Abstract
Slotted liners have predominantly been selected to provide a low cost control of sand/solids production in heavy oil applications where the need for steam injection is required to reduce the oil's viscosity in place making it mobile. The biggest challenge with slotted liners is the inflow area. Typically, this can range from 2-3% depending on the width, length, and number of slots per foot. This leads to plugging tendency over time.
The advent of wire wrap screen jackets was an improvement to slotted liner technology. Using a longitudinal wire rib and a shaped wrap wire, a series of openings representing a specific gauge can be manufactured into a wire jacket. This wire jacket is then slipped onto a perforated base pipe, creating a screen product. Although wire jackets improved the area to flow, it was still limited to inflow areas of 6-12% depending on the slot opening. Albeit an improvement to plugging resistance, it still provides a less than desirable flow area to accommodate plugging over time without restricting flow. Typically, the least amount of flow area can be found in the perforated base pipe.
Both slotted liners and wire jacket screens have vast experiences in thermal applications but very limited experiences using a mesh filter type media in these applications. As premium mesh filtering screens have become recognized and accepted during the past few decades there has not been much in the form of thermal testing to qualify these products for cycling temperature environments. The design of a premium mesh can deliver inflow areas in the range of 30-55% depending on the nature of the design, woven v. stacked layers bonded or sintered in place. This improvement in inflow area increases the time to plug exponentially.
The intent here is to show the results of thermal testing conducted with an economical mesh screen, supporting its use in the high temperature cycling that occurs during cyclic steam and SAGD applications. Using a myriad of designs, with and without welds, tests of multiple thermal cycles ranging from ambient to 950°F were conducted in the following modes: 1) free floating, 2) both ends fixed, 3) a single end fixed, and 4) gravel packed in place. Based off these results an optimal design prevailed.
