大油气区地质勘探理论及意义

Geological exploration theory for large oil and gas provinces and its significance

"十一五"期间,中国石油提出并形成了大油气区地质勘探理论,在这一理论指导下取得了一大批重大发现。大油气区是指同一大型构造背景上,由相似成藏条件决定、以某一种类型油气藏为主,纵向上相互叠加、横向上复合连片的大型含油气区,由多个油气藏(田)群或带构成。大型构造背景、良好烃源条件、广泛分布的非均质储集层3要素的有机配置是大油气区形成的关键。大油气区主要发育于陆相坳陷、前陆盆地和海相克拉通盆地的大型构造背景上,含油气面积大、储量规模大;油气藏类型相对单一,多以某一种类型油气藏为主;储集层大面积分布,但以低孔低渗储集层为主,非均质性强;油气分布不受局部构造控制,无统一油气水界面,油气水性质变化大。根据储集层岩类将大油气区划分为碎屑岩、碳酸盐岩、火山岩3大类,进一步划分为低孔渗碎屑岩岩性型、山前复杂高陡深层构造型、碳酸盐岩岩溶地层型、碳酸盐岩台缘礁滩型、火山岩地层型等5个亚类大油气区,并形成了集地震、钻井、测井、试油于一体的针对性关键配套技术。大油气区勘探强调"整体研究、整体勘探、整体控制"3个整体的勘探思路和"勘探开发一体化、上产增储一体化"两个一体化勘探评价方法,最大限度地提高勘探开发整体效益。

In the period of ＂11th Five-year Plan＂,PetroChina proposed and developed the geological exploration theory for large oil and gas provinces,under which a group of major discoveries have been achieved.Large oil and gas provinces are large oil/gas-bearing areas consisting of several groups or belts of reservoirs（oil/gas fields） under the same large structural setting,which are controlled by similar accumulation conditions,dominated by a certain type of hydrocarbon reservoirs,and overlaid vertically and connected horizontally.The combination of large structural setting,favorable source rock,and widely distributed heterogeneous reservoir is essential for formation of large oil and gas provinces.Large oil and gas provinces are mainly developed in large structures such as continental depressions,foreland basins,and marine craton basins,with large oil/gas-bearing area and considerable reserves.Oil and gas pools are mostly a single type.Reservoirs are widely distributed,mainly with low porosity and low permeability and high heterogeneity.Hydrocarbon distribution is not controlled by local structures and there is no uniform oil/gas/water contact but varying properties of oil,gas and water.Based on the reservoir lithology,large oil and gas provinces are divided into 3 types of clastics,carbonates and volcanics,which are subdivided into five sub-types,i.e.low porosity and permeability clastic;complex,steep and deep foreland structural;carbonate karst stratigraphic;carbonate platform margin reefal;and volcanic stratigraphic.Moreover,key technologies integrating seismic survey,drilling,logging and formation test have been developed.To maximize the benefit of exploration and development,the exploration in large oil and gas provinces stresses the concept of ＂overall study,overall exploration and overall control＂ and the evaluation method of ＂integrating exploration and development,integrating production expansion and reserve growth＂.