鄂尔多斯盆地青平川油田长4+5储层特征与储层发育影响因素分析

RESERVOIR CHARACTERISTICS OF YANCHANG 4+5 MEMBER AND INFLUENCING FACTORS ON ITS DEVELOPMENT,QINGPINGCHUAN OILFIELD,ORDOS BASIN

对岩心观察、铸体薄片、扫描电镜和实验分析资料研究表明,青平川油田长4+5储层以细粒长石砂岩为主,成分成熟度低,结构成熟度中等。储集空间以粒间孔隙和溶蚀孔隙为主,属于低孔特低渗储层。分析认为,长4+5储层储集性能受沉积环境、构造作用以及成岩作用的综合影响,且以成岩作用较为突出。其中沉积环境是影响储层储集性能的地质基础,在宏观上控制着储层砂体分布和原始孔渗性;成岩作用中机械压实和胶结作用使孔隙大量减少,而溶蚀作用和构造作用形成的裂缝有效地改善了储层物性。

Some data obtained from the core observation, casting thin section, scanning electron microscope and experimental analysis of Yanchang 4+5 Member, Qingpingchuan oilfield, illustrates that (1) this reservoir mainly consists of fine-grained arkose with low mineral maturity and middle textural maturity; (2) its space is dominantly composed of intergranular and dissolution pore; and (3) it is a low-porosity and extra low-permeability reservoir. Also, it is considered that the reservoir performance is simultaneously impacted by sedimentary environment, tectonism and diagenesis, especially outstanding for diagenesis. Sedimentary environment is a geological base to impact this performance and macroscopically controls either sandbody distribution or original porosity and permeability. Diagenesis including compaction and cementation may reduce pores a lot. And fractures formed by dissolution and tectonism can effectively improve physical property.