Journal of Petroleum Technology | 2021
Against the Grain: Three Proppant Delivery Approaches That Buck the Status Quo
Abstract
Pumping proppant down a wellbore is the easy part.\n Ensuring that the precious material does its job is another matter.\n A trio of field studies recently presented at the 2020 SPE Annual Technical Conference and Exhibition (ATCE) highlight in different ways how emerging technology and old-fashioned problem solving are moving the industry needle on proppant and conductivity control.\n These examples include the adoption of unconventional completion techniques in a conventional oil field in Russia and work to validate the use of small amounts of ceramic proppant in North Dakota’s tight-oil formations. Both studies seek to counter widely held assumptions about proppant conductivity.\n A third study details a recently developed chemical coating that Permian Basin producers are applying “on the fly” to sand before it is pumped downhole. The new adhesive material has found a niche in helping operators mitigate the amount of sand that returns to surface during flowback, a sectorwide issue that drives up completion costs and later may spell trouble for artificial lift systems.\n Disproving “The Overflush Paradigm”\n After conventional reservoirs are hydraulically fractured, both from vertical and horizontal wells, it has been standard practice for decades to treat the newly propped perforations with a gentle touch.\n The approach to this end is known as underflushing.\n When underflushing, the goal is to leave behind just a few barrels’ worth of proppant-laden slurry over the perforations before attempting to complete further stages. The motivation for this boils down to the need for an insurance policy against displacing the near-wellbore proppant pack and causing the open fracture face to pinch off before it ever has a chance to transmit hydrocarbons.\n Such carefulness comes at a price. Underflushing raises the risk of needing a cleanout before oil can flow optimally to surface. This not only delays the arrival of first oil, it means extra equipment and personnel are required.\n However, a more glaring downside to underflushing is that it appears to be an unnecessary precaution. The near-wellbore fracture area is, in fact, more robust than what conventional wisdom allows credit for.