石油学报 ›› 2011, Vol. 32 ›› Issue (4): 611-620.DOI: 10.7623/syxb201104008

• 地质勘探 • 上一篇    下一篇

胶莱盆地莱阳凹陷莱阳组低渗透砂岩储层特征及物性控制因素

周  勇 1  纪友亮 1  张善文 2  万  璐 3   

  1. 1中国石油大学油气资源与探测国家重点实验室  北京  102249; 2中国石化胜利油田分公司  山东东营  257061; 3中国石油东方地球物理勘探有限公司研究院  河北涿州  072751
  • 收稿日期:2010-09-09 修回日期:2011-01-08 出版日期:2011-07-25 发布日期:2011-09-22
  • 通讯作者: 周 勇
  • 作者简介:周 勇,男,1984年6月生,2007年毕业于中国石油大学(华东),现为中国石油大学(北京)在读博士研究生,主要从事储层地质学、沉积学及层序地层学方面的研究。
  • 基金资助:

    国家重点基础研究发展规划(973)项目(2006CB202302)资助。

Characteristics and controlling factors on physical properties of low-permeability sandstones of the Laiyang Formation in the Laiyang Sag, Jiaolai Basin

ZHOU Yong 1  JI Youliang 1  ZHANG Shanwen 2  WAN Lu 3   

  • Received:2010-09-09 Revised:2011-01-08 Online:2011-07-25 Published:2011-09-22

摘要:

以野外露头、岩心观察为基础,综合采用普通薄片、铸体薄片、阴极发光薄片、扫描电镜、物性分析、黏土矿物X射线衍射等多种测试手段,对胶莱盆地莱阳凹陷下白垩统莱阳组碎屑岩储层基本地质特征进行了分析。在此基础上,结合盆地构造活动、沉积特征、成岩特征研究了该碎屑岩储层物性的控制因素,探讨了低渗透砂岩背景下优质储层的形成条件。研究结果表明:胶莱盆地莱阳凹陷莱阳组砂岩以低成分成熟度、中等结构成熟度为特征,孔隙度一般小于10%,渗透率多小于1×10-3 μm2,为特低孔隙度特低渗透率储层。沉积作用是形成低渗透储层的最根本因素,它决定了后期成岩作用的类型和强度,成岩早期强烈的压实作用和胶结作用对形成低孔隙度低渗透率储层起了决定性作用;优质储层的形成主要受有机酸溶蚀作用、早期碳酸盐胶结作用、绿泥石环边胶结作用和后期构造活动的控制。其中后期构造活动是影响低渗透砂岩中有效储层发育的关键因素,白垩纪末期—新生代的构造抬升使孔隙得以保存,同时构造活动产生的微裂缝不仅可以作为油气储集空间,而且还可以作为油气运移的通道并改善储层的渗滤特征。寻找裂缝性储层是该区下一步油气勘探的方向和突破点。

关键词: 低渗透储层, 物性控制因素, 成岩作用, 构造活动, 裂缝, 莱阳组, 莱阳凹陷, 胶莱盆地

Abstract:

The present paper investigated basic geological characteristics of clastic reservoirs of the Laiyang Formation in the Laiyang Sag, Jiaolai Basin based on outcrop and core observations by applying various measurements, such as analyses of normal thin-sections, cast thin-sections and cathodoluminescence thin-sections, scanning electron microscope, X-ray diffraction of clay minerals. The paper dealt with controlling factors on physical properties of these reservoirs by combining the measurement results with tectonic activities, depositional and diagenetic characteristics of the basin, and discussed conditions for forming high-quality reservoirs on a background of low-permeability sandstones. The results demonstrated that the sandstones were characterized by low compositional maturity and medium textural maturity. They were tight reservoirs with ultra-low porosity and permeability (Φ<10% and K<1×10-3 μm2). Sedimentation was thought to be a fundamental factor that controlled the formation of such low-permeability reservoirs and determined types and intensity of the late diagenesis. The strong compaction and cementation during the early diagenesis played a key role in forming low-porosity and low-permeability reservoirs. The formation of these high-quality reservoirs was significantly affected by dissolution of organic acids, cementation of early carbonates, rim cementation of authigenic chlorites and later tectonism. Among which the later tectonic activity was the key factor affecting the development of effective reservoirs in low-permeability sandstones, and played an important role in improving physical properties of low-permeability sandstones. Uplifting in latest Cretaceous-Cenozoic allowed the preservation of some porosities, and microfractures produced by tectonism, on the one hand, created space for oil and gas accumulations, on the other hand, provided oil and gas migration pathway to improve the filtration of the low-permeability reservoirs. Therefore, the fracture reservoir is new targets and breakthrough point for further exploration in the Laiyang Sag.

Key words: low-permeability reservoir, controlling factors on physical property, diagenesis, tectonism, fracture, Laiyang Formation, Laiyang Sag, Jiaolai Basin