Deterministic and Probabilistic Approaches for Estimating Oil Reserve in Carbonate Reservoir: A Case Study for the Buzrgan Oil Field, Southern Iraq
Main Article Content
Abstract
The accuracy in oil reserve estimation is very important, as decisions should be made based on this value. The present paper will deal with estimating oil reserves by using deterministic and probabilistic approaches. The case study is the Mishrif formation of the Buzrgan oil field that located in Missan Governorate, southern Iraq. The deterministic approach is represented by the material balance equation, while the probabilistic approach is represented by Monte Carlo simulation. The data used in the material balance equation are production, PVT, and pressure data, along with needing to calculate bulk volume and porosity, while the Monte Carlo simulation needs volumetric equation parameters, which are porosity, fluid saturation, net pay thickness, and reservoir bulk volume. The linearized material balance equation, the Havlena – Odah method, is used. Monte Carlo simulation is applied as a volumetric equation, but each input parameter is modeled to get the best value. The result of the oil reserve by the material balance equation was 4.368 billion stock tank barrel while by Monte Carlo simulation was classified by Hefner and Thompson’s classification as P90 proven reserves is 1.03279 billion stock tank barrel, proved and probable oil reserves P50 is 1.98761 billion stock tank barrel, and proved, probable, and possibly reserve P10 is 4.3694 billion stock tank barrel. The material balance equation cannot be used before the production stage, while the Monte Carlo simulation can be applied before that.
Downloads
Article Details
Section
How to Cite
References
Abdulmajeed, M.N., Kadhim, F.S., and Saed, G.N., 2020. Estimation of Original Oil in Place Using Different Methods for Mishrif Formation –Amara Oil Field. Master's thesis, University of Technology, Oil and Gas Engineering Department.
Agnia, A., Algdamsi, H., Amtereg, A., Alkouh, A., and Alusta, G., 2021, Monte carlo simulation for uncertainty quantification of probabilistic original hydrocarbon in place estimation a convergence study how many samples with a particular sampler are needed, society of petroleum engineers (SPE), Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, UAE, SPE-207241-MS, https://doi.org/10.2118/207241-MS
Ahmed, M.A., Naji, J.M.AS., Ali, A.M., Al-Khafaje, A. Q. 2024. Asphaltene phase behavior modeling using Peng-Robinson 78A-EOS for a crude oil sample from Buzurgan Oil Field. Pet. Chem. 64, pp. 840–848. https://doi.org/10.1134/S096554412405013X.
Al Said Naji, J.M., Ahmed, M.A., Hammad, H.M., and Fadhil, A.M., 2023. Effect of using different property modelling strategies on the calculated value of the initial oil in place by volumetric method, Iraqi Journal of Oil & Gas Research, 3(2), pp. 50-62. http://doi.org/10.55699/ijogr.2023.0302.1051.
Al-Ali, M.M., Mahdi, M.M., and Alali, R.A., 2019. Microfacies and depositional environment of Mishrif Formation, North Rumaila oil field, southern Iraq. Iraqi Geological Journal, 52(2), pp. 91-104, https://doi.org/10.46717/igj.52.2.7Ms-2019-12-30
Aldarraji, M.Q., and Almayahi, A.Z., 2019. Seismic structure study of Buzurgan Oil field, Southern Iraq, Iraqi Journal of Science, vol.60, no.3, pp. 610-623, https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/703
Al-Dujaili, A. N., 2023. Reservoir rock typing and storage capacity of Mishrif Carbonate Formation in West Qurna/1 Oil Field, Iraq. Carbonates and Evaporites, 38(4), 83. https://doi.org/10.1007/s13146-023-00908-3
Al-Dujaili, A. N., Shabani, M., & AL-Jawad, M. S. 2024. Lithofacies and electrofacies models for Mishrif Formation in West Qurna oilfield, Southern Iraq by deterministic and stochastic methods (comparison and analysis). Petroleum Science and Technology, 42(13), pp. 1656-1684. https://doi.org/10.1080/10916466.2023.2168282.
Alhusseini, A.K. and Hamd-Allah, A.M., 2022. Estimation of initial oil in place for Buzurgan oil field by using volumetric method and reservoir simulation method, Iraqi Geological Journal, 55(2C), https://doi.org/10.46717/igj.55.2C.9ms-2022-08-22
Al-Ismaily, O. S., 2017. Use borehole image log technique to estimate Mishrif Reservoir Characterization in Buzurgan oilfield. Ph.D. thesis, Basrah University.
Al-Khalifa M.A., Payenberg, T.H.D., and Lang, S., 2007. An innovative approach to uncertainty assessment of hydrocarbon estimates in fluvial systems: A case study. Society of Petroleum Engineers (SPE)/ the Asia Pacific Oil and Gas Conference and Exhibition. SPE-108304-MS. https://doi.org/10.2118/108304-MS.
Ampomah, W., Balch, R.S., Chen, H.Y., Gunda, D., and Cather, M., 2016. Probabilistic reserves assessment and evaluation of sandstone reservoir in the Anadarko Basin. Society of Petroleum Engineers (SPE). IAEE Hydrocarbon Economics and Evaluation Symposium. SPE-179953-MS. https://doi.org/10.2118/179953-MS
Craft, B.C., and Hawkins, M.F.Jr., 1991. Applied Petroleum Reservoir Engineering, 2nd ed., Prentice Hall, Inc., Englewood Cliffs, New Jersey, P. 66.
Cronquist, C., 2001. Estimation and Classification of Reserves of Crude Oil, Natural Gas, and Condensate. SPE Books: Richardson, Texas, USA, SPE, P. 416.
