摘要
针对南海西部涠洲1-1、乌石1-1、文昌1-1等3个典型低渗油藏的储层岩性不同导致微观孔喉结构特征与渗流规律存在明显差异的问题,选取研究区173块岩样的压汞实验数据并利用分形理论进行了不同岩性低渗储层分形特征的差异对比,同时结合铸体薄片实验进行了成因分析。涠洲1-1油田细砂岩储层发育原生粒间孔,分形曲线呈线性特征;乌石1-1油田砂砾岩储层原生孔与次生孔共生,长石溶孔发育,分形曲线呈“凹”形折线特征,随孔喉半径的增大,分形维数呈现“小-大-小”的特点;文昌1-1油田粉砂岩储层原生孔与次生孔共生,泥质、有机质对粒间孔隙的充填增加了孔喉结构的复杂性,分形特征曲线呈“凸”形折线特征,分形维数随孔喉半径增大而增大。通过对比相同孔喉尺度范围不同岩性储层的分形曲线,认为影响低渗储层渗流能力的主要因素是微观孔喉结构的差异尤其是较大尺寸孔喉的分形特征与所占比例,因此研究区3种岩性储层渗流能力由好到差依次为涠洲1-1油田细砂岩、乌石1-1油田砂砾岩和文昌1-1油田粉砂岩。
For the problem that different lithologies of the three typical low permeability reservoirs of WZ1-1,WS1-1 and WC1-1 in the western South China Sea have led to obvious differences in the micro pore throat structure characteristics and the seepage law,the mercury penetration test data of 173 rock samples in the study area were selected.Besides,the differences in the fractal characteristics of low permeability reservoirs with different lithologies were compared by using the fractal theory,and the geneses of the reservoirs were analyzed in combination with the casting thin section experiment.Primary intergranular pores were developed in the fine sandstone reservoir of WZ1-1 oilfield,and the fractal curve was linear.The primary and secondary pores coexisted in the sand-conglomerate reservoir of WS1-1 oilfield,with feldspar dissolved pores developed and the fractal curve appearing as the“concave”broken line.With the increase of pore throat radius,the fractal dimension presented the characteristics of“small-large-small”.Similarly,the primary and secondary pores coexisted in the siltstone reservoir of WC1-1 oilfield.The filling of intergranular pores by argillaceous and organic matters increased the complexity of pore throat structure.The fractal characteristic curve showed a“convex”curve,and the fractal dimension increased with the pore throat radius.By comparing the fractal curves of reservoirs with the same pore throat scale range and different lithologies,it is considered that the main factor affecting the seepage capability of low permeability reservoirs is the difference in micro pore throat structures,especially the fractal characteristics and proportion of larger pore throat.Therefore,the seepage capabilities of those three types of reservoirs are ranked from good to poor as the fine sandstone reservoir in WZ1-1 oilfield,the sand-conglomerate reservoir in WS1-1 oilfield and the siltstone reservoir in WC1-1 oilfield.
作者
赵楠
王磊
黄俊
张辉
彭小东
ZHAO Nan;WANG Lei;HUANG Jun;ZHANG Hui;PENG Xiaodong(CNOOC China Limited,Zhanjiang Branch,Zhanjiang,Guangdong 524057,China)
出处
《中国海上油气》
CAS
CSCD
北大核心
2020年第1期87-94,共8页
China Offshore Oil and Gas
基金
“十三五”国家科技重大专项“南海西部海域低渗油藏勘探开发关键技术(编号:2016ZX05024-006)”部分研究成果
关键词
南海西部
低渗油藏
储层岩性
分形特征
微观孔喉结构
渗流能力
the western South China Sea
low permeability reservoir
reservoir lithology
fractal characteristics
micro pore throat structure
seepage capability
