DOWNHOLE TOOLS HAVING NON-TOXIC DEGRADABLE ELEMENTS

摘要

Downhole tools for use in oil and gas production which degrade into non-toxic materials, a method of making them and methods of using them. A frac ball and a bridge plug comprised of polyglycolic acid which can be used in fracking a well and then left in the well bore to predictably, quickly, and safely disintegrate into environmentally friendly products without needing to be milled out or retrieved.

主权项

1. A settable downhole tool for use in a hydrocarbon well with production casing to engage the production casing and temporarily isolate an upper zone above the tool from a lower zone below the tool, so the upper zone can be fracked in isolation from the lower zone, the tool comprising:
a mandrel comprising hard solid-state high-molecular-weight polyglycolic acid which has at least short-term stability in ambient conditions, a longitudinal passage therein and a ball seat; a frac ball comprised of hard solid-state high-molecular-weight polyglycolic acid capable of being pumped down the well from the surface with a wellbore fluid without an appreciable effect on the ball's short-term hardness, the ball capable of seating securely into the ball seat to block the passage; the tool is capable of engaging the casing and being used in a hydraulic fracking operation as a conventional settable zonal isolation downhole tool; the ball in the ball seat having sufficient compression resistance and structural integrity to be capable of causing the tool to isolate the upper zone from the lower zone so the upper zone can be fracked in isolation from the lower zone; the ball is capable of losing sufficient compression resistance and structural integrity within less than two days from being pumped down the well responsive to hydrostatic pressure from above the ball due to the ball degrading in the wellbore fluid to pass through the ball seat, causing the tool to cease isolating the upper and lower zones from each other without drilling out the tool; the tool is capable of releasing from the tool's engagement with the casing without drilling out the tool within less than two days of the mandrel's entry into the wellbore fluid due to the tool degrading in the wellbore fluid; and the tool is capable of degrading in the wellbore fluid enough to not obstruct production of hydrocarbons from the well without drilling out the tool.