PATENTED METHOD: Slickline, wireline and/or coiled tubing are presently used on Drilling Rigs during Phase 1 Reservoir Abandonment (1) and can now be used in Phase 2 Intermediate abandonment (3) to compact tubing, cables and clamps (2), so as to avoid the need for a Drilling Rig. In Phase 2 Intermediate Abandonment (3), the tubing can be split (4) and severed. A thru-tubing inflatable packer (5) can be expanded and pressured by fluid (6) pumped through the existing wellhead to drive the packer/piston and compact tubing, cables and clamps (7). Thru-Tubing Logging (8) can be used to verify cementation behind the casing. After confirming well integrity, cement placement through the tubing can be used to form a barrier (9). Compaction and cementing can continue with the surface controlled sub-surface safety valve (SCSSSV) and control line disposed of downhole to provide an unobstructed plug. After the environmental cement plug is placed, Phase 3 well abandonment of the conductor and surface casings can be riglessly cut and removed by conventional pinning, jacking and cutting (10).
The method of Downhole Tubing Disposal is favoured by the laws of physics, whereby the design of well plug and abandonments can be designed according to conventional hydraulic, helical buckling and yield equations based upon the unique characteristics of every well. Stage 1 compaction comprises driving a whole piece of tubing next to a split piece of tubing within the 80% to 90% liquid space within all oil and gas wells. Stage 2 compaction comprises helical buckling and yield of the steel tubing. An inflatable piston with a travelling valve and lower injection point compacts tubing and disposes of fluid below the piston. Water or heavy fluids can be used drive the piston with viscous fluids inhibiting any leaks with the hydraulic compaction system. It just everyday oilfield hydraulics.
PATENTED METHOD: After splitting the tubing, placing the tubing bridge plug and severing the un-split tubing, and before inflating and pumping against the inflatable piston packer, the cleaning Fluid 1 is placed and allowed to soak. After sufficient chemical cleaning time has occurred, the compaction piston is inflated. The packer can act as a piston within the tubing to force separation where necessary to ultimately expand against the casing inside diameter. Pressure P1in is placed against the inflated piston to start compaction of the tubing. As the pressure is increased from P1in to P2in, slip-like scratchers on the inflatable piston scrape the casing inside diameter as it is pumped downward during compaction. A viscous Fluid 2 is pumped after the piston to improve the seal against the casing and separate any cleaning fluid expelled from the relief valve from Fluid 3, which can be seawater, brine or drilling mud depending upon the pressure integrity of the casing. After logging the cement bond behind the now clean and water wettable inside diameter of the casing, cementing can occur.
PATENTED METHOD: After compaction cement placement can occur in several ways. Option-1 uses a slickline dump bailer to place cement on top of the compaction piston used to dispose of tubing downhole, scrape and clean the casing walls. Option-2 places cement between two wiper plugs and uses circulation to drop and "gravity channel" cement on top of the compaction plug. U-tube pressure control can be used to control the downward cement velocity.
PATENTED METHOD: Another option for cementing (Option-3 above) can use a slickline placed telescopic stinger secured to the end of the remaining severed tubing after compaction and logging. Cemented is pumped down the existing tubing to extend the telescopic stinger and place cement using circulation through the annulus and existing wellhead. The cement is displaced with a lighter fluid (note: the wiper plugs are not shown) and the bouyancy of the ligther fluid within the telescopic stinger is used as bouyancy to retract the stinger and complete the setting of a balanced cement plug.
PATENTED METHOD: Yet another alternative (Option-4 above) is to use slickline to place a telescopic stinger in the end of the severed tubing after cleaning compaction and logging to that is extended when cement is circulated down the tubing with returns through the annulus and existing wellhead. The telescopic stinger is arranged to lock into an extended centralised position and a wiper plug is used to clear the stinger so that thru-tubing logging can occur after the abandonment plug is placed. After confirming a well abandonment plug cement bond, a slickline dump bailer is used to fill the telescopic stinger and complete the well abandonment plug.
PATENTED METHOD: Column 1 depicts tubing (or casing) within casing that is uncemented. Column 2 shows setting a bridge plug in the tubing (or casing) after splitting the tubing (or casing) for compaction. Column 3 illustrates a thru-tubing inflatable packer (similar to your car tyre) that has been inflated to clean the casing and compact the tubing (or casing). Column 4 depicts shredded casing used to remove any eccentricity issues (see Section B.1) by removing the casing’s ability to shield areas and cause fluid friction. Column 5 illustrates an inflatable packer on coiled tubing that forces fluid circulation and vibration of the shredded casing strands to clean the casing and well bore. Alternatively, an angled fluid jetting tool can be used to vibrate casing strands and clean both the casing and well bore. Column 5 shows the inflatable packer initially used to clean fully inflated to expand the shredded casing strands, popping the upper casing coupling, and providing annulus support for jetted cementing operations.
Use coiled tubing with our enabling compaction method to vibrate shredded "guitar-like" casing strands to improve cleaning and cementing. The inside diameter of the shredded casing has a sail-like shape and, hence, when a fluid jetting force hits the curved surface it applies force to move the shredded casing strand inward and outward while vibrating and twisting the strand as the jet crosses the curved surface. Pushing the shredded strands increases the space between strands and fluid can be jetted into the annulus. Fluid already in the annulus, or newly jetted into the annulus, is pumped or pushed across the well bore surface by the moving and vibrating shredded casing strands. Jetting cleaning fluid can provide a water wettable well bore surface and jetting cement into the annulus while vibrating the shredded casing strands creates a rebar-like strengthening effect.
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