Oil & Natural Gas Projects
Exploration and Production Technologies
Advanced Oil Recovery Technologies for Improved Recovery from Slope Basin
Reservoirs, Nash Draw Brushy Canyon Pool, Eddy County, NM
This project was selected in response to DOE's Reservoir Class III solicitation,
DE-PS-22-94BC14972/73, for Slope and Basin Clastic Reservoirs. The goal of the
program was to extend the economic production of domestic fields by slowing
the rate of well abandonments and preserving industry infrastructure and to
increase ultimate recovery in known fields by demonstrating better methods of
reservoir characterization and advanced oil recovery and production technologies.
The chief objective of this project is to demonstrate that a development program
based on advanced reservoir characterization methods can significantly improve
ultimate oil recovery at Nash Draw field. The plan includes developing a control
area with conventional reservoir management techniques and comparing the performance
with an area that was developed with advanced reservoir management methods.
Specific goals are 1) to demonstrate that an advanced development drilling and
pressure maintenance program can significantly improve oil recovery as compared
with existing technology applications and 2) to transfer these advanced methodologies
to oil and natural gas producers in the Permian Basin and elsewhere throughout
the U.S. oil and gas industry.
Strata Production Co.
The project has used advanced technologies, including reservoir characterization,
reservoir simulation, 3-D seismic, advanced log analysis, and horizontal drilling
to identify and develop previously unattainable reservoirs. 3-D seismic has
identified potential reservoir targets underlying potash mines. Horizontal drilling
was used to drill through multiple seismic anomalies and access reserves that
would not be developed using vertical wells. To date, three directional/horizontal
wells have been drilled at the Nash Draw project. These three wells have developed
recoverable revenues of 1,000,000 barrels of oil and 5 billion cubic feet of
The ability to image, predict, and reach reserves that are restricted via typical
vertical development are significant and vital to the energy need of the United
States. There are 500,000 acres of federally owned land comprising the potash
area in southeastern New Mexico. In excess of 1 billion barrels of oil equivalent
(BOE) reserves are believed to lie beneath this area. Vertical development is
restricted due to mines and potential potash reserves. By employing drilling
islands and deviated/horizontal drilling, much of these reserves can be accessed.
The Nash Draw field in Eddy County, NM, produces oil and associated gas from
the Permian (Guadalupian age) Brushy Canyon Formation. The Brushy Canyon is
a relatively new producer in the Delaware Basin of West Texas and New Mexico.
Many of the recent discoveries in the Brushy Canyon were in wells originally
drilled to deeper zones, particulary the Morrow Sandstone (Lower Pennsylvanian)
in search of gas. These wells were completed in the Upper Pennsylvanian and
Lower Permian only when the deeper zones proved unproductive or when these zones
were abandoned after production declined to uneconomic rates. There is generally
little attempt to fully develop the upper pay zones, and the full potential
of many of these fields remains to be proven. Regionally, the fine-grained sandstones
of the Brushy Canyon contain as much as 400-800 million barrels of original-oil-in-place
(OOIP), and thus this formation represents a significant reservoir interval
in the Permian Basin. However, low permeability and petrophysical heterogeneity
limit primary recovery to as little as 10-15% of OOIP.
Low recovery in the Nash Draw Unit (NDU) reservoir is caused by low reservoir
energy, less-than-optimum permeabilities and porosities, inadequate reservoir
characterization, and poor past reservoir-management strategies. Based on the
production constraints due to high gas-oil ratios that have been observed in
other, similar Delaware fields, pressure maintenance in continuous parts of
the reservoir is a likely requirement at NDU.
Three basic constraints to producing the Nash Draw Unit Brushy Canyon Reservoir
are 1) limited areal and interwell geologic knowledge, 2) lack of an engineering
tool to evaluate the various producing strategies, and 3) limited surface access
that will prohibit development with conventional drilling. The limited surface
access at NDU is caused by the proximity of underground potash mining and surface
The use of advanced geophysical log analysis techniques developed from the Nash
Draw project have proven useful in defining additional productive zones and
refining completion techniques. The advanced geophysical log analysis program
proved to be especially helpful in locating and evaluating potential recompletion
intervals, which has resulted in low development costs with only small incremental
increases in lifting costs.
