Helical coil annular access plug and abandonment
A method for creating access to annular spacing during plug and abandonment operations is described. Specifically, helical coils are cut into one or more casings before the plugging material is set. The plugging material is able to exit the helical coils, forming multiple, small rock-to-rock seals.
1. A method of sealing a well, said method comprising:
a) deploying a cutting tool downhole to cut a helical coil opening in one or more casings at a section of well to be sealed, wherein said helical coil opening provides access to an open annular space external to an outermost casing;
b) deploying solid bismuth alloy and a tracer to said section;
c) deploying a heater to said section to melt said solid bismuth alloy to form molten alloy;
d) squeezing said molten alloy to force it to flow out said helical coil openings into said open annular space and allowing said molten alloy to solidify, thereby plugging said section with a plug; and
e) drilling through said plug to form a drilled plug;
f) logging said tracer to evaluate a quality of said drilled plug; and
g) optionally refilling said drilled plug.
2. The method of claim 1 , wherein said cutting tool is a laser or an abrasive cutter.
3. The method of claim 1 , wherein helical coil cuttings from said cutting tool fall to a bottom of said well.
4. The method of claim 1 , wherein additional solid bismuth alloy is deployed to said section and melted and cooled to extend a length of said plug.
5. The method of claim 1 , wherein additional solid bismuth alloy is deployed to said section and melted and cooled to refill said drilled plug.
6. The method of claim 1 , wherein said drilled plug is refilled with cement or resin or a bismuth alloy or combinations thereof.
7. The method of claim 1 , wherein a base plug is deployed below said section, said base plug comprising cement, resin or bismuth alloy.
8. The method of claim 1 , wherein an inner tubing string is cut or removed at said section before said outermost casing is cut.
9. The method of claim 8 , wherein a mill is used to remove said inner tubing string.
10. The method of claim 8 , wherein a laser is used to cut said inner tubing string.
11. The method of claim 8 , wherein additional solid bismuth alloy is deployed to said section and melted and cooled to extend a length of said plug.
12. The method of claim 8 , wherein said drilled plug is refilled with cement or resin or a bismuth alloy or combinations thereof.
13. The method of claim 8 , wherein additional solid bismuth alloy is deployed to said section and melted and cooled to refill said drilled plug.
14. The method of claim 8 , wherein said cutting tool is a laser or abrasive cutter.
15. The method of claim 8 , wherein helical coil cuttings from said cutting tool fall to a bottom of said well.
16. The method of claim 8 , wherein a base plug is deployed below said section, said base plug comprising cement, resin or bismuth alloy.