西南石油大学学报(自然科学版) ›› 1999, Vol. 21 ›› Issue (1): 1-5.DOI: 10.3863/j.issn.1000-2634.1999.01.001

• 油气藏工程 •    下一篇

川西致密砂岩气层的工程地质特征与保护对策

康毅力1 罗平亚1 杨勇2 王平2

  

  1. 1.西南石油学院油井完井技术中心,四川南充637001;2.西南石油局第十一普查勘探大队
  • 收稿日期:1998-07-14 修回日期:1900-01-01 出版日期:1999-02-20 发布日期:1999-02-20
  • 通讯作者: 康毅力

ENGINEERING GEOLOGICAL CHARACTERISTICS OF TIGHT GAS SANDSTONE RESERVOIRS IN WESTERN SICHUAN BASIN AND STRATEGY OF FORMATION DAM-AGE CONTROL

Kang Yili1 Luo Pingya1 Yang Yong2 Wang Ping2
  

  1. Southwest Petroleum Inst
  • Received:1998-07-14 Revised:1900-01-01 Online:1999-02-20 Published:1999-02-20
  • Contact: Kang Yili

摘要: 为了揭示川西致密砂岩气层保护技术实施的工程地质条件,研究了川西致密砂岩气藏的工程地质特点:(1)发育多套气层,砂层厚度和规模差异显著;(2)地层压力剖面为超高压异常,呈现多个压力系统;(3)储层由浅部的近常规渐变为致密、超致密类型,基块毛管压力急剧升高;(4)裂缝发育非均质,微裂缝提供了致密砂岩储层的主要渗透性;(5)粘土矿物类型丰富,储层表现为强烈的水敏和碱敏性;(6)储层渗透率对应力变化异常敏感。致密砂岩气藏的工程地质特点决定了其损害机理显著地不同于常规油气层,保护技术措施更应强调针对性。分析表明,应用水平井技术、气体类工作流体或屏蔽式暂堵技术对裂缝性致密砂岩气层保护较理想。

关键词: 致密砂岩, 致密气, 工程地质, 四川盆地

Abstract: Formation damage has been recognizes as one of the key factors limiting the efficiency of exploration and development for natural gas in tight sandstones. A comprehensive research on the engineering geological conditions of tight gas sandstone reservoirs in western Sichuan Basin revealed the following characteristics:①existence of multiple pay zones differing markedly in thickness and areal extent;②abnormally high formation pressure and multi-pressure systems;③capillary pressure increasing sharply with increased burial and decreased permeability of the reservoirs;④fractures occurring heterogeneously,with microfractures being the major contributor of reservoir permeability;⑤strong water and alkaline sensitivity related to abundant clays, and⑥reservoir permeability being very sensitive to variations in stress conditions. Analyses indicate that horizontal wells, gas based working fluids, and temporary shielding techniques are suitable for the protection of such tight gas sandstone reservoirs.

Key words: tight sandstone, formation damage control, geological engineering, Sichuan basin

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