| 摘要: |
| 通过莺歌海盆地的烃源岩、温压特征及底辟活动规律研究,对水溶气出溶成藏的条件进行分析,并根据天然气的地球化学和同位素特征,研究水溶气出溶成藏的证据。结果表明:莺歌海盆地烃源岩气源供给充足,中浅层和深层天然气溶解度差异大,底辟构造周期性开启提供了流体向上运移的通道,具备水溶气运移出溶成藏的理想条件；在中浅层1.5～2.0km深度范围内,天然气干燥系数较大、异构烷烃与正构烷烃含量比值大、甲烷碳同位素组成偏重、芳烃富集,表明水溶气出溶成藏是中浅层气藏形成的重要机制之一；在底辟活动期间,深层溶解大量天然气的水沿着底辟形成的断裂运移至中浅层,由于温压大幅度降低,天然气从水中释放,进入到底辟上部或附近的圈闭中形成气藏。 |
| 关键词: 水溶气 出溶 莺歌海盆地 地球化学特征 成藏 |
| DOI：10.3969/j.issn.1673-5005.2014.01.005 |
| 分类号:TE 122.1 〖HTH〗 |
| 基金项目:“十二五”国家科技重大专项(2011ZX05023-004-008) |
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| Characteristics of water-soluble gas exsolution and accumulation in Yinggehai Basin |
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LIU Jiang-tao1,2, HUANG Zhi-long2, ZHU Jian-cheng3, TONG Chuan-xin3
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(1.SINOPEC Research Institute of Petroleum Engineering, Beijing 100101, China; ;2.State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249,China; ;3.CNOOC Zhanjiang Branch Company, Zhanjiang 524047,China)
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| Abstract: |
| Based on geochemical parameters and carbon isotope values of the natural gas, the exsolution and accumulation conditions of the water-soluble gas reservoir in Yinggehai Basin were analyzed through systematic analyses of the characteristics of the source rock, the temperature-pressure relationship and the diapiric action. The results show that Yinggehai Basin has perfect conditions for water-soluble gas accumulation, including a sufficient gas source, a very wide range of solubility between the mid-shallow layer and the deep layer, and a fluid pathway by periodic diapiric activities. In the mid-shallow layer (depth ranging from 1.5km to 2.0km), the natural gas reservoir is characterized by high dry coefficients, large content ratios of isoalkane and normal paraffin hydrocarbons, heavier methane carbon isotope δ13C, and abundant aromatic hydrocarbons. The exsolution and accumulation of water-soluble gas is one of the crucial mechanisms of gas reservoir formation in the mid-shallow layer in Yinggehai Basin. During diapiric activities, water dissolves a great deal of gas which migrates to the mid-shallow layer through faults formed by diapirs. The gas is released from water due to temperature and pressure drop, and enters into the traps in or near diapir belts to form gas reservoir. |
| Key words: water-soluble gas exsolution Yinggehai Basin geochemical characteristics accumulation |
