Numerical Modeling of Gas Production from Fractured Shale Matrix Using Dual Porosity Approach

2017 ◽  
Author(s):  
P. Thawrani ◽  
A. Kaligi ◽  
G. Suresh Kumar
Keyword(s):  
Numerical Modeling ◽  
Gas Production ◽  
Dual Porosity

An Efficient Multiscale Method for the Simulation of In-situ Conversion Processes

SPE Journal ◽  
2015 ◽  
Vol 20 (03) ◽  
pp. 579-593 ◽  
Author(s):  
Hangyu Li ◽  
Jeroen C. Vink ◽  
Faruk O. Alpak
Keyword(s):  
Numerical Modeling ◽  
Reaction Rates ◽  
Sensitivity Study ◽  
Gas Production ◽  
Multiscale Method ◽  
Fine Scale ◽  
Computational Performance ◽  
Simulation Results ◽  
Coarse Grids

Summary Numerical modeling of the in-situ conversion process (ICP) is a challenging endeavor involving thermal multiphase flow, compositional pressure/volume/temperature (PVT) behavior, and chemical reactions that convert solid kerogen into light hydrocarbons, which are tightly coupled to temperature propagation. Our investigations of grid-resolution effects on the accuracy and performance of ICP simulations have demonstrated that ICP-simulation outcomes—specifically, chemical-reaction rates, kerogen-accumulation profiles, and oil-/gas-production rates, may exhibit relatively large errors on coarse grids. Coarse grids are attractive because they deliver favorable computational performance. We have developed a novel multiscale modeling method for simulating ICP that reduces numerical-modeling errors and reproduces fine-scale-simulation results on relatively coarse grids. The method uses a two-scale solution method, in which the reaction kinetics of the solids is solved locally on a fine-scale grid, with interpolated temperatures obtained from coarse-grid simulations of thermal flow and fluid transport. We demonstrate the accuracy and efficiency of our multiscale method with representative 1D models. It is shown that the method delivers accurate solutions for key ICP performance indicators with very little computational overhead compared with corresponding coarse-scale models. The robustness of the multiscale method has been verified over a number of physical-parameter ranges with a limited-scope sensitivity study. Numerical results show that the multiscale method consistently improves the simulation results and matches the fine-scale reference results closely.

Damage Tolerance of Well-Completion and Stimulation Techniques in Coalbed Methane Reservoirs

2005 ◽  
Vol 127 (3) ◽  
pp. 248-256 ◽  
Author(s):  
Hossein Jahediesfanjani ◽  
Faruk Civan
Keyword(s):  
Coalbed Methane ◽  
Damage Tolerance ◽  
Horizontal Wells ◽  
Gas Production ◽  
Productivity Index ◽  
Dual Porosity ◽  
Formation Damage ◽  
Hydraulic Fractures ◽  
Well Completion ◽  
Reservoir Conditions

Coalbed methane (CBM) reservoirs are characterized as naturally fractured, dual porosity, low permeability, and water saturated gas reservoirs. Initially, the gas, water, and coal are at thermodynamic equilibrium under prevailing reservoir conditions. Dewatering is essential to promote gas production. This can be accomplished by suitable completion and stimulation techniques. This paper investigates the efficiency and performance of the openhole cavity, hydraulic fractures, frack and packs, and horizontal wells as potential completion methods which may reduce formation damage and increase the productivity in coalbed methane reservoirs. Considering the dual porosity nature of CBM reservoirs, numerical simulations have been carried out to determine the formation damage tolerance of each completion and stimulation approach. A new comparison parameter, named as the normalized productivity index Jnp(t) is defined as the ratio of the productivity index of a stimulated well to that of a nondamaged vertical well as a function of time. Typical scenarios have been considered to evaluate the CBM properties, including reservoir heterogeneity, anisotropy, and formation damage, for their effects on Jnp(t) over the production time. The results for each stimulation technique show that the value of Jnp(t) declines over the time of production with a rate which depends upon the applied technique and the prevailing reservoir conditions. The results also show that horizontal wells have the best performance if drilled orthogonal to the butt cleats. Long horizontal fractures improve reservoir productivity more than short vertical ones. Open-hole cavity completions outperform vertical fractures if the fracture conductivity is reduced by any damage process. When vertical permeability is much lower than horizontal permeability, production of vertical wells will improve while productivity of horizontal wells will decrease. Finally, pressure distribution of the reservoir under each scenario is strongly dependent upon the reservoir characteristics, including the hydraulic diffusivity of methane, and the porosity and permeability distributions in the reservoir.

