Gas-Assisted Gravity Drainage in Naturally Fractured Reservoir

The major issue in any successful EOR is to increase sweep and microscopic
displacement efficiency. In naturally fractured reservoir, the high permeability contrast
between fracture and matrix becomes the main issue on the low oil recovery. The
injected gas in conventional gas injection method tends to flow through high
permeability fracture channel, displaces some oil in the fractures and moves toward the
producer which results in early gas breakthrough. Consequently, most of oil in the
matrix is left behind. Therefore, the main objective of this project is to investigate
productivity of gas-assisted gravity drainage (GAGD) in naturally fractured reservoir.
Previous lab experiment proved the prospect of GAGD as the replacement for existing
teclmiques. In this simulation, an injector and a producer are simulated in a gridblock
model. The simulation focuses on three (3) parameters which are horizontal producing
well depth; horizontal producing well length and injection rate. Based on simulation
result, the author anticipated to see the optimum parameters which give the highest
recovery. Besides, the old method which are continuous gas injection (CGI) and water
alternating gas (WAG) will be compared against GAGD based on literature review. The
scopes of study will be revolving around the crude oil, the use of horizontal well and
carbonate reservoir type. For methodology part, PVT data from the selected SPE papers
are exported into dual porosity model which originally from Msc. Thesis of University
of Texas. The outcome are analyzed and discussed thoroughly.