Methods of Well Cleanout, Stimulation and Remediation and Thermal Convertor Assembly for Accomplishing Same

Abstract

A thermal convertor is formed from a controlled combustion chamber selectively supplied by an appropriate fuel, preferably diesel, and compressed air. The control over the temperature of the combustion chamber is provided by regulating the flow of fuel, air and pressure into and out of the combustion chamber. Flow control valves open or close the inputs of fuel and water to, and the output of the superheated vapors from, the combustion chamber to specifically control the behavior of the combustion chamber and the composition and quality of the output from the combustion chamber. This assembly is then used to inject superheated nearly oxygen-free vapors including well treatment chemicals into a well bore cleaning the well, including the annulus and rathole, near-well bore and perforations of fines and asphaltenic particles, then stimulating an existing but newly cleaned well to produce additional oil. These methods can also be used to stimulate high paraffinic wells or wells with high viscosity crude oil, and for the maintenance of well pressure to enhance production rates.

1 . A method of cleaning a well bore including a rat hole below the perforations of the producing zone comprising:
 removing all production equipment from the well;   reinserting a production tubing without the production equipment to a point below the perforations;   circulating superheated vapor from a surface thermal convertor for a period of time through the annulus and returning up the production tubing until the returns are clean;   step-wise lowering the production tubing into the well bore until the well bore including the rathole returns are clean;   pressurizing the near well bore production formation by partially closing the wing valve on the return for an abbreviated period of time, then releasing the built-up pressure until the near well bore return is clean; and,   incrementing the time of shut-in in similar abbreviated time increments and rapidly releasing pressure until the formation break-in pressure and a permeable flow rate is established.   
     
     
         2 . A method of cleaning a well bore comprising:
 pulling a production string and replacing the tubing to a position the greater of ten feet below the production perforation or three feet above resistance from well bore solids and build-up;   injecting superheated vapor in the annulus and allow a return up the production tubing for a period of at least thirty minutes;   circulating superheated vapor to clean the well bore until the return is clean;   incrementally adding subs to the production string to extend the string to the maximum depth and continuing the clean out of the well bore   
     
     
         3 . A method of injecting one or more selected vapors into a well bore to clean the well bore comprising:
 pulling all pumping rods and production equipment from the well bore;   sweeping a wellbore by delivering the superheated gas and vapor-phase cleaning agents to the near and extended near wellbore formation;   cleaning the wellbore by delivering the superheated gas for a short interval while inhibiting outflow from the wellbore, and rapidly relieving back pressure to induce movement of fines and sediment from the near and extended near well bore to a surface collection outlet;   rinsing the well bore using saturated steam;   dehydrating the well bore with the continued introduction of the superheated inert gas stream without additional water;   connecting a thermal convertor comprised of a source of fuel providing a controlled flow of fuel, a source of compressed air providing a controlled flow of gas, a source of other liquids providing a controlled flow of such liquids to the thermal convertor, a mixer connected to both the source of fuel and the source of compressed air to combine the fuel and air flows in a homogeneous mixture, a water cooled combustion chamber with a controlled ignition source connected to the mixer to burn the homogeneous mixture of fuel and air at a specifically controlled temperature, and an outlet port from said combustion chamber providing a controlled outlet flow of near oxygen-free vapor, to a well bore;   selecting one or more liquids to add to the controlled outlet flow of superheated vapor from the combustion chamber to vaporize said one or more liquids and injecting said selected combined vapor stream into a well bore for a period of time; and,   disconnecting the thermal convertor and initiating production from the well after the period of time.   
     
     
         4 . The method of  claim 3  wherein the liquid is an alkali metal hydride. 
     
     
         5 . The method of  claim 3  wherein the liquid is a biodegradeable non-ionic cleaning and a solvent or wetting agent selected from environmentally safe terpenes or another naturally-occurring essential oils. 
     
     
         6 . The method of  claim 3  wherein the thermal convertor additionally provides a catalytic convertor at the outlet from the combustion chamber. 
     
     
         7 . The method of  claim 3  wherein the outlet provides a backpressure valve. 
     
     
         8 . The method of  claim 3  wherein the fuel is diesel. 
     
     
         9 . The method of  claim 3  wherein the fuel is propane. 
     
