珠江口盆地开平凹陷A油田恩平组特低渗储层特征及主控因素  

Characteristics and Main Controlling Factors of Ultra-Low Permeability Reservoirs of Enping Formation in Oilfield A,Kaiping Sag,Pearl River Mouth Basin

作　　者：吴文娟 戴建文 王华 宋刚 文鑫 李潇 Wu Wenjuan;Dai Jianwen;Wang Hua;Song Gang;Wen Xin;Li Xiao(Shenzhen Branch of CNOOC Ltd.,Shenzhen Guangdong 518067)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518067

出　　处：《中外能源》2024年第12期41-47,共7页Sino-Global Energy

基　　金：中国海洋石油集团有限公司“十四五”重大科技项目“海上低渗及潜山油气田有效开发技术”(编号:KJGG2022-0702)。

摘　　要：以珠江口盆地开平凹陷A油田古近系恩平组储层为研究对象,综合利用铸体薄片、扫描电镜、物性分析、压汞实验等分析手段,对恩平组储层开展岩石学特征、成岩作用及储层主控因素研究。结果表明,恩平组主要发育辫状河三角洲沉积体系,岩石类型以长石岩屑砂岩和岩屑砂岩为主,恩平组上段主要为原生粒间孔、下段以粒间溶孔为主,整体为一套低—特低孔、低—特低渗储层。沉积作用和成岩作用共同控制储层质量。储层宏观上受控于沉积作用,沉积物中岩石粒度与储层物性呈正相关,即粒度相对越粗储层物性越好。凝灰质含量与储层物性呈负相关。成岩作用对储层的影响主要是强压实作用造成储层原生孔隙体积大量损失,同时多种胶结作用进一步影响孔隙体积、堵塞孔喉,进而降低储层物性;而溶蚀作用产生的次生孔隙有助于改善储层的孔隙度,但对渗透率的改善作用不明显。该地区优质储层受物源体系和水动力的影响,寻找具有稳定供源体系的优势相带应是下一步勘探的重点方向。The petrological characteristics,diagenesis,and main controlling factors of the reservoirs of the Enping Formation in Oilfield A of Kaiping Sag in the Pearl River Mouth Basin were studied using casting thin slices,scanning electron microscope,physical property analysis,and mercury injection test.The results show that a braid river delta sedimentary system developed mainly in the Enping Formation with feldspar lithic sandstones and lithic sandstones.The Enping Formation is a set of low-ultra-low porosity,low-ultra-low permeability reservoirs with primary intergranular pores in the upper part and intergranular dissolved pores in the lower part.Sedimentation and diagenesis control reservoir quality together.The reservoir is controlled by sedimentation macroscopically,and the grain size of the rock in the sediment is positively correlated with the physical properties of the reservoirs,that is,the coarser the grain size,the better the physical properties of the reservoirs.Tuff content is negatively correlated with reservoir physical properties.The impact of diagenesis on reservoirs is mainly the strong compaction that causes a large loss of primary pore volume in the reservoirs.Meanwhile,various cementation processes further affect the pore volume and plug the pore throat,thus weakening the physical properties of the reservoirs.The secondary porosity produced by dissolution can improve the porosity of the reservoirs,but the improvement effect on permeability is not obvious.The high-quality reservoirs in this area are affected by provenance systems and hydrodynamics.Finding a dominant facies belt with a stable provenance system should be the focus of the next exploration.

关 键 词：开平凹陷 岩石学特征 沉积作用 成岩作用 储层物性 孔隙体积 

分 类 号：P618.13[天文地球—矿床学]