An elemental and 87Sr/86Sr isotopic restitution of contaminated pore waters from sandy sediments of the Peciko gas field (Mahakam Delta, Indonesia)

2021 ◽  
pp. 108891
Author(s):  
Norbert Clauer
Keyword(s):  
Pore Waters ◽  
Gas Field ◽  
Sandy Sediments ◽  
Mahakam Delta

Unlocking Oil Resources without Artificial Lift Using Testing Barge in Tambora Gas Field

2020 ◽  
Author(s):  
J., A. Anggoro
Keyword(s):  
Oil Recovery ◽  
Gas Field ◽  
Artificial Lift ◽  
Oil Resources ◽  
Cumulative Production ◽  
Inspection And Maintenance ◽  
Routine Inspection ◽  
Prime Condition ◽  
Safety Operation ◽  
Mahakam Delta

Tambora field is a mature gas field located in a swamp area of Mahakam delta without artificial lift. The main objective of this project is to unlock existing oil resources. Most oil wells could not flow because there is no artificial lift, moreover the network pressure is still at Medium Pressure (20 Barg). Given the significant stakes, the option to operate the testing barge continuously as lifting tool is reviewed. The idea is to set the separator pressure to 1-3 Barg, so that the wellhead flowing pressure could be reduced to more than 15 Barg which will create higher drawdown in front of the reservoir. The oil flows from the reservoir into the gauge tank, where it is then returned to the production line by transfer pumps. The trial was performed in well T-1 for a week in November 2017 and successfully produced continuous oil with a stable rate of 1000 bbls/d. What makes this project unique is the continuous operation for a long period of time. Therefore, it is important to ensure the capacity of the gauge tank and the transfer pump compatibility with the rate from the well, the system durability which required routine inspection and maintenance to ensure the testing barge unit is in prime condition and to maintain vigilance and responsiveness of personnel. This project started in 2018 for several wells and the cumulative production up to January 2020 has reached 158 k bbls and will be continued as there are still potential oil resources to be unlocked. Innovation does not need to be rocket science. Significant oil recovery can be achieved with a simple approach considering all safety operation, production and economic aspect.

Integrated Subsurface Study to Convert Upside Intrabeta Subzone Stakes into Additional Main Targets in Tunu Gas Field, Mahakam Delta, Indonesia

2021 ◽  
Author(s):  
Dwiki Drajat Gumilar ◽  
Riksa Pribadi ◽  
Dhanny Fadlan ◽  
Ramsyi Faiz Afdhal ◽  
Adnan Syarafi Ashfahani ◽  
...  
Keyword(s):  
Value Creation ◽  
Fluid Dynamic ◽  
Additional Contribution ◽  
Post Mortem ◽  
Main Zone ◽  
Gas Field ◽  
Creation Process ◽  
Dynamic Synthesis ◽  
Mahakam Delta ◽  
Value Creation Process

Abstract "Intrabeta" is a subzone located in the upper part of Tunu Main Zone between MF3-MF6 regional stratigraphic marker. Total cumulative production from this subzone is at 51 Bcf of gas and 4.96 MMBbl of oil. This interval is situated between Tunu Shallow Zone and Tunu Main Zone, which are the main producing intervals of Tunu Field, a giant mature gas field in Mahakam Delta, Indonesia. With Intrabeta reservoir depositional context more dominated by channel facies and more varied production fluid properties, the development of Intrabeta subzone became more challenging and previously classified as upsides. As Tunu Field is getting more matured, the challenge to deliver infill wells that economically profitable become more arduous. Thus, all attempts to give additional value to the future infill wells should be properly assessed. This paper aims to provide a comprehensive summary of how strategic collaboration between static and dynamic synthesis of Intrabeta subzone has given additional contribution in Tunu Field continuous value creation process. The method started by conducting an extensive post-mortem review on all perforated reservoirs in Intrabeta subzone. Insights from the perforated reservoirs that comprise of production behavior, perforation success ratio, cumulative hydrocarbon production and updated portfolio are then utilized to provide initial prolific area map for future candidates maturation. Data coming from the dynamic analysis were then combined with static depositional analysis on how the hydrocarbon was distributed in Tunu Intrabeta subzone. A new structural map that has been corrected from seismic push-down effect due to shallow gas presence above Intrabeta interval was then utilized to map the structurally promising area. Deterministic channel boundaries and possible sweet spots are then identified and ranked based on the development confidence level. Four wells with additional stakes from Intrabeta subzone have been proposed and drilled in Tunu Main Zone. All wells have successfully found the targeted Intrabeta targets with various post-mortem findings. While in some wells significantly better post-drilling results were encountered, in other cases slightly lower results were found due to static channel development and fluid dynamic uncertainties. All the lesson learned gathered from the pilot wells provide valuable insights on future improvement toward better and more robust Intrabeta candidate maturation methodology. The insights gained from this study have given essential understanding of Tunu Intrabeta subzone characteristics and possible future potentials. Furthermore, this paper provides a comprehensive summary, systematical approach and lesson learned in enhancing previously upside potential of Intrabeta subzone in Tunu Main Zone to compelling additional targets in Tunu Main Zone future wells as part of the continuous value creation process in a giant mature gas field.

