深水钻井抗高温水基钻井液体系研究及应用

RESEARCH AND APPLICATION OF HIGH TEMPERATURE RESISTANT WATER-BASED DRILLING FLUID SYSTEM USED IN DEEP WATER DRILLING

深水钻井时存在易形成气体水合物、高温和低温并存对钻井液性能产生严重影响等问题。因此,为满足深水钻井作业的需要,通过对水合物抑制剂、抗高温增黏剂以及抗高温降滤失剂的优选与评价,研制了一套适合深水钻井施工的抗高温水基钻井液体系,并对钻井液体系的综合性能进行了评价。结果表明,该钻井液体系在低温到高温变化过程中黏度和切力变化幅度不大,仍能保持良好的流变性能;当钙膨润土的加量为15%时,钻井液体系仍能保持较好的流变性和较低的滤失量,具有良好的抗污染性能;钻井液体系的沉降因子在0. 5左右,具有良好的沉降稳定性;钻井液体系对储层钻屑的滚动回收率可以达到94. 5%,具有良好的抑制性。现场应用结果表明,S-1井钻井施工过程顺利,无井下复杂情况出现,说明该钻井液体系能够满足深水高温高压井的钻井施工需求。

In deep water drilling,gas hydrate is easy to form,and the coexistence of high temperature and low temperature has a serious impact on the performance of drilling fluid.Therefore,in order to meet the needs of deep-water drilling operation,a set of high temperature resistant water-based drilling fluid system suitable for deep-water drilling operation has been developed by optimizing and evaluating hydrate inhibitors,high temperature resistant viscosifiers and high temperature resistant filtrate reducers, and the comprehensive performance of the drilling fluid system has been evaluated. The results show that the viscosity and shear force of the drilling fluid system change little from low temperature to high temperature,and it can still maintain good rheological properties. The drilling fluid system can maintain good rheological property and low filtration rate when the addition of calcium bentonite is 15%,and has good anti-pollution performance;the sedimentation factor of the drilling fluid system is about 0. 5,which has good sedimentation stability;the rolling recovery rate of drilling fluid system to drilling cuttings can reach 94. 5% which has good inhibition. Field application results show that the drilling process of Well S-1 is smooth and there is no downhole complex situation,which indicates that the drilling fluid system can meet the drilling requirements of deep water high temperature and high pressure wells.