利用声波测井估算裂缝型水合物储层水合物饱和度  

Gas hydrate saturation estimation in fractured reservoirs with acoustic logging

作　　者：肖昆 邹长春[2] 邓居智[1] 卢振权[3] 张华 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,江西南昌330013 [2]中国地质大学(北京)地下信息探测技术与仪器教育部重点实验室,北京100083 [3]中国地质调查局油气资源调查中心,北京100029

出　　处：《石油地球物理勘探》2017年第5期1067-1076,共10页Oil Geophysical Prospecting

基　　金：中国地质调查局天然气水合物勘查与试采专项(GZHL20110313);东华理工大学博士科研基金项目(DHBK2015314);国家自然科学基金项目(41604086);江西省自然科学基金项目(20161BAB211029);江西省教育厅科技计划项目(GJJ150574)联合资助

摘　　要：水合物饱和度参数的准确计算对水合物资源量的评价至关重要。本文提出利用超声波测井资料与两端元层状介质模型相结合的方法,可有效评价祁连山冻土区钻孔地层的水合物饱和度变化特征,并在典型裂缝型水合物钻孔DKXX-19进行了应用。研究区钻孔地层裂缝内充填水合物体积分数的变化对纵、横波速度影响较大,而裂缝倾角的变化对纵、横波速度影响较小,可将利用两端元层状介质模型正演模拟得到的纵波相速度直接转换为纵波群速度;通过正演模拟识别出5个井段存在水合物;水合物赋存井段地层的水合物饱和度变化范围为14.1%~89.9%,平均值为69.4%,与现场观测结果接近。研究结果可为祁连山冻土区水合物地层测井评价和地震勘探提供理论依据和技术支撑。Accurate calculation of gas hydrate saturation is very important to gas hydrate resource evaluation.In this paper,we propose a gas hydrate saturation estimation in fractured reservoirs with acoustic logging.This approach combining ultrasonic logging data with two-component laminated media model can be effectively used to evaluate gas hydrate saturation characteristics of borehole formation in the Qilian Mountain permafrost.We apply it to a typical fracture-filling gas hydrate borehole DKXX-19.The change of gas hydrate volume fraction in fractured reservoirs in the study area has great influence on P-and S-wave velocity,but the change of fracture dip has small influence on Pand S-wave velocity.The P-wave phase velocity of the forward modeling by two-component laminated media model could be directly converted into the group velocity.The 5 intervals are identified as existing gas hydrate by the forward modeling.The range of gas hydrate saturations are between 14.1%~89.9% with an average value of 69.4%,which is close to the field observations.Our research results could provide an important reference for gas hydrate reservoir evaluation based on logging data and seismic exploration in the Qilian Mountain permafrost.

关 键 词：祁连山冻土区 裂缝 超声波成像测井 两端元层状介质模型 水合物饱和度 

分 类 号：P631[天文地球—地质矿产勘探]