The application of horizontal completions in lowerpermeabilityformations is continuing to proliferate on aglobal scale. Caused either by formation damage issues or thevery heterogeneous nature of many such reservoirs, actualwells will underperform when compared to originalpredictions from reservoir simulations. This will continue toresult in a need for effective hydraulic-fracturing stimulationsfor many of these wells to reach economic production levels.Horizontal completions in moderate- to low-permeabilityreservoirs present the challenge of cost constraints that seldomallow the use of long-proven methods such as cementedcompletions and individual-fracturing of numerous zones withbridge plug isolation and multiple perforating runs. Some newmethods being applied to overcome this problem requireexpensive downhole 'jewelry' and some added risks that theliner and jewelry can be entirely run to the predetermineddepth. In some methods, the operator must also accept reducedcompletion Ids that can later restrict production rates orhinder workover operations. These increased costs and risksmust be accepted even before the actual fracturing treatmentsare attempted.This paper will discuss a new approach to controlledplacement of multiple-stage fracturing treatments without therisks involved with packers or bridge plugs. By implementinga coiled tubing (CT) deployed hydrajet-perforating method,immediately followed by a fracturing treatment pumped downthe annulus, the operator can use lower cost (and lower risk)liner completions, and delay the decision of selecting exactlywhere the perforated sections should be placed. In many cases,the final decisions on placement of the next perforatedlocation can even be delayed until after the wellboredisplacement of the preceding fracturing stage. By pumpingthe fracturing fluid slurry down the annulus of the CT and thecasing the allowable frac rates can be higher than with tubingdeployedtechniques. The total stimulation related costs aregreatly reduced by being able to perforate/frac multiple timeswithin the same day. Even where more than one day isrequired to complete the stimulation of all desired locationsalong the lateral, only one CT intervention and one pumpingservice company mobilization and rig-up will be needed,which will still improve the job economy over conventionalmethods. An additional benefit includes a reduction in thepotential for excessive multiple fractures or near-wellboretortuosity encountered with explosive charge perforating.
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