Techniques Studying Of Carbonate Reservoir Evaluation

Carbonate oil and gas fields occupy a very important position in the world oil and gas fields distribution, and half or more than half of the world’s oil and gas from the carbonate reservoir.The carbonate reservoir evaluation has a long history, because carbonate reservoirs of oil and gas fields are widely distributed in the world.Carbonate reservoir occupies an important position and the dual nature of the carbonate reservoir in the oil and gas reservoirs have very complex features, in the logging research field of fractured reservoirs in carbonate rocks, many logging interpretation experts made a lot of research work, Published a lot of papers and works, and establishment of a carbonate reservoir log evaluation of the base model, methods, and laid a solid theoretical basis. In foreign countries, the most in-depth study carried out in the field is Schlumberger, the most in-depth study carried out in this field in China is Sichuan Petroleum Administration. However, to So far, a perfect assembling and systemic method for carbonate fractured reservoir logging evaluation is not performed yet, because the vast majority of logging methods and the logging tools are based on homogeneous formation model carbonate reservoir, which with complex characteristics of anisotropy and heterogeneity。Evaluation of carbonate reservoirs is a major problem.According to the basic characteristics of carbonatite reservior in Puguang gas field, this paper uses core, conventional and imaging logging data to evaluate the field’s conbonate rocks’ reservior, comprehensively, in order to ascertain the standard that may divide the categorical of carbonatite reserbior stratum.By means of the incorporation of systematic theory and realistic study,this paper establishes and consummates a set of logging evaluation methodology which is appropriate for the area of conbate reserviors in PuGuang Gas Field.The main reservior lithology of PuGuang Gas Field is conbonate,and this lithology possess the following feature:has strong non-hornogeneous; different forms of high sulfur-bearing gas reservoir(pore assemblage,fracture-pore assemblage); variable lithofacies; with a strong anisotropy; low matrix reservoir porosity; these characteristics increase the difficulties of reservoir recongnition.The main difficulties display as follows:(1) Carbonate reservoir lithology is more complex,which is difficult to distinguish between different lithology by conventional logging data.(2) Fracture discrimination, because the logging response characteristics of the crack reservoirs don’t have very strong regularity, it’s difficult to identify them accurately by well logging curves.(3) Confirm reservoir of the study area is reef-bank dual medium, which has the complex reservoir space structure and unconspicuous logging response characteristics.This paper main researches and evaluates the firs、second section in Feixianguan Group and Changxing Group of PuGuang Gas Field.The main reaserch methods are as follows:1、On the basis of the PuGuang Gas Field’s geological feature, according to the lithology and rock character of this area, then systematic understand the basic geological characteristic of the area’s carbonate diagenesis and the reservoir’physical and electrical.In addition, embeded studied the feature development circumstance of this area, which systematic statisticed the cracks of the PuGuang Gas Field according to the analysis of cracks produced like filling situation and the other directions.2、Summarized the reservoir logging response characteristics and extracted the reservoir characteristic parameters on the basis of the flakes and core data information, which is priorred to conventional logging data and supplemented by imaging logging data.And divided carbonat reservoir form by using SVM(support vector machine)method as well.3、Established the carbonate reservoir interpretation model, divided the reservoir levlel, and ascertained the standard of the dividing of the PuGuang Gas Field’s reservoir level according to the characteristic of the storage space of carbonate rock’s pore structure in this area.In additon, calculated the shale index, porosity and permeability on the basis of the logging interpretation model in the studing area.