Enhanced Oil Recovery and Residual Oil Zone Studies at the

U.S. Geological Survey

P.D. Warwick and U.S. Geological Survey Enhanced Oil Recovery and Carbon Dioxide Storage Assessment Team

2017 EOR Carbon Management Workshop – Midland, TexasPart of the Annual CO2 Conference Week, December 4-7, 2017

U.S. Geological SurveyDepartment of the Interior

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Outline for Presentation

• Part 1: Current activities associated with national carbon dioxide enhanced oil recovery (CO2-EOR) assessment

• Part 2: Current investigations associated with residual oil zones (ROZs)

• Summary

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Part 1: Assessment of National CO2-EOR and associated CO2 storage

• Requested by Congress in the Energy Independence and Security Act

• Goals: 1) develop a probabilistic assessment methodology, and 2) estimate the technically recoverable (pre-economic) hydrocarbon potential using CO2-EOR within the United States

• Benefit: CO2-EOR can increase recoverable hydrocarbon production leading to incidental retention of CO2 while also making available pore space for long-term storage of anthropogenic CO2

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Summary of USGS five step probabilistic assessment

methodology for CO2-EOR and associated CO2 storage

Primary data sources:

• IHS Energy Group (2011); IHS Inc. (2012), and NehringAssociates Inc. (2012)

• Other publicly available or donated proprietary data sets

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https://doi.org/10.3133/tm7C16

Carolus and others (2017)

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Screening criteriaproperties (units) Miscible flooding Transitional Immiscible flooding

API gravity of oil (°API) 1>25 22 > API ≤ 25 213 ≤ API ≤ 22

3Viscosity (cP) <10 <10 <10

4Minimum miscibilitypressure (psi) ≤ fracture pressure – 400 ≤ fracture pressure – 400 Not applicable

Screening Criteria Eligible Reservoirs

1 National Petroleum Council (1984).2 Hite (2006).3 Andrei and others (2010).4 To maintain a reasonable level of safety, the minimum miscibility pressure of candidate reservoirs must be at least 400 psi below the reservoir fracture pressure. The 400 psi safety margin is an estimate of current industry practice.

Carolus and others (2017) 6

Other assumptions and conditions• The candidate EOR reservoirs have these characteristics:

net pay >5 ft, permeability >3 mD, OOIP >5 MMbbls(Attanasi, 2016)

• Residual oil zones and active EOR reservoirs are not included

• Oil recovery and CO2 retention factors are modeled with the CO2 Prophet reservoir simulator (Attanasi, 2017)

• About 3,700 reservoirs found to be amenable to miscible CO2-EOR, with about 140 candidate reservoirs amenable to immiscible CO2-EOR (Warwick and others, 2017)

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https://doi.org/10.3133/sir20175062.

Verma, ed. (2017) Describes methods of estimating CO2-EORrecovery factors

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More than 3,700 reservoirs are miscible candidates for CO2-EORMore than 140 reservoirs are immiscible candidates

NOGA = USGS National Oil and Gas Assessment (see Beeman and others, 1996)

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USGS CO2-EOR Assessment Status

• The geologic CO2-EOR assessment is underway and about 90 percent complete

• The results will be compiled into a report, with peer review beginning in 2018, and publication expected in 2019

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Part 2: USGS working definition for residual oil zone:

• The residual oil zone (ROZ) is a naturally occurring reservoir or part of a reservoir where a mix of mobile water and potentially producible hydrocarbons remain

• The ROZ can be either found between a conventional oil/water contact and an oil-free water level, or can be a reservoir on its own

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• Not all reservoirs have a ROZ zone

• Location and extent of ROZs are not well defined

• Well log data usually does not extend into the ROZ

• ROZ production data are limited and often commingled with conventional production

• Need production analogues to assess the technically producible oil and gas from ROZs

• Need additional data to access the potential CO2storage (via CO2-EOR) in ROZs

ROZ assessment challenges and considerations

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Part 2.1ROZ well log study

East Seminole Field, Texas

Jacqueline RouecheC. Özgen Karacan

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ROZ well log study overview

Objectives:• Estimate remaining oil in place of the ROZ

with the use of well logs and core data• Develop a methodology that could be

applied to all sedimentary basins • Identify and characterize the presence of

potential productive ROZs in basins of the United States

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With the use of well logs and core data:

