A thermal steam project has been successfully implemented in a Petroleum Development Oman (PDO) field in the South of Oman. The thermal project developed the crest of the field which has mainly formation A. The thermal response has been favorable as witnessed by the incremental oil recovery. The steam flood is now planned to be expanded further to the South where it will encounter the same formation as currently developed at the crest & to the North where it will encounter two new formations (B & C). The new formations have limited field data on sand production; therefore a sand prediction evaluation for both cold & thermal production conditions is required for these new formations. In this paper we describe the analysis of the sand control potential and the selection process of the sand control technology.
The assessment of the potential for sand production and the requirement for sand control was based on a combination of a) actual field data such as sand production, well performance & completion data; and b) a sand prediction model for the hot and cold operating production conditions utilizing rock-mechanical data. In addition, 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.
The sand evaluation study demonstrated that for formation A has only the probability of transient sand failure under hot operation conditions. The wells will therefore be completed without sand control. On the other hand, formations B & C have a risk of catastrophic sand failure under both cold and hot operation conditions. A completion with thermally compliant sand control is a must for formation B. In case of formation C the selection of sand control is challenging as the sand distribution shows a high percentage of fines. In this case sand control is obtained through selective perforation, excluding the sand prone intervals. The impact of blanking the high GR intervals on inflow is expected to be low as the average the permeability for these intervals is low.
The implementation of the selected Stand Alone Screens for sand control in formation B will be the first thermal application of these screens in PDO.