Statfjord and Gullfaks are "Brown" fields operated by Statoil in the Tampen area of the North Sea. The production from these fields is characterized by large volumes of water and increasing sanding tendencies. The operator has for many years followed a strategy whereby sand produced with the wellstreams has been handled topsides prior to on-site disposal. The adoption of a sand management strategy has been crucial for prolonging economic reservoir development during tail production. By choosing to deal with sand topsides the operator has been able to pursue low cost slot replacement drilling where wells are completed without sand control equipment. The cased-hole functionality has facilitated multitarget drilling and is suited to selective production of each sand member through cheap plug/perf interventions.
Significant gains in production (acceleration) and reserves (IOR) have resulted from the pursuance of sand management in these fields. Examples of wells showing productivity improvements as a direct result of allowing intervals to produce sand are presented. In addition, production gains achieved from replacing choked back "sand free" production with "maximum acceptable sand rate" production are presented. Increased sand tolerance has also led to reserve increases in some wells as unproductive intervals that were previously sanded up have cleaned up and started to flow. It will be argued that this strategy negates many concerns with formation damage during well work because such damage is produced out with the sand and the wells clean up naturally.
The transient nature of sand production is discussed and the production gains observed in each field is presented. Such a strategy requires that the sand production is managed in a safe and controlled manner where the negative consequences of sand production are manageable and predictable. This paper will also discuss the improvements made in sand detection and on-line erosion mapping required to improve the sand tolerance of these facilities.