盐城凹陷朱家墩地区天然气储层特征
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摘要
根据岩心描述所建立的沉积层序特征并结合地震地层学解释结果 ,可将阜一段早期沉积体系解释为中 -低弯度的河流沉积 ,河流主物源来自于西部和西北部地区 ,河道在平面上可相互连接呈交织状河道形态 .朱家墩地区受到由西南向东北方向延伸的河道体系的影响 ,发育了相互叠置的河道砂体 ,可进一步划分为河道沉积、决口沉积和河道间漫滩沉积等沉积微相 .该区天然气储集砂体类型为砂砾岩、砾状砂岩、砂岩和少量粉砂岩 .砂岩类型以长石岩屑砂岩为主 ,并有少量岩屑长石砂岩 .自生矿物主要类型有石英、绿泥石、硬石膏、钠长石、伊利石和碳酸盐等 ,含量变化较大 .天然气储层以次生孔隙发育为特点 ,阜一段天然气储层次生孔隙发育 ,泰二段天然气储层次生孔隙发育较差 .该区天然气储层成岩作用已进入晚期成岩作用阶段的 A亚期早期 .该区气藏为深层中等丰度中等规模的受岩性影响的层状构造砂岩气藏 .位于构造高部位的优质储层天然气充注较好 ,而位于高部位的劣质储层和部分低部位的储层天然气充注较差 .本区储层发育的一大特点是不仅压实强烈 ,次生溶蚀作用也十分强烈 .根据前人对该区油气储层物性和孔隙结构的研究和分类原则 ,对盐城地区天然气储层进行了划分 .
The origins of gas reservoir in Zhujiadun Area of Yancheng Depression are interpreted jointly with careful core descriptions and seismic data. The reservoir in this area represents a middle to low sinuosity channel deposits. Tangwa Dalaba uplift provided the main clastic provenance. Deposits in this area consist of channel and interchannel deposits. The development of fluvial sedimentation produced overlapping sand bodies. The sedimentary microfacies of gas sand bodies are described in detail based on depositional sequence and sand body geometry. The gas reservoir sandstones include conglomeratic sandstone, sandstone and silt. Sandstones are mainly feldspathic litharenite and lithic arkose. The types and characteristics of diagenetic minerals are determined. The authigenic minerals are quartz, chlorite, anhydrite,gypsum, albite, illite, and carbonates. The reservoir porosity is mainly secondary in origin. The sequence of diagenesis in the gas reservoir is determined and the relation between porosity evolution and diagenetic events is studied. The analysis of petrophysics and capillary pressure are used for reservoir evaluation and analysis.
The origins of gas reservoir in Zhujiadun Area of Yancheng Depression are interpreted jointly with careful core descriptions and seismic data. The reservoir in this area represents a middle to low sinuosity channel deposits. Tangwa Dalaba uplift provided the main clastic provenance. Deposits in this area consist of channel and interchannel deposits. The development of fluvial sedimentation produced overlapping sand bodies. The sedimentary microfacies of gas sand bodies are described in detail based on depositional sequence and sand body geometry. The gas reservoir sandstones include conglomeratic sandstone, sandstone and silt. Sandstones are mainly feldspathic litharenite and lithic arkose. The types and characteristics of diagenetic minerals are determined. The authigenic minerals are quartz, chlorite, anhydrite,gypsum, albite, illite, and carbonates. The reservoir porosity is mainly secondary in origin. The sequence of diagenesis in the gas reservoir is determined and the relation between porosity evolution and diagenetic events is studied. The analysis of petrophysics and capillary pressure are used for reservoir evaluation and analysis.
引文
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[2 ] 吴崇筠 ,薛叔浩 .中国含油气盆地沉积学 [M].北京 :石油工业出版社 ,1993. 2 6 8- 2 93.
[3] 林壬子 ,张金亮 .陆相储层沉积学进展 [M].北京 :石油工业出版社 ,1996 .
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