鄂尔多斯盆地上古生界气藏特征与成藏史研究

Petroleum accumulation feature and history of Upper Paleozoic, Ordos Basin

吴青 许化政 周新科 那未红

Wu Qing Xu Huazheng Zhou Xinke Na Weihong

中国地质大学(北京) 地学发展研究中心,北京 100083 中原油田 勘探开发研究院,河南濮阳 457001 中国石化集团 发展计划部,北京 100728 中国石化集团 国际石油勘探开发有限公司,北京 100083

Research Center of Geosciences Development, China University of Geosciences, Beijing 100083, China Research Institute of Exploration and Development, SINOPEC Zhongyuan Oilfield Company, Puyang, Henan 457001, China Development Planning Department, SINOPEC, Beijing 100728, China SINOPEC International Petroleum Exploration and Production Corporation, Beijing 100083, China

鄂尔多斯盆地煤系在埋藏早期因释放有机酸而使地层水呈弱酸性，含氧羧酸溶蚀铝硅酸盐生成大量孔隙而使砂岩易于压实，其后的地层升温促进Al3+和Si2+的络合物分解生成SiO2、自生粘土和铁方解石，导致砂岩区域致密化。晚侏罗—早白垩世的构造热事件导致煤系大量生烃和地层水汽化，促使高压流体（甲烷+水蒸气）充斥整个封存箱，形成盆地级高温高压气藏。晚白垩—古新世盆地区域性抬升剥蚀导致煤系埋藏变浅，地温梯度降低，使地层中甲烷被保留而水蒸气凝析成水，高温高压气藏逐渐转化为低温负压气藏。

During the early burial period, the ground water of coal series in the Ordos Basin became weakly acidic, due to the release of organic acids from coal. The corrosion of oxygen-containing carboxylic acid then generated a large number of pores in aluminum silicate and made sandstone easily to be compacted. The following rise of formation temperature promoted the Al3+ and Si2+ complexation reduce to SiO2, clay and ferrocalcite, which led to the regional sandstone densification. From the Late Jurassic to the Early Cretaceous, tectonic-thermal events resulted in the hydrocarbon generation of coal series and the vaporization of formation water, which promoted high-pressure fluid (methane and steam) flood the whole storage box. A basin-scale high-temperature and highpressure gas reservoir was founded. From the Late Cretaceous to Paleocene, the regional uplift and erosion of strata made the coal series burial depth decrease and the geothermal gradient decrease, so that vapor condensated into water, while the CH4 gas retained gradually. High-temperature and high-pressure gas reservoir was transformed into low-temperature and under-pressure reservoir.

https://doi.org/10.11781/sysydz201305505