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现代地质 ›› 2020, Vol. 34 ›› Issue (06): 1193-1204.DOI: 10.19657/j.geoscience.1000-8527.2020.06.079

• 石油地质学 • 上一篇    下一篇

川东北元坝西地区须三段钙屑致密砂岩储层成岩作用与孔隙演化

王爱1(), 钟大康2,3(), 刘忠群1, 王威4, 杜红权4, 周志恒2,3, 唐自成2,3   

  1. 1.中国石化石油勘探开发研究院,北京 100083
    2.中国石油大学(北京) 地球科学学院,北京 102249
    3.中国石油大学(北京) 油气资源与探测国家重点实验室,北京 102249
    4.中国石化勘探分公司,四川 成都 610041
  • 收稿日期:2019-10-11 修回日期:2019-12-25 出版日期:2020-12-22 发布日期:2020-12-22
  • 通讯作者: 钟大康
  • 作者简介:钟大康,男,教授,博士生导师,工学博士,1961年出生,沉积学专业,主要从事储层地质学及沉积岩石学方面的教学及研究。Email:zhongdakang@263.net.
    王 爱,男,博士,1989年出生,地质学专业,主要从事储层地质学和沉积岩石学方面的研究。Email:wangai.syky@sinopec.com
  • 基金资助:
    国家科技重大专项“川东地区致密砂岩沉积特征及储层成岩作用研究”(2016ZX05002004-011);中国石油化工股份有限公司科技部项目“川东北须家河组储层评价与甜点预测技术”(P19012-2)

Diagenesis and Porosity Evolution of Calcareous Sandstone Reservoirs of Xu-3 Member in Western Yuanba of Northeastern Sichuan Basin, China

WANG Ai1(), ZHONG Dakang2,3(), LIU Zhongqun1, WANG Wei4, DU Hongquan4, ZHOU Zhiheng2,3, TANG Zicheng2,3   

  1. 1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
    2. College of Geosciences, China University of Petroleum, Beijing 102249, China
    3. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
    4. SINOPEC Exploration Company, Chengdu,Sichuan 610041, China
  • Received:2019-10-11 Revised:2019-12-25 Online:2020-12-22 Published:2020-12-22
  • Contact: ZHONG Dakang

摘要:

基于薄片观察、扫描电镜和物性测试等数据,分析了川东北元坝西地区须三段致密砂岩岩石学特征、成岩作用、孔隙类型和物性特征,建立其成岩序列和孔隙演化过程,为须三段致密砂岩的勘探开发提供思路。研究表明元坝西须三段主要由龙门山二叠系和三叠系碳酸盐岩母岩提供物源,发育辫状河三角洲平原—前缘细中粒钙屑致密砂岩,经历的成岩作用主要包括压实作用和压溶作用、方解石胶结作用、重结晶作用、溶蚀作用和破裂作用;其孔隙类型为晶间微孔隙、裂缝与溶蚀孔隙,孔隙度为0.41%~7.16%,渗透率为0.001 2×10-3~533.59×10-3 μm2。钙屑砂岩高钙屑含量的成分特殊性造成了典型的“强胶结强重结晶弱压实弱溶蚀”成岩特征,埋藏成岩的特殊性导致了钙屑砂岩孔隙和物性的特殊性。早期强烈钙质胶结导致钙屑砂岩压实作用弱,原生孔隙几乎损失殆尽,进一步导致其溶蚀作用也很弱;后期钙屑中的泥晶藻屑砂屑发生强重结晶作用形成晶间微孔,平均孔隙度只有2.0%,物性较差;钙屑砂岩的主要碎屑颗粒和胶结物均为具有脆性特征的碳酸盐矿物,在构造运动作用下容易产生裂缝,形成裂缝沟通大量的重结晶微孔、粒间溶孔、残余粒间孔的孔隙系统。

关键词: 钙屑砂岩, 成岩作用, 孔隙演化, 重结晶作用, 须三段, 川东北地区

Abstract:

Based on data of thin-section micropetrography, scanning electron microscopy (SEM) and physical property test, we analyzed the petrological characteristics, diagenesis, pore type and physical properties of the tight sandstone of Xu-3 Member in the western Yuanba area (northeastern Sichuan Basin). We established its diagenetic sequence and pore evolution process, which can shed light on the exploration of the Xu-3 Member tight sandstone. We show that the Xu-3 Member tight sandstone is mainly provided by the parent rocks of Longmenshan Permian and Triassic carbonate rocks, and was mainly developed in the braided river delta plain-deltaic front of medium-fine grained calcareous sandstone. Diagenesis of these sandstones includes mainly compaction and pressure dissolution, calcite cementation, recrystallization, dissolution and fracturing. The pore types include intercrystalline micropores, cracks and dissolved pores, with the porosity of 0.41% to 7.16% and permeability of 0.001,2×10-3 to 533.59×10-3 μm2. The uniquely high-Ca content of the calcareous sandstone may have formed the typical diagenetic characteristics of strong cementation and recrystallization, but weak compaction and dissolution. The unique burial diagenesis has formed the special pores and physical properties of the calcareous sandstone. Early intensive calcite cementation may have resulted in weak compaction of calcareous sandstone, almost loss of primary pores, and weak dissolution. In the later stage, recrystallization of the muddy algae sands in the calcite chips formed many intercrystalline micropores. Average porosity of the calcareous sandstone is only 2.0%, and the physical properties are poor. The detrital particles and cement of the calcareous sandstone are mainly carbonate minerals with brittle characteristics. Under tectonic movements, cracks are readily formed which connected the pore system to communicate a large number of recrystallized micropores, intergranular dissolved pores, and residual intergranular pores.

Key words: calcareous sandstones, diagenesis, porosity evolution, recrystallization, Xu-3 Member, northeastern Sichuan Basin

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