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Quebrache Field: Evaluations to Date of this Natural CO2 ReservoirHeron Gachuz-Muro, SPE, Pemex-Heriot Watt University; Jose L. Sanchez-Bujanos, SPE, Pemex; Israel Castro-Herrera, SPE, UNAM; Jose A. Rodriguez-Pimentel, SPE, Schlumberger

Copyright 2011, Society of Petroleum Engineers

This paper was prepared for presentation at the SPE EUROPEC/EAGE Annual Conference and Exhibition held in Vienna, Austria, 2326 May 2011.

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not beenreviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, itsofficers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission toreproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

Abstract

In the search for oil and gas during the past century, other gases have been encountered. These gases had little or no economic

value and areas known to contain them were avoided during drilling.

Deposits of CO2 rich gas (>50 %) are present worldwide but in limited areas USA, mainly. Few studies of natural CO2

reservoirs are currently available to determine and analyze its accurate exploitation. CO2 concentrations ranging between 71

and 98 % have been discovered in the Northeast of Mexico. Preliminary evaluations (SPE-107445) of the available data for

Quebrache field indicated potential gas reserves.

Complementary analyses to date have shown that on balance, the Quebrache field offers a significant opportunity for

developing Enhanced Oil Recovery (EOR) projects. This new study divides the field into tree important areas. This paperpresents: a) recent reservoirs discovered b) estimated reserves for all tree areas with CO2 sources (Central Area, Northern Area

and Southern Area), c) efforts made to evaluate its potential d) opportunities to invest in and operate a world-class CO2reservoir, etc. The Central Area reveals 2 important reservoirs. These reservoirs are relatively continuous and could produce

and drain reserves during long period. Original Gas-In-Place (OGIP) volumes are likely conservative because in its calculation

it is assumed a gas-water contact (there is contact apparent in the well logs). The Quebrache field would provide strategic

value to CO2 injection programs.

The CO2 accumulations described in this paper could play a major role in recovering additional oil from fields in the North of

Mexico. Thus, CO2 accumulations in the right place and at the right time may become production targets in the future.

Introduction

Carbon dioxide (CO2) is found both free and combined with other gases, such as petroleum gas and flue gases resulting from

combustion. CO2 is marketed either as a solid (dry ice) or as a liquid. Even if the ultimate use of the carbon dioxide requires itto be a gas, it is purchased from the manufacturer as a solid or liquid and sublimed or reduced to a gas at the place of use. Prior

to 1970, the main uses of CO2 produced were numerous: refrigeration, heat and cold treatement, laboratory uses, carbonating

beverages, fire extinguishing, etc. The volume for these purposes was small.

During the 1970s, however, a new use for CO2 emerged. Injection of this gas into mature oil fields could mobilize oil that has

been left behind by primary or secondary recovery techniques. This new application substantially increased demand for carbon

dioxide. Mainly, two main factors have made carbon dioxide an attractive resource target in some specific areas, a) it has

shown that in Enhanced Oil Recovery (EOR) processes can increase oil production and b) the rise of the price of oil has madeattractive its exploitation. Part of the economic feasibility of these EOR methods is a source of carbon dioxide which can be

transported and injected at a reasonable cost. Sources of CO2 are quite diverse but there are three primary options: a) Supplies

from natural reservoirs, b) Anthropogenic sources or c) Recicled CO2.

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Natural sources of CO2 occur, as gaseous accumulations of CO2, CO2 mixed with natural gas, CO2 dissolved in formation

water or coexisting with oil fields as dissolved gas and gas cap.These accumulations have been studied in the United States,

Hungary, Australia, Romania, Turkey, etc. Natural accumulations take place in a number of different types of sedimentary

rocks, principally limestones, dolomites and sandstones and with a variety of seals and a range of trap types, reservoir depths

and CO2 bearing phases.

Despite the amount of information available from these sites, in many natural CO2 reservoirs the source of the CO2 and basin

scale processes that act on them are poorly understood. This is partially due to the multiple origins of CO 2 in natural gases.

These include methanogenesis, oil field biodegradation, kerogen decarboxyilation, hydrocarbon oxidation, decarbonation of

marine carbonates, degassing of magmatic bodies, etc.

In Quebrache, it seems reasonable to think that the origin of the CO2 is closely related to an inorganic origin. The gases of

Quebrache were generated from the primary cracking of kerogen, corresponding to an open system without any evidence of

secondary cracking.

