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Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs

Received: 28 September 2019     Accepted: 25 October 2019     Published: 11 November 2019
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Abstract

Oil rim reservoirs present unique problems during production. This is because of the proximity of the water and/or gas to the oil in the pay zone leading to phase distortion due to pressure disequilibrium during production of the oil. The resultant effect is early water/gas breakthroughs which ultimately lead to increased well operational cost, damage to production equipment and eventually to early loss of the well. Production rate becomes crucial as it directly or indirectly affects the overall recovery efficiency from the well. Low rate production signifies longer well production period due to delayed breakthrough time but at the expense of higher well operational cost per unit volume of oil produced, while higher rate production signifies higher oil volume per unit cost of well operation but with increased risk of losing the well due to water/gas breakthrough. Operators produce at a rate deemed economic in order to make profits. Most economic rates are higher than the critical rate which is the rate considered that coning would be maximally delayed. To optimize production, it is necessary to recover most of the fluid from the reservoir before abandonment. Higher recovery factors means that less volume of fluid is left in the reservoir at abandonment. The optimum oil production rate is the best economic oil rate that would result to the highest recovery factor obtainable from that well. The question is what rate is considered optimal and how can it be calculated? This work presents a mathematical model solution for the calculation of the optimum oil production rate. It takes cognizance of the recovery factor and the time value of money and present an analytical model to calculate the optimum oil production rate. From the work the optimum oil production rate was calculated to be 918.63stb/d while the critical oil rate was calculated to be 20.17stb/d.

Published in Petroleum Science and Engineering (Volume 3, Issue 2)
DOI 10.11648/j.pse.20190302.14
Page(s) 60-67
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2019. Published by Science Publishing Group

Keywords

Oil Rim, Optimum Oil Rate, Coning, Economic Rates

References
[1] Aladeitan, Y. M, Akinyede, O. M. (2016). Optimization of Oil Rim Development by Improved Well Design. Journal of Scientific and Engineering Research, 3 (4): 169-174.
[2] Ogolo, N. A., Molokwu, V. C., Oyekonwu, M. O. (2018). Proposed Technique for improved oil recovery from thin oil rim reservoirs with strong aquifers and large gas caps. SPE-189126-MS.
[3] Idoko, J. J, Saka, M, Lawal, K., (2019). Simple guidelines for screening development for oil-rim reservoirs.
[4] Ogiriki, S. O, Imonike, G. O, Ogolo, N. O, Onyekonwu, M. O (2018). Optimum Well Type for Oil Rim Reservoirs with large Gas-cap and strong Aquifer. SPE-193411-MS.
[5] Olamigoke, O, Peacock A., (2009), “ First pass Screening of Reservoirs with Large Gas Caps for Oil Rim Development", Paper SPE 128603, Presented at Nigeria Annual International Conference and exhibition Abuja, 3-5 August.
[6] Ogolo, N. A., Molokwu, V. C., Oyekonwu, M. O. (2018). Technique for effective oil production from the oil rim reservoirs. SPE-193382-MS.
[7] Obidike, P., Oyekonwu, M. O., Ubani, C. E. (2019). Exploitation of the thin oil rim with large gas cap-critical review.
[8] Amoni, N., Molokwu, V., Oyekonwu, M. (2017). Proposed Technique for improved oil recovery from thin oil rim reservoirs with strong aquifer and large gas caps. SPE-189126-MS.
[9] Keng, S. C, Azmukiff, M. K, Nasir, D (2012), “Breaking Oil Recovery Limit in Malaysian Thin Oil Rim Reservoirs: Water Injection Optimization. SPE14157 Presented at the international Petroleum Technology Conference Bangkok. 7-9 March.
[10] Uwaga, A. O and Lawal K, A (2006). “Concurrent Gas-cap and Oil Rim Production”, SPE 105985 presented at the 30th Annual Technical Conference and Exhibition Abuja, Aug 1-2.
[11] Bourenane, M., Tiab, D and Recham, R. 2004: “Optimization of Perforated Completions for Horizontal Wells in a High-Permeability, Thin Oil Zone—Case Study: Hassi R’mel.
[12] Silva, J. M. D. and Dawe, R. A. (2010). The Challenge of Producing Thin Oil Rims in Trinidad”, The West Indian Journal of Engineering, 32, 36-41.
[13] Onyeukwu, I. H, Peacock, A., Matemilola, S. A (2012), “Improving Recovery from Oil Rim Reservoirs by Simaultaneous Gas and Water Injection”, Paper SPE 162956, Presented at the Nigerian Annual Technical Conference and Exhibition Abuja, 6-8 August.
[14] Lyare, U. C. and Silva, J. M. D. (2012). Effect of Gas Cap and Aquifer Strength on Optimal well Location for Thin Oil Rim Reservoirs”, SPETT Energy Conference and Exhibition, SPE 158544.
[15] Maroua Jeoua (2019). Optimisation of oil production in an oil rim reservoir using Numerical simulation with focus on IOR/EOR application. SPE-196709-MS.
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    Obibuike Ubanozie Julian, Ekwueme Stanley Toochukwu, Ohia Nnaemeka Princewill, Igwilo Kevin Chinwuba, Igbojionu Anthony Chemazu, et al. (2019). Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs. Petroleum Science and Engineering, 3(2), 60-67. https://doi.org/10.11648/j.pse.20190302.14

