邦戈尔盆地潜山风化壳发育特征与主控因素分析

Characteristics and Main Controlling Factors of Weathering Crust Reservoirs in Buried-hill of Bongor Basin

邦戈尔盆地潜山储层为前寒武纪花岗质风化壳储层,风化壳储层岩性复杂,物性较差,储层类型多样。为明确潜山风化壳储层发育主控因素、建立风化壳储层评价标准,通过分析储层岩性矿物元素差异、储集空间类型和裂缝分布特征确定风化壳储层发育主控因素,并将主控因素进行级别定义和相互匹配,建立风化壳储层评价标准。结果表明:岩性是形成储层的宏观背景,风化淋滤作用是控制储层孔隙发育的基础,构造作用是影响储层裂缝形成的重要因素;花岗质风化壳储层可以划分为三大类,其中Ⅰ类储集性能最好,Ⅲ类最差。风化壳储层评价标准的提出可进一步为风化壳潜山储层的高效勘探开发提供更为准确的指导。

The buried-hill reservoir in Bongor Basin is the weathering crust of precambrain granite,and reservoir has complex lithology,poor physical properties and diverse types.In order to identify the main controlling factors of buried-hill weathering crust reservoir and establish evaluation criteria of weathering crust reservoir,the differences of lithologic mineral elements,the reservoir space type and fracture distribution characteristics were confirmed and the evaluation criteria of weathering crust reservoir could be established by defining the main controlling factors and matching with each other.The results show that lithology is the macroscopic background of reservoir,weathering and leaching is the basis of controlling reservoir pore development,and tectonism is an important factor affecting fracture formation.The granitic weathering crust reservoirs can be divided into three categories,of which the first type has the best reservoir performance and the third type is the worst.The proposed evaluation criteria of weathering crust reservoirs can provide more accurate guidance for the efficient exploration and development of weathering crust buried-hill reservoirs.