In many cases (concerning to the oil industry), when CO 2 is found as a natural source, it is an unwelcomed dilutent and

corrosive agent in hydrocarbon natural gases. These uncommon instances were traditionally classified as failure, i.e., the gases

had little or no economic value and areas known to contain them were commonly avoided during further drilling.

EOR projects using CO2 have risen dramatically in recent years. More than 100 CO 2 projects were reported in 2010, figure 1.

Numerous other developments were announced and planned. Nevertheless, the supply is of great concern to the oil companies.

In order for this technology to be safely implemented the long term consequence of injecting CO2 into the reservoirs must be

quantifed.

Figure 1.-USA EOR Projects under Gases, (source OGJ-2010).

The objective of the present paper is to assess the CO 2 reserves of Quebrache field in 660 km2 under traditional methods

published. The results of these studies corroborate its potential EOR application. It is therefore important to point out that

Quebrache field, in the right place and at the right time, may become production target in the future.

Historical Development

Beginning in 1901, prolific oil areas were discovered in Northeastern Mexico. Drilling in the southwestern portion of Tampico

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found mainly high-purity CO2 or variable gas mixtures with high concentrations of CO2. Only sporadic exploration efforts

continued in the area in the search for oil and gas. CO2 had little or no economic value (absence of a CO2 market) and areas

known to contain it were avoided during drilling.

Quebrache field was discovered in 1915. The producing formations are rocks of Cretaceous and Tertiary ages. It is still largely

undeveloped and it extends over an area of 2,500 km2. The discovery well encountered high-purity CO2 (90 %) with minor

amounts of nitrogen and the rest being hydrocarbon gases. The well remained closed few years. Interest in CO2 development

remained low until exploitation studies, in the late 1990s, indicated that operations of gas lift could lead to the successfulrecovery of additional oil. Production began in 1997 and has continued at a rate of approximately of 2.2 MMscfd since then.

Interest in this field increased because it was the closest and best source of CO2 to develop an EOR program in a mature oil

field. Two years ago, a project study group was formed to cover all aspects of a possible development. Part of this revision

divided the field into tree important areas: a) Central Area b) Northern Area and c) Southern Area (figure 2). The Central Area

is more than 85 % pure whereas the Northern Area and Southern Area contain between 60-92 % mol. Neither structure has

been fully developed. Currently, 17-20 wells provide about 12 MMscfd of carbon dioxide. This volume is transported via

pipeline to a nearby heavy oil field for gas lift operations.

Figure 2.-CO2 accumulations in Quebrache Field (660 km2

was evaluated).

Recent Studies

This section of the paper is divided by areas of importance for its reading. Each area was reviewed in detail with the available

data.

The Central Area

The review of various electric logs, several well tests and analyses of recovered gas led the existence of natural CO 2 into 231

km2. Numerous structures in the zone have been defined as CO2 targets. Two of these structures have been tested. Although

tests have proven the new wells are capable of producing at rates of more than 4 MMscfd, production has been limited by

pipeline dimensions. The concentrations exceed 85 % purity. A preliminary evaluation of the data for this area indicated

recovery potentials (SPE-107445).

We have divided this section informally into upper and lower members because of rock quality. The secondary formation

(upper member) does not have enough information. The lower member is the biggest of these reservoirs and contains

estimated reserves up to 1 Tscf. We focused on this unit which provided complementary information. A well was exploitedand operated for industrial use; however, the main information is unknown. For this reason, we decided to exclude it from our

evaluations. These formations are occurring at depths of 900-1100 m and consisting of a 9-45 m thick, upper member, and 13-

40 m thick, lower member. The wells also produce minimal amounts of formation water and condensate (1 bl/MMscf and 5-10

bls/MMscf, respectively). One well with sufficient information was selected representing a natural behavior in this area. We

used the method stablished by Cinco-Ley to evaluate its latent volume. The adjusted model was Infinitely Acting Reservoir,

figure 3. A second case then, figure 4, was run where a closed system was simulated. This allowed obtaining a proven volume,

329.84 Bscf. The volume confirmed the presence of relatively continuous formations where the CO2 could be produced and

drained during long period.

MEXICO

U.S.A.

