This paper presents an analysis of the high-pressure, gas-driven LPG-slug process, based on fluid flow tests in areal models. Two types of tests were made. One series was made in low-pressure models which permitted observation of fluid movement. Three completely miscible analog fluids were used. A second series of tests was made in high-pressure models using methane, propane and a light refined oil saturated with methane at room temperature and 1,550 psig. Under the test conditions of room temperature and a pressure level of 1,550 psig, the phase diagram for the fluids used is similar to those for many of the field systems where the process is considered for use. A method for using these laboratory data to calculate field performance of the process is outlined.As a result of this work, it is concluded that small banks of LPG (5 per cent HV or less) are not effective in increasing oil recovery in horizontal reservoirs. Instead, where small banks are used, the driving gas quickly penetrates the LPG bank because of fingering and channeling; and from this point on, the process behaves essentially as an immiscible gas-injection project. The validity of this conclusion was substantiated by: (1) laboratory studies of the effect of rate, model size and mobility ratio on miscible displacement in areal models; and (2) calculation of field recovery, which compared closely with actual field recovery.
A method is presented for predicting the character of gas or water displacement in a radial system, which can be either horizontal or inclined. The latter case would comprise cone-shaped or dome-shaped symmetry. The method considers the one dimension of radial distance, taken parallel to the bedding planes. Approximate allowance can be made for segregation of the two fluids perpendicular to the bedding planes.A complete saturation history can be obtained in about a day's time with the use of a desk calculator. Results of an example calculation agree well with the performance of simulated gas drive in a large model representing a section of a cone. This pie-shaped, sand-packed model was 8-ft long and 4-in. thick.The method of solution is useful in handling other partial differential equations of first order and first degree.
A phase-behavior approach to the prediction of the performance characteristics of a dissolved-gas-drive reservoir is unique in that the problem of choosing flash, differential, or composite-solution gas-oil ratios and formation-volume factors has been circumvented. Data required are a compositional analysis of the reservoir fluid, the bubble point of this fluid, and the relative-permeability curves for the reservoir rock.Gas-oil ratios and formation-volume factors were'calculated under conditions duplicating the performance of the reservoir. A comparison was then made between these results and those obtained by calculations involving a differential, a flash, and a composite process. A vital factor in the solution of the problem is the accuracy of the calculated equilibrium constant. Agreement within 3% was obtained when a calculated differential formation-volume curve was compared with an experimentally determined curve.This assumed Fg/ro is compared with the average V J V , calculated from-the two instantaneous formations (V,/Vo) (i) associated with the liquid saturations at P2 and PI. This latter value is calculated by the use of Equation (8).
A phase-behavior approach to the prediction of the performance characteristics of a dissolved-gas-drive reservoir is unique in that the problem of choosing flash, differential, or composite-solution gas-oil ratios and formation-volume factors has been circumvented. Data required are a compositional analysis of the reservoir fluid, the bubble point of this fluid, and the relative-permeability curves for the reservoir rock.Gas-oil ratios and formation-volume factors were'calculated under conditions duplicating the performance of the reservoir. A comparison was then made between these results and those obtained by calculations involving a differential, a flash, and a composite process. A vital factor in the solution of the problem is the accuracy of the calculated equilibrium constant. Agreement within 3% was obtained when a calculated differential formation-volume curve was compared with an experimentally determined curve.This assumed Fg/ro is compared with the average V J V , calculated from-the two instantaneous formations (V,/Vo) (i) associated with the liquid saturations at P2 and PI. This latter value is calculated by the use of Equation (8).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.