A thermal steam project has been successfully implemented in a Petroleum Development Oman (PDO) field in the South of Oman. The steam flood developed the crest of the field and incremental oil recovery from formation A has been obtained. Based on this success expansion of the steam flood in the field is planned. The southern extension will encounter the same formation A as developed at the crest. The northern extension, however, will contain two new formations (B and C).
For these two new formations limited field data on sand production is available, and a sand prediction evaluation for both cold & thermal production conditions is required. Additional to that, the field development strategy requires that the oil producers will be re-completed after steam breakthrough and a flexible placement of the pump above/below the perforations at different phases of the steam flood. Successful implementation of conformance control in wells with sand control has a significant impact on the oil recovery and thus economics of the project.
This paper focuses on formation B. The assessment of the likelihood of sand production and the requirement of sand control was based on a combination of a) actual field data such as sand production, well performance & completion data; and b) a sand production model for the different production conditions (hot and cold) utilizing rock-mechanical data. The sand evaluation study demonstrated that there is a risk of catastrophic sand failure under both cold and hot operation conditions and thus a completion with thermally compliant sand control and conformance control is required for this formation.
Core sieve analysis data were used to determine the Particle Size Distribution (PSD), which was used to select the sand control type and screen slot width. A standalone wire wrap screen has been selected for sand control in formation B.
A completion that combines a standalone wire wrap screen, with the provision of conformance control by isolating perforation intervals, with placement of a 4.5" tubing pump below the (isolated) sand screen is challenging to design. Multiple completion types have been evaluated and a new type of technology for PDO of sand control with an isolation sleeve is proposed to meet the requirements of the field development plan. It is expected that this new design with flexible recompletion of the sand control system will have a large impact on the oil recovery.