Hydraulic Fracturing Trends
Data Illustrates Evolution Of Fracturing Designs In Resource Plays
By Leen Weijers, Kevin Fisher and Paul Weddle
Even as horizontal well development techniques continue to evolve in U.S. resource plays, many key questions remain unanswered regarding wellbore spacing, parent/child well interactions, “right-sizing” of proppant and fluid volumes during hydraulic fracturing, optimal lateral lengths, frac staging and perforation strategies.
The jury is not fully in agreement on the optimal answers, although the use of real data and multivariate analyses has provided many clues as to the direction these processes should take for maximum efficiency. However, much data mining still is needed to converge on the best techniques in shale and ultratight oil and gas reservoirs. Because of differences in how production is reported, Texas is a state where data sharing among operators would be especially useful.
Hydraulic fracturing treatments have evolved from simple, small treatments with minimal chemistry and low proppant volumes to extremely complex viscous fluids with high proppant concentrations, but still relatively low volumes in vertical wells, to today’s super-sized treatments that often use in excess of 20 million pounds of sand and 10 million gallons or more of water in a single horizontal well.
Because of the logistics involved in delivering sand, fluid and chemicals in a modern well, some of the real data analytics, modeling and engineering work that was performed routinely in the past now is being omitted in favor of more efficiently delivering the desired treatment plan. It may be worth reopening the case for data analysis (including determining which data is most pertinent) in order to converge on the optimal range of treatment parameters in a given field or reservoir within a horizontal resource play.
Perforation strategies are focusing on extreme limited-entry techniques with fewer perforations, but more clusters, to obtain more effective frac initiation points. With chemical additives, it appears the industry is “going back to the start” with minimal additives at low concentrations across the board. Proppant is heading toward the cheapest option, focusing on “just good enough” for created-fracture conductivity.