Sand screens often serve as the primary barrier to sand production from weakly consolidated reservoirs. Screen technology has improved significantly in the areas of sand retention, mechanical integrity, and quality control. As future field developments trend towards more hostile environments, requiring fewer wells at higher rates, the overall reliability and longevity of sand screens will be increasingly more important in this high cost environment.
This paper introduces a self-mitigating sand screen technology, MazeFlo™, that uses redundant sand control and compartment baffles to improve reliability and longevity for sand-prone well production. The technology self-mitigates downhole screen damage by isolating the effects of any mechanical failure of the screen to a local compartment, while allowing continued hydrocarbon flow through the undamaged sections. The compartment maze is comprised of baffles and tortuous flow paths that balance the incoming flow momentum from the outer screen. This flow redistribution mitigates risk of inner screen failure, while posing no additional plugging risk over conventional screens.
These self-mitigating screens reduce the frequency of sand-related workovers, extend well production, and increase recovery. Due to its simplicity and unique passive control capability, self-mitigating sand screens will expand the applicability of less complex and more cost effective standalone screen completions. Self-mitigating screens can also be easily combined with other emerging technologies such as zonal isolation and inflow control devices.
Downhole sand control is often installed when producing hydrocarbons from poorly consolidated or unconsolidated reservoirs. Conventional sand control methods include standalone screens, gravel packs, or frac packs in either open-hole or cased-hole completions. In each downhole sand control technique, a screen serves as the final barrier to prevent ingress of formation sand, gravel, or proppant into the wellbore. If the screen becomes damaged, sand can directly enter the wellbore and cause borehole plugging, reduced well productivity, erosion of downhole equipment, sand production to surface thereby eroding surface equipment and filling separators, or ultimately, loss of the well. All of these outcomes to sand screen failure come with a resulting remediation cost and a significant detrimental impact to production.
The importance of screen reliability has long been recognized due to its impact on production and well integrity. Previous studies1–8 have developed criteria or testing procedures for both sand control selection and screen slot design with regard to formation sand, gravel, or proppant to enhance the sand retention characteristics. Improved engineering design, testing, and manufacturing processes have also resulted in more robust screens9. Various standards10, practices, and inspection procedures were also developed to assure screen quality. These advancements along with rigorous planning, installation, execution, and surveillance have delivered field success11–12 in each downhole sand control method.