Reservoir Surveillance - Fluid Contact Monitoring in Fractured Carbonate TA-GOGD Project

Edwards, John E.; Brown, George; Vincent, Mark; Keshishian, Avo; Putra, Pristiwanto H.; Bettembourg, Solenn

doi:10.2118/145554-ms

Cited by 3 publications

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“…Examples of indirect methods include Conventional Well Logs (Geng et al, 1983;Dahlberg and Ference, 1984;Tan, 1999), Dielectric Constant and Sonic Log (Ding et al, 2000), T2 Differential Spectrum from NMR Logs (Coates et al, 1999), and Seismic Data (Hamada, 2004). The recent attempts include using Wavelet Transform (Wen -Yue et al, 2006), a modification of the former algorithms (Abd-ElMoula, 2010), a study on fractured hydrocarbon reservoir (Edwards et al, 2011) and NMR and Downhole Fluid Analyzers data. This paper uses three data processing methods (Classification, Wavelet Analysis and Data Fusion) in order to identify reservoir fluid types from PLs in a carbonate reservoir from an oil field located in southwestern Iran.…”

Section: Introductionmentioning

confidence: 99%

Proposing a New Integral Method for Fluid Type Identification from Petrophysical Logs in a Carbonate Reservoir

Mollajan

Memarian

Tokhmechi

2013

Energy Exploration & Exploitation

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This paper proposes a new method through combining three data processing techniques: Classification, Wavelet Analysis and Fuzzy Data Fusion, to identify reservoir fluid types from Petrophysical Logs (PLs). The proposed method was applied on well log data of interval of Sarvak Formation related to five wells, located on an oil field in southwestern Iran. The obtained results were compared with production test results to check validation of the introduced method. It is concluded that the method proposed by this research is significantly able to identify different types of reservoir fluids with an average accuracy of 62%. Furthermore, applying data fusion techniques improved the final accuracy of generalization step approximately to 13%.

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Section: Introductionmentioning

confidence: 99%

Proposing a New Integral Method for Fluid Type Identification from Petrophysical Logs in a Carbonate Reservoir

Mollajan

Memarian

Tokhmechi

2013

Energy Exploration & Exploitation

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A Reservoir Management System for the World’s First Thermal Gas Oil Gravity Drainage Project

Rawnsley¹,

Ikwumonu²,

Bettembourg³

et al. 2012

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Thermally Assisted Gas Oil Gravity Drainage of a fractured carbonate heavy oil field in Oman is starting the full field phase. Unlike a normal steam flood, steam is used as a heating agent to enhance the existing gravity drainage mechanisms. The project has been piloted successfully. The project start-up sequence consists of increasing off take from deviated producers followed by steam injection and aquifer pump-off. Steam will progressively fill the fractures whilst heated oil drains down in the matrix blocks and accumulates in an oil rim below the steam in the fractures. The fracture oil rim will be lowered by approximately 100m. Horizontal producers will be completed in the final fracture oil rim position. As no analogues exist a large degree of flexibility has been incorporated in the field development plan to cover uncertainties including caprock integrity, erratic oil rim movement and heterogeneous steam distribution. To facilitate decision making an enhanced reservoir surveillance, modelling and management system has been built. Reservoir pressures, oil rim positions, temperatures and rock strain data are obtained from a range of observation wells. Further data are obtained from surface uplift, microseismic monitoring and fluid sampling. Static, fracture, dynamic and geomechanical reservoir models have guided the design of the reservoir surveillance program and underlie the operating guidelines for the reservoir. These provide operator reactions for a wide range of "what-if" events. A corporate real time data portal has been optimised for the unique requirements of this project allowing for analysis of all data streams. A system allows 3D display, through time, of reservoir data and model forecasts to ensure optimum performance analysis. Initial application has resulted in identification of optimised well configurations and start-up sequence giving higher oil forecasts. The learning is being applied further in Oman and has wider application.

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Technologies for Monitoring Matrix Oil Saturation for TA-GOGD

et al. 2012

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TA-GOGD is thermally assisted gas-oil gravity drainage suited for heavy oil in highly fractured formations. Steam is injected into the fractures to serve two purposes: to apply a gas gradient across the matrix blocks so that the oil in the matrix drops down by gravity and to heat the carbonate matrix blocks so that the reduced viscosity oil drips out faster. The reservoir has two fluid systems, which are gas/oil/water levels in the fractures and gas/oil/water contacts in the matrix blocks that are separated by the fractures. Reservoir surveillance requires logs of the remaining oil saturation to confirm the recovery, which is dependent upon the heterogeneities of fracture intensity and vertical permeability. The changing fluid saturations in the matrix are primarily oil replaced by hydrocarbon gas, but six fluids could be present and change: methane and steam, hot low-viscosity and cold high-viscosity oil, formation water, and condensed steam. The important zone is above the fracture gas/oil contact, where drained oil is replaced by the secondary gas cap or steam. Time-lapse pulsed neutron capture logs during the pilot phase did not provide the required matrix fluid saturations due to interference from variable annular fluids in the poorly cemented casing that masked the reservoir response. There is no logging tool available that is capable of measuring the matrix oil saturation change without being influenced by the other fluids in the matrix or the fracture-controlled fluid levels in the casing annulus, or characterized for an open gas-filled borehole, and built to withstand 247°C. The physics of nuclear magnetic resonance (NMR) provides the best chance to fulfill this reservoir surveillance requirement. This paper recounts the decision process that preceded this conclusion, and suggests a method of building a high-temperature non-metallic and non¬magnetic flask to facilitate NMR time-lapse logging in dedicated openhole observation wells in TA-GOGD developments.

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Reservoir Surveillance - Fluid Contact Monitoring in Fractured Carbonate TA-GOGD Project

Cited by 3 publications

References 0 publications

Proposing a New Integral Method for Fluid Type Identification from Petrophysical Logs in a Carbonate Reservoir

Proposing a New Integral Method for Fluid Type Identification from Petrophysical Logs in a Carbonate Reservoir

A Reservoir Management System for the World’s First Thermal Gas Oil Gravity Drainage Project

Technologies for Monitoring Matrix Oil Saturation for TA-GOGD

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