Gas reservoir simulation for enhanced gas recovery with nitrogen injection in low permeability coal seams

Abstract Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.

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Experimental Study on a New Enhanced Gas Recovery Method by Nitrogen Injection from a Methane Hydrate Reservoir

Journal of MMIJ ◽

10.2473/journalofmmij.123.386 ◽

2007 ◽

Vol 123 (8) ◽

pp. 386-393 ◽

Cited By ~ 3

Author(s):

Yasuhide SAKAMOTO ◽

Hironori HANEDA ◽

Taro KAWAMURA ◽

Kazuo AOKI ◽

Takeshi KOMAI ◽

...

Keyword(s):

Experimental Study ◽

Methane Hydrate ◽

Recovery Method ◽

Enhanced Gas Recovery ◽

Gas Recovery ◽

Nitrogen Injection ◽

Hydrate Reservoir

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ESTIMATION OF TECHNOLOGICAL EFFICIENCY OF WORK AND SHUTDOWN OF PRODUCTION WELLS WITH NITROGEN INJECTION INTO THE DEPLETED GAS RESERVOIR

Prospecting and Development of Oil and Gas Fields ◽

10.31471/1993-9973-2018-3(68)-7-11 ◽

2018 ◽

pp. 7-11

Author(s):

R. M. Kondrat ◽

L. I. Khaidarova

Keyword(s):

Group Program ◽

Gas Reservoir ◽

Gas Recovery ◽

Nitrogen Injection ◽

Technological Efficiency ◽

Modeling Group ◽

Production Wells ◽

Residual Gas ◽

Composite Modeling ◽

Depleted Gas Reservoir

The main directions of increasing hydrocarbon output from depleted gas deposits and possible options of injecting nitrogen into the reservoir are described. For the conditions of a depleted hypothetical gas reservoir, a mathematical modeling of the process of displacement of the residual gas by nitrogen using the composite modeling module GEM, which is part of the CMG (Computer Modeling Group) program, was performed. Based on the results of the research, the effect on the gas recovery factor for the residual gas and other technical indicators was established on the development of the work and production wells shut-down zone when nitrogen was injected into the deposit with different time periods.

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THE EFFECT OF THE CYCLICAL NITROGEN INJECTION ON THE FINAL COEFFICIENT OF GAS RECOVERY AT DIFFERENT RATES IN THE DEPLETED GAS RESERVOIR

Prospecting and Development of Oil and Gas Fields ◽

10.31471/1993-9973-2018-4(69)-15-22 ◽

2018 ◽

pp. 15-22

Author(s):

R. M. Kondrat ◽

L. I. Khaidarova

Keyword(s):

Gas Production ◽

Reservoir Pressure ◽

Hydrocarbon Gases ◽

Gas Reservoir ◽

Recovery Coefficient ◽

Research Results ◽

Gas Recovery ◽

Nitrogen Injection ◽

Residual Gas ◽

Depleted Gas Reservoir

The application of non-hydrocarbon gases with the aim of displacing residual gas from depleted fields is substantiated. Mathematical modeling is carried out of the process of residual gas displacing with nitrogen in the GEM compositional simulating module under the conditions of a hypothetical gas reservoir of circular shape. The said module is a part of the licensed CMG computer program. The effect of the cyclical nature of the aquifer injection nitrogen into depleted gas reservoir at different rates till the final gas recovery coefficient for residual gas is developed. The study concerns different durations of nitrogen injection cycles into the reservoir (6, 12, 18, 24, 30, and 36 months) and various correlations of the rates of nitrogen injection and gas production in reservoir conditions of 1:1; 1.5:1; 2:1. During the nitrogen injection into the reservoir, the output wells stopped; whereas after surcease of the nitrogen injection, they were again exploited until the reservoir pressure reached to 0.1 Pprimary. Then the process of cyclic nitrogen injection into the layer continued, until nitrogen break through into the producing wells and its content in the produced products reached 5% vol. The research results were processed in the form of graphical dependencies of reservoir pressure, gas flow rate and gas recovery coefficient for residual gas at the end of the cycle of nitrogen injection into the reservoir as a function of the number of such cycles. The research results indicate a significant effect on the gas recovery coefficient for the residual gas of the duration of the cycle of nitrogen injection into the reservoir and the ratio of rates of nitrogen injection and gas production, with an increase in which the coefficient of gas output gradually decreases. According to the research results, the optimal parameters of the process of nitrogen injection into the reservoir should be chosen on the basis of technological results, as well as technical and economic calculations.

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