Mature field Development to Periphery Area: Tambora West Flank development

2021 ◽  
Author(s):  
Y. S Priastomo
Keyword(s):  
Seismic Data ◽  
Sediment Provenance ◽  
Reservoir Properties ◽  
The West ◽  
Gas Field ◽  
Field Development ◽  
Dynamic Uncertainty ◽  
Mahakam Delta ◽  
Fully Connected ◽  
Positive Results

Tambora gas field, discovered in 1974 is located in a swamp area at the apex of Mahakam Delta, and it is adjacent to Nilam field, which is operated by another operator. Geologically, the Tambora and Nilam Fields have the same anticline structure that originates from the sediment provenance west of Kalimantan as reflected in present day Mahakam Delta. Therefore, this study aims to analyze the challenges to unlock the potential of the west flank area of Tambora Fields. The geological synthesis of both Tambora and Nilam fields shows similar net sand and pay distribution in lateral and vertical proportions. Most developments in the Tambora Anticline area are in the crest and the distances between wells are ~100-200m. Challenges to unlock potential in flank areas are derived from the limitation of wells and seismic data. Based on data and knowledge of the flank areas in both fields, the west flank has better productivity compared to the east. Therefore, geological synthesis is conducted in the west flank area to define hydrocarbon and reservoir properties. Furthermore, channel models were made from 2D seismic scouring, controlled by the continuation of well log channel facies in the anticline crest area. Based on the preliminary approach, 3 wells were proposed to unlock west flank Tambora potential and were integrated into the plan of development. Primarily, dynamic uncertainty affects the potential of the west flank since production in the anticline crest area is enormous, and the uncertainty was analyzed by drilling one recent well. The result shows that hydrocarbon in the flank is not fully connected with the anticline crest area and has proven the sidebar heterogeneity concept. These gave more confidence to seek further positive results and develop west flank Tambora to sustain Mahakam production in the future.

Machine Learning Technology to Improve Precision and Accelerate Screening Shallow Gas Potentials in Tunu Shallow Gas Zone, PT Pertamina Hulu Mahakam

2021 ◽  
Author(s):  
R. Herbet
Keyword(s):  
Machine Learning ◽  
Learning Technology ◽  
Gas Reservoirs ◽  
Shallow Gas ◽  
Gas Field ◽  
East Kalimantan ◽  
Main Challenge ◽  
Shallow Zone ◽  
Learning Probability ◽  
Mahakam Delta

Tunu is a giant gas field located in the present-day Mahakam Delta, East Kalimantan, Indonesia. Tunu gas produced from Tunu Main Zone (TMZ), between 2500-4500 m TVDSS and Tunu Shallow Zone (TSZ) located on depth 600 - 1500 m TVDSS. Gas reservoirs are scattered along the Tunu Field and corresponds with fluio-deltaic series. Main lithologies are shale, sand, and coal layers. Shallow gas trapping system is a combination of stratigraphic features, and geological structures. The TSZ development relies heavily on the use seismic to assess and identify gas sand reservoirs as drilling targets. The main challenge for conventional use of seismic is differentiating the gas sands from the coal layers. Gas sands are identified by an established seismic workflow that comprises of four different analysis on pre-stack and angle stacks, CDP gathers, amplitude versus angle(AVA), and inversion/litho-seismic cube. This workflow has a high success rate in identifying gas, but requires a lot of time to assess the prospect. The challenge is to assess more than 20,000 shallow objects in TSZ, it is important to have a faster and more efficient workflow to speed up the development phase. The aim of this study is to evaluate the robustness of machine learning to quantify seismic objects/geobodies to be gas reservoirs. We tested various machine learning methods to fit learn geological Tunu characteristic to the seismic data. The training result shows that a gas sand geobody can be predicted using combination of AVA gather, sub-stacks and seismic attributes with model precision of 80%. Two blind wells tests showed precision more than 95% while other final set tests are under evaluated. Detectability here is the ability of machine learning to predicted the actual gas reservoir as compared to the number of gas reservoirs found in that particular wells test. Outcome from this study is expected to accelerate gas assessment workflow in the near future using the machine learning probability cube, with more optimized and quantitative workflow by showing its predictive value in each anomaly.

