Reservoir Performance Under Solution Gas - Drive and Gravity Drainage

摘要

This work examines the well and reservoir performance underrnboth solution gas-drive and gravity drainage in homogeneousrnsystems. Based on synthetic information obtained with a fullyrnimplicit black-oil simulator, the influence of differentrnparameters like oil rate, position of the producing interval,rnwellbore pressure level, skin factor, and vertical permeability,rnfor both constant oil rate and constant pressure productionrnmodes are documented. Analytical results for the reservoirrnperformance during the boundary dominated flow period arernderived. An approximate expression that describes thernvariation of oil saturation with average pressure is presented.rnFor constant oil rate production, the influence of gravityrndrainage on the inflow performance relationships curves isrnstudied, and a new correlation is presented. For constantrnpressure production, the decline curve behavior is analyzedrnand it is found that under favourable gravitational effects, thernproduction behavior shows two decline stages such as doublernporosity systems; however, it does not follows the typicalrndecline type curves for naturally fractured reservoirs. Atrncertain backpressure values during the first stage anrnexponential decline behavior could be observed, while duringrnthe second stage values of the decline exponent less than zerornare observed.