通过薄片鉴定,扫描电镜、物性和孔隙结构分析,对珠江口盆地白云凹陷珠江组深水扇储层特征、控制因素和分布规律展开研究.该深水扇沉积体系的储层主要为一套碎屑流沉积的灰色中-粗粒长石岩屑砂岩和中-细粒岩屑长石砂岩,储集空间以原生粒间孔为主,次为粒间溶孔和裂缝等,具有排驱压力及中值压力小,孔喉半径大、配位数高和分选好等好的孔隙结构,多数属于中-高孔高渗型储层.储层发育主要受陆架坡折带和沉积相控制,后者包括沉积微相、砂岩粒度和砂体发育规模在内的三要素.由于深水扇砂体较早地进入超压旋回,仅经历了相当于中等埋藏深度的早成岩阶段A→B期的成岩改造,对储层发育的影响不大,因此,储层预测可以砂体成因类型和发育规模为主要依据,以深水扇内扇和中扇分流水道为最有利的勘探开发目标.%Based on the thin section identification, scanning electron microscope, physical property and pore structures, this paper discusses the characteristics of the submarine fan sandstone reservoirs, their controlling factors and distributions of Miocene Zhujiang Formation in the Baiyun sag of Pearl River Mouth Basin in detail. The result shows that the reservoirs are mainly gray medium-coarse grained feldspathic litharenite sandstones and medium-fine grained lithic feldspar sandstones deposited by debris flow. The reservoir spaces include major primary intergranular pores, subordinate intergranular dissolution pores and fractures. The pore structures have small displacement pressure, small saturation median point pressure, big pore throat radius and big coordination number. Most of the reservoirs have high porosity and high permeability. The reservoirs are mainly affected by shelf break zones and lithofacies. The lithofacies further include the three factors of depositional microfacies, sandstone size and sandbody size. Because the submarine fan sandbodies have entered the superpressure cycle early, only suffered equivalent A→B stage of the early diagenesis in a moderate burial depth, and had little affects on the reservoir, therefore, the reservoir prediction can be based on the genetic type and size of sandbodies. The distributary channels of the inner fan and the middle fan can be taken as the most advantageous prospecting targets in the submarine fan.
展开▼
