The Relationship Between Net Pressure Development During Hydraulic Fracture Treatments and Productivity in Fruitland Coal Completions

摘要

This paper describes an innovative fracture treatment designrnapproach that has been successfully used to improve thernproductivity of Fruitland coal CBM completions. The processrnintegrates real-time treating pressure evaluation to adjust keyrntreatment parameters on the fly and maintain a low netrnpressure development. The low net pressure developmentrnindicates good proppant distribution through the createdrnfracture geometry and minimizes potential formation/fracturerndamage from the fracturing fluids. This results in shorter dewateringrnperiods and accelerates peak production of thernFruitland Coal completions.rnIn the Fruitland Coal, the dominant fracturing mechanismrncontrolling the ability to distribute proppant laterally into thernfar-field is the quality of the near-wellbore connection.rnComplex near-wellbore fracture geometries result in arnconvoluted slurry pathway, which hinders lateral proppantrndistribution into the far-field. Further, if the near-wellborernconnection was not mitigated effectively, the overall netrnpressure development while placing proppant becamernexcessive. This paper discusses the innovative changes madernto improve the near-wellbore connection, allowing therntreatment to be completed and productivity of thernwell increased.rnBased on an offset well study, it was observed that excess netrnpressure development damaged the fracture conductivityrnand/or the cleat system of the coal. When an excessive levelrnof net pressure was developed, polymer dehydration into therncleat system caused irreparable damage to the existingrnpermeability. Evidence of the damage was indicated by thernextended load fluid recovery time. Since de-watering of therncoal begins only after the load is recovered, it was observedrnthat gas production was significantly delayed when the netrnpressure development during the propped fracture treatmentrnwas excessively high.rnObserving this relationship, treatment designs werernaltered, but more importantly, real-time assessment of therntreatment pressure character was found to be essential inrnachieving design objectives. The completion approachrndiscussed in this paper has been employed in over thirty-fivernFruitland Coals completions over the past three years withrnexcellent production results.