塔里木盆地顺北地区超深层凝析油地球化学特征及其成藏过程  

Geochemical characteristics and accumulation process of ultra-deep condensate oil in the Shunbei area of Tarim Basin

作　　者：黄诚[1] 曹自成[2] 李海英[2] 朱莲花[1] HUANG Cheng;CAO Zicheng;LI Haiying;ZHU Lianhua(Exploration and Development Research Institute,Sinopec Northwest Oilfield Company,Urumqi,Xinjiang 830011,China;Oil and Gas Exploration Management Department,Sinopec Northwest Oilfield Company,Urumqi,Xinjiang 830011,China)

机构地区：[1]中国石化西北油田分公司勘探开发研究院,新疆乌鲁木齐830011 [2]中国石化西北油田分公司油气勘探管理部,新疆乌鲁木齐830011

出　　处：《世界石油工业》2025年第2期23-36,共14页World Petroleum Industry

基　　金：国家自然科学基金项目“碳酸盐岩走滑断裂带控储控藏机制研究”(U21B2063);中国石油化工集团有限公司科技部项目“顺北东部多类型储集体成藏主控因素与目标评价”(P23078)和“顺北超深碳酸盐岩高产富集规律与目标评价”(P21033-3)。

摘　　要：为了明确塔里木盆地顺北地区南部和东部凝析气藏中高丰度甾萜烷以及25-降藿烷类化合物的来源和成因机制,揭示其对油气成藏的意义,采用原油有机地球化学、宏观沥青观察以及流体包裹体分析等方法对顺北油田F5、F4、F8以及F12号断裂带12个凝析油样品及对应井岩心进行深入探究。研究结果表明,研究区凝析油处于成熟—高成熟度阶段,芳烃参数换算的等效镜质体反射率值在1.1%~1.5%之间。凝析油中可检测到高丰度甾烷和25-降藿烷类化合物,且藿烷峰型完整,说明生物标志物不受热演化控制。沥青和包裹体证据显示,该区奥陶系储层至少经历了加里东晚期、海西中晚期、喜马拉雅期三期油气充注。加里东晚期充注的原油遭受强烈生物降解,储层中有固体沥青及沥青包裹体。海西晚期和燕山—喜马拉雅期充注的成熟—高熟原油是主要油气来源。早期低熟油生物降解沥青和晚期中—高成熟油的混合使得凝析气藏普遍存在25-降藿烷。结论认为,塔里木盆地海西早期大范围构造抬升使加里东晚期古油藏的破坏程度远超以往认知,分布范围更广,不仅存在于塔北和塔中隆起构造高部位,而且在顺托果勒低隆起区构造低部位也广泛存在。该项研究成果对深入理解塔里木盆地加里东晚期—海西早期油气成藏及破坏过程具有重大意义,并且可以为顺托果勒低隆起区超深层油气勘探提供指导。Gas reservoirs in the southern and eastern Shunbei area of the Tarim Basin contain high abundance of steranes and 25-norhopanes.The origin and genetic mechanism of these steranes and 25-norhopanes are still unclear,and their significance for hydrocarbon accumulation needs to be revealed.In this paper,12 gas condensate samples and corresponding well cores from F5,F4,F8 and F12 fault zones in Shunbei area of Tarim Basin are selected for organic geochemistry,macroscopic asphalt observation and fluid inclusion analysis of crude oil.The results show that the gas condensate samples in the study area is generally in the mature-high maturity stage,and the equivalent vitrinite reflectance value converted by aromatic hydrocarbon parameters is between 1.1%and 1.5%.Not only high abundance of steranes and 25-norhopanes can be detected in gas condensate,but the hopanes still retain a complete peak shape,indicating that the biomarker in crude oil is not controlled by thermal evolution.The evidences of asphalt and fluid inclusions show that the Ordovician reservoirs in Shunbei area have experienced at least three stages of oil and gas charging in the late Caledonian,middle and late Hercynian and Himalayan periods.The crude oil charged in the late Caledonian has been strongly biodegraded,and solid bitumen and trapped bitumen inclusions can be detected in the reservoirs.The mature-high maturity crude oil charged in the late Hercynian and Yanshan-Himalayan periods is the main contribution of oil and gas in the Shunbei area.The mixing of early low mature oil from biodegraded asphalt and late medium-high maturity oil is the main reason for the prevalence of 25-norcholane in condensate gas reservoirs.It is concluded that the destruction of paleo-oil reservoirs in the late Caledonian caused by the large-scale tectonic uplift in the early Hercynian of the Tarim Basin is far more severe and widely distributed than previously recognized.It not only occurs in the high parts of the Tabei and Tazhong uplifts,but also widely develops in the l

关 键 词：顺北油气田 生物标志物 生物降解 25-降藿烷 油气充注 成藏期 塔里木盆地 

分 类 号：TE122.133[石油与天然气工程—油气勘探]