Abstract An important aspect of horizontal hole completions is selection of downhole tools for placement and control of stimulation fluids. Physical parameters imposed by the curved and horizontal sections of a wellbore can severely limit the number of tools, and indeed, the number of tool systems that will provide effective reservoir stimulation. The selection of an appropriate total stimulation program is optimized when the downhole tool string options are considered in the planning stages, before the well is drilled. Completion style and tools to be utilized have direct bearing on the drilling operation.
Some conventional tool assemblies that operated successfully in vertical hole are readily applicable to stimulation treatment operations in horizontal wellbores. Consideration of modifications existing tools, tool limitations, new tool limitations, and particular attention to details operating procedure in early stages of the well can maximize the total stimulation program.
In this paper, case histories of tool developed for different interval treatment techniques and successfully used in horizontal stimulation are presented. Straddle packer systems, permanent packers for zone isolation, and selective injection packer systems packers for zone isolation, and selective injection packer systems are among the examples. Factors in selecting an appropriate stimulation tool system for horizontal completions are discussed. New tool systems under consideration and/or development are presented. presented
Introduction Increased activity in horizontal hole drilling projects and completion technology in the last decade have challenged well service companies to provide economically viable systems for initial and workover stimulation needs in the horizontal wellbore. Most early horizontal wellbores were completed as drain holes with slotted liners. Although less expensive than cemented and perforated liners, the slotted liner in open hole affords fewer options in initial stimulation and remedial workover of the well.
As cementing and perforating technology in horizontal wells become more established and economically feasible with successful experiences, well stimulation alternatives become more flexible. it is the challenge of the service companies to offer effective stimulation programs to help increase reservoir productivity in these horizontal wellbores.
One aspect of the total stimulation program is providing workable downhole tools for placement, diversion, and control of fluids for proper treatment. Packers, valves, and diverting tools are needed in horizontal hole completions as they were needed in vertical wellbores. Unique physical parameters of horizontal hole completions require special tailoring of individual tools, new tool developments, unique operational modes, and special attention to procedure for successful total system operation. procedure for successful total system operation. Consulting service companies during the planning stage of the well can help the operating company optimize the choice of tool systems available. Factors that influence the choice of tools, and ultimately, the stimulation program for a particular well are:–Casing Program
–Tool Operation
–Wellbore Environment
–Zone Isolation
–Interval Treatment Technique
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