cbm persentation dsign
TRANSCRIPT
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 1/21
COALBED METHANE
By :
Febriarto (113070153)
Ferry Apriadi (113070176)
Class : C
Petroleum Engineering Departement
Mineral Technology Faculty Universitas Pembangunan Nasional ³Veteran´ Yogyakarta
2011
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 2/21
� ABSTRACT
� INTRODUCTION
� COAL CHARACTERISTIC
� DIFFERENCES WITH CONVENTIONALRESERVOIR
� COMPARISON PRODUCTION METHOD
� CBM IN INDONESIA
� CONCLUSION
O
utline
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 3/21
Abstract
Coalbed methane (CBM) is an increasingly important source of the world¶s natural gasproduction with many countries, including
Indonesia, actively developing this unconventionalenergy source.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 4/21
Introduction
Natural gas is a substance called methane(CH4). Coal bed methane (CBM) is found in coalseams. CBM is generated from a biological process
as a result of microbial action or from a thermalprocess. Often a coal seam is saturated with water,
with methane is held in the coal by water pressure.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 5/21
Figure 1: Coalification
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 6/21
Coal Characteristic
Similar to conventional naturally fracturedreservoirs, coal is generally characterized asa dual-porosity system because it consists of
a matrix and a network of fractures.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 7/21
Figure 2: Coal is a DualPorosity System
Figure 3: Example of Coal
Cleat Structure
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 8/21
Differences With Conventional Reservoir
The most significant differences are:
1. In a conventional reservoir, the majority of the gas is contained in the pore space but in aCBM reservoir, the majority of the gas isadsorbed (bonded to the coal molecules) inthe matrix.
2. In a conventional reservoir, reservoir gasexpands to the producing wells in directresponse to any production-induced pressuregradient. But CBM reservoirs generally require that reservoir pressure be below somethreshold value to initiatemgas desorption.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 9/21
3. In a CBM reservoir, a gas molecule must firstdesorb and diffuse through the coal matrix toa cleat. It can then move through the cleated
fracture system and the hydraulic frac-stimulation to the wellbore via conventionalDarcy flow.
Cont«
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 10/21
To encourage the CBM to flow, the naturalpressure in the coal seam must be decreased by de-watering the coal. A pump located at the
wellhead removes the water that naturally occupies the cleats. This lowers the reservoirpressure along the particular coal seam, drawsthe gas out of the coal and allows it to flow intothe well bore. Effective de-watering may take
anywhere from several months to several years.
Cont«
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 11/21
Figure 4: CBM Development Process
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 12/21
Comparison Production Method
y W ell Spacing
for same large area, CBM field needs moreproduction well then coventional gas field.
Conventional Gas : 640 acres per well
CBM : 80 ± 320 acres per well
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 13/21
y Production Profile
During start-up operations, a conventionalnatural gas well produces large volumes of gasand very little water. O ver time, gas production
decreases while the water increases, until the gasreserve is depleted or the volume of water
becomes too great. Conversely, CBM wellsproduce large quantities of water at first and
only small amounts of gas. During the initial de- watering phase (usually several months), gasproduction increases steadily while the amountof water decreases.
Cont«
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 14/21
Figure 5: Generalized Production Profilefor CBM
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 15/21
y Infrastructure
CBM operations require gas and water-gathering systems. W ater is collected in
storage tanks at the well and transported by truck to a disposal site or moved by pipelineto a suitable central disposal site
Cont«
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 16/21
Coalbed Methane in Indonesia
y Indonesia has the 2nd largest CBM reserves. Totalpotential CBM reserve in Indonesia is estimated of about 453.3 TCF from 11 basins stretching out over
the regions
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 17/21
Figure 6: CBM in Indonesia
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 18/21
y The economic potency of CBM in Indonesia must be supported by well developed legal infrastructure.CBM falls into the oil and gas regulations regime
due to its nature as a gas fuel. Currently, thespecific legal basis for the exploration andexploitation of CBM is regulated by Minister of Energy and Mineral Resources No. 36 of 2008 onCBM Business Activities (CBM Regulation).
Cont«
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 19/21
Conclucions
1. Coalbed methane is formed during coalification.
2. CBM reservoir, the majority of the gas is adsorbed(bonded to the coal molecules) in the matrix
3. To encourage the CBM to flow, the natural pressurein the coal seam must be decreased by de-wateringthe coal.
4. During start-up operations, a conventional naturalgas well produces large volumes of gas and very little water. O ver time, gas production decreases
while the water increases, until the gas reserve isdepleted or the volume of water becomes too great.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 20/21
5. Total potential CBM reserve in Indonesia isestimated of about 453.3 TCF from 11 basinsstretching out over the regions.
6.The economic potency of CBM in Indonesia must be supported by well developed legalinfrastructure.
8/6/2019 cbm persentation dsign
http://slidepdf.com/reader/full/cbm-persentation-dsign 21/21