石油学报 ›› 2018, Vol. 39 ›› Issue (4): 365-378.DOI: 10.7623/syxb201804001

• 地质勘探 •    下一篇

库车前陆盆地深层高效致密砂岩气藏形成条件与机理

鲁雪松1,2, 赵孟军1,2, 刘可禹3, 卓勤功1,2, 范俊佳1,2, 于志超1,2, 公言杰1,2   

  1. 1. 中国石油勘探开发研究院 北京 100083;
    2. 中国石油天然气集团公司盆地构造与油气成藏重点实验室 北京 100083;
    3. 中国石油大学地球科学与技术学院 山东青岛 266580
  • 收稿日期:2017-07-17 修回日期:2017-10-25 出版日期:2018-04-25 发布日期:2018-05-03
  • 通讯作者: 鲁雪松,男,1982年11月生,2004年获石油大学(华东)学士学位,2009年获中国石油勘探开发研究院博士学位,现为中国石油勘探开发研究院石油地质实验中心高级工程师,主要从事油气成藏综合地质研究与实验分析。Email:luxs@petrochina.com.cn
  • 作者简介:鲁雪松,男,1982年11月生,2004年获石油大学(华东)学士学位,2009年获中国石油勘探开发研究院博士学位,现为中国石油勘探开发研究院石油地质实验中心高级工程师,主要从事油气成藏综合地质研究与实验分析。Email:luxs@petrochina.com.cn
  • 基金资助:

    国家科技重大专项(2016ZX05003-002)和中国石油天然气股份有限公司科技开发项目(2016B-0502)资助。

Forming condition and mechanism of highly effective deep tight sandstone gas reservoir in Kuqa foreland basin

Lu Xuesong1,2, Zhao Mengjun1,2, Liu Keyu3, Zhuo Qingong1,2, Fan Junjia1,2, Yu Zhichao1,2, Gong Yanjie1,2   

  1. 1. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
    2. CNPC Key Laboratory of Basin Structure and Hydrocarbon Accumulation, Beijing 100083, China;
    3. School of Geosciences, China University of Petroleum, Shandong Qingdao 266580, China
  • Received:2017-07-17 Revised:2017-10-25 Online:2018-04-25 Published:2018-05-03

摘要:

由于深层油气勘探成本高,因此钻前预测深层致密砂岩气藏的含气性显得尤为重要。库车前陆盆地深层致密砂岩气田具有高丰度、高含气饱和度、高压、高产、稳产的特征,为高效致密砂岩气藏。在对致密砂岩气藏含气性影响因素及机理的理论分析基础上,以库车前陆盆地深层大北、克深、迪北等高效致密砂岩气田为例,通过与四川盆地、鄂尔多斯盆地典型致密砂岩气藏的对比分析,探讨了库车深层高效致密砂岩气藏的形成条件与机理。结果表明,库车前陆盆地深层高效致密砂岩气藏的形成条件可归结为超压充注、裂缝发育、"早油晚气"成藏过程和优质保存条件4个方面。其中超压充注和裂缝发育是库车前陆深层高效致密砂岩气藏形成的最主要因素;优质烃源岩条件及其造成的高源储压差和超压充注是致密砂岩形成高含气饱和度的前提条件;裂缝发育控制了致密砂岩气藏的成藏、富集与高产;早期油充注对储层润湿性的改变有利于晚期天然气的充注,而优质膏盐岩盖层保存条件则是气藏保持超压和高含气饱和度的关键。这4个方面有利因素的匹配使库车前陆盆地能够形成有别于其他盆地的高丰度、高含气饱和度和高产的致密砂岩气藏。在致密砂岩储层基质物性相差不大的情况下,源储过剩压差、裂缝发育情况、保存条件和现今地层超压情况是深层致密砂岩气勘探评价中需要考虑的最主要因素。

关键词: 深层, 致密砂岩气, 含气性, 形成条件, 超压充注, 润湿性, 裂缝, 库车前陆盆地

Abstract:

Considering the high cost of deep oil and gas exploration, the pre-drill prediction on gas-bearing properties is particularly important for deep tight sandstone gas reservoir. Deep tight sandstone gas fields in Kuqa foreland basin have high abundance, high gas saturation, high pressure as well as high and stable yield, indicating the highly effective tight gas reservoir. Based on the theoretical analysis of influence factors and mechanisms of gas-bearing properties for tight sandstone gas reservoir, taking the tight sandstone gas fields with high effectiveness such as Dabei, Keshen and Dibei gas fields in Kuqa foreland basin as examples, this study conducts a comparative analysis on typical tight sandstone gas reservoir in Sichuan Basin and Ordos Basin, and explores the forming condition and mechanism of highly effective tight sandstone gas reservoir in Kuqa area. The results show that its forming condition can be concluded as four aspects, including overpressure charging, fracture development, "early-oil and late-gas" accumulation process and favorable preservation condition. Among them, overpressure charging and fracture improvement are the most important factors for the formation of highly effective tight gas reservoirs in Kuqa foreland basin. High-quality source rock conditions and the high source-reservoir pressure difference and overpressure charging induced thereby are preconditions for the formation of tight sandstone with high gas saturation. Fracture development controls the accumulation, enrichment and high yield of tight sandstone gas reservoir. The reservoir wettability changed by early oil charging is beneficial to late natural gas charging, and the preservation condition of high-quality gypsum cap rock is the key for gas reservoir to maintain overpressure and high gas saturation. The matching of above four favorable factors leads to the tight sandstone gas reservoir with high abundance, high gas saturation and high gas production in Kuqa foreland basin, which is very different from other basins. Under the condition of a little difference in physical property of tight sandstone reservoir, excessive source-reservoir pressure difference, facture development, preservation conditions and formation overpressure are the most significant factors to be considered in deep tight sandstone gas exploration and evaluation.

Key words: deep layer, tight sandstone gas, gas-bearing properties, forming condition, overpressure charging, wetting property, facture, Kuqa foreland basin

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