Numerical modeling of hydrogen-rich gas production from gasoline autothermal reforming in a plug flow reactor for electric vehicles

2021 ◽  
pp. 1-24
Author(s):  
Ergin Kosa ◽  
Cuneyt Ezgi
Keyword(s):  
Numerical Modeling ◽  
Electric Motor ◽  
Flow Reactor ◽  
Plug Flow ◽  
Gas Production ◽  
Autothermal Reforming ◽  
Hydrogen Gas ◽  
Plug Flow Reactor ◽  
Gas Generation ◽  
Adiabatic Case

Abstract Due to the increase in the greenhouse effect, lowering emissions is becoming a certain issue all over the world. It is a concern to develop alternative options to minimize the spread of exhaust gases. For this purpose, in this study, the plug flow reactor in the system consisting of solid oxide fuel cell (SOFC), reactor, electric motor, battery, burner, and the heat exchanger is considered. Numerical modeling of hydrogen gas generation in a plug flow reactor is studied. The reactor indicated on-board hydrogen gas generation for an electric motor automobile has not been modeled in the literature yet. Autothermal reforming of isooctane is simulated in the COMSOL multi-physics software program in the reactor particularly. Conversion of isooctane and H2O are examined at different overall heat transfer coefficients, input temperatures, and steam/carbon ratios. Also, there are certain differences between adiabatic and non-adiabatic conditions. The produced synthesis gas of hydrogen drastically increases in the non-adiabatic case. The obtained results from the model are compared with experimental data obtained from the literature. H2 production at the end of the autothermal reforming process indicates the power provided from the reactor can operate a motor of an automobile. In the study, the achieved power is 65.8 kW (88 HP) is sufficient for an automobile. Simulation results show that the reactor volume of 75 L supplies 0.18 mols−1 of H2 and 0.08 mols−1 of CO in the non-adiabatic case.

scholarly journals Tight carbonate gas well deliverability evaluation and reasonable production proration analysis

2021 ◽  
Author(s):  
Jiang Li ◽  
Xianchao Chen ◽  
Ping Gao ◽  
Jingchao Zhou
Keyword(s):  
Numerical Model ◽  
Stress Sensitivity ◽  
Gas Production ◽  
Productivity Index ◽  
Dual Porosity ◽  
Gas Reservoirs ◽  
Gas Well ◽  
Well Production ◽  
Tight Carbonate ◽  
Single Well

AbstractIt is very important to accurately predict the gas well productivity and reasonably allocate the gas production at the early development stage of gas reservoirs. However, both the non-Darcy and stress sensitivity effects have not been investigated in dual-porosity model of tight carbonate gas reservoirs. This paper proposed a new dual-porosity binomial deliverability model and single-well production proration numerical model, which consider the effects of non-Darcy and stress sensitivity. The field gas well deliverability tests data validated the accuracy of the new analytical model, which is a very helpful deliverability method when lacking deliverability test. A geological model was built on the results of the well log, well testing, and well production analysis. Then, a reasonable production proration analysis was conducted based on history matched single-well numerical model. The gas productivity index curve and production–prediction of MX22 several simulation cases were adopted to analyze the reasonable production proration. The results indicate that 1/6 may be suitable for high productivity gas well proration. In addition, the absolute open flow rate from the numerical simulation is higher than that from the new deliverability equation, which also shows that the pressure transient analysis sometimes has some deviation in formation property prediction. It is suggested comprehensively utilizing the analytical binomial model and the single-well numerical model in tight carbonate gas well deliverability evaluation.

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