卡塔尔上古生界低渗透砂岩储层特征及物性控制因素

中海油研究总院,北京 100028

卡塔尔; 上古生界; Unayzah组; Jauf组; 低渗透储层

Characteristics and controlling factors on physical properties of Upper-paleozoic low-permeability sandstones in Qatar
HUANG Xing-wen,CHEN Quan-hong,LI Hai-bin

(China National Offshore Oil Corporation Research Center,Beijing 100027,China)

Qatar; Upper paleozoic; Unayzah; Jauf; low-permeability reservoirs

DOI: 10.13800/j.cnki.xakjdxxb.2015.0311

备注

波斯湾盆地古生界砂岩储层发育,是中东油气勘探的一个新层系、新领域,但由于埋深大,资料少,储层研究程度较低。以岩心、薄片、测井等资料为基础,从沉积相、岩石学特征、成岩作用及孔隙特征等方面刻画了卡塔尔中泥盆统Jauf组和下二叠统Unayzah组砂岩的储层特征。在此基础上,结合沉积、成岩特征分别分析Jauf组和Unayzah组储层物性控制因素,探讨了低渗透砂岩背景下优质储层形成条件。结果 表明,Jauf组主要为滨岸相,Unayzah组主要为河流-三角洲相,储集空间主要为残余粒间孔,孔喉为微细喉、微喉,储层以“低填隙物含量、高成分成熟度和中-高结构成熟度”为特征,孔隙度一般小于12%,渗透率多小于10 mD,为低孔低渗储层。沉积作用是储层物性的主控影响因素,它决定了成岩作用的类型和强度。Jauf组和Unayzah组强烈的压实作用和胶结作用对形成低渗透储层起了决定性作用,溶蚀作用较微弱,改善了储层物性。

Paleozoic sandstone reservoir is a frontier and new play for Persian Gulf Basin.The sandstone reservoirs are buried deep and less explored with few research data.Sedimentary,petrology,diagenesis and pore character of Devonian Jauf and Permian Unayzah Fm sandstone reservoir in Qatar were analyzed based on core,thin section and logging data in the paper.Controlling factors over Jauf and Unayzah reservoir quality were discussed,and further discussed in what conditions the low-permeability sandstones would have higher reservoir quality.It was indicated that:Jauf and Unayzah are dominated by shore and fluvial-delta environment,respectively.Pore space are mainly residual intergranular pores,micro to micro-fine pore throat, and reservoirs are characterized by low filler content,high component maturity and mid-high textural maturity,which are mainly low-porosity and low-permeability reservoirs,and porosity and permeability are mainly less than 12% and 10md,respectively.Sedimentation is the key controlling factor over reservoir quality,control of type and intensity of diagenesis.Strong compaction and cementation are key factors over the formation of Jauf and Unayzah low-permeability reservoirs,while dissolution slightly improved the reservoir quality.