Apparatus and Method for Oilfield Material Delivery

Abstract

An embodiment of a method of operating at least two pressure vessels to inject a particulate slurry into a high-pressure line, comprises a first operating cycle comprising: isolating a pressure vessel from the high-pressure line, introducing, under low-pressure conditions, particulate solids into the pressure vessel through a particulate solids inlet aperture, a second operating cycle comprising: providing high-pressure flow into the pressure vessel, and providing a high-pressure slurry flow from the pressure vessel into the high-pressure line. The method further comprises causing a pressure vessel to operate in the first operating cycle while operating a pressure vessel in the second operating cycle, and synchronizing switching a first vessel from the first operating to a second operating cycle and switching a second vessel from the second operating cycle to the first operating cycle such that at least one of the vessels is operating in the second operating cycle.

1 . A method of operating at least two pressure vessels to inject a particulate slurry into a high-pressure line, comprising:
 a first operating cycle comprising:
 isolating a pressure vessel from the high-pressure line; 
 introducing, under low-pressure conditions, particulate solids into the pressure vessel through a particulate solids inlet aperture; 
   a second operating cycle comprising:
 providing high-pressure flow into the pressure vessel; and 
 providing a high-pressure slurry flow from the pressure vessel into the high-pressure line; 
   causing the at least one pressure vessel to operate in the first operating cycle while operating at least one pressure vessel in the second operating cycle; and   synchronizing switching a first pressure vessel from the first operating to a second operating cycle and switching a second pressure vessel from the second operating cycle to the first operating cycle in a manner such that at least one of the at least two pressure vessels is operating in the second operating cycle at any one time.   
     
     
         2 . The method of  claim 1  further comprising switching a first pressure vessel from the first operating cycle to the second operating cycle and switching a second pressure vessel from the second operating cycle to the first operating cycle, and synchronizing the switching in a manner such the at least two pressure vessels are operating in the second operating cycle simultaneously. 
     
     
         3 . The method of  claim 1  wherein the at least two pressure vessels is at least four pressure vessels organized as independent pairs. 
     
     
         4 . The method of  claim 1  wherein the at least two pressure vessels is at least four pressure vessels organized in at least two phased pairs wherein at least one pair of pressure vessels switch between first and second operating cycles at a time that is different from when at least one other pair switch between first and second operating cycles. 
     
     
         5 . The method of  claim 1  wherein the at least two pressure vessels is at least three pressure vessels (sequentially numbered 1 through n wherein n is the total number of pressure vessels) and wherein synchronizing comprises:
 cycling the pressure vessels such that when pressure vessel i mod n+2  transitions from the second operating cycle to the first operating cycle and pressure vessel i mod n+1  transitions from the first operating cycle to the second operating cycle.   
     
     
         6 . The method of  claim 1  wherein the first operating cycle further comprises returning overflow of fluid created by introduction of particulate solids from the pressure vessel to a clean fluids reservoir. 
     
     
         7 . The method of  claim 1  wherein providing comprises diverting clean fluid from the high-pressure line upstream from a location at which the high-pressure slurry flow from the pressure vessel is introduced into the high-pressure line. 
     
     
         8 . The method of  claim 1  wherein the second operating cycle further comprises:
 equalizing the pressure of the pressure vessel and the high-pressure line by increasing the pressure in the pressure vessel prior to providing high-pressure clean-fluid flow into the pressure vessel.   
     
     
         9 . The method of  claim 8  wherein equalizing comprises operating a pressure multiplier device connected to the pressure vessel. 
     
     
         10 . The method of  claim 1  wherein introducing comprises allowing the particulate solids to fall under gravity from a particulate solids reservoir into the pressure vessel. 
     
     
         11 . The method of  claim 10  wherein introducing further comprises metering the particulate solids introduced into the pressure vessel through a feeder valve. 
     
     
         12 . The method of  claim 1  wherein the first operating cycle further comprises feeding the particulate solids into the pressure vessel by rotating a feed screw located inside the pressure vessel. 
     
     
         13 . The method of  claim 1  wherein the first operating cycle further comprises:
 mixing the particulate solids with clean fluid prior to introducing the particulate solids into the pressure vessel;   wherein the introducing comprises pumping the mixture of particulate solids and clean fluid into the pressure vessel using a low-pressure pump.   
     
     
         14 . The method of  claim 1  wherein the second operating cycle comprises:
 causing the pressure of the pressure vessel to slightly exceed the pressure of the high-pressure line thereby producing the high-pressure slurry flow from the pressure vessel into the high-pressure line.   
     
     
         15 . The method of  claim 1  wherein the high-pressure clean-fluid flow is introduced into the pressure vessel in a location substantially near the top of the pressure vessel. 
     
     
         16 . The method of  claim 1  further comprising depressurizing the pressure vessel and a line carrying overflow from the pressure vessel to the clean fluids reservoir by decreasing the pressure in the pressure vessel prior to opening a valve permitting overflow clean-fluid flow out of the pressure vessel. 
     
     
         17 . The method of  claim 16  wherein depressurizing comprises operating a pressure reducing device connected to the pressure vessel to decrease the pressure in the pressure vessel. 
     
