Lake Facies Carbonate Reservoir Causes And Characteristics Study Of Subei Basin

In recent years, the practices of oil and gas explorations in China have show thatlacustrine carbonate rocks can also become important oil and gas reservoir. Carbonatereservoir extensively develop in Subei Basin. But because of its complexity, it has beendifficult to exploit. According to the data analysis of some wells which have producing,carbonate reservoir in Subei Basin generally is bioclastic limestone. There are manydissolved pores. The production of part of the area is high and can succeed as capacity. Itwill play an important role in keeping production stable for Jiangsu oilfield.This paper presents a thorough study to lacustrine carbonate rocks’sedimentarycharacteristics and model, reservoir characteristics and causes in E1f2of Gaoji Oilfield andFanzhuang Oilfield synthetically using of experimental analysis and well logging data.Through observing the cores and identifying the casting slices, carbonate rocks inE1f2can be divided into four lithofacies, that is argillaceous limestone, bioclastic limestone,oolitic limestone, sand-clastic limestone. On the base of core observations, synthesizesmud log, well logging and analytical data to identify the sedimentary environment isshallow lake, and the microfacies include four types that are transitional face, oolitic beach,organic beach and mud-crystal beach. Different microfacies have big differences inphysical property and oiliness. Organic beach’s physical property and oiliness are the bestand followed by transitional face and oolitic beach. Mud-crystal beach almost does notinclude any oil content.By studying lots of initial value, testing and production performance data, andaccording to actual situations in the oilfields, 11 big parameters, which can be acceptedeasily and whose characteristics are obvious, are chosen to as carbonate reservoirevaluation indexes. Applying AHP design hierarchy model, and build evaluation methodand system of lacustrine carbonate reservoir. Research results laid the foundation forSubei Basin in lacustrine carbonate reservoir’s development.