학술논문
塔中地区奥陶系油气充注特征及运移方向 / Ordovician hydrocarbon charging characteristics and migration direction in Tazhong area
Document Type
Academic Journal
Author
Source
石油学报 / Acta Petrolei Sinica. 39(1):54-68
Subject
Language
Chinese
ISSN
0253-2697
Abstract
油气充注特征及运移方向对于确认塔中地区奥陶系有利富集区至关重要.通过现有油气勘探成果、断裂体系特征等资料,利用常规测井、地震及地球化学等多种方法,对研究区目的层油气充注特征及运移方向开展深入研究.结果表明,塔中地区多期充注的原油与天然气均通过11个油气充注点注入奥陶系储层,进而沿NW—SE向发生局部运移,11个油气充注点均位于NW向逆冲断裂与NE向走滑断裂纵切形成的断裂交汇部位.油气点状充注特征及NW—SE向局部运移控制了原油与天然气相关参数的分布:靠近油气充注点,油气性质出现异常分布,自NW—SE向异常逐渐减弱,表现为随着距油气充注点距离的增大,油气充注强度变小,原油密度逐渐增大,原油Ts/(Ts+ Tm)指数、金刚烷指数(MDI)、TMNr指数、TeMNr指数逐渐减小,天然气干燥系数、气油比、油气产能逐渐减小,天然气甲烷碳同位素逐渐变轻.塔中地区奥陶系油气充注特征及运移方向研究表明,研究区目的层下一步油气勘探应更多聚焦于北部斜坡带西部,尤其是断裂交汇部位的上倾构造部位.
The hydrocarbon charging characteristics and migration direction is of great significance for determining the Ordovician favorable abundance zone in Tazhong Area.Through analyzing the data such as existing hydrocarbon exploration achievements and fault system characteristics,multiple methods of conventional logging,seism and geochemistry are used to carry out the in-depth research on the hydrocarbon charging characteristics and migration direction of the target stratum in the study area.The results show that multistage-charging crude oil and natural gas in Tazhong area were all injected into Ordovician reservoirs through 11 hydrocarbon charging points,and then locally migrated along the NW-SE trend.All the 11 hydrocarbon charging points are located in the fault intersection zone formed by the rip cutting between NW-trending thrust fault and NE-trending strike-slip fault.The distribution of the relative parameters of crude oil and natural gas is controlled by hydrocarbon charging points and NW-SE local migration.Adjacent to the hydrocarbon charging points,the hydrocarbon properties present abnormal distribution with NW-SE anomaly gradually weakening.It is shown that with the increasing of the distance away from hydrocarbon charging point,hydrocarbon charging intensity becomes smaller,crude oil density gradually increases,while Ts/(Ts + Tm)index,adamantine index (MDI),TMNr index and TeMNr index of crude oil gradually decline,as well as natural gas aridity coefficient,gas-oil ratio and hydrocarbon productivity;meanwhile,the methane carbon isotope of natural gas becomes gradually lighter.Finally,the study on Ordovician hydrocarbon charging characteristics and migration direction in Tazhong area shows that the further hydrocarbon exploration of target stratum in the study area should focus more on the west of northern slope belt,especially the updip tectonic position of fault intersection zone.
The hydrocarbon charging characteristics and migration direction is of great significance for determining the Ordovician favorable abundance zone in Tazhong Area.Through analyzing the data such as existing hydrocarbon exploration achievements and fault system characteristics,multiple methods of conventional logging,seism and geochemistry are used to carry out the in-depth research on the hydrocarbon charging characteristics and migration direction of the target stratum in the study area.The results show that multistage-charging crude oil and natural gas in Tazhong area were all injected into Ordovician reservoirs through 11 hydrocarbon charging points,and then locally migrated along the NW-SE trend.All the 11 hydrocarbon charging points are located in the fault intersection zone formed by the rip cutting between NW-trending thrust fault and NE-trending strike-slip fault.The distribution of the relative parameters of crude oil and natural gas is controlled by hydrocarbon charging points and NW-SE local migration.Adjacent to the hydrocarbon charging points,the hydrocarbon properties present abnormal distribution with NW-SE anomaly gradually weakening.It is shown that with the increasing of the distance away from hydrocarbon charging point,hydrocarbon charging intensity becomes smaller,crude oil density gradually increases,while Ts/(Ts + Tm)index,adamantine index (MDI),TMNr index and TeMNr index of crude oil gradually decline,as well as natural gas aridity coefficient,gas-oil ratio and hydrocarbon productivity;meanwhile,the methane carbon isotope of natural gas becomes gradually lighter.Finally,the study on Ordovician hydrocarbon charging characteristics and migration direction in Tazhong area shows that the further hydrocarbon exploration of target stratum in the study area should focus more on the west of northern slope belt,especially the updip tectonic position of fault intersection zone.