Study On The Reservoir Characteristics And Enrichment Regulations Of Oil And Gas Accumulation Of JIV1Reservoir In Lunnan Oil Field

Lunnan Oilfield which is the main exploration and development block ofTarim Oilfield Company located in the Lunnan fault horst of the middle of Tabeiuplift in Tarim Basin. JIV1sandgroup is the main oil-bearing layer of theJurassic strata and can be an important resource for research and use in thecurrent development situation, has great significance on the protection of oilstable yielding and increase yielding. To further study the regular pattern of oilaccumulation in the region, it is necessary to do carefully research on thesedimentary facies, reservoirs, reservoir features and so on，analysis the majorcontrolling factors of oil accumulation.In this paper, petroleum geology, sedimentary petrology, reservoir geology,logging geology are taken as guidance, on the basis of existing research results,a large number of basic geology datas, such as drilling, core, logging, oil testingare comprehensively used. Formation, structure, sedimentary facies, diagenesis,micro-pore configuration, properties and heterogeneity of JIV1reservoirs arestudied by means of thin section identifieation, X-diffraction, mercurypenetration analysis and SEM etc. Reservoir evaluation criteria of JIV1 sandgroup is established， and then to analysis the impact of the majorcontrolling factors of oil and gas accumulation.The results show that JIV1sandgroup of well2in Lunnan oilfield isinterpreted to be syndrome differentiation of delta plain parfacies, developingbraided distributary channel, and channel sandbar microfacies; JIV1sandstonehas alreadv been in B stage of early diagenesis to initial period of A stage of latediagenesis, with the latter being the majority. Residual grain pore anddissolution pore are the main space for oil and gas accumulation. JIV1sandgroup are the typical middle-pore, middle-permeability reservoirs, with thelayer heterogeneity and plane heterogeneity heterogeneity are very strong, whileinterlayer heterogeneity is weak. Reservoir evaluation results indicate that theJIV1reservoir types are mainly Ⅱ (better) type with middle holes andmiddle-miniature throats, followed byⅠ(good) type with big holes and coarse-miniature throats, Ⅲ(medium) type with miniature holes and middle-miniaturethroats.The crude oil of JIV1reservoir in the study area belongs to light crude oil,which is waxy, low density, low sulphur, low solidification point; formation water is mainly for calcium chloride, high-salinity; the reservoir rock is stronglyhydrophilic; trap types are mainly for structural-lithological trap. JIV1reservoirsare mainly distributed in JIV11layers, with big thickness and good continuity.Effects of tectonism, deposition, and diagenesis are the main factors for JIV1reservoirs, of which tectonism controls the oil gathering and distribution,sendimentation dominates the thickness and distribution of sandstone,diagenesis plays a key role on the storage performance of JIV1reservoirs.