Waterflood Pressure Pulsing for Fractured Reservoirs

Abstract

Conventional tvaterfiooding often is uneconomic in highly fractured reservoirs because of the gross bypassing of the reservoir oil by injected water. imbibition and pressure imlse flooding have been used in at [east one fractured reservoir in an attempt to achieve better oil recovery per. formtnce. This paper presents the results of laboratory fiOW tests conducted On large cores t? evaluate~!,e possib~e applicability of zhese methods (parncuiarly pressure pulse fioo(iing) to different types of reservoir system:r, Test data were obtained on both water-wet and oii-wet systems, and h OILsystems having two widely riifferen t Ievels of cotn pt xs ibiiity and ffow capacity. Resuits indicate that pressure pul.re recoveries. from fractured reservoirs will likely not excee(i 5 to 10 per cent pore space with maxim u})1response achieved during titc first pulse cycle. !mproved recovery -i~y this tnetkod is possfble from both oil-wet and waterwet reservoirs, Comparable saturation distributions durittg imbibition and pressure pulse production suggest that an initial pressure pulse cyc[e to speed production iesponse would not interfere with subsequent imbibition fiooding in waler-wet reservoirs..

Cyclic Water Injection in San Jorge Gulf Basin, Argentina

“…Elkings and Skov (1963), one of the earliest references showing field results to cyclic waterflooding, already attribute the success of the process to end effects. Moreover, laboratory results as shown by Owens and Archer (1966) and Pooladi-Darvish and Firoozabadi (2000) demonstrate the influence of capillary forces in oil imbibition. Shchipanov et al (2008) also included the influence of compressibility difference on propagation velocity of the pressure pulse on the different fluid mainly in high frequency cycles.…”

Oil recovery from naturally fractured reservoirs by steam injection methods. Final report

“…One of the unknowns in the model is the driving capillary pressure P c SW j-this value can be estimated from the capillary tubes model. The capillary pressure in a capillary tube is expressed by p _2_acos9 (3.16) and the permeability of a bundle of tubes is given by Owens and Archer (1966) reported that the mobilities of the imbibing water and expelled oil on the core surface stayed equal during a counter-current capillary imbibition. If this conclusion is assumed to be true for water-gas imbibition, the mobility terms in Eq.…”

Modeling, analysis, and screening of cyclic pressure pulsing with nitrogen in hydraulically fractured wells

“…Initial applications were with water as an improved way of waterflooding (Owens and Archer 1966;Felsenthal and Ferrell 1967;Raza 1971). Shelton and Morris (1973) used rich hydrocarbon gases instead of steam to increase the reservoir energy (as a short-term benefit) and reduce oil viscosity (as a long-term benefit).…”