温度测井在东北冻土区天然气水合物勘查中的应用

摘要

冻土厚度是影响永冻区天然气水合物形成及分布的重要因素,准确地划分多年冻土层底板深度对东北冻土区天然气水合物资源勘查具有重要意义.文中利用温度测井曲线对冻土层的响应特征,建立了地温模型,并对研究区的8个天然气水合物勘查孔的实测温度曲线进行了研究,结果表明:①温度测井曲线在冻土层底板处存在明显的拐点,拐点以上曲线斜率小于拐点以下曲线斜率,可用于准确划分冻土层底板深度;②钻孔涌水或井液平衡时间太短,会影响温度测井的准确性;③日照时间长短影响冻土层发育深度.%The thickness of permafrost is an important factor for the formation and distribution of gas hydrate in permafrost areas.Recog nizing permafrost thickness accurately is significant for gas hydrate resource exploration in permafrost areas of Northeast China.Based on the characteristics of permafrost from temperature logging,the authors established the geothermal temperature model and carried out research on temperature logging data from the nine gas hydrate exploration holes.Some conclusions have been reached:(1) The temperature logging curve has an obvious inflection point at the bottom floor.The slope of the temperature logging curve above the inflection point is less than that under the inflection point.Using the temperature logging data can accurately recognize the permafrost bottom floor.(2) Too short hole over-flow water and drilling fluid equilibrium time can influence the accuracy of temperature logging data.The length of sunshine duration influences the development depth of permafrost.