Apparatus and Method for Oilfield Material Delivery

Abstract

An apparatus for mixing and delivering a material to a high pressure flow of fluid, comprises a pressure vessel comprising: a particulate solids inlet aperture located substantially in an upper portion of the pressure vessel; a first liquid inlet in fluid communication with a first high pressure line and the pressure vessel and comprising a first valve; and a first outlet in fluid communication with the pressure vessel and a second high pressure line and comprising a third valve.

1 . An apparatus for mixing and delivering a material to a high pressure flow of fluid, comprising:
 a pressure vessel comprising:
 a particulate solids inlet aperture located substantially in an upper portion of the pressure vessel; 
 a first liquid inlet in fluid communication with a first high pressure line and the pressure vessel and comprising a first valve; and 
 a first outlet in fluid communication with the pressure vessel and a second high pressure line and comprising a third valve. 
   
     
     
         2 . The apparatus of  claim 1 , further comprising a second liquid inlet in fluid communication with at least one additive source and the pressure vessel and comprising a second valve. 
     
     
         3 . The apparatus of  claim 1 , further comprising a particulate solids reservoir connected to the particulate solids inlet aperture. 
     
     
         4 . The apparatus of  claim 3  wherein the particulate solids reservoir is one of a funnel, a silo, and a hopper. 
     
     
         5 . The apparatus of  claim 3  further comprising a valve connected between the pressure vessel and the particulate solids reservoir and operable to control flow of particulate solids from the particulate solids reservoir to the pressure vessel. 
     
     
         6 . The apparatus of  claim 1 , further comprising a first pumping equipment connected to the first liquid inlet and capable of inducing a pressure exceeding the pressure of the high-pressure line. 
     
     
         7 . The apparatus of  claim 1 , wherein the first high-pressure line is connected to the second-high-pressure line upstream of a choke, the choke disposed between the first high pressure line and the first outlet, wherein the choke is operable to reduce the pressure of the second high-pressure line below the pressure of the first high-pressure line. 
     
     
         8 . The apparatus of  claim 1 , further comprising an additive carrying line connected to at least one additive source and to the second liquid inlet. 
     
     
         9 . The apparatus of  claim 8 , wherein the additive source is a source containing an additive selected from the group including proppant coating, viscosity breakers, friction reducing agents, cross-link delaying agents, lubricants, fiber, explosive chemicals, bonding agents, adhesives, clean frac fluid, a scale inhibitor, and combinations thereof. 
     
     
         10 . The apparatus of  claim 1 , wherein the third valve is a one-way valve operable to isolate the pressure vessel from the second high-pressure line and to selectively enable flow from the pressure vessel to the second high-pressure line. 
     
     
         11 . The apparatus of  claim 1 , further comprising a pumping apparatus connected to the second high-pressure line upstream of the first liquid inlet. 
     
     
         12 . The apparatus of  claim 1 , wherein the pressure vessel is a tubular vessel. 
     
     
         13 . The apparatus of  claim 1 , further comprising a second outlet having a fourth valve and in fluid communication with the pressure vessel in the upper portion of the pressure vessel. 
     
     
         14 . The apparatus of  claim 13  wherein the second outlet is connected to an overflow destination. 
     
     
         15 . The apparatus of  claim 1  wherein the pressure vessel is a horizontally oriented tubular vessel. 
     
     
         16 . The apparatus of  claim 15  further comprising an internal feed screw operable to transport the particulate solids from a location near the particulate solids inlet to a location near the first outlet. 
     
     
         17 . The apparatus of  claim 1  wherein the pressure vessel comprises at least two pressure vessels connected to the main high-pressure line down-stream from the high-pressure pumping mechanism. 
     
     
         18 . The apparatus of  claim 17 , further comprising pumping equipment connected to the at least two pressure vessels and capable of selectively inducing a pressure exceeding the pressure of the high-pressure line into the at least two pressure vessels. 
     
     
         19 . The apparatus of  claim 17 , wherein the pressure vessels are connected to separate additive sources. 
     
     
         20 . A method for mixing and delivering a material to a high pressure flow of fluid, comprising:
 introducing a particulate solid into a mixing apparatus;   introducing a liquid additive into the mixing apparatus and thereby mix the solid and liquid additive;   increasing the pressure of the mixing apparatus to a pressure exceeding the pressure of a high-pressure line; and   opening a valve between the mixing apparatus and the high-pressure line to release the particulate solid and the liquid additive into the high-pressure line.   
     
     
         21 . The method of  claim 20 , wherein increasing comprises:
 closing valves on lines for introducing the particulate solid and for introducing the liquid additive; and   introducing a fluid, that is substantially the same as fluid present in the high-pressure line, into the mixing apparatus.   
     
     
         22 . The method of  claim 20 , wherein increasing further comprises:
 diverting flow from the high-pressure line to a pressure increasing device;   operating the pressure decreasing device to decrease the pressure of the high-pressure line such that at a point downstream from the diversion the pressure in the high-pressure line is lower than the pressure in the diverted flow; and   directing the diverted flow into the mixing apparatus.   
     
     
         23 . The method of  claim 20 , wherein introducing comprises increasing the pressure in a line carrying the liquid additive to the mixing apparatus to a pressure exceeding the pressure of the high-pressure line. 
     
     
         24 . The method of  claim 20 , wherein the liquid additive is an additive selected from the group including proppant coating, viscosity breakers, friction reducing agents, cross-link delaying agents, lubricants, fiber, explosive chemicals, bonding agents, adhesives, clean frac fluid, and combinations thereof. 
     
     
         25 . The method of  claim 20 , further comprising opening a valve to divert overflow created by the introduction of particulate solid or liquid additive into an overflow destination. 
     
     
         26 . A method of adding an additive to a proppant flow on the high-pressure side of a stimulation treatment apparatus, comprising:
 operating pumping equipment to pump a clean frac fluid at a desired high pressure into a high-pressure line;   isolating a pressure vessel connected to the high-pressure line from the high-pressure line;   introducing a proppant into the pressure vessel;   introducing an additive into the pressure vessel thereby mixing the proppant and the additive into a proppant-additive slurry;   increasing the pressure in the pressure vessel to exceed the clean frac fluid pressure; and   opening a valve from the pressure vessel into the high-pressure line thereby introducing the proppant-additive slurry into the high-pressure line downstream of the pumping equipment.