RRL Advantages Remain Underbalance w/o Connections Increase In Overall ROP Decreased Motor Wear Increased Coiled Tubing Life Increased Annular Velocity Increased Production Improved Hole Cleaning Uses Low Cost BHA Drill A Tanget Section Sidetracking Environmental Benefits

Design Uses Traditional Low Cost BHA
One of the advantages of using the RRL system is that a traditional low cost 4 ¾” motor and MWD system can be utilised.

To obtain a change in wellbore angle the surface rotation of the coil can be halted, the tool face oriented and a slide initiated. When the slide has been completed the surface coil can then be rotated to maintain hole angle.

This has obvious cost and equipment availability benefits which are not found with traditional coil tubing BHA’s which use either hydraulic or electric orienters.

In addition the BHA’s and motors being larger will have a far greater MTBF that traditional coil tubing BHA’s due to the larger equipment size which is more robust in the downhole environment.

The larger hole size and potential annular clearance of the BHA will present a greater number of fishing options (0.625” annular clearance). In addition the ability to rotate the coil will mean that spiral grapples could be used to retrieve a fish. This option is not available with traditional coil for obvious reasons.

RRL will apply a philosophy of BHA evolution. It is envisaged that the BHA design will develop in the following manner.

• Traditional 4 ¾” BHA (MWD or EMWD in multiphase environment) with CT BHA mechanical components (Coil connector, Release Tool, Circ Sub, etc.).

• 4 ¾” electric CT BHA with no orienter and a traditional PDM (Currently available). The removal of the orienter is only possible due to the ability of the RRL unit to rotate the coil at surface.

• 4 ¾” electric CT BHA with a RSS steerable system which will lead to significant increases in ROP as it will negate the need to slide drill to achieve angle change. It will also increase the potential outreach of the well as any frictional lock up while sliding will be overcome

• 4 ¾” electric CT BHA with a RSS steerable system with a downhole multiphase meter which will allow us to production test while drilling with all of the advantages listed above.

The staged philosophy of BHA evolution presents a logical order of complexity to the development of BHA options. The will mean that the first wells where the learning curve will be greatest with the surface system will employ the least complicated BHA option which reduces the complexity and potential risk.

Once a reasonable degree of satisfaction is achieved with the performance of the surface system the BHA options will be ramped up to then harness the true potential of the RRL system

Well Design Allows for Drilling A Tangent Section
Current well design for coiled tubing wells has to take into account the lack of an ability to drill a tangent section, this has two primary disadvantages:

1. The well path azimuth has to be drilled in an “S” shape to allow it to intersect the target. To achieve this requires additional footage to be drilled which in turn increases well costs and delays production.

2. The increase in the wellbore tortuosity has a negative impact on the potential length of the horizontal section due to an increase in friction in turn leading to mechanical lock up of the coil. When this is combined with an inability to rotate the potential horizontal outreach is severely limited.

Therefore, with rotation of the surface coil, the two disadvantages listed above are countered by the ability to drill a tangent section and rotate to overcome frictional lock up. This then means that extended horizontal well sections can then be drilled when compared to traditional coil tubing.

Sidetracking
The effect of frictional lock also has a detrimental effect on the ability to side track (open hole and mechanical) with traditional coil tubing. Due to the nature of sidetracking it needs to be done slowly to cut either a ledge or to prevent re entering the original wellbore as the drill bit will always follow the path of least resistance.

This in itself creates a problem if weight cannot be transferred steadily to the bit as the required drilling parameters cannot be met. This situation is exasperated as the sidetrack point becomes further away from the vertical. This therefore limits where in the horizontal section it is possible to sidetrack from. This problem is not experienced when using the RRL unit as again the frictional lock is overcome by rotation.

The lack of a limitation for the sidetracking point means that potentially a larger drainage radius patterns can be drilled. This in turn provides more effective drainage of a reservoir or potentially more effective injection for CO2 flooding or hydraulic support for a reservoir from a single wellbore with obvious cost benefits.

Environmental Benefits
The economics of a project do not solely decide whether a potential candidate or field development goes ahead. In areas where environmental concerns are highlighted even the most sustained demand for hydrocarbons can be overridden by the environmental lobby.

It is widely acknowledged that the most eco friendly manner for drilling is with coiled tubing as it is a closed system when compared to a jointed pipe operation.

It is closed by the use of a closed circulation system with a smaller footprint than a normal rig. Unfortunately the limitations of coiled tubing (as discussed above) mean that often it is a less than ideal methodology for accessing the reservoir section. The RRL system though brings you the environmental benefits associated with coiled tubing drilling in addition to the technical benefits listed above.

Therefore it is not necessary to have to compromise the technical goals to achieve the necessary environmental goals and is ideally suited to drilling in environmentally sensitive areas.

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