南海东方气田高密度抗高温钻井液完井液室内研究

南海东方气田地层温度高,储层渗透率低,钻完井过程中钻井液、完井液的高温稳定性及储层保护性能至关重要。针对该问题,通过滚动老化与配伍性试验优选了各类抗高温处理剂,研制出了高密度(2.2 kg/L)抗高温(170 ℃)的水基钻井液体系和甲酸铯无固相完井液体系。采用堵漏试验、岩心流动试验及流变性、滤失性测试等,评价了其综合性能。研究得出,高密度抗高温水基钻井液体系在高温高压条件下流变性、滤失性良好,高温高压滤失量小于15 mL,岩心渗透率恢复率达85%以上,极压润滑系数为0.131,抗盐、抗钙、抗劣土能力分别为5.0%,0.5%和8.0%;甲酸铯无固相完井液体系腐蚀速率仅为0.066 9 mm/a,页岩回收率为87.28%,岩心渗透率恢复率达88%以上。性能评价认为,研制的钻井液完井液体系能够满足海上高温高压气井的钻井要求,为南海东方气田安全高效开发提供了技术支持。 

Laboratory Research on High Density and High Temperature Drilling and Completion Fluids for Dongfang Gas Field in South China Sea

The high temperature stability and reservoir protection performance are key factors for the development of Dongfang Gas Field in the South China Sea which has high formation temperature and low-permeability reservoirs.In view of these problems,rolling aging test and compatibility test were used to sort out high temperature treating agents,and the high density (2.2 kg/L) high temperature resistance (170 ℃) water based drilling fluid and solid free cesium-formate completion fluid were developed.Core flow experiment,plugging experiment,rheology and filtration test were adopted to evaluate its comprehensive performance.According to the laboratory evaluation results,the high temperature and high density water based drilling fluid showed good rheological behavior under high temperature with filtration of less than 15 mL and the permeability recovery of more than 85%.Its tolerances to salt,calcium,poor soil contamination were 5.0%,0.5%,8.0% respectively and the extreme pressure lubrication factor was 0.131.The solid free cesium-formate completion fluid with the permeability recovery of more than 88%,and the rolling recovery of up to 87.28%.It could lower the corrosion of drilling tools to 0.0669 mm/a.So it is concluded that the drilling fluid and completion fluid can meet the demand of HTHP gas well drilling and provide technical support for safe and efficient development of Dongfang Gas Field.