Fluid

深水钻井作业环境温度低,常规钻井液的使用已不能满足现场技术要求。室内研制出了一种不含膨润土的深水恒流变钻井液体系,该体系在不同测试温度下具有恒定的动切力、良好的触变性及剪切稀释性能,易形成平板流,携岩能力强。室内评价结果表明,研制的深水恒流变钻井液抑制效果佳,泥页岩回收率达95%以上,膨胀率小于10%,具有较强的抗盐岩污染能力及储层保护功能,可降低井内压力激动、ECD值及井眼钻井液漏失量,防止振动筛跑浆,改善井眼清洁,节约非生产作业时间。该技术还克服了海上利用膨润土配制海水钻井液存在水土分层、重晶石下沉等现象,可以满足海洋深水钻井的要求。

The operation of deepwater drilling is under low temperature environment,so the normal drilling fluid can not be used in that condition.In this paper,a constant rheology clay-free deepwater drilling fluid system is developed.The system has constant yield value,good thixotropic property,high cuttings carrying capability and strong shear dilution performance,which is easy to form flat-plate flow.The evaluation results indicate that the mud shale recovery rate is more than 95%,the expansion ratio is less than 10%.Additionally,it has strong capabilities of anti-pollution and reservoir protection.It can not only effectively reduce the surging pressure,ECD value and mud losses but also prevent mud running out of the vibrating screen and save non-production time.Moreover,this technology overcomes the problems of stratification and barite sinking.