Single-Trip Multiple-Zone Completion Technology Has Come of Age and Meets the Challenging Completion Needs of the Gulf of Mexico's Deepwater Lower Tertiary Play

There is little doubt that the success and reliability of frac-pack completions in the Gulf of Mexico has become the yard-stick by which Gulf of Mexico sand control completions are currently measured. Simultaneously, StressCage has become common practice as a method to overcome challenges drilling through depleted zones, in order to cope with complex mud-window constraints for new developments and infill wells. The success of these drilling and completion approaches and their rapid widespread application has resulted in ever more depletion. This has potentially created a vicious circle in terms of drilling the well to desired depth vs. the ability to install a low-skin frac-pack completion.While these two techniques in isolation represent uniquely optimal solutions to their individual challenges, there is growing evidence that their application within the same wellbore has the potential to create conflicting ideals. The StressCage application is associated with the plugging of small fractures which have been induced in the wellbore wall, thereby increasing the effective fracture gradient, which allows for the drilling of substantial depletion. However, the presence of a range of widely distributed particle sizes in the mud system, as well as increased general solids loading, may result in deep and invasive plugging of the permeable formations and any smaller fractures within the same open-hole sections. When these plugged formations are then the target for subsequent fracturing operations, there is a significant potential to create near wellbore problems that complicate or bring into question the ability to install a frac-pack completion.This paper will provide a number of examples of the application of StressCage, where resulting frac operations appear to have been hampered or complicated by the use of the StressCage approach and/or associated mud conditions. These examples will provide some evidence of such interactions but, more importantly, demonstrate the contradiction that these two techniques potentially represent. The paper will also outline a scenario resulting from a sand-control lower completion assembly in place, in a new borehole drilled with StressCage method, that could be resistant to any form of frac breakdown (or simple mechanical intervention), and, thereby, compromise the frac and well completion itself.In addition to the case histories, the paper will outline various engineering approaches that should be considered, including geo-mechanical analysis of well placement, identification of near wellbore issues prior to and during the fracturing operations, careful management of stress caged solids makeup, mud management and frac-pack design in order to avoid or overcome such challenges. All of this helps ensure that we do not create the paradox of being able to drill through the undrillable but then creating the unfraccable as a result.

Section: Otc-26900-msmentioning

confidence: 99%

StressCage and Frac Pack: Drilling the Conventionally Undrillable Without Creating the Unfraccable

Rylance

Mahadev

2016

“…The system integration testing and fracture qualification testing are discussed in depth in paper SPE 128323 (Burger et al 2010). Two test fixtures housing fracture service tools, fracture sleeves, and 9-7/8-in.…”

Section: Proppant Delivery System Qualificationmentioning

confidence: 99%

The Successful Development and Installation of a New Single-Trip Multizone Completion System Developed for the Deepwater Gulf of Mexico Lower Tertiary Formation

Grigsby

Jannise

Goodman

et al. 2016

Development of the Wilcox stacked oil sands in the Lower Tertiary fields in the Gulf of Mexico (GOM) requires zonal stimulation; however, when the decision was made to produce this formation, the stacked sand-control systems currently available would have been cost prohibitive. Thus, a special team was commissioned to develop a single-trip multizone completion system to address the challenges of producing this ultradeepwater GOM field. This paper chronicles the development, qualification, and installation of a new one-trip high-rate fracture system that meets the needs of cased-hole installations in the Lower Tertiary formations with well depths reaching 28,000 ft TVD, as well as in cased-hole shallow-depth wells in the Asia Pacific area.A dedicated development team began tool-system development in January 2007. The first systems integration test (SIT) was conducted in December 2007 after only 11 months. The successful SIT led to the assignment of three land wells by a major international oil company to prove out the multizone system. After two successful installations, the third installation was eliminated, because the multizone system was classified as operationally ready.Drilling issues lead to the plugging and abandonment of the planned inaugural ultradeepwater installation. The operational moratorium in the GOM in 2010 also changed the original target wells. The first commercial cased-hole installation was run in the Asia Pacific area in a shallow-depth well environment using water-pack treatments. Subsequently, multiple ultradeepwater installations have been performed to date.Lessons learned from the SIT process and from the initial installations that included the ultradeepwater Lower Tertiary fields are presented.

“…But these single trip completions must have high proppant amount, pressure and pumping rates to complete the sizeable stimulation jobs (Burger et al, 2010). The thickness of the Lower Tertiary formations requires multiple perforated intervals with deepwater Frac-Pack operations.…”

Section: Completion Selectionmentioning

confidence: 99%

An Integrated Geomechanical Modeling and Completion Selection for Production Enhancement from Lower Tertiary Wells in GOM

Bağcı

Tjengdrawira

Park

et al. 2016

An integrated study involving geological, geomechanical, reservoir and completion analyses were conducted to design a new completion system for optimizing production in Lower Tertiary play in deep-water Gulf of Mexico (GOM). Lower Tertiary reservoirs are generally characterized by lower productivity potential due to low permeability and poor reservoir energy in some areas due to low GOR, little/no gas cap and very limited water drive. Multiple reservoir sand layers need to be hydraulically fractured for production under a potentially high geo-pressure and stress environment. The design of a lower completion system focused on stimulation, sand control systems and their impact on production. The proposed lower completion system has a large ID to maximize production rates and supports stimulating reservoirs with high proppant volumes and pump rates to increase the number of treatment zones.Petrophysical and geological analyses were conducted to determine the distribution of sand bodies in thirty study wells drilled across from Alaminos Canyon through Keathley Canyon to Walker Ridge (W-E). A geomechanical analysis was conducted to determine the variation of rock mechanical properties and stresses across these regions. Sanding analysis was conducted to assess the risk of rock failure and the effect of production in open-hole completion under the high draw-down scenarios.Frac-Pack fracture modeling was conducted with an optimized stress profile for a candidate well for three lower completion systems to select the optimal fracturing intervals and treatment schedules that will maximize well performance. Possible oil production rates were estimated for various scenarios involving natural flow, ESP and subsea boosting.This study focusing on understanding the reservoir characteristics for lower completion systems design ensures optimal technology selection to ultimately enhance well productivity and ROI with better production rates and ultimate recovery.