松辽盆地三肇凹陷扶余油层致密储层分类精细评价

Classification and evaluation of tight reservoirs in Fuyu oil layer,Sanzhao Sag,Songliao Basin

精细评价的方法主要体现在精细分类和纵向细分层2个方面。通过沉积及砂体特征的精细研究,利用恒速压汞、高压压汞以及纳米微观分析等手段综合研究,认为扶余油层致密储层可以划分为2大类3小类,即Ⅰ-1,Ⅰ-2和Ⅱ类,其中致密油储层与常规储层的分界物性为孔隙度12%,渗透率1×10^(-3)μm^2,孔喉半径为350 nm;其余Ⅰ-1和Ⅰ-2类以及Ⅰ-2和Ⅱ类物性标准分别以孔隙度10%和8%,渗透率0.25×10^(-3)μm^2和0.1×10^(-3)μm^2为界,对应的孔喉半径分别为150 nm和75 nm。通过纵向细分层精细12分的砂层组级研究,每一层砂层组内仅含有1~2个砂体,I类致密油集中发育在FⅠ2-1,FⅠ3-1以及FⅡ2-2砂层组。在分层落实不同类型致密油剩余资源后,通过致密油水平井钻探及大规模体积压裂,可以有效开发致密油资源。

Fine evaluation is mainly embodied in two aspects： fine classification and vertical subdivision. The tight reservoirs in Fuyu oil layer can be divided into three categories, namely Ⅰ-1, Ⅰ-2 and Ⅱ combined with the study of sedimentary and sandbody characteristics, and by means of constant pressure mercury injection, high pressure mercury injection and nano microcosmic analysis. The boundary between tight oil reservoirs and conventional reservoirs is porosity 12%, permeability 1×10-3 μm2, pore throat radius 350 nm. The remaining Ⅰ-1 and Ⅰ-2 classes, as well as the Ⅰ-2 and Ⅱ standards, respectively, with the porosity of 10% and 8%, permeability of 0.25×10-3 μm2 and 0.1×10-3 μm2 as the boundary, corresponding to the pore throat radius of 150 nm and 75 nm. Each layer of the sand groups contains only 1-2 sand bodies based on the fine study of the longitudinal subdivision layer. Ⅰ class reservoirs mainly developed in FⅠ2-1, FⅠ3-1 and FⅡ2-2 sand groups. The remaining resources of different types of tight oil are implemented by layer, and through tight oil horizontal well drilling and large volume fracturing, tight oil resources can be explored effectively.