Well Performance in a Previously Condemned Prospect: The J Sand Formation in theNortheast Wattenberg Field

摘要

The J Sand formation is a main pay zone in the extensivelydeveloped Wattenberg field of Colorado. Until recently,operators deemed the reservoir in the northeast part of thisfield uneconomical due to significant production of formationwater in this low permeability and sub-pressured gas zone. Bymodifying the conventional completion techniques of the JSand,an operator relatively new to the area has been able toeconomically exploit this reservoir. Key factors that havecontributed to the success include improvements instimulation design and production techniques. Typically,hydraulic fracture stimulation treatments for the J-Sand utilizea low viscosity, guar based, zirconium crosslinked fluidpumped at injection rates up to 24 bbl/min. The aboveoperator differs in stimulation design by incorporating ahigher viscosity, low polymer carboxy methyl guar fluidpumped at a relatively low injection rate (e.g. 12 bbl/min).Well performance evaluations utilizing the ReciprocalProductivity Index (RPI) production analysis method inconjunction with log analysis quantify stimulationeffectiveness. Treatment pressure history matching with 3Dfracture simulators also identify advantages in achievedfracture geometry and proppant placement with the modifiedtreatment design.