Sand production is one of the major issues in unconsolidated sandstone gas and oil reservoirs. The amount of the produced sand in gas wells might vary from a few grams to a few kilograms per hour, yet it can lead to the erosion of downhole and surface equipment and to partial or complete filling of the perforations, the screens or gravel pack completions downhole, hence localizing and quantifying the amount of sand downhole is a necessity for sand production management and sand shut-off, and to update accurately the existing geomechanical models to save huge costs involved from the CT clean-out operations and the repairs caused by erosion.
A newly developed downhole sand production measurement was successfully tested. The tool incorporates an innovative design that enables enhanced sensitivity to minute sand entries within the wellbore with minimal interference from the logging environment. This novel measurement was trial tested in different well completions. The carefully designed logging programs involved combining production logging tools – either conventional or array logging tools – along with the downhole sand detection tool for comprehensive log data interpretation. In this paper we illustrate with examples the results of the trial test and pinpoint the advantages as well as limitations of this new technology.
Log results in the vertical gas well were generally superior to those from other wells. Where the tool illustrated high sensitivity to locating small grains of sand production across the perforated intervals, as well as providing representative qualitative assessment of downhole sand production volume. Yet, most importantly it helped obtain the optimum drawdown for the free sand rate in this well. The tool was deployed also in one deviated oil well and two horizontal gas wells. These wells are completed with smart completions, sand screens and frac ports. The results helped reveal the efficiency of the screens and the integrity issues of frac ports and determine future plan to patch the frac ports to shut-off sand production. It is generally observed that log data quality and interpretation were challenged by the downhole logging environment and the well condition during log data acquisition.
The new downhole sand detection technology shows added value to allocate and qualitatively quantify sand production, check the integrity of sand screens and gravel packs, and several other applications. Candidate selection, job design and real-time log monitoring are crucial for the optimum benefit of the logging survey.