TAO field is a high rate gas development in the Mediterranean Sea, operated by North Sinai Petroleum Company (NOSPCO), a joint venture of Perenco and EGPC. The field comprises multichannel sandstone reservoirs from the Nile Delta depositional environment. Earlier exploration and appraisal stages had proven reserves for three of the six sands, with the remaining three identified as potential (unconfirmed) gas bearing reservoirs, all of which require sand control.
A multidisciplinary project team put forward and implemented a field development plan to maximize profitability through effective measures for overall cost reduction, while ensuring sustained delivery of the production commitment. This paper will detail the field development plan, implementation and results, along with the case histories. This plan included:
Batch drilling and batch completion to minimize drilling and completion costs, and maximize data gathering as early as possible.
Completing two of the four wells as openhole gravel packs targeting the most prolific sand to ensure that the production target is met with the productivity benefit of an openhole completion and reliability of gravel packing as a sand control technique.
Completing the remaining two wells as cased hole gravel packs in squeeze mode to increase well productivity by ensuring maximum amount of gravel behind casing and targeting the two remaining sands with proven reserves as well as the sands with potential reserves in order to sustain the production commitment over project life, while avoiding to drill two dedicated appraisal wells.
All gravel packs were performed with filtered seawater as the base brine and mesh type sand control screens, with the exception of one of the zones, where alternate path screens were used in conjunction with a seawater compatible viscoelastic surfactant carrier fluid. Openhole gravel packs utilized a service tool that allowed post-gravel-pack filtercake cleanup treatment.
Post completion multi-rate tests concluded that both openhole gravel pack wells fulfilled the required productivity, showing potential productivity above 110 MMSFCD per well. In addition, the two of the zones tested in each of the cased-hole gravel packs showed potential productivity above 50 MMSCFD per zone.