• Identify one active CO2-EOR brownfield for testing the methodology

• Identify the ROZ as a function of depth

• Predict remaining oil saturation in ROZ

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East Seminole FieldGaines County, TXSan Andres Formation

(Modified from Merrill and others, 2015)

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Statistical techniques were used to identify patterns of association and relationships from the acquired core and log data

Core Data:• Monte Carlo and triangular distribution• Calculate probabilistic in-situ oil saturations

Well Logs:• Neural network from raw log readings – training and testing

Combine Well Logs with Core Data:• Identify main pay (MP) vs ROZ as function of depth• Predict oil saturation from will logs without core data

Roueche and Karacan (in press) 17

Part 2.2ROZ Carbonate Production

Analogues

West Carney Hunton FieldHossein Jahediesfanjani

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Map showing production locations from the Silurian-DevonianHunton Group and informal Misener sandstone of the Woodford Shale, and Hunton Group thickness; contour interval is 250 feet.(Modified from Gaswirth and Higley, 2014)

West Carney Hunton Field

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West Carney Hunton as a ROZ• In the Hunton Formation, the original oil was

displaced by aquifer water influx in geological times

• Some of the oil was displaced to shallower formations, while some remained trapped in the Hunton Formation

• The amount of trapped oil, which mostly remained in relatively tighter rock, is a function of porosity and homogeneity of the reservoir

• The matrix that contains low permeability is oil wet and hence the oil could not be displaced

(Kelkar, 2007) 20

West Carney Hunton Field Properties

RegionOil

SaturationWater

Saturation Porosity

Central West 0.48_ 0.52_ 0.045

Central East 0.486 0.513 0.045

East 0.382 0.617 0.067

West 0.279 0.72_ 0.079

(Kelkar, 2007)

West Carney Hunton Field

Representative wells with production data

(IHS Markit, Inc.)

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Next steps: IHS Markit, Inc. well production data analysis

Part 2.3 Red Fork Sandstone

ROZ Analogue

Mt. Vernon FieldLincoln County, OK

Jacqueline Roueche

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Location of the Cherokee Platform Province

Mount Vernon Field

Pennsylvanian Cherokee GroupRed Fork sand production

Modified from Drake and Others (2015)

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Modified from Chernicky and Schad (2002)

Mount Vernon Field

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Modified from Chernicky and Schad (2002)

Mount Vernon Field

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Next steps: IHS Markit, Inc. well production data analysis

Summary

• The USGS is conducting a probabilistic assessment of the technically recoverable hydrocarbon potential using CO2-EOR within the United States; expected publication in 2019

• Well log data need to be calibrated with core data to better define oil and water saturations in ROZs

• Multiple challenges remain before ROZs can be assessed on regional and national scales (see page 12)

• Regional reservoir hydrocarbon production and CO2 storage analogues are needed to calibrate ROZ assessment estimates

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U.S. Geological Survey Enhanced Oil Recovery and Carbon Dioxide

Storage Assessment Team

Emil AttanasiMadalyn BlondesSean BrennanMarc BuursinkColin DoolanJoseph East Philip FreemanHossein JahediesfanjaniC. Özgen Karacan

Celeste LohrMatthew MerrillRicardo Olea Jacqueline RouecheJenna Shelton Ernie SlucherBrian Varela Mahendra VermaPeter Warwick

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`Utilization of Carbon and other Energy Gases—Geologic Research and

Assessments Project

For more information contact:Peter D. Warwickpwarwick@usgs.gov703-648-6469

Project Website

Selected Publications

http://go.usa.gov/8X8

http://go.usa.gov/xZDpz 28

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Energy Congress, September 15, 2010, 20p., http://worldwidescience.org/topicpages/c/co2+enhanced+oil.html.Attanasi, E.D., 2016, A strategy for low cost development of incremental oil in legacy reservoirs: Society of Petroleum Engineers, p. 1-17, paper SPE-179997-MS.Attanasi, E.D., 2017, Using CO2 Prophet to estimate recovery factors for carbon dioxide enhanced oil recovery, chap. B of Verma, M.K., ed., Three approaches for

estimating recovery factors in carbon dioxide enhanced oil recovery: U.S. Geological Survey Scientific Investigations Report 2017–5062, p. B1–B10, https://doi.org/10.3133/sir20175062B.

