准噶尔盆地玛湖凹陷百口泉组致密砂砾岩孔隙分形特征及影响因素探讨

致密砂砾岩储层孔隙结构复杂,孔隙类型多样,非均质性强,储层孔隙结构表征困难。基于高压压汞毛细管压力曲线,利用多种分形模型计算反映储层孔隙结构的分形维数,对比分析了分形维数与孔隙度、渗透率以及孔隙结构特征参数之间的关系。相比于J函数曲线分形模型与热力学分形模型,毛细管束分形模型计算的分形维数能更好地表征致密砂砾岩储层孔隙结构。进一步从岩石颗粒粒度、碎屑成分、黏土矿物及孔隙类型等多方面探讨分析了致密砂砾岩分形维数的影响因素。分析结果显示,碎屑成分与黏土矿物是影响分形维数的主要因素,孔隙类型多样及复杂程度是分形维数的直接表现。现场应用实例表明,试油产能越大,分形维数越小,产能与分形维数有着密切的关系,可以通过分形维数评价产能大小。基于致密砂砾岩储层孔隙分形特征,利用分形维数评价储层孔隙结构的方法为砂砾岩储层孔隙结构的评价提供了新的思路与研究途径。

Fractal Feature about the Pore Structure and Controlling Factor in Tight Glutenite Reservoir in Baikouquan Formation of Mahu Depression in Junggar Basin

T he tight glutenite reservoir has many chareateristics , such as the complex pore structures ,various types of pores ,strong heterogeneity ,difficult pore structure characterization . With the mercury injection capillary pressure curve , this thesis uses many fractal models to calculate the fractal dimensions of the tight glutenite reservoir .Then it analyzes the relationship between fractal dimension and porosity ,permeability ,pore structure characteristic parameter by the cross plot technique .It shows that the fractal dimension gained from the capillary buddle subsection model can better present the pore structure tight glutenite reservoir . Finally , the influence factors of fractal dimension are discussed in four aspects of rock grain‐size , clastic constituents ,clay mineral and stype of pore .It is denmonstrared that clastic constituents ,clay mineral are the influence factors of fractal dimension .The various types of pore and complexity are direct performance for fractal dimensions .The actual applications show that the greater oil production capacity ,the smaller the fractal dimension ,w hich has the close relation and through fractal dimensions oil production capacity is evaluated . It is based on the pore fractal characteristics ,which provides an effective and new research way for the evaluation of pore structure of the reservoir in the studied area .