基于自然伽马测井评估四川盆地磨溪地区沉积层生热率对地热的贡献  

Assessing the contribution of sedimentary layer heat generation rate to geothermal energy based on natural gamma logging in the Moxi area of the Sichuan Basin

作　　者：岳雯秀 何骁[2] 赖芳 杨文博 文绍牧[2] 管洪亮 罗玮琦 丁敬博 李忠权[1] YUE Wenxiu;HE Xiao;LA Fang;YANG Wenbo;WEN Shaomu;GUAN Hongliang;LOU Weiqi;DING Jingbo;LI Zhongquan(State Key Laboratory of Oil and Gas Reservoir Geology and Erploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China;PetroChina Southwest Oil&Gasfield Com pany,Chengdu,Sichuan 610051,China;Sichuan Railway Vocational College,Chengdu,Sichuan 611732,China)

机构地区：[1]成都理工大学地球与行星科学学院,四川成都610059 [2]中国石油西南油气田公司,四川成都610051 [3]四川铁道职业学院,四川成都611732

出　　处：《矿物岩石》2024年第4期193-205,共13页Mineralogy and Petrology

基　　金：四川省自然科学基金项目(编号:2024NSFSC0096)。

摘　　要：近年来,随着油气勘探开发的深入和对地热能资源的持续关注,岩石热物性的研究越来越受到重视。岩石的放射性生热率是岩石关键的热物理属性,对于深入探讨和研究沉积盆地的热状态具有极其重要的意义。与传统的分析技术不同,利用自然伽马(GR)测井数据,可以直接换算出生热率(A),高效简便。目前,四川盆地岩石热物性相关研究较少,磨溪地区仅寒武系龙王庙组初步估算的水热型地热资源量为5.94×10^(8)m^(3),地热能资源是四川省煤炭能源消耗总量的2.3倍,可见地热能的利用潜力是十分巨大的。因此,本论文选择以四川盆地磨溪地区作为研究对象,利用该区20口井的自然伽马测井曲线对区内沉积层生热率进行计算,共15070个生热率数据点,以此来评价沉积层生热率对本区大地热流值的贡献,为评估磨溪地区的生热能力及地热资源提供科学依据。研究发现,磨溪地区沉积层的平均生热率为0.855±0.311μW/m^(3),其中岩性是影响地层生热率的主要因素,页岩的生热率最高,平均为1.40μW/m^(3),泥岩次之,平均为1.35μW/m^(3),砂岩为1.08μW/m^(3),灰岩较低为0.99μW/m^(3),白云岩最低仅为0.40μW/m^(3)。岩石生热率对本区平均热流贡献为3.17mW/m^(2),贡献率为4.5%,这一增温效应在地热梯度中得到明显的反映,导致磨溪地区的平均地热梯度达到27℃/km,其中大约1.2℃/km是来自沉积层的放射性热产生的。The radiogenic heat production rate is a crucial thermal property of rocks,essential for under-standing the thermal state of sedimentary basins.This paper introduces a method for directly converting natural gamma ray(GR)data into heat production rates(A)using logging data,providing a more efficient and straightforward approach in relative to traditional analytical techniques.In the Moxi area of the Si-chuan basin,GR logging data from 20 key drilling wells were analyzed,yielding a total of 15,070 heat pro-duction data points within the sedimentary layers.The research indicates that the average heat production rate of the sedimentary layers in the Moxi area is 0.855±0.311μW/m.Rock type is identified as the pri-mary factor affecting the heat production rates,with shale exhibits the highest heat production rate(aver-age 1.40μW/m^(3)),followed by mudstone at 1.35μW/m^(3),sandstone at 1.08μW/m^(3),limestone at 0.99μW/m,and dolomite,which has the lowest rate(o.40μW/m').The contribution of radiogenic heat pro-duction to the average heat flow in the Moxi area is 3.17 mW/m^(3),accounting for 4.5%of the total heat flow.This warming effect is evident in the geothermal gradient,resulting in an average geothermal gradi-ent of 27℃/km.Of this,approximately 1.2℃/km is attributed to radiogenic heat generated within the sedimentary layers.

关 键 词：自然伽马测井数据 沉积层生热率 地热 

分 类 号：P314[天文地球—固体地球物理学]