摘要
查明低孔、低渗砂岩储层非均质性的原因,对该类油藏的研究、勘探和开发具有重要的理论和实际意义。对蟠龙探区上三叠统长2砂岩进行了沉积相、砂岩岩石学和成岩作用及储层物性演化影响等研究,结果表明:其物性受沉积相、裂缝发育程度与规模、砂岩碎屑成分及成岩作用的控制,辫状河河心砂坝中细-细砂岩具有较高的孔隙度(平均13.5％)和渗透率(平均16.656×10-3μm2),曲流河天然堤粉细砂岩和细砂岩的孔隙度(平均11.2％)和渗透率(平均7.085×10-3μm2)较低;埋藏压实作用是导致砂岩孔隙丧失的主要原因,使平均孔隙度丧失23.3％,胶结作用使平均孔隙度丧失6.4 ％,碳酸盐是砂岩孔隙度丧失的主要胶结物;次生溶解作用是物性得到改善的重要途径;裂缝(平均1.8％)对砂岩渗透率的提高起了重要贡献。认为裂缝是导致砂岩储层非均质性较强和影响油田注水开发效果的主要因素之一。
It is important both theoretically and practically in exploration and development for sandstone reservoirs to investigate factors which cause their heterogeneity. Detailed studies on sedimentary facies, petrology and diagenesis of the sandstones as well as their impact on reservoir quality evolution show that the reservoir quality is strongly influenced by the depositional facies,development and dimension of fractures, detrital components and diagenesis of the sandstones. The medium to coarser-grained (av. 0. 2-0. 3 mm) and fine-grained (av. 0. 15 -0. 25 mm) sandstones in the braided facies are of higher porosity (av. 13. 5%) and permeability (a v. 16. 656× 10-3μm2) ;while sandstones with fine grained (av. 0. 1-0. 2 mm) and very fine-grained (av. 0. 07-0. 2 mm) in the meandering facies are of relatively lower porosity (11. 2%) and permeability (7-085 × 10-3μm2). The mechanical compaction in the early diagenetic phase,which resulted in 23. 3% average porosity loss, is the main factor caused the loss of porosity for the sandstones. The average porosity loss caused by cementation is 6. 4%. In the cements, carbonate is the main cement that reduced the porosity of the sandstones. A better retention of reservoir quality of the sandstones is attributed to dissolution. Fractures (av. 1. 8%) developed in the Chang 2 sandstone reservoirs may have a critical contribution in increasing permeability,and are one of the major factors that resulted in the heterogeneity and influence the effect of injection exploration for the Chang 2 reservoirs.
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2003年第6期723-728,共6页
Journal of Northwest University（Natural Science Edition）
基金
国家自然科学基金资助项目(40172055)
"973"资助项目(2003CB214603)
西北大学"跨世纪人才"资助项目
关键词
长2砂岩储层
沉积相
成岩作用
储集物性
蟠龙探区
Chang 2 sandstone reservoirs
depositional facies
diagenesis
reservoir-quality
Panlong Oil Area
