An evaluation of sand control performance on wells in an area within the Trinmar acreage is presented. This evaluation was conducted to determine the causes of the failures and to recommend and implement procedures to improve the performance of the sand control jobs.

Petrotrin Trinmar Operations is located in the Gulf of Paria, south western Trinidad. There are four main producing regions and traversing the field is a major geological feature the Los Bajos fault.

Sand production in association with crude oil is one of the main issues affecting the production from wells and sand control techniques have been used as a mechanism to stop or reduce the production of sand.

For the purpose of this paper, sand control failure occurs when there is

  • A decrease in production post sand control

  • Continued sand production resulting in sand accumulation of surface facilities and

  • Mechanical failures during the execution of the sand control job

A total of fifteen (15) jobs were evaluated. In this paper the process flow for sand control was reviewed and each activity in the process was critically reviewed ranging from design, selection of sand control type, execution and producing technique after sand control. The basis for the current design was examined and it was found to be dictated by current practices which appear to be successful in the other fields of the operation.

Attempts were made to examine peculiarities in reservoir characteristics and completion methods. It has been observed that within a specific area of the fieldLocation 13, the highest failure rate of sand control occurs.

The major failure type was a severe decrease in production post sand control. It was found that the high silt content of the reservoir was creating a reduction in permeability thus accounting for the drop in production and gravel sizing was based on current practice instead of sieve analysis of formation sand.

There was no evidence to suggest that the reduction in production was due to fluid compatibilities or clay swelling.

This paper reinforces the need for emphasis on the design phase with the necessary data set and detailed post job analysis. This would bring forth the most appropriate technical and economical solution which will result in the optimum exploitation of the reserves.

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