Petrovietnam Journal An official scientific journal of the Vietnam National Oil and Gas Group en-US Petrovietnam Journal 2615-9902 <p>1. The Author assigns all copyright in and to the article (the Work) to the Petrovietnam Journal, including the right to publish, republish, transmit, sell and distribute the Work in whole or in part in electronic and print editions of the Journal, in all media of expression now known or later developed.</p> <p>2. By this assignment of copyright to the Petrovietnam Journal, reproduction, posting, transmission, distribution or other use of the Work in whole or in part in any medium by the Author requires a full citation to the Journal, suitable in form and content as follows: title of article, authors’ names, journal title, volume, issue, year, copyright owner as specified in the Journal, DOI number. Links to the final article published on the website of the Journal are encouraged.</p> Application of machine learning to decline curve analysis (DCA) for gas-condensate production wells with complex production history due to add-on perforation of new reservoirs <p>For every oil and gas operator, DCA plays an essential role since it provides crucial information for production planning and reserves estimation. DCA is the analysis of the decline in production rate or pressure over time, which can be done by fitting a curve through production or pressure historical data points and making a forecast for the well based on the assumption that the same declining trend will continue in the future. However, the conventional DCA method has been shown to have some limitations. On the other hand, machine learning has been vigorously and extensively researched in the last decade; its applications can be found in every aspect of life as well as in the oil and gas industry. Therefore, it is the ideal time to study the application of machine learning to DCA, to complement this important analysis. In this case study, machine learning was used to predict the decline of wellhead pressure, thereby determining well life as well as estimating reserves. The method was applied to 2 wells with very complex production histories due to add-on perforation of new reservoirs. The prediction was verified to have high reliability by comparison with dynamic modeling results.</p> Huu Hai Ngo Hoang Duy Pham Ngoc Tan Nguyen Ky Son Hoang Ngoc Trung Tran Vu Tung Tran Copyright (c) 2023-12-25 2023-12-25 2 4 9 10.47800/PVSI.2023.02-01 Application of machine learning to predict the time evolution of condensate to gas ratio for planning and management of gas-condensate fields <p>One of the most important parameters for the evaluation, forecast, and management of gas-condensate fields is the evolution of the condensate to gas ratio (CGR) over time. This parameter tends to decrease as reservoir pressure declines. In the conventional approach, gas and condensate samples are collected at the beginning of production and periodically later to conduct laboratory experiments on composition, CGR, and fluid properties. However, sample collection, transportation, and analysis require a lot of time and effort and could be very expensive. Likewise, dynamic models are also frequently used to predict CGR over time. However, these models could include many uncertainties due to ambiguous input data, including reservoir structures, fluid phase interaction, and reservoir property distribution. Therefore, the application of machine learning to predict the time evolution of CGR in this research could be a new and effective approach to supplement conventional methods.</p> Huu Hai Ngo Xuan Vinh Trinh Ngoc Tan Nguyen Ky Son Hoang Tuan Anh Ngo Ngoc Trung Tran Vu Tung Tran Sy Tuan Nguyen Copyright (c) 2023-12-25 2023-12-25 2 10 18 10.47800/PVSI.2023.02-02 Integration of geological and well log and geomechanical modeling toward a safe mud weight for wellbore stability: A case study of Ruby field, Blocks 01&02, Cuu Long basin <p>There is a high density of drilled wells in Blocks 01&amp;02 which is a part of the Cuu Long basin. The geological settings of this area have undergone a complicated evolution, resulting in heterogeneous lithology and variable stresses. Consequently, drilling activities in the Ruby oil field have faced numerous challenges, such as stuck pipe, gas kick, mud loss, and even lost well, etc. leading to substantial time and financial setbacks. It is essential to thoroughly understand the geomechanical characteristics of Ruby field to ensure safe operation and optimize drilling. In this paper, several downhole geophysical data sets such as wireline logging data as gamma ray (GR), density log (RHOB), neutron (NPHI), compression/shear sonic travel time (DTC/DTS), image formation log (FMI), pressure test (MDT) and leak of test (LOT, XLOT) are used to construct the 1D geomechanical model. The objective of this modelling is to compute parameters of pore pressure, vertical stress, horizontal stress, elastics properties, rock strengths. Then, these parameters are used to analyze the wellbore stability and to recommend appropriate drilling mud weights for the wells under study. This analysis can subsequently be extended to cover the entire Ruby oil field for the future drilling operations to enhance overall safety and efficiency.