RIASSUNTO
Abstract
This paper will describe a new sand control method used in an area of Ecuador, South America where workover rigs are not readily available. Sand production had been significantly affecting maintenance costs on surface and downhole production equipment and had impacted performance of the downhole jet pump, subsequently causing a decrease in well production. By installing a small diameter, sintered metal gravel-pack screen across the perforation interval and placing the gravel-pack sand with coiled tubing, the sand production was successfully controlled. The procedure and equipment used to perform this technique as well as post job data that provide results obtained will also be presented. Noteworthy advantages, such as recompletion without removal of the existing production completion string and without use of a workover rig, will also be discussed.
Introduction
When sand problems occur in existing wells, remedial operations must be capable of providing the cost efficiency needed to maintain profitability in today's oil and gas climate. In many wells, it is not economically or geographically feasible to recomplete with traditional methods and workover rigs, and therefore, other methods must be reviewed, not only for remedial capability but also for economic efficiency. It is this latter assessment that often decides the fate of the well. Many technological advares in gravel pack fluid systems, downhole equipment, and service operations have been developed to respond to the stringent economic needs governing today's oilfield; these have enabled realization of greater rates of success and lower costs in thru-tubing recompletions.
Sand control techniques that are most effective are those that are implemented early in the life of the well - before water production or formation damage causes sanding problems. High production rates such as those that are experienced in typical jet pump installations can put excessive stress on weakly consolidated formations, and the capability of the cementitious material to bond the sand gins together is impaired. Formation damage results, and subsequently, as was evident in the case history presented in this paper, sand production occurs. The formation of sand increases wellbore pressure and causes wellbore plugging and equipment damage. Once this scenario takes place, effective sand control methods become more difficult to apply and harder to justify - particularly in marginal wells with poor reserves that may not support the cost of a major workover program.
As a result of current oilfield cost constraints, operators are reviewing most wells with downhole problems as possible candidates for thru-tubing remedial operations.
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