Method and apparatus for providing heated water for fracing

Abstract

In an oil field fracing operation, a direct fire heater is provided that is mobile and self-contained on a trailer chassis. The direct fire heater has the maximum heat exchange possible between a burning gas and the fracing fluid by direct contact therewith. Recirculation is provided to maintain the fracing fluid at the desired temperature. A stack for the direct fire heater is removable for movement from one frac job or frac water heating site to another. Pellets in the stack helps insure a more complete heat exchange between the fracing fluid and the burning gas.

What I claim is: 
     
         1 . An apparatus for supplying heated water to a well to be fraced comprising:
 a source of water;   a direct fire heater for heating some of said water from said source;   a source of gas for burning in a combustion chamber of said direct fire heater;   storage facility for temporarily storing said heated water;   a source of a proppant such as sand;   a blender for blending together said heated water, said proppant and chemicals into a fracing mixture;   a pump for pumping said fracing mixture under high pressure into said well to be fraced;   said burning gas in said direct fire heater transferring heat therefrom to said water being sprayed from a top down through a heater stack into a main heater chamber, which main heater chamber receives said burning gas from said combustion chamber mounted on a side of said main heater chamber.   
     
     
         2 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 1  wherein said heater stack is removable from said main heater chamber of said direct fire heater so that said direct fire heater is transportable in a trailer chassis. 
     
     
         3 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 2  wherein water pumps pump said water through a spray nozzle mounted in said top of said heater stack and subsequently into said storage facility. 
     
     
         4 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 3  wherein some of said heated water is recirculated to maintain said heated water in said storage facility at a predetermined temperature. 
     
     
         5 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 4  wherein said direct fire heater is portable from one frac site to another frac site. 
     
     
         6 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 5  wherein said heater stack has a perforated plate near the bottom thereof, heat exchange pellets being held above said perforated plate in said heater stack, said heat exchange pallets being heated by said burning gas and transferring said heat to said water being sprayed thereon. 
     
     
         7 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 6  further comprising filters between said source of said water and said spray nozzle to remove solids from said water. 
     
     
         8 . The apparatus for supplying heated water to the well to be fraced as recited in  claim 7  wherein said direct fire heater has a generator for generating electricity to run said direct fire heater, said generator being mounted on said trailer chassis. 
     
     
         9 . A method of heating fracing fluid for a hydrocarbon well to be fraced comprising the steps of:
 receiving water from a source into a direct fire heater;   igniting a source of fuel in a combination chamber of said direct fire heater;   blowing air into said combustion chamber of said direct fire heater to aid combustion of said fuel;   discharging burning fuel and air from said combustion chamber into a main heater chamber with heated air and flames flowing upward through a heater stack above said main heater chamber;   spraying said water from a top of said heater stack, through said heater stack and into said main heater chamber;   collecting heated water in a bottom of said main heater chamber; and   pumping heated water from the bottom of said main heater chamber to a warm water collecting container prior to injection into said well.   
     
     
         10 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 9  includes an additional step of recirculating some water from said warm water collecting container to maintain water therein at a predetermined temperature. 
     
     
         11 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 10  includes a further step of heat exchanging between heat exchanger pellets in said heater stack and said water sprayed there over. 
     
     
         12 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 11  includes the use of multiple combustion chambers for each main heater chamber. 
     
     
         13 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 12  includes the use of multiple heater stacks. 
     
     
         14 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 9  wherein said heater stack is removable. 
     
     
         15 . The method of heating fracing fluid for a hydrocarbon well to be fraced as recited in  claim 14  wherein said direct fire heater is mounted on a trailer and is transportable over public roads.