     
         10 . The method of  claim 3  wherein the fuel is methane. 
     
     
         11 . A method of cleaning an oil well to stimulate additional production comprising:
 generating a superheated inert gas;   sweeping a wellbore by delivering the superheated gas and one or more vapor-phase cleaning agents to the near and extended near wellbore formation;   cleaning the wellbore by delivering the superheated gas for a short interval while inhibiting outflow from the wellbore, and rapidly relieving back pressure to induce movement of fines and sediment from the near and extended near well bore to a surface collection outlet;   rinsing the well bore using saturated steam;   dehydrating the well bore with the continued introduction of the superheated inert gas stream without additional water; and,   continue pressurizing the formation to create a pressure drive to enable increased production of oil.   
     
     
         12 . The method of  claim 11  wherein the cleaning of the wellbore also includes the rathole. 
     
     
         13 . The method of  claim 11  wherein the treatment of well bore is accomplished chemically treating the well by introducing an alkali metal hydride in a vapor phase in the amount of 0.00125% to 0.01% by weight into the well bore and extended well bore to treat formation surfaces to break up and clean out the production zone to increase the flow of oil from the formation and to inhibit the production of carbonic acid from the carbon dioxide in the well bore, minimizing acid corrosion of the well bore. 
     
     
         14 . The method of applying corrosion treating to a well comprising:
 generating a superheated inert gas;   sweeping a wellbore by delivering the superheated gas and vapor-phase cleaning agents to the wellbore and production tubing;   cleaning the wellbore and rathole by delivering the superheated gas for a short interval, and rapidly relieving back pressure to induce movement of fines and sediment from the well bore and rathole;   rinsing the wellbore and production tubing with saturated steam to remove all chemical cleaning agents;   drying the wellbore and production tubing with superheated inert gas;   vapor phasing a solution of alkali metal hydride from about 5 to 10% by volume and injecting down the annulus and up through the production tubing to coat the surfaces; and   continue injecting superheated inert gas to cure and set the alkali metal hydride in the well bore and production tubing for corrosion inhibition.   
     
     
         15 . A thermal convertor comprising:
 a source of fuel providing a controlled flow of fuel;   a source of compressed air providing a controlled flow of air;   a source of water providing a controlled flow of water;   a mixer connected to both the source of fuel and the source of compressed air to combine the fuel and air flows into a homogeneous mixture;   a water cooled combustion chamber with a controlled ignition source connected to the mixer to burn the homogeneous mixture of fuel and air at a specifically controlled temperature and pressure; and,   an outlet port from said combustion chamber providing a controlled outlet flow of vapor.   
     
     
         16 . The thermal convertor of  claim 15  further comprising a source of chemicals connected to the outlet port from the combustion chamber to provide chemicals to the vapor stream produced by the combustion chamber. 
     
     
         17 . The thermal convertor of  claim 15  further comprising a catalytic convertor attached to the outlet port from the combustion chamber. 
     
     
         18 . The thermal convertor of  claim 15  further comprising a back-pressure valve positioned on the outlet port to control the flow throughput from, and pressure within, the combustion chamber. 
     
     
         19 . A method for chemical treatment of a cleaned well bore comprising:
 spotting the production tubing between six to eight feet below the lowest perforation of the production zone to permit a pump mechanism to be occupy a space within the static fluid level of the well bore;   injecting vapor phase well treatment chemicals into the well bore and into the producing zone; and,   starting the prime mover to move oil up the production tubing to the surface.   
     
     
         20 . The method of re-treating a clean well bore with additional chemicals comprising:
 stopping the prime mover in the producing well bore and allowing the pump mechanism to be covered in the static fluid level;   attaching the thermal convertor and injecting well treatment chemicals in vapor phase into the well bore production zone at a pressure above the break-in pressure of the formation for the producing zone, and   continuing to inject superheated gas and vaporized well treatment chemicals;   discontinuing treatment and commencing pumping operations at a rate which maintains a gas-liquid seal in the near well bore production zone.   
     
     
         21 . The method of  claim 20  wherein the well treatment chemicals are a non-ionic surfactant and an environmentally safe solvent. 
     
     
         22 . The method of  claim 21  wherein the non-ionic surfactant is no more than 20% and the solvent is at least 80% of the well treatment chemicals by weight.