The NPD's offices, STAVANGER
As the industry is drilling deeper wells the likeliness for gas condensate discoveries increases. The development of gas condensate fields creates challenges to current understanding and need for new technology. The overall problem is to assess the deliverability of production wells correctly in the development phase of a gas condensate field in order to meet the sales volume with the planned number of producers.
Productivity impairment due to condensate build-up in the near-wellbore area has to be modelled correctly. Deep and high pressure reservoirs will often be undersaturated and near critical temperature with a high condensate yield. Extended well testing will not necessarily give information about the productivity impairment when the reservoir pressure drops below the dewpoint and liquid banking occurs.
The flow in the near-wellbore area will depend on the gas velocity. Both the relative permeability and the critical condensate saturation are dependent on velocity and interfacial tension. Understanding the near-wellbore flow mechanisms is also important for the interpretation of well tests.
Hydraulic fracturing can be used to increase the deliverability of a producer. However, the experience with this method to also overcome productivity impairment from condensate banking is not unambiguous. Commingled production of oil and condensate reservoir zones can be the only viable method to produce some complex reservoirs and asphaltene flocculation may be initiated. Reserve calculations require permeability cut off criteria which can be a real challenge in tight and complex formations. Process design and the specification of product streams require an accurate composition of the well stream during the depletion period. Expansion of lumped composition from reservoir simulators to the necessary number of defined components needed for process simulations is a challenge.
The industry is working hard on these issues and the understanding has significantly improved during the last years. In order to get a common understanding of the current knowledge in the various oil companies and to define and discuss challenges and problems, the FORCE member companies have decided to arrange a multidiscipline 1 1/2 days seminar.
A workgroup, consisting of Sigbjørn Kalvenes, (Mobil), Jon Knut Ringen (Statoil), Arne Skauge (Norsk Hydro), Hans Petter Hjermstad (Saga) and Kirsti Veggeland (FORCE Secretariat), has organised the seminar.
The attached agenda shows a variety of presentations, and the timeschedule showed is flexible. For every presentation it is allowed for discussions after. The committee encourages the participants to be informal and join the discussions. The panel discussion at the end of the seminar will hopefully conclude with a prioritised list of problem areas for which there can be further work.