Geothermal Electric Power Projects In Texas

Texas Renewables ’05 05
November 13-15, 13 15, 2005 – Hilton University Of Houston – Houston
Geothermal Electric Power Projects In Texas
Dr. Richard Erdlac – PI (geology/geophysics)
Linda Armour-Finch
Armour Finch – Research Geologist
Robert Lee – Petroleum Engineer
Susan Primeaux – Economics/Energy Policy
3 Students:
Mike Sorensen – geology/mathematics
Jordon Horton – geology
Mike Matteucci – geology
Contact Information:
erdlac_r@utpb.edu
erdlac_r@utpb. edu
http://www.utpb
http://www. utpb.edu edu/ceed ceed/index. /index.htm htm

UTPB/CEED has begun renewable energy
investigations with funding provided by
federal/state agencies.
ACKNOWLEDGEMENTS
* DOE grant of $194,458 to study deep Permian Basin
geothermal energy (part of an anticipated 3-year 3 year
Congressional appropriation) (# ( # DE-FG36 DE FG36-05GO 05GO 85023). 85023).
* State Energy Conservation Office grant of $40,000 to help
develop a state-wide state wide geothermal program (# ( # CM540). CM540).
* DOC/EDA grant of $115,000 + matching to study
geothermal, wind, and solar energy strategies in West
Texas (# ( # 08-06 08 06-04006 04006). ).

What evidence supports the development of geothermal
electrical energy in Texas?
1) Existing oil and gas wells document temperatures within the range range
for electrical
power production using conventional equipment.
2) DOE demonstration plant ran successfully in 1989-1990 in Brazoria, Texas.
Proved the potential of a hybrid (gas + hot water) power plant system.
3) Independent preliminary commercial investigations in 1999-2000 1999 2000 at a Delaware
Basin well location suggests that a plant in West Texas is feasible feasible
(GeothermEx
( GeothermEx, ,
Inc.).
What benefits does geothermal energy have for Texas?
1) Builds off existing oil and gas infrastructure throughout the state.
2) Generates a new energy income for Texas energy industrial base.
3) Employment generation from electrical power generation alone has a
large potential (many thousands) when looking at the entire state.

Five Target Areas For Electrical
Texas Anadarko
Basin
Delaware and
Val Verde Basins
Trans-Pecos
Region
Power Generation
East Texas HDR
& Geopressured
Area
Geopressured
Gulf Coast
(Successful
Demonstration
Project)

In the late 1970’s, 1970 s, the DOE started funding a long-
term project to investigate the entire Northern Gulf
Coast in Texas and Louisiana for its geopressured
geothermal potential.
Three forms of energy recovery were being considered:
Chemical energy – methane dissolved in brine.
Thermal energy – hot brines over 225 oF F (107 oC). C).
Mechanical energy – high brine flow rates (>20,000
bbls/day) and high well head pressure.

Sixteen wells tested to acquire
data on:
Reservoir and fluid properties for
assessing resource magnitude and
potential.
Direct and indirect uses.
Environmental impacts.
Commercial viability for resource
development.
Two testing programs
developed:
Wells of
opportunity – oil
and gas wells made
available by
industry.
Design wells –
drilled on
potentially
favorable
geopressured sites
based upon
existing
geological/geophysi
cal studies.
Two long-term long term tested design wells :
Gladys McCall #1 in Cameron Parish, Louisiana.
Pleasant Bayou #2 in Brazoria County, Texas.
First successful use of well in a hybrid binary
cycle system for electrical power production.
Frio sandstone; 300 oF; F; perfs 14,644-14,700 14,644 14,700 ft;
12 million bbls brine; 231,000 mcf gas.

SW Galveston
& S Brazoria
Counties
Frio geopressured-
geothermal fairways,
depositional models, and
reservoir quality descriptions
as defined by Gulf Coast
studies. Pleasant Bayou –
syndepositional down to the
basin faults most active
during early Oligocene.
Structural map on top of the T5
marker. The T5 marker begins at a
depth of –13,600 13,600 feet (-4,145 ( 4,145 m) and
continues much deeper. Sandstones
in T5-T6 T5 T6 zone correlate with
Anomalina birateralis Foraminifera
zone of the lower Frio.

Wellhead production estimated at a minimum of 20,000
bbls/day brine with 22 scf/bbl of gas – plant operated on only
10,000 bbl/day.
10,000 bbl/day = 420,000 gal/day = 17,500 gal/hr = 292 gal/min
Scale & corrosion inhibitors effective throughout operating
range of brine temperatures.
BHT = 309.2 o F (154 o C)
Max brine T = 277 o F (136.1 o C)
Permeability 159.8 md
Reservoir area = 36,000 acres (56.25 sq mi)

Fire protection
system at
Pleasant Bayou
Binary Turbine at
Pleasant Bayou
Gas Engine at Pleasant Bayou
Sept 1989- 1989 May 1990
Brazoria, Texas
Minimum rating 1.191
Binary Cycle Turbine 541 kW
Gas Engine 650 kW
Parasitic Load -209 kW
Capacity factor 80.2%
(3-day plant outage & 4-wk turbine outage)
Plant availability 97.5%
3,445 MWh from 121 days of operation were
sold to HPL
Minimum rating of 1.191 MW
For 1 year @ 1.187 MW = 10,433 MW =
$532,091 @ 5.1 cents/kWh = 12,374 bbl @
$43/bbl = 34 bbl/day

Compare with Ormat, Imperial Valley
Geothermal
Three heat exchangers at
Pleasant Bayou
Fire protection system at Pleasant Bayou
Condensers at Pleasant
Bayou
Well was highly
successful but was
never able to be
commercialized
due to the low cost
of alternative
resources,
specifically oil and
gas. There did not
then exist a Texas
mandate for
renewable energy
production, nor
were most people
concerned about
electricity
availability. This
was before the
California and NE
blackouts.

