珠江口盆地珠江组碳酸盐岩储层质量评价

岩芯观察、薄片鉴定及物性分析等研究表明，珠江口盆地东沙隆起惠州、流花和陆丰3个地区珠江组碳酸盐岩储层质量明显不同。惠州地区珠江组碳酸盐岩在成岩过程中发育多期次的胶结作用，强烈的胶结作用严重阻塞孔隙，面孔率大多小于1%，渗透率以小于1 mD为主，储层质量最差；广泛的不同期次的溶解作用使得流花地区以粒间溶孔、铸模孔、超大孔及晶洞孔等次生孔为主，孔隙度和渗透率值在3个地区中最高，孔渗分布显著正偏，显示良好的孔隙度渗透率关系，对于获得某一特定渗透率所需的较低的截止孔隙度值，储层质量最好；陆丰地区成岩早期发育的胶结作用有利于原生孔隙的保存，后期受到一定的溶解作用改造，但溶解作用远不及流花地区发育，孔隙构成以粒间孔、生物骨架孔、粒内孔等原生孔为主，原生孔相对较差的连通性使其孔隙度虽然与流花地区大致相当，但渗透率却要比流花地区低得多，获得相同渗透率所需要的截止孔隙度比流花地区高，储层质量中等。

Reservoir Quality Evaluation of Carbonates in the Zhujiang Formation of the Early Miocene Pearl River Mouth Basin

Core observation, thin section identification, and physical property analysis show that the carbonate reservoir quality of the Lufeng, Huizhou, and Liuhua areas in the Pearl River Mouth Basin is significantly different. The carbonate reservoir quality of the Huizhou area is the lowest of the three areas because of extensive cementation; the reservoir has a visual porosity and an average permeability below 1 mD. Extensive dissolution, including early meteoric and burial dissolution, generates a great amount of secondary porosity, such as intergranular pores, mold pores, alter-large pores and geode pores, in the Liuhua area, which contributes to more than 80% of the whole thin section porosity. The carbonates of this area have the highest porosity and permeability, high porosity and permeability correlation coefficient, and low cutoff porosity. Therefore, the best carbonate reservoir was developed in the Liuhua area. Early cementation is very helpful for the preservation of the primary porosity in the Lufeng area, where the dissolution is much weaker than in the Liuhua area, which makes the porosity in the Lufeng area approximately equal to that of the Liuhua area. However, its permeability is much lower than that of the Liuhua area due to the low connectivity of the primary porosity and the cutoff porosity is the highest. Thus, the Lufeng area is characterized by medium carbonate reservoir quality.