鄂尔多斯盆地演武油田长3储层物性影响因素

FACTORS AFFECTING THE PHYSICAL PROPERTY OF CHANGE 3 RESERVOIR IN YANWU OILFIELD OF ORDOS BASIN

鄂尔多斯盆地演武油田长3储层物性特征及其影响因素研究相对薄弱,制约着油藏高效开发。利用106口井50块铸体薄片样品、50块扫描电镜样品、30块阴极发光样品及40块样品高压压汞等实验测试数据,研究演武油田长3储层特征及物性影响因素。研究表明,研究区以细砂及极细砂长石岩屑砂岩为主,孔隙类型主要为残余粒间孔、长石溶孔,面孔率分别为4.1%,3.4%,高压压汞测试表明Ⅰ类孔隙具有双孔隙结构特征;分流河道及水下分流河道的中-细粒长石岩屑砂岩储层物性较好,平均渗透率为10.2×10^(-3)μm^2,成岩作用中压实作用、胶结作用使原生孔隙度减少12.5%,10.9%,溶蚀作用使孔隙度提高8.9%,早成岩期粘土矿物的生长提高储层抗压实强度,绿泥石、高岭石的环边生长抑制石英加大,保护原生孔隙;晚成岩期碳酸盐矿物的生长堵塞孔喉,降低储层物性。通过物性影响因素分析旨在为沉积甜点分布及高效建产开发提供地质依据。

The poorly studied physical characteristics and its affecting factors over Chang 3 reservoir in Yanwu oilfield of Ordos Basin restrict the efficient development of oil and gas energy. Research of casting thin sections, SEM, X-ray diffraction and high pressure mercury experiment shows that the lithology in the area is dominated by fine sandstone and very fine feldspar lithic sandstone. The pore types in the sandstone are mainly composed of residual intergranular pore and feldspar dissolved pore, concentrated in middle pore and small pore with double pore structure characteristics. Early growth of chlorite and kaolinite enhanced the anti compaction strength of the rocks,while carbonate minerals blocked primary pores and reduced porosity and permeability of the rocks. The chlorite and carbonate minerals inhibited the secondary enlargement of quartz and preserved the original pores. The study of physical property and its affecting factors on the reservoir rocks provides geological basis for favorable targets of energy exploration and high efficient development of oil and gas field.