The SIMGPH is a numerical simulator for the design of the Gravel Pack installation operation in horizontal wells.
Oil bearing unconsolidated sandstone formations with low structural resistance are very common. This low mechanical resistance requeires the use of inferior completions equipped with Gravel Pack, so that its structural integrity is maintained, and also establish a sand production control.
The gravel pack is installed between the production screen and the formation rock, providing a sand bed support for the formation and a filter that prevents formation’s loose fines from migrating to the well. Gravel Pack installation in vertical wells can be considered a trivial operation but for horizontal wells scenarios can be very complex.
Gravel Packs are installed pumping sand / gravel, on its designed granulometry, through the annulus, circulating the installation fluid trough a wash pipe. During that process, since sand grains are heavier it precipitates, depositing at the inferior half section of the well from the heel up to the well toe, where the wash pipe intake (for returning the pumped fluid) is located. This resulting sand wave is called “alpha wave”, from heel to toe.
After filling all the lower section of the well, sand commences depositing in the upper section of the well, in the inverse sense, from toe to heel. Starting a new sand wave denominated “beta wave”, that fills the well’s upper half, completing with sand the whole volume between screen and wellbore (Thanks Baker Hughes for this video). It sounds trivial but the challenges and criticality of such operation demands a proper and extra ensured design, establishing working flow rates, pressures, gravel granulometry, fluid rheological parameters, etc. Poorly executed Gravel Pack installation can compromise a well.
SIMGPH is an expert application, its development started at CENPES (Petrobras Research Center) and in the last 3 years SimWorx is heading the support, the formulation evolution along with inserting new numerical models improving the representation of the phenomenon. The updated model supports also installation of Gravel Packs for flow equalization completions equipped with selective perforated screens (See ProDiv, ICDs, etc). The numerical simulator started as a Desktop application and is now upgraded to a web version, part of Petrobras’s Poço Web.