To develop additional reserves at lower costs, zones behind pipe in existing
wells were evaluated using techniques developed for the Brushy Canyon sandstones.
Geophysical log analysis techniques developed in Phase I of the project were
used to complete a total of 13 producing intervals of the Nash Draw wells in
shallower zones. Four wells were recompleted in 1999, which allowed the development
of economic reserves during a period of low crude oil prices. An additional
four wells were recompleted in 2000, which resulted in 123,462 barrels of oil
and 453,424 million cubic feet of natural gas reserves being added at a development
cost of $1.57 per BOE. Two wells, the Nash Draw #29 and #38, were recompleted
in 2001, which added 7,000 barrels of oil and 18,000 million cubic feet of natural
gas reserves at a cost of $9.70 per BOE. The Nash Draw wells #1, #12, #15, and
#20 were completed in shallower zones during 2002 and 2003, which added 128,000
barrels of oil and 150,000 million cubic feet of natural gas reserves at a cost
of $1.62 per BOE. Overall, the weighted average development cost is $1.87 per
One of the technologies being tested at the Nash Draw project is the Fuzzy
Expert Exploration Tool, developed by Dr. Bob Balch and his team at New Mexico
Institute of Mining and Technology's Petroleum Recovery Research Center, that
was used to predict the expected outcome of the drilling of the Nash Draw #34
well. The expert tool uses regional geology, source rock data, offset wells,
and other parameters to predict a project's success.
Six new wells were drilled for data acquisition. Multiple sidewall cores were
obtained for analysis. Approximately 203 feet of full core was cut from 6,641
to 6,844 feet in the Nash Draw Unit #23 well. The routine core analysis included
porosity, permeability, and saturation for each foot of core. Special core analysis
to determine wettability, relative permeabilities, mineralogy, pore structure,
and clay content were utilized for characterization. Normal suites of logs were
obtained in all wells, and a magnetic resonance tool was run in Nash Draw Unit
#23 for comparison with the cores taken. Well data, including logs, cores, fluid
properties, and production history and analysis, were distributed to the multidisciplinary
geoscience team using the interactive data base. A vertical seismic profile
survey was performed in the Nash Draw Unit #25 well, and the data obtained was
used to calibrate the 3-D seismic data that was obtained in June 1996.
The 3-D data set has been used to create the geologic model. Reservoir modeling
used advanced log analysis data to develop the second-generation model. Seismic
amplitudes were used to distribute reservoir attributes in the third-generation
reservoir model. The 3-D seismic data have yielded drilling targets, indicated
that the proposed pilot area may be compartmentalized, and identified a more
continuous area of the reservoir. Two wells were drilled into seismic anomalies,
and a directional/horizontal well was drilled to reach a seismic anomaly located
beneath a playa lake and potash reserves.
Analysis of production rates versus cumulative production, bottomhole pressure
versus gas/oil ratio, and seismic data using geostatistics have helped identify
drainage areas and boundaries. Incremental oil production since the beginning
of the project is 274,206 barrels of oil, and, if successful, this project will
recover an additional 18.5 million barrels of oil, raising the field recovery
from 10% to 45% of OOIP. Researchers identified two potential products: an advanced
log analysis program and a database management system.
Current Status (August 2005)
The Nash Draw #34 has been drilled, and the toe zone completion is being evaluated.
A rocket fuel breakdown was done in the open hole to reduced breakdown pressures
and near-wellbore tortuosity. This appears to have been successful and will
be used on the two zones to be completed in the heel section. Additional targets
in the Nash Draw project are being evaluated, and deviated/horizontal wells
are being evaluated for two other projects in the Nash Draw area.
Project Start: September 25, 1995
Project End: September 30, 2005
Anticipated DOE Contribution: $7,832,006
Performer Contribution: $12,763,549 (62% of total)
NETL - Daniel Ferguson (firstname.lastname@example.org or 918-699-2047)
Strata - Mark Murphy (email@example.com or 505-622-1127)
Drilling the Nash #34 well on the edge of the playa lake with a potash mine
shaft in the background.
3-D seismic amplitude map.
Nash #34 wellbore path.