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得克萨斯州墨西哥湾沿岸渐新统费里奥组砂岩中广泛发育着由碳酸盐矿物和硅酸盐矿物,特别是钾长石溶解而形成的次生孔隙。普遍认为有机物质的脱羧作用生成的二氧化碳就是溶解作用所需要的酸。物质平衡计算指出,费里奥组页岩中有机物质脱羧作用产生的二氧化碳,只能在费里奥组砂岩中造成1%或2%的区域性平均次生孔隙率;然而计点数据却表明有平均为10%的次生孔隙率。因此,必须考虑有长距离的液体输送(数公里)和(或)其他产生酸的机制。地层水中的溶解状无机碳,天然气中的二氧化碳,以及碳酸盐胶结物中的碳同位素数据指出,脱羧作用所生成的二氧化碳对这些碳储集层的影响只是次要的。干酪根+水→甲烷+二氧化碳的反应能够解释这种同位素数据,但是,除非把长距离的物质输送计算在内,否则单独用来计算全部次生孔隙率是不够的。
Secondary pores formed by the dissolution of carbonate minerals and silicate minerals, especially potassium feldspar, are widely developed in the Oligocene Feirosian sandstone along the Gulf Coast, Texas. It is generally accepted that the decarbonation of organic matter produces carbon dioxide as the acid required for dissolution. Material balance calculations indicate that the carbon dioxide produced by the decarboxylation of organic matter in the Fellio Formation shale can only contribute 1% or 2% of the regional average secondary porosity in the Fellio Formation sandstone; however, There is an average of 10% secondary porosity. Therefore, liquid transport over long distances (several kilometers) and / or other acid-generating mechanisms must be considered. Dissolved inorganic carbon in formation water, carbon dioxide in natural gas, and carbon isotope data in carbonate cements indicate that the effect of decarbonation on the formation of these carbonaceous reservoirs is only of secondary importance. The reaction of kerogen + water → methane + carbon dioxide can explain this isotope data, but the calculation of total secondary porosity alone is not sufficient unless long-distance transport of material is taken into account.