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