Development and Field Testing of Advanced Ceramic Proppants

Abstract

AbstractA unique family of advanced ceramic proppants has been developed based on formulated mixed-metal oxides. In contrast to conventional top-down ceramic proppant manufacturing, a bottom-up process is used to coat ceramic cores with highly-engineered layers of mixed-metal oxide. This process yields a very strong, light proppant with well-controlled porosity, and a narrow size distribution.Laboratory results show that individual advanced ceramic proppant beads are much stronger than conventional ceramic proppant grains, and that the strength distribution is also much tighter than conventional ceramic proppants. The strength profile of the engineered beads bears a close relationship to the generation of conductivity-damaging crush fines. As a result, the conductivity measured in industry-standard tests is as much as 40% higher than that of conventional ceramic proppants, and this improvement is maintained over a wide range of closure stresses and multiple stress cycles. There is thus a critical link between individual proppant bead behavior and overall proppant pack performance.Proppant transport in slickwater is a result of three major mechanisms: gravity settling (Stokes Law), sedimentation (dune formation), and saltation. The low density of advanced ceramic proppants reduces the settling rate, and the low coefficient of friction reduces the height of dunes, resulting in proppant transport further into the fracture.An important new property related to proppant transport in slickwater has been identified, i.e., the coefficient of restitution. A high coefficient of restitution reduces clustered settling, and results in more active saltation. A new laboratory test to compare the coefficient of restitution of different proppants has been developed. In this test, advanced ceramic proppant beads typically move approximately 40% further than conventional ceramic particles, and twice as far as sand.A comprehensive field test of Advanced Ceramic Proppants was performed in the Permian Basin. Ten pairs of wells were selected and the new material was pumped into one member of each pair, while conventional ceramic proppant was used in the other. Advanced Ceramic Proppant increased cumulative 12-month oil production by 20% compared to the offset wells. The statistical techniques which demonstrate this improvement also identified some key variables which impacted production, including stimulation treatment execution and interference effects.The use of Advanced Ceramic Proppant increased the NPV of the wells by 25% relative to conventional ceramic proppant, and the incremental cost of the treatment was paid back in 3 to 4 months.