High-pressure Injection Proppant System

Abstract

A high-pressure injection proppant system for stimulating coal bed methane production preloads proppant, such as sand, into one or more high-pressure vessels, for delivery into a fluid stream, such a N 2 gas stream. A screw auger arrangement meters the proppant volumes and rates into the fluid stream. Two such vessels operationally mounted in parallel can function separately or concurrently depending on the demand for proppant in a particular formation. The system provides for the injection of surfactants into the fluid stream to enhance the performance of the proppant, to aid in the placement of the proppant into a fracture network, and to demote proppant flowback during production and embedment. The system can be operated manually or by computer automation to aid in the accuracy of the mixing of the fluid stream components.

1 . A high-pressure injection proppant apparatus comprising: 
 at least one pressure vessel;    means for filling the vessel with proppant;    means for delivering a fluid containing nitrogen gas to the vessel and pressuzing the vessel therewith; and, a metering arrangement operatively coupled to the vessel and in fluid communication therewith for metering the proppant from the pressurized vessel into a fluid stream containing nitrogen gas for delivery to a target formation.    
   
   
       2 . The apparatus of  claim 1  further comprising means for injection of a surfactant into the fluid stream.  
   
   
       3 . The apparatus of  claim 1  wherein the metering arrangement comprises an auger device disposed at a lower end of the vessel.  
   
   
       4 . A method of injecting proppant into a target formation comprising: 
 providing at least one pressure vessel and a metering arrangement operatively coupled to the vessel and in fluid communication therewith;    charging the vessel with proppant;    pressurizing the vessel with a fluid containing nitrogen gas; and,    operating the metering arrangement to meter the proppant from the pressurized vessel into a fluid stream containing nitrogen for delivery to the target formation.    
   
   
       5 . The method of  claim 4  further comprising directing proppant and the fluid from the vessel to the metering arrangement after pressurizing the vessel.  
   
   
       6 . The method of  claim 4  further comprising injecting a surfactant into the fluid stream.  
   
   
       7 . The method of  claim 6  wherein the injecting is downstream of the metering arrangement.  
   
   
       8 . The method of  claim 6  wherein the injecting is upstream of the pressure vessel.  
   
   
       9 . The method of  claim 4  further comprising diverting a portion of the fluid for pressurizing the vessel into the metering arrangement, thereby by-passing the vessel.  
   
   
       10 . The method of  claim 9  further comprising allowing the diverted fluid flow through the metering arrangement to clear an outlet valve thereof prior to said operating of the metering arrangement.