Patent ID: 9217319
Filing Date: 2015-12-22
Classification: E21B

Abstract:
1. A method of recovering hydrocarbons with a solid-state dissolvable tool, namely a frac ball operated bridge plug, comprising: inserting the bridge plug into a well bore, the bridge plug containing a primary structural member, namely a mandrel, the mandrel consisting essentially of high-molecular weight polyglycolic acid, namely Kuredux or its substantial equivalent, which is suitable for a high-pressure downhole fracking operation, has at least short-term stability in ambient conditions, and which is capable of losing crystalline structure due to hydrolysis in the wellbore under thermal stress of 250° F., and thereafter degrades in the wellbore into naturally-occurring glycerin, the bridge plug having a ball seat; pumping the bridge plug down the well bore from the surface with a pumping fluid which does not have an appreciable effect on the short-term structural integrity of the bridge plug; setting the bridge plug in the wellbore; pumping the frac ball, consisting essentially of solid-state high-molecular weight polyglycolic acid, namely Kuredux or its substantial equivalent, down the well bore from the surface with a pumping fluid which does not have an appreciable effect on the short-term structural integrity of the frac ball to seat the frac ball securely into the ball seat, the frac ball seated in the ball seat isolating a wellbore zone above the bridge plug from a wellbore zone below the bridge plug, allowing the zone above the bridge plug to be fracked in isolation from the zone below the bridge plug; fracturing the zone above the bridge plug; allowing the frac ball to lose sufficient crystalline structure due to hydrolysis within less than approximately 48 hours to pass through the ball seat, causing the bridge plug and frac ball combination to cease isolating upper and lower zones from each other without drilling out the bridge plug or other intervention from the surface; and allowing the bridge plug to degrade through hydrolysis into products which are not harmful to the environment without drilling out the bridge plug or other intervention from the surface, one of the degradation products being glycerin.