极地冷海浅层天然气水合物地层声学特性模拟实验研究  

Simulation study on acoustic characteristics of shallow gas hydrate formation in cold water area of the arctic

作　　者：王磊 胡志强[1] 柯珂 张辉 李莅临 闫莉 WANG Lei;HU Zhiqiang;KE Ke;ZHANG Hui;LI Lilin;YAN Li(SINOPEC Research Institute of Petroleum Engineering Co.,Ltd.,Beijing 102206,China;Collegeof Safety and Ocean Engineering,China University of Petroleum,Beijing 102249,China)

机构地区：[1]中石化石油工程技术研究院有限公司,北京102206 [2]中国石油大学(北京),北京102249

出　　处：《中国海上油气》2022年第4期218-224,共7页China Offshore Oil and Gas

基　　金：国家重点研发计划项目“极地冷海钻井关键技术研究(编号:2016YFC0303300)”;中国石化重点项目“天然气水合物钻完井关键技术与取心装备研制(编号:P20040—3)”;中国博士后科学基金项目“高温高压气井油套环空带压泄露点关键参数地面诊断技术研究(编号:2020M670584)”部分研究成果。

摘　　要：极地冷海区块巨厚冻土层下聚集的浅层天然气水合物地层在钻井过程中易分解,聚集喷发造成灾难性事故。为对钻井过程中冷海浅层存在的天然气水合物地层进行预测和识别,基于搭建的低温天然气水合物声学特性实验系统和人工水合物试样,研究了天然气水合物地层声波速度在不同参数条件下的变化规律,建立了浅层天然气水合物地层的声学特征响应模型,并对冷海浅层天然气水合物钻井风险进行评估。研究结果表明,浅层天然气水合物的声波速度与地层饱和度呈正相关,与地层孔隙度呈负相关,钻遇浅层天然气水合物地层风险分为红、橙、黄、蓝四个等级,其中红色风险等级最高,设计上应考虑重新制定井位,避免钻遇天然气水合物区域;通过开展针对冷海浅层天然气水合物地层风险评估,可以有效提高天然气水合物地层的识别精度,避免钻遇复杂地质灾害,能有效指导极地冷海安全高效勘探。The shallow gas hydrate strata accumulated under the super-thick permafrost in cold water area of the arctic are easy to decompose during the drilling process,and the accumulation and eruption will cause catastrophic accidents.In order to predict and identify the gas hydrate formation in the shallow cold sea during drilling,the low temperature gas hydrate acoustic characteristics simulation experiment system and artificial hydrate sample were developed,experiments on the variation law of acoustic velocity with different physical property parameter of low temperature gas hydrate formation were carried out,and a characteristic model of acoustic parameter response of gas hydrate formation was established,enabling a risk assessment for gas hydrate formation drilling in cold sea shallow layer.Results show that a positive correlation between p-wave velocity and gas hydrate saturation and a negative correlation with porosity exist,and the risk of drilling in shallow gas hydrate is divided into four risk level:red,orange,yellow and blue.The red zone has the highest risk rating,and the well design should consider relocating the site to avoid encountering gas hydrate zones by carrying out risk assessment of shallow gas hydrate formations in the cold sea.Through this risk assessment,the identification accuracy of gas hydrate formation can be effectively improved,so as to avoid drilling complex geological disasters and guide the safe and efficient exploration in cold water area of the arctic.

关 键 词：极地 冷海 浅层 天然气水合物 

分 类 号：TE52[石油与天然气工程—油气田开发工程]