The production strategy in the Nong-Yao field considered the unconsolidated nature of the reservoirs and an effective drawdown strategy given the use of Electrical Submersible Pump (ESP) for artificial lift. The particle size distribution analysis demonstrated a broad range of sand grain size that would ideally require sand control methods like gravel packing which was not preferred due to cost and complexity. A simpler and cost-effective solution using an advanced sand screen technology was implemented. Applying a minimum drawdown across horizontal inflow across the sand face via gradual increase of ESP frequency was initially adopted to complement the use of screen only completion.
The specially designed sand screen with compressed metal-wool was installed in 14 wells in the Nong Yao field. All wells were completed with ESP for artificial lift. After one year of production, the wells have produced sand free with no sand observed at surface, even though some wells are high water-cuts and ESP frequencies have been ramped up. Analysis performed using downhole ESP pressure data indicate very low draw-down across the sand face, suggesting no issues with downhole plugging of the screens. This observation shows that the implemented completion design, along with the production start-up strategy is working well. This same strategy is being applied in the next phase of the field development.
This is the first application of the compressed metal-wool sand screen in the Gulf of Thailand. The analysis and deployment of this sand control method to fit the reservoir sand characteristics, in combination with artificial lift and production strategy to meet operational challenges, to reduce development cost and to achieve production performance. The success achieved with this in the Nong Yao field could be extended to other marginal field developments, which have similar sand face completion challenges.