Operators who drill horizontal wells must address a unique set of downholeconditions for each application. Problems such as frictional drag, screenplugging, openhole cleaning, key seating, and fluid loss can occur during thefinal stages of well completion, compromising the efficiency of the well; bycareful selection of tools and completion techniques, however, the operator canplan for successful management of these problems. Recent enhancements to screentechnology, better mechanical fluid-loss control systems, and improved runningprocedures that will facilitate control of these problems can assist theoperator in the completion design, subsequently increasing the productionpotential of the well. These new design enhancements also offer a more positiveapproach to fluid loss prevention during the completion process and providemore efficient hole-cleaning techniques and running procedures.
This paper will present an overview of the new screen technology, mechanicalfluid-loss control methods, and installation techniques that are specific tobetter operator management of the problems normally encountered in the finalstages of horizontal openhole completions. A case history will be presentedthat illustrates benefits derived from use of these new enhancements andcompletion techniques.
The first part of this paper will review the types of prepack screensavailable today and focus on new screen designs and the advantages they offer.The second section will highlight screen enhancements that increase wellproductivity screen flexibility characteristics, fluid-loss preventive measuresoffered by flapper systems, available circulation and rotation options, and useof various isolation systems. Finally, the case history will be presented andgeneral conclusions concerning horizontal completion design criteria.
It is important to understand that each prepack screen design on today'smarket offers unique performance capabilities; therefore, careful considerationmust be given to the merits of each type before the appropriate selection canbe made for the given set of well conditions.
Prepack screen assemblies for horizontal open or cased hole completionequipment should be designed with a circulating feature that allows circulationahead of the bottomhole assembly (BRA) as it passes through the bend andhorizontal section. Even if circulation is not required to run the prepackscreen assembly to bottom, the ability to circulate is still needed to cleanthe open hole of any lost circulation materials or filter cake after the BHA isset on bottom.