Waterflood Appraisal-Well Delivery with Expandable Tubulars

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractPetroleum Development Oman (PDO) is planning a major brown-field re-development project. For that reason a waterflood appraisal drilling campaign has been executed. Drilling through fractured reservoir sections causes drilling losses that have to be cured prior to liner cementation. Liner cementation in wells with severe or heavy drilling losses has had limited success despite novel loss curing materials.Expandable tubulars with swelling elastomer seals have been applied in 8 wells as an alternative to cemented liners with the objective to • Provide zonal isolation, to • Attempt time savings by eliminating loss curing and liner cementation and to • Slim down the well design.The reservoir sections of 2 vertical water injector wells and 6 vertical oil producer wells were drilled with losses and lined with expandable casing. Elastomer seals isolate the multiple reservoirs from each other. Expandable casing enables a slim oil producer design still using a 2 7/8" gaslift string. 4 slim wells were drilled. Zonal isolation has been created without cement. This novel approach to drill fractured carbonate reservoirs has proven technically feasible in terms of installation operations, zonal isolation and slimming down well designs. The paper describes the experience with expandable tubular technology for waterflood well delivery.

Mechanical Testing and Characterization of a Swelling Elastomer

“…The technology has proven to be extremely useful in a relatively low-cost setting [4]. A major brown-field redevelopment project for drilling through fractured carbonate reservoir sections, using swelling elastomer seals for zonal isolation, was successfully carried out in Oman [5].…”

Analytical solutions for one-phase seepage flows impeded by wellbore seals

“…Fokker et al, 2005;Lighthelm et al, 2006;Marketz et al, 2005;Ozkaya and Richard, 2006) because of unwanted water production due to early water breakthrough through these zones. Uneven sweep of the reservoir leaved oil bypassed and unrecoverable without any wellbore and fracture isolation treatments.…”

“…The elastomers are engineered to swell when in contact with formation water at downhole conditions, i.e. they act as "hydrodynamic semiconductors", which admit oil at earlier stages of recovery and block water breaking through the fractures at mature stages of flooding (Marketz et al, 2005;Welling et al, 2007). This non-invasive (with respect to the reservoir rock) technique is called EZIP (Expandable Zonal Isolation Profiler) and applied in several wells of Omani oil fields with water rates reduced by up to 40% and oil gains of up to 45 m 3 /day/well .…”

Tubular Expansion in Irregularly Shaped Boreholes—Computer Simulation and Field Measurement

“…Over the past 30 years, liner cementation in wells with severe or heavy drilling losses has had limited success despite many innovations in loss curing and liner cementation methods. Therefore, expandable tubular and elastomer sealing technologies have been introduced for waterflood appraisal drilling as an alternative to cemented liners (Marketz et al, 2005). This is done to (a) provide zonal isolation, which is critical for profile control; (b) eliminate the need for curing losses and liner cementation; and (c) enable a slim well design.…”