Dake, L. P., 1978. Fundamentals of Reservoir Engineering. Elsevier, New York City, pp. 73-102.
Havlena, D., and Odeh, A.S., 1963. The material balance as an equation of a straight line. Journal Petroleum Technology, SPE-559-PA, 15(8), pp. 896–900. https://doi.org/10.2118/559-PA
Havlena, D., and Odeh, A.S., 1964. The material balance as an equation of a straight line—Part II. Field Cases, Petroleum Technology, SPE-869-PA, 16(7), pp. 815–822. https://doi.org/10.2118/869-PA.
Hefner, J.M., and Thompson, R.S., 1993. A comparison of probabilistic and deterministic reserve estimates: A case study. SPE Annual Technical Conference and Exhibition, SPE 26388, Houston, Texas, Oct 3-6.
Hussein, I. J., 2012. Building a Geological Model for the X oil field, Mishirif. M.Sc. Thesis, College of Engineering, University of Baghdad.
Idrobo, E.A., Jiménez, E.A., and Bernal, M.C., 2001. A new tool to make quick estimates of probabilistic reserves from production trends. Society of Petroleum Engineers (SPE)/ the SPE Hydrocarbon Economics and Evaluation Symposium, SPE-68597-MS, Dallas, Texas. https://doi.org/10.2118/68597-MS.
Jubair, A. Q. and Hadi, F. A., 2021A. Development of 3D-geomechanical model for Buzurgan Oil Field using actual and ANN-developed synthetic Logs. American Rock Mechanics Association, Paper presented at the ARMA/DGS/SEG International Geomechanics Symposium.
Jubair, Q.A., and Hadi, F.A., 2021B. Development of 1D-synthetic geomechanical well logs for applications related to reservoir geomechanics in Buzurgan Oil Field. Iraqi Geological Journal, 54(2F), pp. 74-88, https://doi.org/10.46717/igj.54.2F.7ms-2021-12-24.
Khashman, M. A., Shirazi, H., AL-Dujaili, A. N., & Sulaiman, N. M., 2025A. Optimizing facies analysis, capillary pressure, and flow units identification of Mishrif carbonate reservoir in a selected oilfield, Southern Iraq. Petroleum & Coal, 67(2).
Khashman, M. A., Shirazi, H., and Al-Dujaili, A. N., 2025B. Comparative evaluation of productivity indicators in carbonate reservoir modeling by a case study for the Mishrif Formation in the Iraqi Buzurgan Oilfield. Discover Geoscience, 3(17). https://doi.org/10.1007/s44288-025-00118-5
Kim, J.S., Shin, H.J., and Lim, J.S., 2014. Application of a probabilistic method to the forecast of production rate using a decline curve analysis of Shale Gas Play. The International Society of Offshore and Polar Engineers (ISOPE)/Twenty-fourth (2014) Conference Busan, Korea, pp. 15-20.
Komlosi Z. and Komlosi J., 2009. Application of the Monte Carlos simulation in calculating HC-Reserves. SPE 121256, EUROPEC/EAGE Annual Conference and Exhibition, pp. 8–11. Amsterdam. https://doi.org/10.2118/121256-MS.
Kosova, R., Shehu, V., Naco, A., Xhafaj, E., Stana, A., and Ymeri, A., 2015. Monte Carlo simulation for estimating geologic oil reserves. A case study from Kucova Oilfield in Albania. Journal of Muzeul Olteniei, Craiova. Oltenia. Studii și comunicări. Științele Naturii. 31(2), pp. 20-25.
Mohammed, A.I., Abdurahman, H., Ibrahim, S.D., and Adamu, B.M., 2018. Uncertainty modelling in multi-layered reserve estimation using Monte Carlo simulation, Society of Petroleum Engineers (SPE)/ the SPE Nigeria Annual International Conference and Exhibition, SPE-193454-MS, https://doi.org/10.2118/193454-MS.
Schilthuis, R. J., 1936. Estimation of petroleum reserves - active oil and reservoir energy. The American Institute of Mining, Metallurgical, and Petroleum Engineers.
Simpson, D.E., Huffman, C.H., and Thompson, R.S., 1995. Net present value probability distributions from decline curve reserves estimates. Society of Petroleum Engineers (SPE)/Hydrocarbon Economics and Evaluation Symposium, SPE-30044-MS. Dallas, Texas, March. https://doi.org/10.2118/30044-MS.
Sissakian, V. K, Shihab A.T., Al-Ansari N., and Knutsson, S., 2017. New tectonic findings and its implications on locating oilfields in parts of the Gulf Region. Journal of Earth Sciences and Geotechnical Engineering, 7(3), pp. 51-75.
Tarek, A., 2001. Reservoir Engineering Handbook. 2nd edition, Gulf Professional Publishing, Butterworth-Heinemann.
Thanh, T.T., 2002. An improved method for reserves estimation. Society of Petroleum Engineers (SPE). The SPE Asia Pacific Oil and Gas Conference and Exhibition, Melbourne, Australia. SPE-101939-STU. https://doi.org/10.2118/101939-STU
Turgay, I., 2014. Error Analysis on the Parameters of the Material Balance equation for synthetic gas cap reservoir, Master's thesis, Istanbul Technical University- Institute of Science and Technology, published thesis, Turkey.
Yee, C.P., 2011. Estimation of reservoir parameters using material balance method. Dissertation submitted to the PETRONAS University as a partial fulfilment of Bachelor's degree in petroleum engineering.