Successful Open-Hole Gravel Pack with Alternate Path Technology in Depleted Reservoirs: A Mindset Change in Gulf of Mexico

In Gulf of Mexico (GoM) deepwater, the majority of reservoirs are unconsolidated formation sands that require a sand control completion. Cased hole frac-pack has historically been the default technique. However, in many fields, prioritization of pay access across multiple stacked sand packages or across faults in the reservoir has driven the operator to evaluate the feasibility of Open-Hole Gravel Pack (OHGP) completions. This paper discusses the successful execution of two OHGP completions in two different fields with depleted reservoirs. The wells in this paper address different problem statements when it comes to pay access but face similar challenges to well delivery. Well 1 is a ~1,500 ft long, nearly horizontal well intended to combine production from multiple fault blocks in a depleted reservoir. Given the faults in the reservoir act as baffles to flow, each fault block is itself a small pool when targeted with the default completion type—cased hole frac pack (CHFP). Well 2 is a ~300 ft long, low angle well, intended to cut across two tightly spaced sand lobes, achieving pay access where a traditional stacked CHFP approach had previously failed in an offset wellbore. Both wells were designed to balance the competing risks of shale instability and low sand frac gradient due to depletion during construction. The ability to deliver OHGP completions in this narrow operating environment required the need for managed pressure during part of the completion phase. A Surface Back Pressure MPD system was used during this campaign. (Moghazy et al. 2018)