Shallow Gas Identification using LWD Monopole Sonic: A-non Radioactive for Safe and Effective Logs Acquisition in Tunu Field, Mahakam Delta

2020 ◽  
Author(s):  
A.T. Santoso
Keyword(s):  
Oil And Gas ◽  
Neutron Density ◽  
Shallow Gas ◽  
Gas Field ◽  
Safety Issues ◽  
East Kalimantan ◽  
Main Challenge ◽  
Gas Identification ◽  
Fluid Interpretation ◽  
Mahakam Delta

The Tunu field is a swamp giant gas field located in the Mahakam Delta, East Kalimantan. Stratigraphically, this field has an anticline structure with three main intervals; Tunu Shallow Zone (TSZ), Fresh Water Zone (FWZ), and Tunu Main Zone (TMZ). Shallow gas reservoirs of TSZ have been produced since 2008, following the production of TMZ in the 1990s. Drilling targets in the shallow gas reservoir decreased significantly due to limited reservoir targets, high inclination wells and a low oil price environment. The utilization of radioactive source logging (density and neutron) on Logging While Drilling (LWD) tools is not recommended to be performed in open hole mode for operational and safety issues (e.g: tool stuck). Thus, LWD Monopole sonic is chosen as a replacement of LWD Neutron-Density logs and helps to differentiate between shallow gas potential and coal lithology which is the main challenge in TSZ at interval depth above 1200 mSS. The methodology utilized sonic semblance (STRA) and compressional slowness (DTc) data at real-time and memory data logs, so early decision can be made in drilling mode. In a gas-bearing reservoir, both semblance and slowness are missing, while in coal it produced strong semblance. In order to differentiate carbonate lithology, additional data, such as cutting, calcimetry, drilling Rate of Penetration and Gas While Drilling are utilized. During 2018-2020, 5 wells have been drilled using LWD Monopole sonic together with LWD GR-Resistivity-Neutron-Density (Triple Combo) to calibrate the fluid interpretation and 3 trial wells with only GR-Resistivity-Monopole Sonic. As a result, LWD Monopole sonic is able to differentiate between Gas and Coal based on semblance and slowness with a success ratio up to 80%. This LWD Monopole Sonic provides a non-radioactive solution for safe and effective logs acquisition for shallow gas identification that could be applied in oil and gas fields outside Mahakam.

Integrated Reservoir Management Strategy in Sisi Nubi Mature Gas Field to Unlock Reserves and Production Optimization

2020 ◽  
Author(s):  
R. M. P. Azhar
Keyword(s):  
Management Strategy ◽  
Reservoir Management ◽  
Production Optimization ◽  
Difficulty Level ◽  
Driving Mechanism ◽  
Gas Field ◽  
Technical Limitation ◽  
Well Completion ◽  
Mahakam Delta ◽  
Gravel Pack

Sisi and Nubi are two gas fields located in the Mahakam Delta, 25 km offshore the modern Mahakam Delta to the east, in 60-80m of water depth. Sisi was discovered in 1986 and Nubi in 1992. The fields have been in production since November 2007 from 5 wellhead platforms. Peak production reached 450 MMscfd in 2010, and by the end of 2019 the average production is 150 MMscfd with cumulative production around 1.28 Tcf of gas and 31.3 MMstb of condensate. Having gravel pack and tubingless as well completion in Sisi Nubi leads to several limitations such as some reservoirs were not perforated due to Gravel Pack (GP) technical limitation or are not accessible due to some restrictions such as bridge plug and sediment. Building a simple yet vivid and properly integrated reservoir management strategy was done to tackle the aforementioned issue. The work was to map the remaining potential as well as production risk of both perforated and unperforated reservoirs and to develop the integrated production and development strategy for Sisi Nubi’s optimum’s production and recovery. The works involved multi entities; geoscientists, reservoir engineers, well intervention, and also the well performance team. Up to 2000 meters of unperforated reservoirs within 664 intervals, have been thoroughly studied, covering detailed geological correlation at reservoir scale, initial and current fluid status, driving mechanism, current pressure estimation, and reservoir-level volumetric calculation. Well obstacle classification based on the difficulty level to re-access perforation targets as a well strategy to produce reservoirs were performed in joint coordination with the well intervention team. The final deliverables are selected candidates that qualified both technical criteria and stakes were proposed for execution. An increase of Fifty-five (55) Bcf of stated reserves from existing wells have been booked thanks to this work. In addition, having the systematic strategy allows optimum offshore intervention barge planning.

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