The Dougga gas condensate field is located in the Sicily channel in the Gulf of Hammamet offshore Tunisia in a water depth of 328m.
The field is 100% owned and operated by ADX Energy (ADX), which is currently carrying out a pre-feasibility study.
The company plans to drill an appraisal well on the Tunisian field to establish its commerciality viability.
Dougga field discovery
The Dougga gas field was discovered in 1981 by the Dougga-1 discovery well drilled by Shell. The discovery well encountered a 500m hydrocarbon column under a thick regional seal of more than 500m. It confirmed the presence of condensate-rich gas after a short mechanically failed test.
Field development was abandoned as the gas was considered to be of no use and condensate stripping was unavailable at that time. The field is also located at a depth, which during that time was considered to be the technical limitation for the development.
Seismic data has further identified the Dougga West exploration prospect located 9km north of the field. The prospect is expected to contain 227 million barrels of prospective reserves. The seismic data has indicated a high correlation with the discovery well.
Reserves of the Tunisian gas field
Dougga gas field is estimated to contain mean resources of 74 million metric barrels of oil equivalent (Mmboe), including 196 billion cubic feet (bcf) of gas and 42 million metric barrels (Mmbbl) of condensate.
The field is rich in liquids and contains approximately 30% carbon dioxide.
Appraisal on Dougga
The Dougga gas field has been established as a valuable resource, based on 3D seismic data. An appraisal well is planned to be drilled in 2018 on the Abiod Limestone reservoir in order to prove the commercial potential of the field.
Drilling of the Dougga South appraisal well will also help in establishing commercial flow rates and increase the gas and liquids reserve base of the field. ADX is currently carrying out development concept studies for the project.
The company also plans to carry out a high-quality seismic 3D study over the prospect. A 3D geological modelling of the prospect, completed in May 2017, indicated a 103% increase in contingent resources. The seismic study will help in establishing the reserves and also help in appraisal well drilling and planning.
Based on the seismic data, ADX is seeking a farminee to farm out equity interest in the field and fund the drilling of the appraisal well. The company expects to attract a partner by the end of 2017.
Dougga field development details
The gas field is located in close proximity to onshore gas processing facilities and can take advantage of domestic infrastructure as the demand for gas is high. The project also has the potential to access the high-value gas markets of Europe through the Transmed pipeline.
Despite these advantages, lack of good project economics hindered the field development. The Tunisian authorities recently expressed their willingness to revise the fiscal terms for the project thereby advancing its development.
The original development option for the field included the use of offshore floating facilities. The revised plan now includes a 45km tie-back to an onshore production plant, where the produced hydrocarbons will be processed to recover condensate and natural gas.
The revised development option is expected to reduce the capex required to develop the field. The possible development option for the field will include six wells tied back to a 100MmCFD onshore gas plant. A potential gas hub is also planned to be developed to tie-back nearby fields including the Dougga west prospect.
ADX has contracted TechnipFMC to study development options for the project.