Developing the Obaiyed Tight Gas/Condensate Field, Egypt-A Case Study

摘要

The Obaiyed tight Gas-Condensate field was discovered in 1992 and following 4 appraisal wells and 3 additional exploration wells the first integrated field development plan was issued in 1996. This formed the basis for an agreement to deliver 300 MMscf/d. The field was brought on stream in 1999 reaching full capacity in 2001. However, reservoir pressures dropped much faster than expected (30% rather than expected 10% annual production decline). In addition condensate production only reached 60% of initial expectation levels. A complete subsurface review in 2000-1 showed 5 key areas of concern that requiring specific attention in the FDP update: [1] more severe reservoir compartmentalisation, [2] poorer reservoir quality in NW part of the field, [3] lower CGR's, [4] Temperature constraints on flow lines, [5] Multiple fluid contacts. Consequently expected production levels and recovery factors had to be adjusted downward. A root cause underlying most of these issues (points [1], [3], [4], and in part [5]) can be traced back to the design and duration of the early well tests. Three years after the integrated review the reservoir/well behavior is very much in line with the 2001 model, indicating the quality work done at the time. Based on the above solid models, the future development of the field has been optimized. It comprises the following key activities: 1. Improved field & reservoir management 2. Full field booster-compression 3. Production acceleration 4. Under Balanced Drilling The aim of the paper is to present the Obaiyed Field Development case, lessons learnt, remedial action taken and future plans.