Near wellbore sand extraction from perforated vertical wells in unconsolidated sand reservoirs results in higher rates and recovery than downhole sand exclusion.
At maximum drawdown sand influx rapidly diminishes to less than 1% sand cut for the life of the well.
Optimum conditions for rapid sand extraction are Big Hole diameter perforations at 26 shots per meter and a pump capable of maximum drawdown with the pump intake landed between 1 and 2 meters below the bottom perforation.
Downhole sand exclusion devices are filters that separate solids from the fluid stream being produced. Unconsolidated sand reservoir is a slurry of 70% sand suspended in viscous oil. This massive volume of solids rapidly creates filtercake over the length of the horizontal well that is impermeable to the viscous oil. With no means of removing the filtercake the well is shut-in leaving more than 65% of OOIP stranded.
Production has been restored and recovery extended when downhole sand exclusion devices in vertical wells were perforated and several hundred cubic meters of near wellbore sand was extracted. This and other features that facilitate near wellbore sand extraction in vertical wells can be applied in horizontal wells to restore production and increase recovery up to 80% of OOIP.