Five Target Areas For Electrical
Texas Anadarko
Basin
Delaware and
Val Verde Basins
Trans-Pecos
Region
Power Generation
East Texas HDR
& Geopressured
Area
Geopressured
Gulf Coast
(Successful
Demonstration
Project)

The Delaware and Val Verde Basins represent the deepest and hottest sub-basins
of the entire Permian Basin. Temperature gradient appears to be lognormal.
Wolfcamp Structure Map
Geological Data Services 2004
Woodford / Devonian
Tectonic Map
West Texas Earth
Resources Institute
Pecos = 2,559; Reeves = 834;
Terrell = 196; Loving = 36
R 2 = Coefficient of Determination
R = Correlation Coefficient

Assume a shallow and deep linear temperature gradient.
Selected Field Temperatures
Delaware / Val Verde Basin Thermal Gradient

2000 Preliminary Investigation Of A Fusselman Location
(Conducted by GeothermEx, GeothermEx,
Inc. for Client Company)
Formation Characteristics
- Depth: ±19,000 19,000 ft
- Net Pay: 200-600 200 600 ft (w. water zone)
- Porosity: 6-10 6 10 %
- Permeability: ~25 md
- Transmissivity kh: kh:
~10,000 md ft
Well Characteristics
- Well Size: variable
13-3/8 13 3/8” casing to 5,000-14,000 5,000 14,000 ft
10-3/4 10 3/4” casing below to formation top
6-1/2 1/2” open hole below
2-7/8 7/8” or 3-1/2 3 1/2” tubing for production
- Well Spacing: 3,700 ft apart
Fluid Characteristics
- Reservoir Pressure: 9,000 psia
- Reservoir T: 280 oF F (137.8 oC) C)
- Geothermal Gradient: 1.1 oF/100 F/100 ft
(nonlinear = ~ 2.8 oF/100 F/100 ft)
- Gas Gravity: 0.58
- H2S S Content in Gas: 0.1%
- Heating Vol. of Gas: 870 Btu/MCF
- Brine Salinity: 130,000 ppm
- Gas Content in Brine: 40 mcf/bbl
Courtesy Subir Sanyal

2000 Preliminary Investigation Of A Fusselman Location
(Conducted by GeothermEx, GeothermEx,
Inc. for Client Company)
Conclusions
- Maximum Brine Rate (self-flowed):
(self flowed): 7,875 bbls/D (125,000 lbs/hr)
- Associated Gas: 315 mcf/D
- Combined Hybrid Power Capacity: 1,400 kW (net)
Brine Component: 438 kW (gross) or 300 kW (net)
Gas Component: 1,100 kW (net) (assuming 30% engine efficiency)
- Net Annual Cash Flow/Well: $235,000 (~15 bbl oil/D @ $43/bbl)
Brine: 95% capacity factor at 4.5¢/kWh 4.5 /kWh = $125,000 annual
Gas: 85% capacity factor at 3¢kWh 3 kWh = $246,000 annual
Annual Gross: $358,000/well
Annual O&M: 1¢/kWh 1 /kWh x 1,400 kW = $123,000/well
- Capital Cost: $1,260,000
Binary Plant: $300,000 ($1,000/kW x 300 kW)
Gas Engine: $660,000 ($600/kW x 1,100 kW)
Well Restoration & Other Installment Costs: $300,000
- Payout: 5.36 years ($1,260,000 / $235,000)
- Improve efficiency by specifically designed equipment for recovery. recovery.
- Savings from the economy of scale when several wells are considered together.
- Obtaining renewable power price for the entire project by designing a hybrid facility
that uses both geothermal brine and the gas in an integrated integrated
way.
- Perforate several brine zones to increase production rate; economics based on 200-600 200 600
ft thickness only.
Courtesy Subir Sanyal

Five Target Areas For Electrical
Texas Anadarko
Basin
Delaware and
Val Verde Basins
Trans-Pecos
Region
Power Generation
East Texas HDR
& Geopressured
Area
Geopressured
Gulf Coast
(Successful
Demonstration
Project)

O&G data
SMU data
Heat flux in the north part of the Trans-Pecos is 80 mW/m 2 and up, higher than the 60-70 mW/m 2
found in the Gulf Coast. Temperatures and heat flux appear to support electric generation.
O&G data
SMU data
R2 = Coefficient of Determination
(T variability explained by depth)
R = Correlation Coefficient
(predictive relation of num pairs)
In these plots, two straight lines are
defined in the normal-normal plot and
one logarithmic curve for the lognormal
plot. In the first plot, the
shallow line gives dT/dz = 21.5 o C/km
with the deep line having dT/dz =
44.5 o C/km, over twice the shallow value.
The log-normal curve gives a better
statistical fit.

CONCLUSIONS
“The The future of the Texas oil and gas industry is tied
to the future of a Texas geothermal industry.” industry.
Companies have the opportunity to use existing and develop new
infrastructures towards geothermal development.
This will require the same entrepreneurial spirit that created the oil
and gas industry to rise and inaugurate a new energy evolution in in
Texas.
This means creating an energy triad triad
…. . oil …. . gas …. . and geothermal
combined.
combined