松科二井取心钻进高温钻井液技术

High-temperature core drilling fluid technology of Well Songke-2

松科二井完钻井深为7108.88 m;完钻时停止钻井液循环后38 h,实测井底温度241℃。针对地层和温度情况,研究出了3种高温水基钻井液:抗温180℃的氯化钾聚磺钻井液;抗温230℃的高温聚合物钻井液;抗温250℃超高温的甲酸盐聚合物钻井液。其中,250℃钻井液以新型高温稳定剂为核心处理剂,凹凸棒土与钠膨润土黏土相,形成了新型甲酸盐聚合物体系。数据表明这几种钻井液具有良好的高温稳定性和较低的高温高压滤失量。工程现场的钻井液实验室结合取心作业特点,实时测试评价现场井浆的常规性能,同时监测井浆的抗温能力和高温流变性,根据实验数据和现场工况针对性的对井浆进行维护、调整,确保高温井段取心作业期间钻井液具有良好的性能。且在长时间裸眼、多次起下钻的工况下井壁稳定,测井、固井作业均得以顺利进行。各体系钻井液在转换时实现了安全平稳的过渡,极大的节约了成本。

The completion depth of Well Songke 2 is 7108.88 m.At the time 38h after the well completion,the bottom hole temperature was 241℃.Three kinds of drilling fluids were investigated in laboratory according to the formation and temperature conditions,and they respectively are the potassium chloride-polysulfonate system which is resistant to temperature of 180℃,the polymer drilling fluid which is resistant to 230℃and formate-polymer drilling fluid which is resistant to 250℃.The experimental data show that these drilling fluids have good high temperature stability and low HTHP filtration loss.Through detecting the quality of drilling fluid real time,the predicted problems could happen through over-temperature detection,which make indoor experiments to guide in-site maintenance in the project construction,ensure the stability performance at high temperature interval,and guarantee the coring operation smoothly.In addition,the drilling fluid of each system achieves a safe and smooth transition during the conversion,without any waste slurry,which greatly saves the cost.The logging and casing running before cementing could be successfully completed at one time,which further proves that the drilling fluid used has good high temperature stability.