鄂尔多斯盆地B192井中生界天然气形成条件探讨

鄂尔多斯盆地白豹地区B192井在中生界延长组长63层试油时获天然气约3万m3。通过对天然气成分分析,认为存在少量气顶气,同时生产过程中有大量溶解气游离析出增加了气量。根据烃类碳同位素值,判定天然气成因类型属于原油伴生气。B192井油气藏类型属于岩性油气藏,认为试油过程中大量天然气出现的原因是：生、储及保存条件有利,古今埋深反差大、低地饱压差使溶解气游离形成气顶,生产过程中流压过低则促使大量溶解气游离析出。

Discussion on Forming Condition of B192 Well in the Mesozoic Erathem of Ordos Basin

The Chang63 of the Yanchang Formation in B192 gained more than 3 ×104m3 gas in the process of testing for oil,the Mesozoic Erathern of Ordos Basin. According to composition analysis of B192 natural gas ,the conclusion is developed that a few gas cap gas being,and abundant dissolved gas dissociation increasing tolerance in the process of testing for oil. Carbonate isotope of CH4 indicated that the natural gas origin is crude oil associated gas.The type of B 192 hydrocarbon reservoir is lithology one. The causes of abundant gas in the process of testing for oil are considered that cruding, storing, and keeping is very favorableness, the great difference of oil bed embedding depth between the Cretaceous period and nowadays, and the small pressure difference between formation pressure and oil reservoir saturated pressure can urge dissolved gas dissociated and formed gas cap gas, the very low floating pressure can also urge dissolved gas dissociated in the process of testing for oil.