川东北地区异常高压形成的地温场背景  

The background of the geothermal field for formation of abnormal high pressure in the northeastern Sichuan basin

作　　者：卢庆治[1] 胡圣标[1] 郭彤楼[2] 李忠平[3] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国石化股份有限公司南方勘探开发分公司,昆明650021 [3]中国石化西南分公司勘探开发研究院,成都610081

出　　处：《地球物理学报》2005年第5期1110-1116,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40172100);中石化南方勘探开发分公司课题资助.

摘　　要：利用四川东北地区现有的钻井测温数据及测定的岩石样品热导率数据,计算了12口钻井的大地热流值.结果表明,川东北地区现今地温梯度为18～25℃km,平均21℃km,大地热流值介于41～57mWm2之间,平均为49mWm2.在此基础上,利用镜质体反射率(Ro)资料对研究区热史进行了恢复,认为研究区在255Ma左右古热流达到最高值(62～70mWm2),此后热流持续降低直到现今;研究区中-新生界不整合面的剥蚀厚度最大,可达约2100m;异常高压是在低热流的地温场背景下形成的.Based on available borehole temperature logging and thermal conductivity measurement of core samples in the northeastern Sichuan Basin, we have estimated 12 terrestrial heat flow values. The results show that the present-day geothermal gradients ranges from 18 to 25 ℃/km, with an average of 21 ℃/km, and that the present-day heat flow varies from 41 to 57 mW/m^2 , with a mean of 49 mW/m^2 . Thermal history reconstruction in the northeastern Sichuan basin using vitrinite reflectance data indicates that the paleo-heat flow reached the maximum values （62- 70 mW/m^2） around 255Ma, and then decreased till present. The maximum erosion occurred on the Mesozoic-Cenozoic unconformity and reached - 2100 m. The abnormal high pressure in the area was formed under geotemperature background characterized by low paleo-heat flow.

关 键 词：川东北 地温梯度 大地热流 热史恢复 剥蚀厚度 

分 类 号：P314[天文地球—固体地球物理学]