The Control Factors And Potential Analysis Of Yanchi Chang6Reservoir

In recent years, with the growth of oil and gas exploration，Chang6Member of TirassicYanchang Formation has become one of the mainly exploited stratums in Yanchi area of OrdosBasin.Based on the researching achievements of sedimentary microfacies，sand bodydistribution, mineral and lithological feature of reservoir and microscopic reservoir porestructure in this paper, it applies the researching method in the way from dots to surface, fromqualitative interpretation to quantitative interpretation and the combination macroanalysis withmicroanalysis, meanwhile，analyzes the main control factors of physical properties ofReservoir according to research methodology. Then, comprehensive evaluation methods of theunivairate and multivairate factors are used in reservoir evaluation.On the basis of analyzinginfluence factors of reservoir productivity, this paper uses a variety of methods to make speedyevaluation and prediction on reservoir productivity of Chang6formation. After havingfinished the above study, the target areas for production building are screened out.This paper suggests that Yan Chi depositional system of Chang6reservoir is formed bythe combined action of northeastenr and notrhwestern sources of sediments，and thenorthwestern action effects stronger. Oil set Chang6belongs to depositional environment ofdelta front and sand body develops along the river channel because sedimentary fades andlfow direction controls the spatial distirbution of sandstone bodies. The river intersectionregion has thick sand body, correspondingly the values of reservoir parameters are relativelyhigh, and therefore it’s considered to be the main layers of reservoir. The research onmicro-characteirstics of reservoir suggests that Chang6, main reservoir rock type is Iithicfeldspar-porphyry sandstone, is characteirzed by ifne granularity, the higher levels ofinterstitial mateiral，ordinary rounded and well sorted. Due to the influences of deposition anddiagenesis, Chang6reservoir has low face pore rate, mainly being the combination ofdissolved pores and inter-granular pores and it is characterized by higher expulsion pressure,median pressure and lower median semidiameter. Reservoirs in Chang6formation of YanchiArea are of particular low porosity and low permeability, with the average porosity of10.72%and penetration rate of0.763x10-3fim2. On the basis of reservoir macroscopic andmicroscopic reservoir characteristic study and the analysis of deliverability sensitivity parameters, the curve characteirstics method, the product method, and the productioncoefficient method have been utilized to make a qualitative analysis and quantitative forecastfor single well production. Finally, according to the research of sedimentary microfacies,reservoir evaluation and deliverability forecast, with the combination of logging indication,well logging interpretation, testing data for oil and production conditions, the favorableexplorationareas of Chang6layer have been screened out The forecast results show that therewill be21favorable exploration areas, with oil-beairng area412.79km2and geologic reserve122million tons.