Mallick, Tanmay (Shell India Markets Private Limited) | Garg, Ashutosh (Shell India Markets Private Limited) | Choudhary, Manish (Shell India Markets Private Limited) | Nair, Saritha (Shell India Markets Private Limited) | Pal, Sabyasachi (Shell India Markets Private Limited) | Jana, Debadrita (Shell India Markets Private Limited) | Singh, Abhinav (Shell India Markets Private Limited) | Goudswaard, Jeroen (Shell India Markets Private Limited) | Faulkner, Andrew (Shell India Markets Private Limited) | Salakhetdinov, Ravil (Shell India Markets Private Limited)
A new seismic and quantitative reinterpretation was carried out for a brownfield in Western Desert, Egypt to improve depth predictability, de-risk appraisal well locations and to better understand producer-injector connectivity.
The study field is located in the Western Desert, Onshore Egypt and comprises of Upper Cretaceous tidal channel systems across four key reservoir levels where sand thicknesses range from 2 to 15 m. The field was discovered in 1993 but development drilling only commenced in 2008. The last integrated field study was performed in 2012. The analysis of wells drilled post-2012 indicated that there is a considerable depth difference along the flanks of the structure between seismic predicted depths and actual well tops (>50 m). The fault interpretation also required a re-look so as to reduce the lateral uncertainty of the main boundary fault and explain the lack of injection response in some areas of the field. This necessitated an update of seismic interpretation, static and dynamic models. A new interpretation could help identify attic volume upsides and help mature new appraisal and producer-injector locations. Further work was also proposed to test the feasibility of using seismic inversion for facies discrimination.
The available Pre-Stack Depth Migration (PreSDM) data was re-interpreted as part of the project. The fault interpretations were quality checked using Semblance/Dip maps, sand box models and wherever possible, were tied to the fault cuts seen in previously drilled wells. The time horizon correlation and seismic polarity were verified and were also cross-checked with the P-Impedance volume before being used in the static modelling workflow. The PreSDM Interval velocity model was used for depth conversion, where an anisotropy correction was applied to tie the wells. Vok and Polynomial methods were also applied, which in turn were used to derive depth uncertainty estimates. The update in the main bounding fault interpretation generated new appraisal locations in the deeper levels. The new interpretation was tested against the results from the latest drilling campaign in the field, and nine out of ten wells were within the one standard deviation uncertainty range.
Simultaneous inversion of the seismic data was also carried out as part of the project using the acoustic, shear and density data from 6 wells over the field. The inverted P-Impedance and S-Impedance were converted to Net to Gross (NtG), and were checked against the remaining 24 wells, which helped in validating the property cubes.
Forward wedge modelling suggested that individual sands of less than 15 m thickness would not be resolved from seismic due to seismic bandwidth limitations. Still, a review of inversion data together with geological insights and dynamic data helped to identify the high NtG areas across the reservoirs.
The integrated interpretation of inverted volumes with well and production data resulted in new insights into the field and helped to mature new appraisal and development well locations.
Bakker, Peter (Brunei Shell Petr. Sdn Bhd) | Liew, Yee Yung (Brunei Shell Petr. Sdn Bhd) | Dale-Pine, Brigitte (Brunei Shell Petr. Sdn Bhd) | Watts, Lee (Brunei Shell Petr. Sdn Bhd) | Salakhetdinov, Ravil (Brunei Shell Petr. Sdn Bhd)
The economic development of thin oil rims associated with large gas caps in multi-stacked reservoirs presents many challenges. In the structurally complex Champion West field, offshore Brunei, innovative well designs together with detailed subsurface studies have unlocked thin oil rims. Earlier development phases comprised deviated and snake wells with multi-zone smart completions. In some areas these wells have resulted in cross-fault depletion of the remaining smaller oil targets. An appraisal strategy was put in place to address the major uncertainties associated with the smaller targets, such as complex fluid distribution and connectivity to existing producers. This strategy comprised drilling pilot holes from development wells, which were evaluated using advanced mud gas logs, downhole pressure measurements and wireline/ logging whilst drilling (LWD) logs to confirm fluid distribution and understand connectivity. This paper discusses one such example, where production data from smart wells has been incorporated with appraisal data to optimise well design, placement and production from a thin depleted oil rim. Multi-rate test information has been used to adjust down-hole inflow control valve (ICV) settings, initially to balance drawdown along the horizontal wells and later to minimise water and gas cap production.
Turco, Agostino (Brunei Shell Petroleum Sdn. Bhd.) | Salakhetdinov, Ravil (Brunei Shell Petroleum Sdn. Bhd.) | Dale-Pine, Brigitte (Brunei Shell Petroleum Sdn. Bhd.) | Van Lelden, Robert (Brunei Shell Petroleum Sdn. Bhd.)
This reference is for an abstract only. A full paper was not submitted for this conference.
The current phase of the Champion West Field Development is one of BSP's most challenging project to date for drilling and completion reasons. The Champion West field was discovered in 1975, but its rich oil and gas reserves lay dormant for 30 years, locked beneath the seabed in a complex web of reservoirs deemed too expensive to develop using conventional development plans. It is a large undeveloped oil and gas resource in Brunei. Hydrocarbons are found in shallow marine reservoirs - these vertically stacked, structurally dipping reservoirs are complex and contain various fluid fills ranging from gas only to gas with oil rims to oil. The project consists developing oil rim reservoirs using the novel snake well design and developing of significant gas resources using highly deviated and high-pressured gas wells. Four wells have been drilled to date utilizing advanced drilling technologies and smart-completion equipment to complete over many stacked reservoirs with different pressure regimes, whilst aiming to maximizing ultimate recovery for those sand units. The world first six- zones Smart completion were successfully installed in 2007 with the objectives of realizing increased recovery and a reduction in life cycle cost through real time monitoring and production optimization and a reduction in well intervention as well as reduction in HSE exposure. Challenges associated within the gas project included: Drilling through depleted and virgin pressure regimes of up to 8200 psi; Extended reach drilling of up to 7.3 km; Perforation; and, Installation of Smart-Completions in high-pressured gas environment. In addition to significant oil production, Champion West has been contributing to around 20% of BSP's gas production with a significant proportion coming from these recently drilled gas wells. This paper describes the well concepts adopted and the experiences developed throughout the project in drilling and installing Smart-Completions in this high-pressure gas environment.