Production Enhancement From Sand Management Philosophy: A Case Study From Statfjord and Gullfaks

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractStatfjord 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.

Design of a Cyclonic-Jetting and Slurry-Transport System for Separators

“…Even with exclusionary well design, solids will report to the surface facilities through equipment failure, completion limitations, or a step change in production profile, such as water breakthrough. In addition, an operating model of sand coproduction is becoming more relevant as a method of improved oil recovery (Geilikman et al 1994;Ahmad et al 2004;Andrews et al 2005). Facilities sand management is tasked with ensuring sustained hydrocarbon production when particulate solids are present in well fluids, while minimizing the impact of these produced solids on surface equipment (Rawlins 2013).…”

“…The preferred location for facilities sand removal is before the choke with a wellhead desander (Rawlins 2013); however, in cases where this technology is not currently used, the produced solids will collect in the primary separating vessel. Accumulated solids in gravity-settling vessels result in loss of residence time, corrosion-enhancement zones, increased sediment in oil, increased oil content in produced water, and degraded injectivity of produced water (Andrews et al 2005). Sand and solids…”

A Novel Approach to Replacing a Gravel Pack Completion Using Hydraulic Screens to Remove the Annular Gap

“…Sand production has been experienced throughout the production history, requiring a passive sand management strategy (Andrews et al 2005). The field produces from two main reservoirs, with reservoir temperatures from 90 o C to 95 o C. From initial field development to 2005, wells were mainly completed with a cemented and perforated liner.…”

Lifetime models for remaining useful life estimation with randomly distributed failure thresholds

“…The application proposed in this paper concerns deterioration of choke valves undergoing erosion (Bringedal et al, 2010;Andrews, Kjørholt & Jøranson, 2005). In offshore oil platforms, choke valves are used on the surface to control the flow of hydrocarbons and protect the equipment from unusual pressure fluctuations.…”

“…In offshore oil platforms, choke valves are used on the surface to control the flow of hydrocarbons and protect the equipment from unusual pressure fluctuations. Production experience has shown that choke valves are prone to sand erosion in the disks and in the outlet sleeve (Andrews et al, 2005). The main parameters determining erosion are the impact velocity and the impact angle of the sand grains through the choke discs.…”