Due to the diversity of pore types, it is challenging to characterize the Middle East’s Cretaceous carbonate reservoir or accurately predict its petrophysical properties. In this paper, pore structure in the reservoir is first classified using a comprehensive method. Then, based on the identified pore structure types, a new permeability model with high prediction precision is established. The reservoir is dominated by 6 pore types, such as intergrain pores and moldic pores, and 6 rock types. Grainstone, algal packstone, algal wackestone, and foraminifera wackestone are porous rock types, and echinoderm wackestone and mudstone are nonporous rock types. The types of pore structure in the study area can be divided into four types. Type I has midhigh porosity and medium-high permeability due to its large throat, while type II has a fine throat type with midhigh porosity and midpermeability. Due to their isolated pores, the permeability is low in types III and IV, and out of these two, type III has better storage capacity. Movable fluid saturation calculated by the spectral coefficient method and can characterize the boundary between the connected pores and unconnected pores very well in the research area. It is not accurate enough to simply classify the pore structure by permeability and porosity. The combination of porosity, permeability, , flow zone indicator, and the reservoir quality index can effectively distinguish and classify pore structure types in noncoring wells. The characteristics of each pore structure type are consistent with those of the fractal dimension, which thereby proves the effectiveness of the pore structure classification. New permeability prediction models are proposed for different pore structure types, and good prediction results have been obtained. This study is of great significance for enhancing oil recovery.

中文翻译：

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北波斯湾盆地白垩纪碳酸盐岩储层孔隙结构特征及渗透率预测模型

由于孔隙类型的多样性，表征中东白垩纪碳酸盐岩储层或准确预测其岩石物理性质具有挑战性。本文首先采用综合方法对储层孔隙结构进行分类。然后，基于确定的孔隙结构类型，建立了具有较高预测精度的新渗透率模型。储层主要由6种孔隙类型（如粒间孔隙和发霉孔隙）和6种岩石类型构成。颗粒岩，藻泥岩，藻泥岩和有孔虫泥岩是多孔岩石类型，棘皮病泥岩和泥岩是无孔岩石类型。研究区域的孔隙结构类型可以分为四种类型。I型由于喉咙大而具有中高孔隙度和中高渗透率，II型为细喉型，具有中高孔隙度和中透性。由于它们隔离的孔，III型和IV型的渗透性较低，并且在这两种类型中，III型具有更好的储存能力。通过光谱系数法计算出的可动流体饱和度在研究领域可以很好地描述连通孔和非连通孔之间的边界。仅通过渗透率和孔隙率简单地分类孔隙结构是不够准确的。孔隙度，渗透性的组合，，流动区指示器，和储液质量指数可以有效地在noncoring阱区分和分类孔结构类型。每种孔隙结构类型的特征都与分形维数的特征一致，从而证明了孔隙结构分类的有效性。提出了针对不同孔隙结构类型的新渗透率预测模型，并获得了良好的预测结果。这项研究对提高石油采收率具有重要意义。