杭锦旗东部盒1段储层宏观非均质性与气藏类型关系研究

Relation between macro-heterogeneity of reservoir and gas reservoir types of He-1 Member in eastern Hangjinqi

针对鄂尔多斯盆地杭锦旗东部盒1段南部和北部砂岩储层宏观非均质性的差异性大及其与气藏类型的关系不明确的问题,以盒1段砂岩储层为研究对象,通过砂岩分类明确储层和隔层的识别标准,建立砂体组合样式。根据研究区储层发育特征,优选砂地比值、储地比值、隔层个数、隔层分布频数及分布密度表征盒1段储层宏观非均质性特征,对盒1段储层宏观非均质性与气藏类型的关系进行了研究。(1)将盒1段砂岩划分为3类,Ⅰ类储层箱型心滩微比Ⅱ类储层齿化箱型河道充填微相物性好;(2)建立了盒1段3种砂体组合模式,南部以Ⅰ类和Ⅱ类砂岩组合模式为主,北部以Ⅲ类砂体组合模式为主;(3)盒1段储层宏观非均质性呈现出南强北弱的特征;(4)南部储地比小于0.3,发育岩性气藏;北东部储地比大于0.3,储层连通性好,主要作为天然气运移通道,有利于形成构造气藏、构造—岩性复合气藏。整体上南部Ⅰ类储层含气性较北部好。研究结果表明:盒1段储层宏观非均质性南部强,北东部弱;储层宏观非均质性影响了气藏的类型,南部为岩性气藏区,北东部为构造—岩性复合气藏区,南部储地比小于0.3的Ⅰ类储层为井位部署有利目标区,为该区盒1段气藏勘探选区指明了方向。

In order to solve the problems of the difference in macro-heterogeneity between the southern and northern sandstone reservoirs in the southern and northern He-1 Member of Hangjinqi, Ordos Basin, and the unclear relationship with gas reservoir types, the He-1 sandstone reservoir is taken as the research object and its identification criteria for reservoirs and compartments are defined by sandstone classification. Then, the sand body combination style is establish. And according to the development characteristics of the reservoir in the study area, the ratio of reservoir thickness to formation thickness, the ratio of reservoir thickness to formation thickness, the number of barriers, and the frequency and density of barriers are selected to characterize the characteristics of macro-heterogeneity of He-1 Member. The relation between the macro-heterogeneity and gas reservoir types is discussed. The researches are conducted as follows.(1) The sandstone of the He-1 Member is divided into three types. The properties of the microfacies of box-shaped core beach in the type Ⅰ reservoir is better than that of the filling facies of the toothed box channel in the type Ⅱ reservoir.(2)Three sand body assemblage modes of the He-1 Member are established. The southern part is dominated by the assemblage modes of type Ⅰ and type Ⅱ sandbody, and the northern part is dominated by the assemblage modes of type Ⅲ sandbody.(3)The macro-heterogeneity of the reservoir in He-1 Member is strong in the south part and weak in the north part.(4) Lithological gas reservoirs are developed in the south part with the ratio of reservoir thickness to formation thickness of less than 0.3. While the ratio of reservoir thickness to formation thickness of the north-east part is greater than 0.3with good reservoir connectivity, which is mainly used as a natural gas migration channel and conducive to the formation of structural gas reservoirs and structural-lithological composite gas reservoirs. The gas-bearing capacity of type Ⅰ reservoirs in the south is better than that in the north. The conclusion is that the macro-heterogeneity of the reservoir of He-1 Member is strong in the south part and weak in the north-east part;the macro-heterogeneity of the reservoir affects the type of gas reservoirs, making the south part to be a lithologic gas reservoir area, and the north-east part to be a structure-lithological complex gas reservoir area.Type Ⅰ reservoirs with a ratio of reservoir thickness to formation thickness of less than 0.3 in the south part are the favorable target areas for well location deployment. It points out the direction for the selection of exploration area in He-1 gas reservoir.