GUATEMALA

GOLFO

DE

MEXICO

OCEANO

PACIFICO

TOPILA

QUEBRACHE

TAMPICO

MEXICO

U.S.A.

GUATEMALA

GOLFO

DE

MEXICO

OCEANO

PACIFICO

MEXICO

U.S.A.

GUATEMALA

GOLFO

DE

MEXICO

OCEANO

PACIFICO

TAMPICO

Gas

Oil

Total Area (660 Km2)

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Figure 3.-Pressure and production data representing a large radius of investigation.

Figure 4.-Adjusted data under a closed system.

The reservoir drive is presumed to be a depletion drive, although an active acuifer is possible (there is a contact apparent in the

well logs). Recovery efficiency is assumed to be 70 % because the formations are relatively continuous units. The limited

production tests have revealed an infinitely acting reservoir.

One of the advantages of the horizontal well is to achieve large reservoirs contact area. The effects of long horizontal wells onproduction rate also were scrutinized. The search provided the selection of a reasonable horizontal well length (200-300 m).

Figure 5 illustrates the variation of gas production rate with well length for different chokes. The chokes used are diverse

because of the low reservoir permeability. After a certain point, it is seen that the curves stayed invariable which showed that a

rise in the horizontal well length does not yield a corresponding growth in the production.

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Figure 5.- Effects of chokes on production rate (kv= 3.5 md, kh= 8.2 md)

It is clear that the permeability has a high effect in production rate indicating an important parameter in optimum well

construction. Vertical permeability is one of the key parameters which could determine the productivity of this area.

The Northern Area

Seismic data (2D seismic) was essential for the identification of new zones. The quality of available data was sufficient to map

structure but insufficient to evaluate correctly seismic stratigraphy. The Northern Area varies significantly throughout the zone

from 60 to 92 % CO2. To date, a total of 10 wells are being exploited. The largest active production occurs at this mature area.

The oldest wells are erratics and not representatives of the reservoir as a whole. Nevertheless, this group of wells provided log

data, stratiraphic column, drilling depths, etc. The completion techniques commonly used for these wells were openhole

completion methods. This method represented to be troublesome due to the difficulties for monitoring data besides did not toprove acceptable for workover operations. Net thickness ranges from 9-45 m with an estimated pressure of 847 psi. Reservoir

porosity is ranging from 5 to 16 % but the permeability is very low. Well tests showed effective permeabilities in the range of

1 md. Production testing exhibited that there are no significant volumes of formation water. There is no sufficient pressure to

produce except for a very short time. To the northwest of this zone are the active heavy oil fields. Analyses yielded an

estimated 0.54 Tscf of estimated reserves. Possible addition to these volumes described above would be in the Southern Area.

The Southern Area

Further analyses delineated a new area with volume of CO2. This discovery includes oil fields where CO2 is found as a gas

mixed (50 % carbon dioxide) and H2S is present in amounts that require treatment. Conservately, we assume that this zone is

potential. In spite of uncertainties involved, the findings of various revisions identify acceptable evidence that a substantial

quantity of gas could be exploited. The area was formed with isopac maps and up to date, 33 km2 as probable area is being

borne in mind. Neither volumen has been considered but its evaluation is being contemplated. It is probable that production

may be developed from an area as great as the Northern Area.

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Remarks

The primary purpose of this paper was to locate all latent CO 2 natural sources within Quebrache Field that could be

used to EOR processes.

Quebrache field could provide a strategic source of supply that is proximate in location to significant current and

possible CO2 floods in the North of Mexico. The close proximity of oil fields could insure economic success of the

EOR-CO2 projects.

New areas would offer an opportunity in mature fields through EOR methods. Additionally, oil fields with low

recovery factors could be included in secondary recovery processes. CO2 demand in Mexico is expected to stay

strong and grow with project expansions and new floods.

Optimization of horizontal well length and well spacing can be critical to the economics of the exploitation of gas

resources for this Region.

Although this paper deals primarily with carbon dioxide gas production in the Northeastern Mexico, the occurrence of

the gas at numerous localities and conceivably in large volumes in Mexico must not be overlooked. Mature oil fields

could become more competitive with this locally produced gas.

Acknowledgements

We would like to thank Pemex E&P for permission to publish this article. The authors also thank Regional Exploration

Bussiness Asset from Northern Region for the support.

