鄂尔多斯盆地下古生界风化壳气藏差异性
Differential distribution of natural gas in the Lower Paleozoic paleokarst gas reservoir, Ordos Basin
魏新善 1魏柳斌 1任军峰 1蔡郑红 1周黎霞1
作者信息
- 1. 低渗透油气田勘探开发国家工程实验室,陕西西安710018;中国石油长庆油田公司勘探开发研究院,陕西西安710018
- 折叠
摘要
对鄂尔多斯盆地伊陕斜坡下古生界风化壳成储、成烃、成藏地质特征及分布规律研究表明,该盆地风化壳储层经历了准同生期层间岩溶、表生期风化壳岩溶及埋藏期局部热液改造,风化壳气藏气源来自上古生界、下古生界2套烃源岩生烃,其中上古生界煤系烃源岩是其主力烃源岩,伊陕斜坡风化壳气藏具有差异聚集分布的特征.靖西地区发育(常规)低渗透风化壳气藏,圈闭类型主要为岩性圈闭,储层类型以裂缝—白云石晶间(溶)孔为主,天然气以油型气为主,气藏分布不连续,有边底水,局部高产富集.靖边地区发育低渗透风化壳气藏,圈闭类型主要为古地貌—地层圈闭,储层类型以裂缝—孔洞型为主,天然气成因具有以煤成气为主,油型气为辅的混源气特征,气藏不合边底水,大面积连续分布.靖东地区发育致密风化壳气藏,圈闭类型主要为古地貌—地层圈闭,储层类型以裂缝—微孔隙为主,孔洞局部发育,天然气以煤成气为主,大面积普遍含气,但单井产能较低.气藏差异聚集主要受控于以下4个方面:①沉积微相是多类型储层发育的基础;②岩溶古地貌为风化壳储层发育创造了条件;③多源烃类有序聚集是天然气差异聚集的关键;④燕山期构造反转奠定了下古生界风化壳气藏差异分布的格局.
Abstract
The study on the geologic characteristics and distribution of hydrocarbon generation and accumulation in the Lower Paleozoic paleokarst reservoir in the Yishan Slope of Ordos Basin,indicates that the reservoir has undergone intraformational syngenetic karst,epigenetic karst development,and buried hydrothermal karst modification in the local area.The paleokarst gas pool was produced from the Upper Paleozoic coal-bearing source rock and the Lower Paleozoic marine source rock,and the Upper Paleozoic coal-bearing source rocks are the main source rocks,the Lower Paleozoic paleokarst reservoir has differential accumulation and distribution in the Yishan slope.Developments of(conventional)low permeability paleokarst gas reservoirs in the western Jingxi area,are mainly lithological traps,dolomit intercrystalline(dissolution) pore,oil-type gas,gas pool is not continuous,with edge water and bottom,local high yield and enrichment.Developments of low permeability gas reservoir in Jingbian area,are mainly palaeogeomorphic-stratigraphic traps,fractured-vuggy pore,coal-type and oil-type of mixture gas,no edge and bottom water,gas pool has large area continuous distribution.Developments of tight paleokarst gas reservoir in the eastern Jingdong area,are mainly palaeogeomorphic-stratigraphic traps,fract ured-micropores,localized vuggy pore,coal-type gas,but single well production capacity is low.The accumulation of gas reservoirs is mainly controlled by the following four aspects:(1)Microfacies are the basis for controlling the development of different types of reservoirs;(2)The paleokarst paleomorphology creates differential paleokarst reservoir;(3)The orderly accumulation of multi-source hydrocarbons is the key to the differential of natural gas;(4)The period of Yanshanian tectonic inversion laid the pattern of the distribution of gas pool.
关键词
鄂尔多斯盆地/奥陶系/差异聚集/风化壳/碳酸盐岩/成藏Key words
Ordos Basin/Ordovician/Differential accumulation/Paleokarst/Carbonate rock/Entrapment引用本文复制引用
基金项目
国家科技重大专项(2016ZX05004006)
出版年
2018
NETL
NSTL
维普
万方数据