贵州石头寨二叠系古油藏油气成藏期分析:流体包裹体与Sm-Nd同位素制约  

Analysis of the charge history of the Shitouzhai Permian paleo-oil reservoir,Guizhou,SW-China:fluid inclusion and Sm-Nd isotope constraints

作　　者：顾雪祥[1] 李葆华[2] 徐仕海[2] 付绍洪[3] 董树义[1] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]成都理工大学地球科学学院,成都610059 [3]中国科学院地球化学研究所,贵阳550002

出　　处：《岩石学报》2007年第9期2279-2286,共8页Acta Petrologica Sinica

基　　金：国家自然科学基金(40573031;40772060);国家重点基础研究发展规划(2006CB701402);地质过程与矿产资源国家重点实验室

摘　　要：贵州石头寨二叠系古油藏是滇黔桂地区众多上古生界生物礁型古油藏的典型代表。该古油藏发育了三期溶孔、裂缝充填方解石,其中含丰富的油气包裹体,三期油气包裹体组合依次为:少量液烃包裹体→液烃包裹体+气烃包裹体→气烃包裹体,与油气包裹体共生的气液水包裹体的均一温度分别为77℃～84℃、91℃～103℃和103℃～155℃。根据含油气包裹体的均一温度,结合沉积盆地热演化史和储层埋藏史,确定石头寨古油藏三期油气充注时间分别为238～235Ma、233～230Ma 和230～185Ma,第三期裂缝充填方解石的 Sm-Nd 等时线年龄为182±21Ma。古油藏的油气充注始于印支中期,于印支晚期至燕山早期达到高峰,燕山中晚期以来遭受破坏形成现今的残余古油藏。The Shitouzhai Permian paleo-oil reservoir in Guizhou province is a typical example of numerous Upper Paleozoic reeftype paleo-oil reservoirs in the Yunnan, Guizhou and Guangxi region. Three stages of pore and fissure filling calcites containing abundant hydrocarbon inclusions are observed. The association of hydrocarbon inclusions in the calcites of three stages is characterized by liquid hydrocarbon inclusions, liquid-gas hydrocarbon inclusions and gas hydrocarbon inclusions, respectively. The homogenization temperatures of saline aqueous inclusions coexisting with the hydrocarbon inclusions in the three stage calcites are 77℃ -84℃, 91℃- 103℃ and 103℃ - 155℃, respectively. Based on the homogenization temperatures, coupled with thermal and burial histories of the sedimentary basin and reservoir, three hydrocarbon charges are determined to be 238 - 235Ma, 233 - 230Ma and 230 - 185Ma, respectively. Sm-Nd isochon of the third stage fissure-filling calcite from the reservoir gives an age of 182 ± 21Ma. It is thus suggested that the hydrocarbon charge of the Shitouzhai reservoir began during the middle Indosinian and reached to a peak during the late Indosinian to the early Yanshannian. The destruction of the reservoir occurred since the middle to late Yanshannian.

关 键 词：流体包裹体 SM-ND同位素 成藏时代 古油藏 石头寨 

分 类 号：P618.130.1[天文地球—矿床学] P597.3[天文地球—地质学]