Conversion Factors

oAPI x 141.5/(131.5+oAPI) = g/cm3

ft3 x 0.02831 = m3oF (oF-32)/1.8 = oC

km2 x 247.1 = acres

kg/cm2 x 14.22 = lb/pg2

bbl x 0.158 9873 = m3acre x 0.00405 = km2

in x 0.0254 = m

References

1. Asghari, K.; Dong, M.; Shire, J.; Coleridge, T.; Nagrampa, J.; Grassik, J. 2006. Development of a Correlation betweenPerformance of CO2 Flooding and the Past Performance of Waterflooding in Weyburn Oil Field. Paper SPE 99789,

SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, April.

2. Blann, J. R.; Laville, G. M. 1997. Gas Lifting a Major Oil Field in Argentina with High CO 2 Content Associated Gas. SPE30368, SPE Production & Facilities, 41-45, February.

3. Chakravarty, A.; Harrison C. J. 2003. Unique Challenges & Novel Solutions for El Trapial Field (Argentina). SPE 80543,presented at SPE Asia Pacific Oil and Gas Conference and Exhibition held in Jakarta, April 15-17.

4. Cinco Ley, H. 1998. Caracterizacin Dinmica de Yacimientos. Asesora y Servicios Petroleros S.A. de C.V. DEPFI,UNAM. November, 1998.

5. Comesa/PEP. 2004. Reingeniera de los Proyectos de Inyeccion de Agua y Diseo de Nuevos Proyectos de RecuperacionSecundaria y Mejorada en la Region Norte. Pemex E&P, Internal Report.

6. Dai, J.X.; Song, Y.; Dai, C.S.; Wang, D.R. 1996. Geochemistry and Accumulation of Carbon Dioxide Gases in China.AAPG, Bulletin, 80 (10), 1615-1625.

8/6/2019 SPE-142851

7/8

[SPE-142851] 7

7. Diaz, D.; Bassiouni, Z.; Kimbrell, W.; Wolcott, J.. 1996. Screening Criteria for Application of Carbon Dioxide MiscibleDisplacement in Waterflooded Reservoirs Containing Light Oil. Paper SPE/DOE 35431, presented at the SPE Improved

Oil Recovery Symposium, Tulsa, Oklahoma, April 21-24.

8. Dobitz, J.K.; Prieditls, J. 1994. A Stream Tube for Model the PC. Paper SPE/DOE 27750, presented at the SPE/DOE NinthSymposium on Improved Oil Recovery, Tulsa, OK, April 17-20.

9. Doleschall, S.; Szittr, A.; Udvardi, G. 1992. Review of the 30 Years Experience of the CO 2 Imported Oil RecoveryProjects in Hungary. Paper SPE 22362, presented at the SPE International Meeting on Petroleum Engineering, Beijing,

China, March 24-27.

10.Gachuz, H.; Berumen, S.; Alcazar, L. O.; Rodriguez, J. A. 2007. Quebrache, a Natual CO2 Reservoir: New Source for EORProjects in Mexico. SPE 107445, presented at the 2007 SPE Latin American and Caribbean Petroleum Engineering

Conference held in Buenos Aires, Argentina, April 15-18.

11.Gachuz Muro, Heron. 2005. Yacimientos de CO2 en Mxico. Alternativa Viable para Programas de RecuperacinTerciaria. (2005 CIPM), Exitep 2005, Veracruz, Mexico, February.

12.Hanif, A.; Green, M. L. 2002. Possible Utilisation of CO2 on Natunas Gas Field Using Dry Reforming of Methane to

Syngas (CO2 & H2). Paper SPE 77926, presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition held inMelbourne, Australia, October 8-10.

13.Henson, R.; Todd, A.; Corbett, P. 2002. Geologically Based Screening Criteria for Improved Oil Recovery Projects. PaperSPE 75148, SPE/DOE Improved Oil Recovery Symposium, Tulsa, Oklahoma, April, 2002.

14.Hosgrmez, H.; Yalin, M. N.; Soylu, C. 2005. Origin of Carbon Dioxide and Hydrocarbon Gases in Dodan and SilivankaFields. (SE-Turkey), 22st International Meeting on Organic Geochemistry, Seville, Spain, 1, 526-527.

15.Hunt, J.M. 1979. Petroleum Geochemistry and Geology. San Francisco, W. H. Freeman and Company Ed., 617.

