摘要
对鄂尔多斯盆地沿25区块、庄40区块长6油藏进行精细描述,指出微裂缝对提高储层的渗流能力,提高特低渗油藏开发水平具有十分重要的意义。阐述了特低渗透储层的岩块、显裂缝系统及其各自特征,指出显裂缝大致由三组裂缝组成。研究认为:岩块系统包括基质和微裂缝两部分,微裂缝一般长度小于200μm,规模小;两区块特低渗储层微裂缝呈条带状展布,且呈平行或雁式排列,具有明显的方向性,条带性随着岩性的变化而变化;可将微裂缝划分为有效缝和无效缝,有效缝对渗流起作用,无效缝充填方解石,对渗流不起作用。微裂缝和基质的储、渗性能差别很大,沿25区块微裂缝的储集能力是基质的0.0377倍,渗流能力是基质的42倍;庄40区块微裂缝的储集能力是基质的0.0337倍,渗流能力是基质的78倍。
Through the reservoir description in the areas of Yan 25 and Zhuang 40 in the Ordos Basin, it is pointed out that micro cracks are of great importance to increase the permeability and development level of low-permeability reservoirs. Firstly, the rock mass, macrofracture systems and their individual characteristics were described. Three sets of fracture made up the macrofracture system. The rock mass system is composed of two parts： matrix and micro cracks, and the micro cracks are less than 200 μm in length. Secondly, the characteristics of micro cracks were expounded. The microfractures are banded, and there are also parallel or echelon micro cracks, they have obvious directionality. The bands vary with lithological change. Effective and ineffective cracks can be divided, the former is favorable to percolation while the latter isn＇ t and both are packed by calcite. The difference in porosity and permea-bility between micro cracks and matrix is great. The storage ability of micro cracks is 0. 0377 multiple to that of matrix in Yan 25, and is 0. 0337 muhiple in Zhuang 40, the permeability ability of micro cracks is 42 multiple to that of matrix in Yan 25, and is 78 muhiple in Zhuang 40.
出处
《矿物学报》
CAS
CSCD
北大核心
2008年第2期215-220,共6页
Acta Mineralogica Sinica
基金
国家重点基础研究发展规划(973)项目(2003CB214600)
关键词
特低渗透油藏
显裂缝
岩块系统
微裂缝
微裂缝开度
裂隙率
微裂缝渗透率
ultra-low permeability reservoir
macro fracture
rock mass
micro crack
crack opening
cracking rate
micro crack permeability