     
         18 . The method of  claim 1  further comprising:
 suctioning out fluid from the pressure vessel to a clean fluids reservoir prior to introducing particulate solids into the pressure vessel.   
     
     
         19 . The method of  claim 1  wherein introducing further comprises isolating the pressure vessel from a particulate solids reservoir located above the pressure vessel using a check valve. 
     
     
         20 . The method of  claim 1  wherein the pressure vessel comprises at least one tubular pipe oriented in a manner not allowing gravity transfer of solids from the inlet aperture to an outlet aperture connected to the high-pressure line. 
     
     
         21 . The method of  claim 1  further comprising causing the pressure of the pressure vessel to exceed the pressure of the high-pressure line sufficiently to divert a substantial portion of the flow of the high-pressure line flow through the pressure vessel thereby producing the high-pressure slurry flow from the pressure vessel into the high-pressure line. 
     
     
         22 . An apparatus for mixing and delivering a material to a high pressure flow of fluid, comprising:
 a particulate solids reservoir; and   a pressure vessel comprising:
 a first liquid inlet in fluid communication with a first high-pressure line and comprising a first valve; 
 a particulate solids inlet aperture connected to the particulate solids reservoir and located substantially in an upper portion of the pressure vessel and comprising a second valve operable to selectively isolate the pressure vessel from the particulate solids reservoir; and 
 a first outlet in fluid communication with a second high-pressure line and comprising a third valve. 
   
     
     
         23 . The apparatus of  claim 22  wherein the particulate solids reservoir is one of a funnel, a silo, and a hopper. 
     
     
         24 . The apparatus of  claim 22  wherein the second valve located between the pressure vessel and the particulate solids reservoir is a high-pressure valve operable to selectively provide a path through which particulate solids may enter into the pressure vessel. 
     
     
         25 . The apparatus of  claim 24  further comprising a feeder valve located below an exit aperture at the bottom of the particulate solids reservoir by which the particulate solids may be metered when introduced into the pressure vessel. 
     
     
         26 . The apparatus of  claim 24  wherein the second valve connected between the pressure vessel and the particulate solids reservoir is a check valve and wherein the pressure vessel comprises a valve seat on the interior surface of the pressure vessel and located at the particulate solids inlet aperture whereby a positive pressure differential between the interior of the pressure vessel and the particulate solids reservoir causes a valve disk of the valve to seat against the valve seat. 
     
     
         27 . The apparatus of  claim 26  wherein the second valve connected between the pressure vessel and the particulate solids reservoir comprises a linear actuator connected to the valve disk whereby a displacement of the linear actuator opens the valve to permit flow of particulate solids for the particulate solids reservoir into the pressure vessel. 
     
     
         28 . The apparatus of  claim 22  wherein the third valve connected between the pressure vessel and second high-pressure line comprises a spring loaded check valve and where the exterior of the pressure vessel comprises a valve seat located at the first outlet whereby a positive pressure differential between the interior of the pressure vessel and the second high-pressure line causes the third valve to open and wherein the spring causes a valve disk of the third valve to seat against the valve seat when the pressure in the pressure vessel is substantially equal or less than the pressure of the second high-pressure line. 
     
     
         29 . The apparatus of  claim 22  wherein the third valve connected between the pressure vessel and second high-pressure line comprises a linear actuator operable to selectively open and close the valve; and where the exterior of the pressure vessel comprises a valve seat located at the first outlet whereby a negative pressure differential between the interior of the pressure vessel and the second high-pressure line causes a valve disk of the third valve to seat against the valve seat and wherein the linear actuator may cause the valve disk of the third valve to move away from the valve seat thereby opening the third valve. 
     
     
         30 . The apparatus of  claim 22 , 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 above the pressure of the first high-pressure line. 
     
     
         31 . The apparatus of  claim 22 , further comprising an overflow outlet located in an upper portion of the pressure vessel thereby providing a mechanism for removing fluid within the pressure vessel displaced by particulate solids introduced into the pressure vessel. 
     
     
         32 . The apparatus of  claim 22 , further comprising an overflow line connected between the first outlet and the third valve, and via a side connection on the connection between the first outlet and third valve, to a suction pump connected to a clean fluids reservoir whereby a portion of the fluid in the pressure vessel may be suctioned out of the pressure vessel by the suction pump into the clean fluids reservoir prior to introduction of particular solids into the pressure vessel thereby avoiding an overflow condition. 
     
     
         33 . The apparatus of  claim 22 , wherein the pressure vessel further comprises:
 a cylindrical wall comprising the first liquid inlet and the overflow outlet integrated into the cylindrical wall.   
     
     
         34 . The apparatus of  claim 22 , wherein the pressure vessel is a long horizontally oriented tubular vessel. 
     
     
         35 . The apparatus of  claim 34  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. 
     
     
         36 . The apparatus of  claim 22 , wherein the pressure vessel is a long horizontally oriented pressure pipe wherein the particulate solids reservoir further comprises a clean fluid inlet and wherein the apparatus further comprises a low-pressure slurry pump connected between the particulate solids reservoir and the pressure vessel and operable to pump a slurry produced in the particulate solids reservoir into the pressure vessel.