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PTE-555
Well Completion, Stimulation & Formation Damage of Coal Bed Methane Field – Powder River Basin, Wyoming
Presented by: Team-13
Amey Dhaygude
Juan Li
Luhe Lu
Ke Pan
Coal is source and reservoir rock, Has a great energy production potential.
Created by biogenic and thermogenic processes.
Coal Properties
- different affinity for different gases
- friability, low compressive and tensile strength
- extensive natural fracture system.
Trapped within a coal seam by formation water.
Recovered from un-mined coal seams (CBM Extraction) by unconventional methods
Coalbed Methane
Juan Li
01
Methane Production From Coal Seams
Luhe Lu
02
Powder River Basin Data
Reservoir Properties
Area 60000 Sq. Km (23166 SqMiles)
Thickness 5150 Meters (16900 feets)
Type of Rock Coalbed Interbedded with Sandstone
Permeability 50-152 mD
Porosity 23%-25%
Amey Dhaygude
03
Well Completion Flow Chart
Amey Dhaygude
04
CBM Well Completion - Methods
Open Hole Completion (Under-Ream)
Open Hole Completion with Cavitation
Cased Hole Completion
Cased Hole Completion – Access by Slotting
Cased Hole Completion – Access by Perforations
05
Luhe Lu
Open Hole Cavitation Process
Success of the cavity completion depends on
Thick seams & Good Permeability
Extensive cleating & Low ash content
Ranks of coal beyond the coalification break
Over pressuring & High In-Situ Stress
Cavitation Types
Injection cavitation
Natural cavitation
Juan Li
06
Formation Damage - Causes
Mud filtrate Invasion while well drilling and cementing
Wettability Alteration of coal matrix by fracturing fluids
Ground water aquifers surrounding shallow, under pressured low strength coal
swelling and damage to coals due to Fluid leak-off associated with gel-base systems
formation damage due to not breaking of gel, irreversibly plugging cleats
07
Ke Pan
Formation Damage - Control
CBMA additive - specifically designed to enhance the dewatering.
- additive maintains wettability of the coal & reduces fines migration into formation.
- Cause standard cased hole well drilling and completion practices to create extensive damage to the coal face
CemNET – fibers form a mat like barrier to avoid getting cement into cleats
LiteCRETE – Improved cements of Low slurry density with high compressive strength reduces formation damage
08
Ke Pan
Stimulation - Methods Hydraulic Fracturing –
- Specially designed CoalFRAC System with nitrified foam
- Solids & Polymer free, Meets environmental standards
- Excellent for initiating, Propagating fractures, Controls leakoffs
Enhanced coal bed methane (ECBM)
- CO2 Injected into Coal seam & Absorbed by Coal
- Displaces & liberates methane
Use of Surfactants –
- Conventional method of Stimulation
- Stimulation fluids can change formation properties
- Degradation of dewatering Process, Special additives may be required
09
Amey Dhaygude
Conclusion
CBM – Unconventional Energy Source, Required specialized technology
Well completion – Open Hole Cavitation
Formation Damage control – CemNET & LiteCRETE Technologies
Stimulation – Hydraulic Fracturing
More Emphasis & Research required of ECBM/CO2 Sequestration
Amey Dhaygude
10