塔里木盆地下古生界碳酸盐岩油气藏特征及其分类

Classification and Examples of Lower Paleozoic Carbonate Reservoirs in Tarim Basin

塔里木盆地下古生界寒武系—奥陶系碳酸盐岩油气藏复杂多样,依据圈闭类型可划分为构造类、地层岩性类、复合类等三大类油气藏。其中地层岩性油气藏还可分为风化壳型、礁滩型、白云岩型三个亚类。根据圈闭与储层特征,三大类油气藏可进一步细分为12个类型。构造类油气藏受局部构造圈闭控制,储层发育,横向连通性好,油气分布比较均一,油气水界面明显。地层岩性油气藏为盆地的主要油气藏类型,储层类型多样,油气藏受储层控制,横向变化大,非均质性强,但同一油气藏具有相近的流体性质、统一的压力-温度系统,多具有统一油气水界面,油气产出变化大。复合类油气藏受局部构造圈闭与储层双重作用控制,构造高部位储层发育区油气高产稳产效果好,低部位含水率高。典型实例分析表明,不同类型油气藏差异大,同一类型油气藏具有相似的特征,针对不同类型油气藏需要采取不同的勘探开发方法与技术措施。

As the lower Palaeozoic carbonate reservoirs are complicated and diversified in Tafim basin, it is important to clarify the characteristics and types of the hydrocarbon reservoirs for exploration and development. Based on the types of oil and gas traps, theses reservoirs can be divided into 3 types, i.e. structural, stratigraphic-lithologic and composite ones, and they can be subdivided into 12 small types. Conlrolled by the local anticlinal lraps, this type of structural reservoirs is characteristic of good reservoir quality, well lateral communication and uniform hydrocarbon distribution with obvious united oil/gas/water interfaces. The stratigraphic-lithologic reservoirs are the most in the basin, and can be subdivided into 3 subtypes that include weathered crust, reef-bank and dolomite ones. Controlled by reservoir property, this type of reservoirs is characteristic of variety, hetero- geneity, considerable lateral changes and great nonuniformity, but within a same reservoir, there are similar fluid proper- ty, accordant P-T system and united oil/gas/water interfaces so that usually oil and/or gas output alters greatly. Controlled by both local traps and reservoir property, the type of composite reservoirs is characteristic of high and stable oil and/or gas output at the well-developed high location but low output and high percent of water yield in the lower location. Analysis of representative reservoirs for examples is shown that the different types of reservoirs are quite differential and the identical type of reservoirs are similar in characteristics. It is suggested that compatible means and technology of exploration and development should be taken for different types of carbonate reservoirs.