Notional Field Development Final Report - EBN

EBN Notional Field Development Plan
On the other hand, retrievable–type bridge plugs require extra time to set and retrieve from the
wellbore and they can require twice as many trips in the hole.
To overcome these problems, composite bridge plugs, flow-thru composite frac plugs and squeeze
packers were developed. They are constructed of high–strength, lightweight, composite materials and
standard drillable elements that make them easy to drill out while maintaining their reliability. These
"composite" tools do not have the long life spans of other types of plugs such as cast iron but their
longevity is not a concern because their useful life is of such short duration. Their more important
benefit is the ease and speed at which they can be removed from the wellbore after the job is finished.
When compared to cast iron plugs, the average composite plug drill out time is remarkably less. Cast
iron bridge plugs require as much as four hours or more to drill out compared to an average of 35
minutes for a composite plug. Additionally, the light weight composite material that the bridge and frac
plugs are composed of enables their cuttings to be easily circulated back to the surface in lightweight,
non–damaging drilling fluids.
In the late 1990’s, composite perf & plug tools were developed and they have continued to evolve to
improve efficiencies in the completions process. The new plugs are made of composite materials and
are employed similarly to conventional permanent bridge plugs. They are available in standard and
high–pressure/high-temperature (HP/HT) models and setting equipment is identical for both versions.
A Flow-Thru Composite Frac Plug (FTCFP) is a specific tool that works as a bridge plug when the pressure
above it (such as during a fracture treatment) is higher. Then, when the pressure above is lower than
the pressure below (such as when flowing the well back), the FTCFP allows fluid-flow from below
through the plug. Using FTCFPs also allows all zones to produce during the completion of the well. Two
benefits to this are that 1), no zones are shut-in for long periods of time, and 2), when the bottomhole
flowing pressure is reduced during flow back, all previously treated zones help to clean up each new
treatment. After a well is completed, the FTCFPs can easily be drilled out or left in the well. There are a
variety of FTCFPs on the market today. All of them provide essentially the same function; isolate lower
stages from the fracture treatment, and then, allow all the zones to produce during completions. Some
of them have a one-way float, or ball built inside the tool; others have a ball cage on the top, and finally,
there are the ones that have a free floating heavy ball.
FTCFP are capable of addressing the current needs to reduce operational costs and improve
productivity. These plugs can be used as an alternative to traditional isolation methods, or induced
stress diversion. The benefits gained from FTCFP usage are derived from the following: being that well
drill-out isn’t required costs are reduced, positive isolation is allowed, and all zones can be produced
during completion.
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