A Multidisciplinary Study Aimed at Optimizing Reservoir Management in a Gas Field With Over 30 Years of Production History

1993 ◽  
Author(s):  
Mario Erba ◽  
Filippo Maioli ◽  
Giuseppe Dadda ◽  
Jean Bolze
Keyword(s):  
Reservoir Management ◽  
Gas Field ◽  
Multidisciplinary Study ◽  
Production History

A Success Story of Unlocking Depleted Channel Reserves in Tunu Gas Field, Mahakam Delta, Indonesia

2020 ◽  
Author(s):  
D. Gumilar
Keyword(s):  
Geological Mapping ◽  
Main Zone ◽  
Success Story ◽  
Gas Field ◽  
Incremental Value ◽  
Static Data ◽  
Water Rise ◽  
Production History ◽  
Potential Channels ◽  
Novel Strategy

Crestal part of Tunu Main Zone has been heavily developed with infill wells mainly targeting the isolated bars, while channel reservoirs in western flank have been depleted and considered as upsides. A novel strategy in targeting depleted channel reservoirs is initiated to challenge the conventional gridding method. The workflow comprises of integration of channel geometry update with current static data, connected gas in place reconciliation, production history, pressure update, and water rise analysis. These become key points in geological mapping of the channel which helps to identify remaining potential channels in the field. The recent result of four wells that have been drilled targeting the depleted channels in Tunu Main Zone gave significant higher reserves and have been producing with more than 1 Bcf cumulative. The success story of those four wells leads the opportunity to propose new wells targeting proven depleted channels. Statistically, those channels have 6-8 meters of thickness, 14-16% of porosity, and 30-60 mD of permeability. A considerable amount of remaining potential in channel reservoirs was caused by commingled production strategy and relatively high flowing pressure in the past existing wells resulting in basket gas. Better production result than prognosis in depleted channel reservoirs is due to selective perforation strategy and lower back pressure due to lower production flowing pressure. Depleted channel reservoirs are still promising to be targeted for future wells candidate using more systematic approach. This paper endeavors to exhibit a systematical approach in converting undervalued potential of depleted channel reservoirs to compelling prospects as an incremental value creation process in a mature gas field.

DEVELOPMENT OF THE WOODADA GAS FIELD

1985 ◽  
Vol 25 (1) ◽  
pp. 316
Author(s):  
C.M. Lane ◽  
R.J. Watson
Keyword(s):  
Gas Production ◽  
Commercial Production ◽  
Permeability Barrier ◽  
Production Mechanism ◽  
Well Bore ◽  
Secondary Porosity ◽  
Gas Field ◽  
The Matrix ◽  
Production History ◽  
Matrix Rock

The Woodada gas field was discovered in May 1980, when the Woodada 1 well flowed gas at a rate of seven million cubic feet per day from a carbonate unit within the Carynginia Formation of the onshore northern Perth Basin. Appraisal and development drilling has resulted in a total of 11 wells, of which seven have produced sales gas.The reservoir is estimated to have contained initially at least forty four billion cubic feet of gas-in-place in the developed part. There is a prospective area to the south with similar potential.The Woodada field is a combination structural/strati- graphic trap, where an up-dip lithology change effecting a permeability barrier seals the reservoir across a north plunging anticline. Porosity within the reservoir is secondary, with natural fractures often contributing to the production mechanism. The presence of fractures has required special attention to drilling and completion techniques. Gas production is significantly enhanced by acidization.Pressure responses measured in or between wells combined with more than two years of production history have demonstrated that there is moveable gas in the fine voids of the matrix rock, as well as in the better developed secondary porosity system. Even where there is no substantial porosity in a well bore, it has been possible to achieve commercial production rates by acid stimulation.

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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