Field and laboratory Analyses
of Gas Shales
CBM Solutions is the industry leader in assessing gas shales. We
have pioneered field desorption and adsorption analyses of gas
shales. We have worked extensively with producing US shales and
all the important potential gas shales in Western Canada
including the Exshaw/Bakken, Nordegg, Duvernay, Second White
Specks, Doig, Montney and Shaftesbury and other strata.
CBM Solutions Gas Shale Evaluation Protocol (GSEP) is a
comprehensive set of
analyses specifically designed to evaluate the gas shale
potential of fine grained strata.
The analytical techniques are designed for purpose and are based
on the recognition
that conventional rock analyses and coalbed methane protocols
are, for the most part, not applicable to tight, fine grained
rocks. We have further refined our methodologies based on
extensive field and laboratory studies such that our protocols
are optimized for specific gas shales with the recognition that
gas shales are diverse and heterogeneous reservoirs.
The
Gas Shale Evaluation Protocol is designed specifically to: 1)
determine the gas in place (sorbed, free and solutions gas)
throughout the stratigraphy; 2) quantify matrix and where
possible bulk permeability and stress sensitivity of
permeability; 3) characterize in situ fractures; 4) select zones
optimal for fracturing; 5) evaluate borehole stability; and 6)
determine zones for horizontal drilling and completions. Our
protocol begins with assisting where necessary with well design,
continues at the well site, through the laboratory and numerical
analyses and culminates with successful well development.
We
recognize that the timing is everything! It is our goal
to provide key data for zone evaluation, frac zones selection
and frac design within a time frame that enables our clients to
utilize the data while the rig is still on site. Our time
sensitive protocol includes providing total gas in place,
porosity, mineralogy and rock mechanics data and where possible
stress sensitive permeability. Since we do almost all analyses
in house; we control the quality, timing and reporting of
analyses.
WELL
SITE SERVICES- Our contributions to the well site begin
in the office where our experienced staff are available to our
clients to assist in the design and optimizing of well drilling,
testing and completion programs. On the well site we handle,
describe and perform fracture analyses, photography, gamma ray
log, preserve and canister samples for desorption and total gas
analyses. Gas samples are collected throughout the desorption
process and integrated for average gas composition values. Well
site sample and fluid preservation is critical for further
analyses. We can utilize cuttings, side wall, wire line
retrieval core and conventional core. On site we determine the
uniaxial compressive strength of representative core specimens
using out portable point load tester and cuttings samples
throughout the well are collected and preserved for near real
time mineralogical and organic carbon analyses. On site samplers
are selected, preserved and analyses began for our proprietary
PRODUCTION ISOTHERM.
TOTAL
GAS STORAGE- Gas storage in gas shales includes gas in
the adsor-----------ee states and in solution. Using our
preserved well site samples effective, total porosity and water
saturation are determined on representative samples. Adsorption
isotherms and production isotherms are collected on all major
strata. Our analyses include measurement of porosity and
permeability of methane or other gases using our proprietary
methodologies. Pore size distribution is determined by a variety
of gaseous
methods, as well as high pressure Hg intrusion (Hg porosimetry).
PERMEABILITY-
Although bulk permeability of fractured reservoirs
requires field tests, in many gas shales the matrix
permeability/diffusion is limiting. We collect crushed sample
permeability and diffusion data as a matter of course during
porosity
determination and from Hg intrusion data, however, we advocate
permeability measuring under reservoir stress condition and we
quantify the stress sensitivity of permeability which allows us
to predict the producability of the strata.
INORGANIC
GEOCHEMISTRY- Inorganic geochemistry starts with
mineralogical analyses by x-ray diffraction. We quantify
the mineralogy by Rietveld analyses where possible and provide
the data in a format suitable for log calibration. Where
needed, additional analyses of the elemental chemistry, mineral
fabric by SEM/EDS, thin section analyses, fluid sensitivity and
particle size distribution may be undertaken.
ORGANIC
GEOCHEMISTRY- The adsorption capacity of fine grained
rocks is closely correlated with the abundance, type and
maturity of the organic matter.. Our protocol using a
combination of total carbon, Rock Eval and organic petrology
with vitrinite
reflectance analyses provides data that can be tied to
adsorption data and integrated through the stratigraphy and
laterally via appropriate calibration of well logs.
Carbon and hydrogen isotopic analyses of gas samples may also be
performed if deemed necessary.
FRACTURE
ANALYSES- Our fracture description and analyses protocol
is integrated with photographs and three dimensional analyses
and provides data that can be used for quantitative analyses
using industry standard software.
ROCK
MECHANICS- Reservoir access is key to exploitation of
unconventional gas reservoirs. CBM Solutions 'geomechanical
stratigraphy' program is specifically designed to provide our
clients with the necessary rock mechanical properties critical
for borehole stability and frac design. When our
geomechanical stratigraphy is linked with our stress sensitivity
permeability analyses, our clients are armed with the key tools
for screening gas shales for exploration and exploitation
through optimization of drilling and completions. All
mechanical tests are carried our using a servo controlled
triaxial apparatus under prescribed stress states and pore
pressure providing compressive strength, all relevant moduli
(Young's, Shear Bulk), Poisson's Ration, Biot's poroelastic
parameter etc. We can deform whole core samples ranging
from 1 inch to 4 inches in diameter, alleviating the necessity
of recoring existing core. We measure ultrasonic
compressional and shear-wave velocities to collect dynamic
elastic moduli that can be used for calibration of sonic logs.
DATA
INTEGRATION- CBM Solutions experts work with our clients
to integrate the myriad of engineering and geological data into
a comprehensive exploration and development program giving our
clients the technical advantages necessary for successful
exploration of unconventional petroleum reservoirs, |