随钻地震技术在莺歌海盆地高温高压地层钻井中的应用

The Application of Seismic while Drilling in High Temperature, High Pressure Reservoirs of the Yinggehai Basin

高永德 刘鹏 杜超 陈鸣 陈艳艳

GAO Yongde LIU Peng DU Chao CHEN Ming CHEN Yanyan

中海石油（中国）有限公司湛江分公司，广东湛江 524057 斯伦贝谢中国公司，北京 100015

Zhanjiang Branch of CNOOC (China) Limited, Zhanjiang, Guangdong, 524057, China Schlumberger China, Beijing, 100015, China

南海莺歌海盆地高温高压地层的钻井安全风险较高，为降低钻井风险，需要准确预测高压地层的压力和深度。为此，在预探井DF-X1井钻井过程中研究应用了随钻地震技术，利用随钻地震数据获得时深关系和地层层速度，实时更新钻头在地震剖面中的位置，确定钻头前方高压储层的深度和地层压力系数。在DF-X1井实钻过程中，应用随钻地震技术准确预测了高压储层A1砂体的地层孔隙压力系数、破裂压力系数和深度，高压储层A1砂体的预测深度与实钻深度相差仅6.00 m，确保了ϕ244.5 mm套管成功下到高压储层上部的泥岩中，确保了ϕ212.7 mm 井段的安全压力窗口；A1砂体孔隙压力系数和破裂压力系数的预测精度分别达到3.0%和1.0%，确保了该探井的顺利完钻。研究结果表明，随钻地震技术可以准确预测地层压力和高压储层深度，能有效降低钻井风险，提高作业效率。

There are high temperature, high pressure (HTHP) formations in the Yinggehai Basin in the South China Sea, and they are considered high-risk for safety when penetrating the HTHP formations. In order to reduce the drilling risk, it is necessary to accurately predict the pressures and at each formation depth. For this reason, the seismic while drilling technology was applied in the pre-exploration Well DF-X1. The technology uses seismic data while drilling to obtain the time-depth relationship and the formation velocity, and it updates the bit position on the seismic profile in real time, and thus it determines the high pressure reservoir depth and formation pressure coefficient in front of the bit. During the actual drilling of Well DF-X1, the seismic while drilling technology was used to accurately predict the pore pressure coefficient, fracture pressure coefficient and depth of the high pressure reservoir A1 sand body. The predicted depth error of A1 sand body was only 6.00 m with the actually drilled depth, which ensured that the ϕ244.5 mm casing was run into the mudstone above the high pressure reservoir. By using seismic while drilling, the prediction accuracy of A1 sand body pore pressure coefficient achieved 3.0%, and the accuracy of formation fracture pressure coefficient up to 1.0%. Based on this, the drilling fluid density of the completion section was optimized to avoid the gas cut and lost circulation, kept the successful drilling of the well. The research results showed that the seismic while drilling technology could accurately predict the formation pressure along with the depth of the targeted high pressure reservoir, thus effectively reduce drilling risk and improving operation efficiency.

国家科技重大专项课题“莺琼盆地高温高压天然气富集规律与勘探开发关键技术(三期)”（编号：2016ZX05024-005）资助

https://doi.org/10.11911/syztjs.2020049