Petrovietnam Journal

Assessment of low-salinity waterflooding (LSWF) for enhanced oil recovery in the Miocene reservoir of the Ruby field, Cuu Long basin

2026-09-09T03:53:24+00:00

The paper evaluates the applicability of low-salinity waterflooding (LSWF) as an enhanced oil recovery method for the Miocene reservoir in the eastern area of the Ruby Field, Cuu Long Basin. The study is based on IOR/EOR screening, laboratory experiments, and performance assessment using reservoir simulation models.

Coreflood experiments conducted on physical reservoir models show that, following the high-salinity waterflooding (HSWF) stage, reducing the injection-water salinity to approximately 3,004 ppm increases the oil recovery factor by an additional 3.8 - 7.3% of pore volume (PV), equivalent to 4.5 - 14.3% of the original oil in place (OOIP).

Reservoir simulation results indicate that converting well RBA-8P from production to low-salinity water injection could yield approximately 3.35 million barrels of incremental oil in the pilot area. At the full-field scale, drilling three injection wells was identified as the optimal development option, with an estimated incremental oil recovery of 8.6 million barrels compared with the natural depletion scenario.

Study on enhanced oil recovery using continuous CO2 injection and CO2-WAG injection in a carbonate reservoir at the North Khosedayu field, Russian Federation

2026-09-09T03:53:42+00:00

The paper evaluates the enhanced oil recovery potential of continuous CO₂ injection and CO₂ water-alternating-gas (CO₂-WAG) injection at the North Khosedayu field, Rusian Federation, based on slim-tube experiments, 1D modeling, and reservoir simulation. The results indicate that oil displacement efficiency increases markedly with injection pressure, reflecting the transition from immiscible to near-miscible and fully miscible displacement.

A reservoir simulation model was then built for a representative sector to evaluate four production scenarios: natural depletion, waterflooding, continuous CO₂ injection, and CO₂-WAG injection. The results show that waterflooding does not improve the recovery, whereas continuous CO₂ injection and CO₂-WAG injection significantly enhance oil recovery compared to natural depletion.

Biostratigraphy and depositional environments of the Late Oligocene - Early Miocene in the southeastern Nam Con Son basin

2026-09-09T03:54:24+00:00

This study integrates microfossil data (foraminifera, calcareous nannofossils, and palynomorphs) with well-log data from seven wells using StrataBugs software to characterize the biostratigraphy and depositional environments of the Late Oligocene - Early Miocene successions in the southeastern Nam Con Son basin. Based on key biostratigraphic markers, the top boundaries of the Late Oligocene and Early Miocene were clearly delineated. The concurrent absence of the M1a foraminiferal zone and the CNM1 calcareous nannofossil zone confirms the presence of a regional unconformity between the Cau and Dua formations.

The results reveal a distinct evolution of depositional environments, from freshwater lacustrine and coastal plain in the Late Oligocene to inner- and middle- neritic settings during the Early Miocene. This study provides a reliable scientific basis for standardizing biostratigraphic interpretation and depositional environment modeling, helping overcome the limitations imposed by the scarcity of diagnostic microfossils and the geological complexity of the study area.

Assessment of fault sealing capacity in Structure A, Oligocene reservoir, Northeastern Cuu Long Basin

2026-09-08T10:11:05+00:00

Statistics indicate that more than 85% of hydrocarbon traps are juxtaposed against and/or directly dependent on the sealing capacity of fault systems. Therefore, the interpretation and quantitative assessment of fault sealing capacity in prospective structures is critical in petroleum geology. At present, fault seal capacity is commonly evaluated using two main approaches: direct and indirect approach. The direct approach determines fault sealing capacity based on experimental capillary pressure measurements on core samples collected directly from the fault damage zone or fractured zone. The indirect approach predicts fault sealing capacity by comparison with the sealing characteristics of nearby discovered structures through correlations between quantitative attributes on the fault surfaces, particularly the shale gouge ratio (SGR), and the pressure differential across the fault. Threshold values established from field data provide the basis for evaluating the sealing potential of undrilled structures.Quantitative assessment of fault sealing capacity not only improves the calibration of the probability of geological success for undrilled structures but also provides a scientific basis for predicting the hydrocarbon column height that can be retained within prospective structures.

Analysis of the current status and development orientation of PETROVIETNAM's drilling activities towards 2030

2026-09-08T10:17:02+00:00

Drilling activities play a pivotal role in increasing reserves, maintaining production, and ensuring investment efficiency across the oil and gas exploration and production value chain, particularly as major producing fields in Vietnam enter a phase of natural decline. However, studies on the scale, structure, and development trends of drilling activities in Vietnam remain limited. Based on the implementation results for the 2021 - 2025 period and the plan for 2026 - 2030, this study analyzes the current status, evolving trends, and emerging requirements for rig capacity, the technical service ecosystem, and drilling human resources.

During the 2026 - 2030 period, the Vietnam National Industry - Energy Group (Petrovietnam) plans to drill 300 wells, with total investment capital exceeding USD 7 billion. This scope of drilling activities is expected to expand from a primary focus on production targets towards comprehensive field life-cycle management, while also creating potential to utilize well data for assessing CO₂ storage capacity under CCS/CCUS schemes. The increase in scale and intensity of drilling activities over the medium term impose greater demands on rig capacity, the technical service ecosystem, and drilling human resources.

On this basis, the study proposes 4 key solution groups: (i) improving the centralized governance and coordination mechanism based on field clusters and field life cycles; (ii) enhancing domestic drilling rig capacity and the technical service ecosystem; (iii) developing drilling human resources across the entire drilling value chain; and (iv) completing end-of-field-life management procedures in association with sustainable development. These measures provide a foundation for Petrovietnam to effectively implement its drilling programs through 2030.

Field trial of the thermally stable, inhibitive water-based drilling fluid system Pro-Dril/Pro-Dril HT in well 2205/BK-22, Bach Ho field

2026-09-08T10:42:29+00:00

As oil and gas exploration and production activities continue to expand into geologically complex environments, such as high-pressure and high-temperature (HPHT), abnormal formation pressures, and deepwater offshore conditions, increasingly stringent requirements are being imposed on the performance and stability of water-based drilling fluid systems. Consequently, the development and technological mastery of water-based drilling fluids with superior shale inhibition and enhanced thermal stability have become increasingly important for drilling operations. In recent years, PetrovietnamChemicals and Services Corporation (PVChem) has developed the Pro-Dril/Pro-Dril HT water-based drilling fluid system, which provides excellent shale swelling inhibition and maintains stable performance at temperatures up to 165°C. This paper presents the results of a field trial of the Pro-Dril/Pro-Dril HT system in well 2205/BK-22, Bach Ho field.