June-14-2022 - Tuesday Daily Update - Mohammad Elkady

 

Daily Update - Mohammad Elkady - (June-14-2022)

1.  What did I do today?

Today, I continued practicing CMG GEM software through the tutorial I have.

2.  What did I find interesting/Work on? 

• The permeability on the reservoir model (on the grids) is different from the permeability entered on the template (real perm) because the model uses a grid width of 2 ft not the provided fracture width so it has to change the value of the permeability to have the same conductivity that to deal with numerical instability.
• Conductivity = f(w) X k (real) = G(w) X k (effective on the grid)
• For the refinements, in general you need more refinements in the flow direction so at the frac level, it is a linear flow perpendicular to the frac but at the perforation node it is a radial flow. 
• If your simulation takes long time, one thing you can change is the DTWELL in the Numerical Controls, but you have to check the log first to see that the material balance error is so small close to zero
• The HF is simply part of the matrix system in dual permeability model but with enhanced permeability.
• For dual porosity model, the HF should be part of the natural fracture because there is no matrix-matrix connection.
• Steps to build a model (Cont’d)
• Add adsorption data (Specify properties)
• Maximal adsorbed Mass(CH4) = 0.10 --> Langmuir volume
• Maximal adsorbed Mass(CH4) - Fracture = 0
• Langmuir adsorption Constant = 0.002
• Langmuir adsorption Constant - Fracture = 0
• Rock density = 120
• Rock density - fracture = 0
• Wells & Recurrent
• Import production/injection data for history matching
• You have to choose a constraint for your simulation either a cell in the production file (produced gas, water) or do total fluid history matching
• It's better practice to add one date at the end and set it as stop point to not lose the last production date
• Well Completion data
• Add  the perforations for your well
• Add Hydraulic fractures
• You have the options to apply HF either at the very start date or at a later date
• Create you template: Primary frac is the HF, Secondary is natural frac
• Fracture width: 0.001 ft
• Center intrinsic perm: 10000 md
• Horizontal tip permeability: 5000 md
• Orientation is perpendicular to the perforation direction (J)
• Number of refinements: 7 7 1
• Half length: 350 ft
• Number of layers above perforation (height of the fracture): that depend on the grid location of you well and perforations
• Good practice to cover the whole reservoir
• After creating the template, choose the fractures locations
• MD/Slab values >> I/J Slab: 22 28 34 40 these are the grid at which the HF will take place
• To export your production and pressure data
• Wells & Recurrent >> create field history file
• Use the fhf files to do the history match with the simulated data in RESULTS
• Simulate and do the history matching using RESULTS
• As shown in the Gas Rate and BHP plots below we have almost perfect match.

3.  What will I do next? 

Next, I will keep practicing CMG GEM software by completing this tutorial first and other resources, meanwhile I will search for simulation based papers about Permian basin and gather the important parameter for more realistic shale model.