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苏北盆地具有形成大型ＣＯ２气田的地质条件，黄桥ＣＯ２气田是目前我国陆地开发利用最大的ＣＯ２气田之一，它具有海相层系与共同成藏、深层气藏和浅层气藏互相沟通的特点。深层气藏以高纯度ＣＯ２为主，浅层气藏以含Ｎ２为主，并含有高浓度的Ｈｅ。浅层气藏是深层气藏衍生的产物。ＣＯ２气藏圈闭于由海相中、古生界层系组成的大型背斜中，海相碳酸盐岩（包括部分碎屑岩）裂隙发育、孔渗条件优越，是ＣＯ２成藏的重要储集岩。ＣＯ２

CHARACTERISTICS OF HUANGQIAO CARBON DIOXIDE GAS FIELD AND ITS EXPLORATION POTENTIAL

Subei Basin is of the geological conditions of forming large-sized carbon dioxide gas fields.Huangqiao carbon dioxide gas field is one of the largest carbon dioxide gas fields developed and utilized in the land of our country at present,being of the properties that its reservoirs are composed of marine strata and continental strata and the deep-lying gas reservoir is interconnected with the shallow one.The former is mainly carbon dioxide and the latter nitrogen,containing high-concentration helium,therefore the latter is the product derived from the former.The carbon dioxide gas reservoirs are trapped in a large-sized anticline being composed of marine strata of Mesozoic-Paleozoic.The marine carbonate rocks(including a part of clastic rocks)are the major reservoir rocks of forming the carbon dioxide gas reservoirs because of their developed fractures and excellent porosity and permeability conditions.The top of the carbon dioxide gas reservoirs is covered by Cenozoic-Mesozoic with a tremendous thickness which constitutes a regional cap formation over the gas reservoirs.Although the gas constituents in various gas reservoirs are obviously different from each other,all the constituents in various gas reservoirs and their isotope properties show that the gases in the reservoirs originated from magma-mantle basically.According to such a genetic mode,considerable carbon dioxide gas prospective reserves may be provided for exploration in Huangqiao region.