石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (3): 582-596.doi: 10.11743/ogg20220308

• 油气地质 • 上一篇    下一篇

微生物碳酸盐岩“三因素”控储地质认识和分布规律

沈安江1,2(), 胡安平1,2(), 张杰1,2, 王小芳1,2, 王慧1,2   

  1. 1.中国石油 杭州地质研究院,浙江 杭州 310023
    2.中国石油天然气集团有限公司 碳酸盐岩储层重点实验室,浙江 杭州 310023
  • 收稿日期:2021-04-17 修回日期:2022-03-10 出版日期:2022-06-01 发布日期:2022-05-06
  • 通讯作者: 胡安平 E-mail:shenaj_hz@petrochina.com.cn;huap_hz@petrochina.com.cn
  • 作者简介:沈安江(1965—),男,博士、教授级高级工程师,碳酸盐沉积储集层。E?mail: shenaj_hz@petrochina.com.cn
  • 基金资助:
    国家科技重大专项(2016ZX05004-002);中国石油天然气股份有限公司直属院所基础研究和战略储备技术研究基金项目(2018D-5008-03);中国石油天然气股份有限公司科技项目(2019-5009-16)

“Three-factor” driven microbial carbonate reservoirs and their distribution

Anjiang Shen1,2(), Anping Hu1,2(), Jie Zhang1,2, Xiaofang Wang1,2, Hui Wang1,2   

  1. 1.Hangzhou Institute of Petroleum Geology,PetroChina,Hangzhou,Zhejiang 310023,China
    2.Key Laboratory of Carbonate Reservoirs,CNPC,Hangzhou,Zhejiang 310023,China
  • Received:2021-04-17 Revised:2022-03-10 Online:2022-06-01 Published:2022-05-06
  • Contact: Anping Hu E-mail:shenaj_hz@petrochina.com.cn;huap_hz@petrochina.com.cn

摘要:

微生物碳酸盐岩是非常重要的油气储层,针对叠层石和凝块石碳酸盐岩比其他类型微生物碳酸盐岩和非微生物碳酸盐岩具有优质储层发育潜力这一科学问题,通过现代微生物碳酸盐沉积特征和现代盐湖碳酸盐沉积特征研究、微生物有机质早期低温降解和晚期热解生酸模拟实验、早期沉淀和交代白云石成因模拟实验,揭示了微生物碳酸盐岩因沉积物和沉积环境的特殊性,储层成因也有其特殊性,提出了“三因素”控储地质认识。①与其他类型微生物碳酸盐岩和非微生物碳酸盐岩相比,叠层石和凝块石碳酸盐岩具有更高的初始孔隙度和微生物有机质丰度,为储层发育奠定了物质基础;②微生物有机质早期低温降解和晚期热解生酸使初始孔隙在沉积后得以保存和进一步扩溶,这是叠层石和凝块石碳酸盐岩储层发育的关键;③早期白云石化有利于孔隙的保存,碳酸盐岩-膏盐岩体系微生物碳酸盐沉积易于发育早期沉淀和交代两类低温白云石,这是叠层石和凝块石白云岩储层主要发育于碳酸盐岩-膏盐岩沉积体系中的原因。这些认识为微生物碳酸盐岩储层分布预测提供了依据,也揭示了微生物碳酸盐岩储层比非微生物碳酸盐岩储层具有更佳的储层发育潜力。碳酸盐岩-膏盐岩沉积体系叠层石和凝块石发育相带是微生物碳酸盐岩储层有利分布区。

关键词: 早期低温降解, 晚期热解, 早期白云石化, 碳酸盐岩-膏盐岩沉积体系, 微生物碳酸盐岩

Abstract:

Microbial carbonates are very important hydrocarbon reservoirs. Stromatolite and thrombolite carbonates are commonly suggested to be better hydrocarbon reservoirs than other microbial and no-microbial carbonates. To check the truth of the suggestion, this study characterizes some modern microbial deposits and salt lake deposits, and performs simulated experiments of early degradation and buried pyrolysis of microbial organic matter, and genesis of dolomites by early precipitation and replacement. The results confirm the suggestion and reveal the uniqueness of microbial carbonate reservoirs with their special sediments and depositional setting. Three factors that control the formation of the reservoir are also proposed. (1) Compared with other microbial and no-microbial carbonates, stromatolite and thrombolite carbonates contain more original pores and microbial organic matter and therefore have a better material basis for becoming hydrocarbon reservoirs. (2) The production of organic acid by early degradation and later pyrolysis of microbial organic matter helps preserving and enhancing the original porosity, serving as a key factor for the development of stromatolite and thrombolite carbonate reservoirs. (3) Early dolomitization favors the preservation of pre-burial porosity and two types of low-temperature dolomitization (early deposition and replacement) tend to occur in carbonate-evaporite sedimentary sequences, which result in the development of stromatolite and thrombolite reservoirs in these sequences. The understanding is of great significance to the prediction of distribution of microbial carbonate reservoirs, based on which stromatolite and thrombolite zones are suggested to be promising hydrocarbon reservoirs in carbonate-evaporite sedimentary sequences.

Key words: early low-temperature degradation, late pyrolysis, early dolomitization, carbonate-evaporite sedimentary system, microbial carbonates

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