石油学报 ›› 2014, Vol. 35 ›› Issue (3): 450-454.DOI: 10.7623/syxb201403005

• 地质勘探 • 上一篇    下一篇

高温高压碎屑岩储层中石膏溶解对方解石沉淀的影响

曹正林1,2, 袁剑英2, 黄成刚2, 魏志福3, 张世铭2, 王莹4, 佘敏4   

  1. 1. 中国地质大学海洋学院 北京 100083;
    2. 中国石油勘探开发研究院西北分院油藏描述重点实验室 甘肃兰州 730020;
    3. 中国科学院地质与地球物理研究所兰州油气资源研究中心 甘肃兰州 730000;
    4. 中国石油杭州地质研究院碳酸盐岩储层重点实验室 浙江杭州 310023
  • 收稿日期:2013-11-01 修回日期:2014-03-12 出版日期:2014-05-25 发布日期:2014-04-11
  • 通讯作者: 曹正林,男,1970年12月生,1994年获兰州大学学士学位,2002年获中国石油大学(北京)博士学位,现为中国地质大学(北京)博士后、中国石油勘探开发研究院西北分院高级工程师,主要从事沉积储层和石油地质综合研究工作。Email:caozl@petrochina.com.cn
  • 作者简介:曹正林,男,1970年12月生,1994年获兰州大学学士学位,2002年获中国石油大学(北京)博士学位,现为中国地质大学(北京)博士后、中国石油勘探开发研究院西北分院高级工程师,主要从事沉积储层和石油地质综合研究工作。Email:caozl@petrochina.com.cn
  • 基金资助:

    国家重大科技专项“前陆盆地油气成藏规律、关键技术及目标评价”(2011ZX05003)和中国石油天然气集团公司重大科技专项“柴达木盆地建设千万吨油气田综合配套技术研究”(2011E-03)资助。

Influence of plaster dissolution on calcite precipitation in clastic reservoirs under high-temperature and high-pressure conditions

Cao Zhenglin1,2, Yuan Jianying2, Huang Chenggang2, Wei Zhifu3, Zhang Shiming2, Wang Ying4, She Min4   

  1. 1. School of Marine Sciences, China University of Geosciences, Beijing 100083, China;
    2. Key Laboratory of Reservoir Description, Northwest Branch of PetroChina Research Institute of Petroleum Exploration and Development, Lanzhou 730020, China;
    3. Lanzhou Center for Oil and Gas Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China;
    4. Key Laboratory of Carbonate Reservoir, PetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, China
  • Received:2013-11-01 Revised:2014-03-12 Online:2014-05-25 Published:2014-04-11

摘要:

一般研究认为有机质演化过程中释放的有机酸会对碎屑岩储层中的方解石等易溶矿物产生溶蚀作用从而生成次生孔隙,进而增大岩石的储集空间和渗透性。但柴达木盆地红柳泉地区始新统下干柴沟组碎屑岩储层为咸化湖盆沉积,偏光显微镜下可见岩石薄片中石膏较为发育。通过流体-岩石动力学模拟实验研究得出,在地层条件下高温高压环境中石膏优先溶解进而使得方解石发生沉淀作用,且二者紧密相关。总体上,这一反应使得岩石的孔隙度和渗透率增大且孔隙结构变好,方解石的沉淀作用造成的储集空间的减小量小于石膏和长石等易溶矿物溶解造成的储集空间的增大量,因此,高温高压的地层条件下酸性流体与岩石的相互作用会对储层物性起到一定的改善作用。

关键词: 石膏, 方解石, 咸化湖盆, 溶解作用, 沉淀作用

Abstract:

It is generally believed that organic acids released from the evolution of organic matter can easily dissolve deliquescent minerals such as calcites in clastic rock reservoirs. This process will lead to the formation of secondary pores, thereby enlarging the reservoir space and improving the permeability of reservoir rocks. In the Qaidam Basin, however, clastic reservoirs of the lower Eocene Ganchaigou Formation are deposits of saline lacustrine basin, with plaster well developed in rock flacks as revealed by polarized light microscopy. Experimental results of fluid-rock dynamics stimulation show that plaster is preferentially dissolved under formation conditions of high temperature and high pressure, leading to calcite precipitation. There exists a close relationship between these two processes. Overall, mineral dissolution increases the porosity and permeability as well as improves the porous structure of reservoir rocks. The reservoir space taken by calcite precipitation is less than that released by dissolution of deliquescent minerals such as plaster and feldspar. Thus, the reactions between acid fluids and rocks can improve physical properties of reservoirs under high-temperature and high-pressure conditions.

Key words: plaster, calcite, saline basin, dissolution, precipitation

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