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A STIMULATION TREATMENT AND EVALUATION OF A GRAVEL PACKED WELL; A CASE STUDY FROM THE STATFORD FIELD Abstract Several wells in the Statfjord field are restricted from producing at their maximum potential due to sand production. To optimize production different sand control techniques have been implemented. Gravel packed wells have contributed significantly to maintain production capacity. Typical production increase after gravel-packing has been 2 – 4000 Sm3/d. However, rapid plugging problems have been experienced after water breakthrough. Extensive scale dissolver and scale inhibitor treatments have been performed with varying success. Plugging problems experienced in the gravel packed wells are difficult to predict and overcome, In order to improve the productivity of the well and to establish a better understanding of the damage mechanisms, it was decided to perform a scale dissolver treatment and evaluate the stimulation effect by the use of a production logging tool (PLT). Well C-32, having a 55.5 m cased hole gravel packed interval was selected. The well was stimulated by a 2% KCl treatment prior to water breakthrough and treated by a scale dissolver and inhibitor shortly after water breakthrough. Production logging performed after installation of the gravel pack in November 1991 gave a basis for comparison, The evaluation of the data has shown that the plugging process is complex and difficult to interpret. We can conclude, however, that injection of fluids has improved the gravel pack productivity. The erosion potential has also been minimized due to reduced draw down across the gravel pack. The plugging mechanism is most likely a combination of scale and fines plugging the wire wrapped screens and the poorly filled perforation tunnels. The first stimulation operation had a payback time of 3 days and the second operation including production logging had a pay back time of 17 days. P. 313 |
