页岩油气储层纵向多重非均质性及其对开发的影响

页岩油气作为烃源岩层系内自生自储的油气资源，其可开发性受页岩储层特征的控制明显。由于不同类型富有机质页岩形成环境的差异性，页岩油气储层在纵向上具有多重非均质性，包括岩性的纵向非均质性、储层物性的纵向非均质性、岩石力学参数的纵向非均质性、地应力的纵向非均质性以及含气性特征的纵向非均质性等，这造成了页岩油气储层的纵向非均质性明显强于横向非均质性，有机质丰度、孔隙度、渗透率、储层的可压裂性、地应力、含气性及吸游比等参数在纵向上的变化均较大，且直接影响了后期页岩油气开发方案的设计与实施。优质开发目的层段的选择首先要考虑单段页岩油气储层的连续厚度在30~50 m左右、有机碳含量均值达到2.0%以上、有效孔隙度大于2.0%、岩石泊松比小于0.25、脆性较大、最小主应力相对上下邻层较小、含气性较高的层段。页岩油气开发井型的选择，水平井段的部署，压裂分段的长短、射孔簇的设计等均要充分考虑这种非均质性的影响。

The multi-anisotropy of shale oil and gas reservoirs in vertical and its influence on oil-gas development

Shale oil and gas are a type of petroleum resource generated and accumulated in source rocks. The exploitability of this oil gas is obviously controlled by reservoir characteristics. The difference of depositional environment of various organic rich shale causes the multi anisotropy of shale oil and gas reservoir in vertical, including lithology anisotropy, reservoir properties anisotropy, anisotropy of rock mechanical parameters, group stress anisotropy and the anisotropy of gas bearing characteristics in vertical, which made the anisotropy of shale reservoir in vertical much stronger than that of shale reservoir in horizontal. The great variation of organic abundance, porosity, permeability, fracability, stress, gas bearing properties and ratio of free to adsorbed gas directly affects the design and implement of oil gas development strategies. The selection of advantaged objective layers for shale oil and gas exploitation should consider the following factors, including the single organic rich shale interval thickness (3050 m), TOC content with an average of >2.0%, high effective porosity (>2.0%), small poisson ration (<0.25), high brittleness, minor principle stress which is much smaller than other adjacent layers and good gas bearing properties. Moreover, the influence of this anisotropy must be fully considered for the selection of the types of shale oil gas development well, the design of horizontal drilling, the length of stage fracturing and the plan of perforation spacing.