Study On The Technology Of Gas Reservoir Characterization In Deep Volcanic Rock

Reservoir characterization is a method used to quantitatively determine reservoir nature and toidentify geological information and the spatial alternation of the reservoir. Its outstanding feature is that itis related with gas reservoir management. So, reservoir characterization includes two aspects of thecontents of technology and benefit. Volcanic rock gas reservoirs are very complex and invisible, and theinvestigators have inadequate knowledge of it, so the research on volcanic rock reservoirs is just in theperiod of exploring at present. Especially for the deep volcanic gas reservoir, the geological characteristicsis extremely complex and the heterogeneity is very serious, but there is no any successful experience canbe learnt from home and abroad, so the technology is the most difficult of characterizing deep volcanicrock gas reservoir.Against the difficulty of the research of volcanic rock reservoir, a technical route of integrated studybased on multi-science is established in the article. On the basis of the data of core, test, well log andseismic, a suite of elementary technology of reservoir characterization for naturally fractured volcanic rockgas reservoir is created and established by a great number of core observations, laboratory experiments,theoretical studies and field practices. The technology includes lithologies Identification, lithofaciesanalysis, Identification and prediction of natural fracture and gas layer, log interpretation of reservoirparameters of duplex media, evaluation of volcanic rock reservoir. The methods are comprehensivelyapplied to the study of qualitative description of the reservoir attributes, cross-plot analysis, principalcomponent analysis, neural network, optimum interpretation, etc. As a kind of attempt and search, thework is useful to both theory research and practical application.There are several conclusions according to the effect of this study. Firstly, the volcano erupted manytimes through many craters;the rock of the reservoir is mainly acidic volcanics of light color;the volcanicrock is sorted into many types, and the lithofacies changed rapidly on the plane. Secondly, thedevelopment of natural fracture is controlled by SongXi fracture belt and its subsidiary fracture;thefracture of the reservoir exists mainly in rubble lava and ignimbrite, high angled tectoclase as the major;the fracture is multidirectional, but pointing to north west firstly and north east secondly on the whole.Thirdly, the reservoir, which connectivity is bad and which energy of edge water and bottom water is weak,belongs to a kind of dry gas reservoir trapped by structural and lithologic units;in the reservoir, therelationship between gas and water layers is very complicated. Fourthly, the reservoir is dual porosityreservoir controlled by many factors, low porosity and low permeability. Fifthly, the reservoirs are dividedinto four categories, and the third type is the major of the reservoir, the second and the third are the majorof the gas reserve volume, so they are relatively worse reservoirs. The result of the research has beenwidely used in the study of gas reservoir engineering and in the design of development plan. It fullyreflects the beneficial side of the technology of reservoir characterization.