</p> Van Hoang Nguyen Quoc Thap Nguyen Quy Ngoc Pham Copyright (c) 2023-12-25 2023-12-25 2 19 28 10.47800/PVSI.2023.02-03 Geomechanics applied to the petroleum industry: Wellbore stability, sand production, and hydraulic fracturing <p>This article introduces three applications of geomechanics in oil and gas industry, encompassing wellbore stability analysis, hydraulic fracturing, and sand production. In this paper, we reviewed three commonly used applications involving transforming stress values from the<em> in situ</em> coordinate system to the wellbore centric coordinate system, which have been published in the previous studies. Subsequently, various failure criteria are applied to these three geomechanical problems. First, wellbore stability analysis involves six distinct scenarios across different oil reservoirs. The results obtained enable the selection of appropriate drilling mud densities to prevent collapses and instability of wellbore. Second, regarding sand production modeling, three oil fields are presented as examples. The results consistently indicate instances of sand production under various well production conditions. Finally, the application of geomechanics in hydraulic fracturing is illustrated. The findings distinctly illustrate the evolutionary pattern of fracture dimensions, highlighting a consistent trend in fracture length development. Notably, the expansion phase of the fracture exhibits a rapid onset during the initial stages, followed by a transition into an exceedingly gradual propagation state.</p> Van Hung Nguyen Copyright (c) 2023-12-25 2023-12-25 2 29 39 10.47800/PVSI.2023.02-04 Porosity cut-off values evaluated by classifying reservoir rock types from cores data. A case study for Triassic reservoir T1, Blocks 433a&416b, Algeria <p>This paper introduces the method to determine the porosity cut-off values by classifying rock types from cores data based on permeability cut-off value by 1 mD (for sandstone reservoir with oil). The purpose of this method is to calculate net pay reservoir more precisely for estimating hydrocarbons initially in place and building static models. Normally, the cut-off values of porosity are defined on a cross-plot of porosity versus permeability obtained from core data. However, the results of petrophysical analysis are not consistent with DST results. There are some wells with reservoir net pay of several meters, but the DST does not deliver flows. The application of a new method determining the porosity cut-off values on T1 reservoir shows the reservoir net pay is consistent with actual data of the field.<br><br></p> Khanh Xa Ngo Van Hai Phung Ngoc Thanh Huy Nguyen Hai An Nguyen Dinh Thanh Le Duc Bieu Pham Duy Khoan Do Copyright (c) 2023-12-25 2023-12-25 2 40 47 10.47800/PVSI.2023.02-05 Method for estimating the probability of geological success: A case study of the HRA-E prospect, Block 106, northern Song Hong basin <p>Petroleum exploration and drilling represent fields fraught with inherent uncertainties, consequently, geological assessment is significantly important for precisely selecting prospects and well locations. The geological evaluation of prospective formations predominantly relies on 5 elements of the petroleum system including source, reservoir, seal, trap, and migration.<br>This article introduces globally applied geological assessment methods, and proposes an applicable methodology for exploration targets across regions with varying levels of available data. Applying this method of evaluating risk criteria for pre-Cenozoic carbonate objects of HRA-E prospect in Block 106 shows that the evaluation results align with the actual probability of success in drilling exploration activities in the region and could be extended to other projects within the Petrovietnam Exploration Production Corporation (PVEP).