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Chernicky, David, and Schad, S.T, 2002, Development of transition-zone reserves around abandoned production-Case study of Mount Vernon Field, Lincoln County, Oklahoma, in Boyd, D.T, ed., Finding and Producing Cherokee Reservoirs in the southern Midcontinent, 2002 symposium: Oklahoma Geological Survey Circular 108, p. 61-72.

Drake, R.M., II, Hatch, J.R., Schenk, C.J., Charpentier, R.R., Klett, T.R., Phuong, A.L., Leathers, H.M., Brownfield, M.E., Gaswirth, S.B., Marra, K.R., Pitman, J.K., Potter, C.J., Tennyson, M.E., 2015, Assessment of undiscovered oil and gas resources in the Cherokee Platform Province area of Kansas, Oklahoma, and Missouri, 2015: U.S. Geological Survey Fact Sheet 2015-3054, 2 p., http://dx.doi.org/10.3133/fs20153054.

Gaswirth, S.B. and Higley, D.K., 2014, Geologic assessment of undiscovered oil and gas resources in the Cambrian– Devonian stratigraphy of the Anadarko Basin, Oklahoma, Kansas, Texas, and Colorado, chap. 5, in Higley, D.K., compiler, Petroleum systems and assessment of undiscovered oil and gas in the Anadarko Basin Province, Colorado, Kansas, Oklahoma, and Texas—USGS Province 58: U.S. Geological Survey Digital Data Series DDS–69–EE, 42 p., http://dx.doi.org/10.3133/ds69EE.

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IHS Inc., 2012, PIDM [Petroleum Information Data Model] relational U.S. well data [data current as of December 23, 2011]: IHS Energy Group, database available from IHS Energy Group, 15 Inverness Way East, D205, Englewood, CO 80112, U.S.A.

Kelkar, Mohan, 2007, Exploitation and optimization of reservoir performance in Hunton Formation, Oklahoma: U.S. Department of Energy Technical Report DE-FC26-00NT15125, 219 p., http://www.tucrs.utulsa.edu/projects_past/15125R31.pdf.

National Petroleum Council, 1984, Enhanced oil recovery: National Petroleum Council and U.S. Department of Energy, Washington D.C., variously paginated, accessed September 9, 2014, http://www.npc.org/reports/rd1984-Enhanced_Oil_Recovery.pdf.

Nehring Associates Inc., 2012, The significant oil and gas fields of the United States database [data current as of December 2010]: Colorado Springs, Colo., Nehring Associates, Inc., database available from Nehring Associates, Inc., P.O. Box 1655, Colorado Springs, CO 80901, U.S.A.

Roueche, Jacqueline, Karacan, C.O., in press, Zone identification and oil saturation prediction in a water flooded field-residual oil zone, East Seminole Field, Permian Basin: Society of Petroleum Engineers (SPE) Improved Oil Recovery Conference, Tulsa, Oklahoma, April 14-18, 2018, 1 p.

Verma, M.K., ed., 2017, Three approaches for estimating recovery factors in carbon dioxide enhanced oil recovery: U.S. Geological Survey Scientific Investigations Report 2017–5062–A–E, variously paged, https://doi.org/10.3133/sir20175062.

Warwick, P.D., Verma, M.K., Attanasi, E.D., Olea, R.A., Blondes, M.S., Freeman, P.A., Brennan, S.T. Merrill, M.D., Jahediesfanjani, Hossein, Roueche, J.N., and Lohr, C.D., 2017, A database and probabilistic assessment methodology for carbon dioxide enhanced oil recovery and associated carbon dioxide retention in the United States: Energy Procedia, vo. 114, p. 7055-7059, https://doi.org/10.1016/j.egypro.2017.03.1847.

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