16.Jokhio, Sarfraz A.; Tiab, D.; Escobar, F. H. 2001. Quantitative Analisis of Deliverability, Decline Curve, and PressureTests in CO2 Rich Reservoirs. Paper SPE 70017, presented at the SPE Premian Basin Oil and Gas Recovery Conference,

Midland, Texas, May 15-16, 2001.

17.Koottungal, L. 2010. Special Report: 2010 Worldwide EOR Survey. Oil and Gas Journal, week of April 19, 41-53.

18.Lorant, F.; Prinzhofer, A.; Behar, F.; Huc, A.Y. 1998. Carbon Isotopic and Molecular Constraints on the Formation and theExpulsion of Thermogenic Hydrocarbon Gases. Chemical Geology, 147, 249-264.

19.Martin, F. David; Taber, J.J. 1992. Carbon Dioxide Flooding. JPT, paper SPE 23564, April.

20.Mohammed-Singh, Lorna J.; Singhal, Ashok K. 2004. Lessons from Trinidads CO2 Immiscible Pilot Projects 1973-2003.Paper SPE 89364, SPE/DOE Fourteenth Symposium on Improved Oil Recovery, Tulsa, Oklahoma, April 17-21.

21.Moritis, G. 2010. Special Report: CO2 Miscible, Steam Dominate Enhanced Oil Recovery Processes. Oil and Gas Journal,week of April 19, 36-40.

22.Muir, J.M. 1936. Geology of the Tampico Region, Mexico. Published by The American Association of PetroleumGeologists, Tulsa, Oklahoma, 280.

23.Popp, V. V.; Marinescu, M. ; Manoui. D.; Ploiesti, A. 1998. Possibilities of Energy Recovery from CO 2 Reservois. SPE48925, presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, September 27-30.

24.Prinzhofer, A.; Mello, M.R.; da Silva Freitas, L.C.; Takaki, T. 2000. New Geochemical Characterization of Natural Gasand its Use in Oil and Gas Evaluation. AAPG, Memoir 73, 107-119.

25.Prinzhofer, A.; Pernaton, E. 1997. Isotopically Light Methane in Natural Gas: Bacterial Imprint or Diffusive fractionation?.Chemical Geology, 142, 193-200.

8/6/2019 SPE-142851

8/8

8 [SPE-142851]

26.Reid B., G. 2003. Improving CO2 Efficiency for Recovering Oil Heterogeneous Reservoirs. Final Report, DOE ContractNo. DE-F626-01BC15346, October 31.

27.Renfro, J.J. 1979. Sheep Mountain CO2 Production Facilities A Conceptual Design. Paper SPE 7796, presented at theSPE Production Operations Symposium, Oklahoma City, Oklahoma, February 25-27.

28.Santiago Acevedo, J.; Carrillo Bravo, J.; Martell, B. 1984. Geologa Petrolera de Mxico: Evaluacin de Formaciones enMxico. Shlumberger, Mxico, I.1-I.36.

29.Schoell, M. 1983. Genetic Characterization of Natural Gases. AAPG Bulletin, 67 (12), 2225-2238.

30.Surguchev, L. M.; Regnhild, K.; Haugen, S.; Krakstad, O.S. 1992. Screening of WAG injection Strategies forHeterogeneous Reservoirs. Paper SPE 25075, presented at the European Petroleum Conference, Cannes, France, November

15-18.

31.Thrasher, J.; Fleet, A.J. 1995. Predicting the Risk of Carbon Dioxide Pollution in Petroleum Reservoirs. Paper from the17th International Meeting on Organic Geochemistry, San Sebastin, Spain, 1086-1088.

32.Tiab, D. 1981. Real Gas Pseudopressures for CO2 Reservoirs. Paper SPE 10128, presented at the SPE Annual Technical

Conference and Exhibition, San Antonio, TX, October 5-7.

33.Weeter, R. F.; Halstead, L. N. 1981. Production of CO2 from a Reservoir - A New Concept. Paper SPE 10283, presented atthe 1981 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, October 5-7.

34.Zana, E. T.; Thomas, G.W. 1969. Some Effects of Contaminants on Real Flow. Paper SPE 2577, presented at SPE 44thAnnual Fall Meeting, Denver, Colorado, September 28-October 1.