Kazakhstan journal for oil & gas industryKazakhstan journal for oil & gas industry2707-42262957-806XKMG Engineering10895210.54859/kjogi108952Research ArticleAssessment of the effectiveness of CAPEX/OPEX associated with the modernization of process facilities within the framework of the development of Field XSatenovKurmet G.<p>Cand. Sc. (Chemistry)</p>k.satenov@kmge.kzhttps://orcid.org/0000-0002-6396-913XSuleimenYerlan M.<p>PhD, Professor</p>syerlan75@yandex.kzhttps://orcid.org/0000-0002-5959-4013KynyrtayMira S.m.kynyrtai@kmge.kzhttps://orcid.org/0009-0000-5075-9283SalimgereyevAsset M.a.salimgereyev@kmge.kzhttps://orcid.org/0009-0008-6453-2416KMG EngineeringK. Kulazhanov Kazakh University of Technology and BusinessSatbayev University30092026831191281102202630072026Copyright © 2026, Satenov K.G., Suleimen Y.M., Kynyrtay M.S., Salimgereyev A.M.2026<p><strong>Background:</strong> The expiry of the design operating life of the production facilities at Field X requires an assessment of the cost-effectiveness of capital expenditures (CAPEX) and operating expenditures (OPEX) associated with the modernization of process facilities, as well as the development of recommendations for optimizing investment decisions, considering the forecast decline in production and the prospects for further field development.</p> <p><strong>Aim: </strong>To assess capital and operating expenditures associated with the modernization of the Phase 2 process facilities in the post-contract period.</p> <p><strong>Materials and methods:</strong> The study is based on data from the Field X Development Project and Field Development Analysis (FDA). As part of the work performed, a model of the main Units 1 and 2 was developed using QUE$TOR software to compare the cost of their potential replacement with the results presented in the previously approved project documentation. The modelling was performed based on the current production capacities of the units.</p> <p><strong>Results:</strong> The option involving the extension of the production plateau using a single liquid hydrocarbon (LH) process train with a capacity of 2.8 million tonnes per year was selected as the most optimal, based on the duration of maintaining the production plateau duration (7 years). Reducing the wellhead pressure of Unit 3 wells from a high to a medium level had a significant impact on increasing LH production, extending the production plateau by an additional 5 years.</p> <p><strong>Conclusion: </strong>The proposed concept was recognized as technically feasible and economically justified. Infrastructure optimization makes it possible to reduce capital expenditures by USD 2.97 billion, achieve additional LH production of approximately 8 million tonnes, extend the production plateau by 12 years, and extend the gas export period by 7 years.</p>liquid hydrocarbon (LH)CAPEXOPEXinfrastructure modernizationnew field development conceptincremental analysisсұйық көмірсутектерCAPEX инвестицияларыOPEX шығындарыинфрақұрылымды жаңғыртуигерудің жаңа тұжырымдамасыинкременттік талдаужидкие углеводородыCAPEXOPEXмодернизация инфраструктурыновая концепция освоенияинкрементный анализ1.Vadetskiy YV. Bureniye neftyanykh I gazovykh skvazhin. Moscow: Academiya; 2013. 352 p. (In Russ).2.Lysenko VD. Razrabotka neftyanykh mestorozhdeniy. Proektirovaniye i analiz. Moscow: Nedra; 2003. 638 p. (In Russ).3.Basarygin YM, Bulatov AI, Proselkov YM. Bureniye neftyanykh i gazovykh skvazhin. Moscow: Nedra-Biznescentr; 2002. 623 p. (In Russ).4.Juman J, Du B, Khamzayeva AV. Current state of the oil and gas industry in Kazakhstan. Bulletin the National academy of sciences of the Republic of Kazakhstan. 2024;2(408):470–485. doi: 10.32014/2024.2518-1467.735 (In Russ).5.Turkov OS, Kuantayev NY, Kulumbetova GY, Yessenaly DD. Atlas neftyanykh i gazovykh mestorozhdeniy Respubliki Kazakhstan. Vol. 1. Almaty: Kazahstanskoe obshchestvo neftyanikov-geologov; 2020. 392 p. (In Russ).6.Amanniyazov KN, Akhmetov AS, Kozhakhmet KA. Neftyanyye i gazovyye mestorozhdeniya Kazakhstana. Almaty: Dauіr; 2003. 400 p. (In Russ).7.Ulyanov DI, Liman IA. Oil and gas condensate field as an economic facility. Progressive economy. 2025;1:90–103. doi: 10.54861/27131211_2025_1_90. (In Russ).8.Ponomarenko T, Marin E, Galevskiy S. Economic Evaluation of Oil and Gas Projects: Justification of Engineering Solutions in the Implementation of Field Development Projects. Energies. 2022;15(9):3103. doi: 10.3390/en15093103.9.Mitulinskiy VV, Saksin AG. Analysis of methods for risk assessment of investment projects in the oil production industry. Vestnik of Samara University. Economics and Management. 2024;15(1):79–86. doi: 10.18287/2542-0461-2024-15-1-79-86. (In Russ).10.spglobal.com [Internet]. S&P Global. QUE$TOR : Oil & Gas Cost Estimation Software [cited 2026 Jan 28]. Available from: www.spglobal.com/energy/en/products-solutions/upstream-midstream-oil-gas/questor-oil-gas-cost-estimation-software.