</p> Dang Hung Tran Quang Viet Nguyen Thi Hue Ly Duc Hung Nguyen Van Chien Nguyen Van Thanh Do Minh Hoang Cu Duong Trung Nguyen Xuan Phong Nguyen Copyright (c) 2023-12-25 2023-12-25 2 48 53 10.47800/PVSI.2023.02-06 A comprehensive technical assessment of well intervention operations across all PVEP’s projects (2017 - 2021 period) and recommendations for ongoing optimization <p>This article provides a summary and assessment of well intervention activities, including perforation (add-perf/re-perf), acid treatment (acidizing), water/gas shut-off (WSO/GSO), hydraulic fracturing (HF), and electric submersible pump installation (ESP) at oil and gas production projects that the Petrovietnam Exploration and Production Corporation (PVEP) has participated in investment, operation, and optimization during the period of 2017 - 2021. Based on this, the effectiveness of well interventions in increasing production and reservoir recovery is evaluated. Additionally, the article analyzes lessons learned and proposes directions for optimizing well interventions for the next phase.</p> Ngoc Thanh Huy Nguyen Hong Nam Tran Khanh Xa Ngo Ngoc Quy Dang Van Hai Phung Van Lam Tran Viet Anh Dinh Van Viet Roan Vo Hiep Phan Dinh Phan Do Van Thiet Nguyen Copyright (c) 2023-12-25 2023-12-25 2 54 67 10.47800/PVSI.2023.02-07 Evaluating the digitalization capability and display of KPIs for two fertilizer plants of Petrovietnam <p>The study partially funded by the Vietnam Oil and Gas Group (Petrovietnam) assesses the infrastructure, OT/IT systems, and data handling at two fertilizer plants. Although well-equipped with automation control technology, the plants lack seamless integration, connectivity, and encounter limitations in communication between systems. To address these issues, the study advocates for the integration of digital technology, emphasizing its potential for enhancing efficiency, facilitating optimal management, and guiding strategic direction. Following an assessment of infrastructure, key performance indicator (KPI) system requirements, and data management, the study proposes an initial application of digital technology to link KPI displays. The outlined scope, initial costs, investment phases, and implementation schedule indicate a total initial investment of around VND 37 - 39 billion, accompanied by annual maintenance costs ranging from VND 3.7 to 4.1 billion. Expected economic and social benefits involve improved management at both Petrovietnam and plant levels through the KPI system, with an estimated energy cost savings of 1%, equivalent to roughly VND 44.6 billion. The project aims to position the fertilizer plants and Petrovietnam as leaders in technology, contributing to sustainability and enhancing their global industry reputation.</p> Minh Thuan Huynh Van Nhan Truong Duong Hai Le Ngoc Thanh Tran Van Chuong Bui Quang Hieu Pham Hong Hoa Pham Minh Hieu Nguyen Copyright (c) 2023-12-25 2023-12-25 2 68 76 10.47800/PVSI.2023.02-08 Petrovietnam leveraging its technology and services inherited from oil and gas operation into the construction and supply chain of offshore wind power <p>In the era of global integration, there is a clear shift from fossil fuels to renewable energies across nations. The investigation and utilization of renewable energy sources, especially offshore wind energy, emerge as a pivotal area for energy companies and corporations.<br>The Vietnam Oil and Gas Group (Petrovietnam) is standing at the threshold of substantial opportunities and challenges in expanding its operational spectrum towards renewable energy with a particular focus on offshore wind power. This study analyzes Petrovietnam's inherent strengths and capabilities with the orientation and strategy to become a leader of the service supply chains for offshore wind power in Vietnam.</p> Hoai Nam Tran Thanh Son Nguyen Duc Thang Tran Thu Ha Nguyen Quy Ngoc Pham Copyright (c) 2023-12-25 2023-12-25 2 78 86 10.47800/PVSI.2023.02-09 Fertilizer packaging companies of Petrovietnam toward circular economy <p>A circular economy is an economic system designed with the intention that maximum use is extracted from resources and minimum waste is generated for disposal... In the context of fertilizer packaging, manufacturers have been striving to produce green fertilizer bags which are recyclable, reusable and cost-efficient. When packages (both reusable and single-use) can no longer serve its function, the material should be circulated through recycling or composting. It is a matter of materials sciences (mono-material construction or material selection) and innovations in packaging formats (flexible packages, jumbo bags, sling bags, etc.) to make progress. Along with these, the sorting and collection infrastructure needs to be set up to keep products after use in a closed loop. As well, the economic attractiveness, incentives for stakeholders are essential to make the system work effectively.</p> Vi Sa Tu Copyright (c) 2023-12-25 2023-12-25 2 87 94 10.47800/PVSI.2023.02-10