A few years ago, I talked to two deep water completion groups who replaced completion engineers lost in the 2014 oil-price crash by cobbling together subsurface, drilling, and mud engineers. They knew little about sand control. One group asked me to explain basic screen test results, the other couldn’t answer detailed questions about their proposed completion. It looked like the old lessons in sand control were fading away as fast as the old soldiers who fought for them.
Increasingly poor economic returns from unconventional fields, however, spurred renewed interest in offshore and deep water. Exhibits A and B were ExxonMobil’s high-profile stakes in Suriname and Guyana, and Petrobras’s sell-off of land and shelf-based assets to invest in deep water. Had it not been for COVID-19, deep water would be trending upward, and it will likely be one of the first areas for exploitation when demand comes back.
Unconsolidated sand generally accompanies deepwater developments. Additional sand-control work will come from workovers and infill drilling of depleted reservoirs, driven by the current low-price oil environment, according to Chris Malbrel, director of development at TPM, a manufacturer of screen cartridges. Malbrel noted that small reserves associated with infill development may not warrant costly gravel pack operations, leaving bare screen completions as the sand control method of choice.
Newly minted completion engineers, therefore, will need to climb a steep learning curve in sand control, a discipline that combines engineering, science, art, experience, and luck in almost equal measures.
Frac-packs are moderately straight forward, but horizontal open-hole completions bring their own special ball of confusion. Gravel pack vs. bare screen, inflow control devices vs. zonal isolation, water-based vs. oil-based drill-in fluid, and filter cake breakers vs. filter cake flowback are questions for every well. How much shale is too much shale? What is the best method to condition the hole before running screen while maintaining sufficient well barriers? Rarely are there objective answers to these questions, and usually the answers lead to more nearly intractable questions.
Screen technology for sand control, for example, was one of the most fiercely contested industry battles of the 90s, but eventually settled into a few generally-accepted precepts: mesh-based screens for stand-alone screen completions, screen aperture size matched to the larger end of the formation size range, and filter cake dissolution with breakers are all now accepted as best practices. The details to achieve these ends are nearly infinite, but that is what extensive testing seeks to sort out.
Malbrel, who was at ground zero in the screen wars at Pall Well Technology and since has sojourned through Weatherford and Baker Hughes as a screen technology manager, believes that the biggest current challenges in screen technology are rationalizing the supply chain and adapting to a commoditized environment while enabling added functionalities to completions.
“With its lower level of complexity, stand-alone completion invites increased competition, shorter delivery times, lower inventory levels, and reduced financial burden on the operator,” Malbrel said. “This will impact the product mix as some screen technologies are inherently slower to manufacture than others (e.g. wrap-on-pipe screens) and some (i.e. mesh screens) are more easily combined with ICDs [Inflow Control Devices] and sliding sleeve assemblies which are increasingly used to add functionality to the lower completion assembly.”
Rick Kenney, owner of screen-supplier PMF Inc., summed up current concerns in sand control by saying “it’s erosion, stupid.” Both screen suppliers and operators are looking at reducing erosion risk by either adopting practices to keep local flow velocities to a minimum across completions or using new materials and coatings to harden screens.
My experience in the oil field, including a stint through screen development and application, leads me to believe that the industry is nearly infinitely adaptable, but painfully slow to adopt new technologies and techniques. For advanced sand control applications, however, new techniques and technologies have been around for years and are only waiting to be rediscovered.
