2000 · 34 citations · 4 references
EngineeringEarth SciencesPetroleum EngineeringHydraulic FracturingReservoir EngineeringUnconventional ReservoirsNaturally Fractured ReservoirsReservoir StimulationRock-fluid InteractionsShale Gas ReservoirsShale Reservoir StimulationUnconventional Reservoir FlowFracturesHydraulic Fracture FlowHydraulic Fracturing FluidsLow PermeabilityLow-permeability ReservoirsPermeability DamageReservoir Stimulation DesignShale Stimulation
The Lewis Shale, a low‑permeability, naturally fractured formation in the San Juan Basin, has been studied since 1999, and prior work indicates that gelled fluids can damage permeability, but non‑aqueous Dry Frac fluids may mitigate or eliminate such damage. The study aimed to test the feasibility of liquid CO₂‑and‑sand Dry Frac treatments and compare their production performance to aqueous‑based systems in the Lewis Shale. The authors compared production and well‑test data from 16 Dry Frac wells treated with liquid CO₂ and sand to 46 wells treated with nitrogen‑foam water‑based fluids to quantify Dry Frac performance.
Abstract In the spring of 1999, Burlington Resources initiated a well stimulation study in the Lewis Shale interval, San Juan Basin. The goal of the project was to establish the operational feasibility of pumping liquid CO2 and sand (Dry Frac) hydraulic fracture treatments1,2,3,4,5,6 in the Lewis Shale, and to compare production response of wells stimulated with liquid CO2 and sand to those stimulated with aqueous based systems. Production comparisons and well tests were used to quantify the results of the Dry Frac technology. The Lewis Shale is present across the San Juan Basin and is part of the Mesaverde formation at approximately 4000'. Of the wells stimulated in 1999, 16 were treated with liquid CO2 and sand’ a water free stimulation technology. The remainder of the wells (46) were treated with nitrogen-foam water based fluids. Prior work completed within the Lewis interval suggests that imbibing gelled fluid into the low-permeability’ naturally fractured formation may cause permeability reductions. Permeability damage to the natural and hydraulic fractures may be eliminated and/or reduced by fracturing and propping the Lewis interval with the nonaqueous based fluids utilized in the Dry Frac process.
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