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    ACS Style

    Obibuike Ubanozie Julian; Ekwueme Stanley Toochukwu; Ohia Nnaemeka Princewill; Igwilo Kevin Chinwuba; Igbojionu Anthony Chemazu, et al. Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs. Pet. Sci. Eng. 2019, 3(2), 60-67. doi: 10.11648/j.pse.20190302.14

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    AMA Style

    Obibuike Ubanozie Julian, Ekwueme Stanley Toochukwu, Ohia Nnaemeka Princewill, Igwilo Kevin Chinwuba, Igbojionu Anthony Chemazu, et al. Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs. Pet Sci Eng. 2019;3(2):60-67. doi: 10.11648/j.pse.20190302.14

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  • @article{10.11648/j.pse.20190302.14,
      author = {Obibuike Ubanozie Julian and Ekwueme Stanley Toochukwu and Ohia Nnaemeka Princewill and Igwilo Kevin Chinwuba and Igbojionu Anthony Chemazu and Kerunwa Anthony},
      title = {Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs},
      journal = {Petroleum Science and Engineering},
      volume = {3},
      number = {2},
      pages = {60-67},
      doi = {10.11648/j.pse.20190302.14},
      url = {https://doi.org/10.11648/j.pse.20190302.14},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.pse.20190302.14},
      abstract = {Oil rim reservoirs present unique problems during production. This is because of the proximity of the water and/or gas to the oil in the pay zone leading to phase distortion due to pressure disequilibrium during production of the oil. The resultant effect is early water/gas breakthroughs which ultimately lead to increased well operational cost, damage to production equipment and eventually to early loss of the well. Production rate becomes crucial as it directly or indirectly affects the overall recovery efficiency from the well. Low rate production signifies longer well production period due to delayed breakthrough time but at the expense of higher well operational cost per unit volume of oil produced, while higher rate production signifies higher oil volume per unit cost of well operation but with increased risk of losing the well due to water/gas breakthrough. Operators produce at a rate deemed economic in order to make profits. Most economic rates are higher than the critical rate which is the rate considered that coning would be maximally delayed. To optimize production, it is necessary to recover most of the fluid from the reservoir before abandonment. Higher recovery factors means that less volume of fluid is left in the reservoir at abandonment. The optimum oil production rate is the best economic oil rate that would result to the highest recovery factor obtainable from that well. The question is what rate is considered optimal and how can it be calculated? This work presents a mathematical model solution for the calculation of the optimum oil production rate. It takes cognizance of the recovery factor and the time value of money and present an analytical model to calculate the optimum oil production rate. From the work the optimum oil production rate was calculated to be 918.63stb/d while the critical oil rate was calculated to be 20.17stb/d.},
     year = {2019}
    }
    

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  • TY  - JOUR
    T1  - Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs
    AU  - Obibuike Ubanozie Julian
    AU  - Ekwueme Stanley Toochukwu
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    AU  - Igwilo Kevin Chinwuba
    AU  - Igbojionu Anthony Chemazu
    AU  - Kerunwa Anthony
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    DO  - 10.11648/j.pse.20190302.14
    T2  - Petroleum Science and Engineering
    JF  - Petroleum Science and Engineering
    JO  - Petroleum Science and Engineering
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    EP  - 67
    PB  - Science Publishing Group
    SN  - 2640-4516
    UR  - https://doi.org/10.11648/j.pse.20190302.14
    AB  - Oil rim reservoirs present unique problems during production. This is because of the proximity of the water and/or gas to the oil in the pay zone leading to phase distortion due to pressure disequilibrium during production of the oil. The resultant effect is early water/gas breakthroughs which ultimately lead to increased well operational cost, damage to production equipment and eventually to early loss of the well. Production rate becomes crucial as it directly or indirectly affects the overall recovery efficiency from the well. Low rate production signifies longer well production period due to delayed breakthrough time but at the expense of higher well operational cost per unit volume of oil produced, while higher rate production signifies higher oil volume per unit cost of well operation but with increased risk of losing the well due to water/gas breakthrough. Operators produce at a rate deemed economic in order to make profits. Most economic rates are higher than the critical rate which is the rate considered that coning would be maximally delayed. To optimize production, it is necessary to recover most of the fluid from the reservoir before abandonment. Higher recovery factors means that less volume of fluid is left in the reservoir at abandonment. The optimum oil production rate is the best economic oil rate that would result to the highest recovery factor obtainable from that well. The question is what rate is considered optimal and how can it be calculated? This work presents a mathematical model solution for the calculation of the optimum oil production rate. It takes cognizance of the recovery factor and the time value of money and present an analytical model to calculate the optimum oil production rate. From the work the optimum oil production rate was calculated to be 918.63stb/d while the critical oil rate was calculated to be 20.17stb/d.
    VL  - 3
    IS  - 2
    ER  - 

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Author Information
  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

  • Department of Petroleum Engineering, Federal University of Technology, Owerri (FUTO), Nigeria

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