Sanding in Sliding Sleeve Completed Wells Without Sand Control in Moderately Competent Sand-Prone Reservoir Formations: A Field Case

A field case is described to show the first application of a sliding sleeve sandface completion without sand control in a moderately competent sand-prone reservoir formation. This type of sandface completion consists of blank pipe segments, isolation packers, and sleeves in between serving as flow ports. This geometrical configuration renders a unique sanding mechanism. Due to a large opening in the annulus, the rock starts to disaggregate at a low reservoir pressure depletion, but its aggregates tend to be blocky and thus favorable in lowering sanding risk as bigger aggregates have a higher frictional resistance and require a higher fluid velocity to transport. Also, annular fluid flow is accumulative, and its velocity is zero at the packer and the highest at the sleeve. An effective practical measure to lower sanding risk, therefore, is to optimize the number and locations of packers and sleeves in relation to reservoir formation strength and sandface flow contributions. The sanding mechanism and practical ramifications are illustrated through historical sanding responses in 11 wells in an oil field in the UK North Sea. Most wells have experienced watercut and the flowrate in some wells is high. Sanding to date, however, is below the design tolerance. A method was developed to estimate the annular fluid velocity. Through cross-referencing historical sanding responses within the sanding mechanism framework, empirical relationships between sand mass per meter length and annular fluid velocity were established to help optimize sandface completion design in future wells and production and interventions in existing wells.