Sand production is a common problem throughout the oil and gas industry, particularly in ‘high rate’ gas reservoirs coupled with low rock compressive strength. Conventional downhole sand control techniques such as gravel packing can act to limit both well geometry and/or productivity. Furthermore, problems with gravel pack installations can lead to preferential inflow, leading to ‘hot spotting’ and ultimately loss of sand control. To evaluate the erosion resistance of sand control equipment under the highly erosive environment of high rate gas wells, innovative testing equipment is needed. This paper will discuss the development of a Gas Sand Screen Erosion Test (GSET) rig and its application to evaluate the erosion resistance of ceramic sand screens.
GSET is designed to simulate ‘accelerated’ erosive down-hole conditions. The GSET cell can accommodate but not limited to a screen stub section, screen coupons and variety of downhole equipment. A combination of high flow rate gas and volume controlled particle reservoir matched sand is coalesced into an acceleration tube. The high velocity sand particles (>80m·s-1) impact the ceramic sand screen, causing erosion within the target area. In this paper, the GSET rig was operated for 48 hours at maximum velocity (>80m·s-1) and with a sand concentration of 750 ppmw. Take into consideration that the velocities seen throughout this paper are significantly greater than what a conventional reservoir/completion system would have to tolerate.
Initial and final sand screen analysis was conducted to evaluate the performance of erosion resistance. An array of analysis techniques was applied with focus on gap aperture size and surface topography. Gap aperture measurements were a focal point, as it is directly proportional to its ability to maintain sand retention capabilities.
This paper highlights the potential of the new GSET rig, enabling laboratory testing of erosion resistance of sand control equipment for high rate gas wells under accelerated conditions. Test results obtained with the ceramic sand screen section underpin the inherent high erosion resistance of ceramic sand screen technology ensuring longevity in highly erosive environments. Thus, providing opportunities to complete both new reservoirs and intervene in existing fields with remedial sand control solutions; through extension of the viability of stand-alone screens, simplification of well construction or intervention and increase in productivity.
The observations made by the authors are supported by extensive laboratory testing. The resources provided in this paper will allow petroleum engineers to appropriately evaluate the potential benefits of utilizing ceramic sand screen technology in their completions.