Frac water heating system and method for hydraulically fracturing a well

摘要

The present invention provides an improved frac water heating system to fracture a subterranean formation at a remote work site to produce oil and gas. The present invention includes a single-pass tubular coil heat exchanger contained within a closed-bottom firebox having a forced-air combustion and cooling system to heat the treatment fluid. In another embodiment, the invention includes multiple, single-pass heat exchanger units arranged in a vertically stacked configuration to heat the treatment fluid. In a preferred embodiment, the improved frac water heating system is used to heat water on-the-fly (i.e., directly from the supply source to the well head) to complete hydraulic fracturing operations. The present invention also includes systems for regulating and adjusting the fuel/air mixture within the firebox to maximize the combustion efficiency. The system may also include a novel hood opening mechanism attached to the exhaust stack of the firebox.

主权项

1. A portable system for heating treatment fluids at a remote work site, comprising:
a closed-bottom firebox having an exhaust stack configured near the top of said firebox; a heat exchanger device contained within said firebox, said heat exchanger device comprising a plurality of single-pass heat exchanger units arranged in a vertically stacked configuration, wherein each of said heat exchanger units comprises a tubular coil having a single inlet for receiving treatment fluid having a first temperature and a single outlet for discharging heated treatment fluid, said plurality of heat exchanger units comprising a first heat exchanger unit comprising a helical coil oriented about a horizontal axis so as to define a combustion chamber for receiving a substantially horizontal combustion flow, said combustion chamber being substantially enclosed by said helical tubular coil on all but one opened side, and a second heat exchanger unit configured above said first heat exchanger unit, said second heat exchanger unit comprising a plurality of stacked horizontal rows of tubing faked down in a series of reversing loops oriented about a vertical axis; a fluid supply system including a fluid supply pump in fluid communication through a common inlet conduit with each inlet of said plurality of heat exchanger units; a plurality of burner assemblies configured in said firebox, each of said burner assemblies comprising a nozzle that projects an atomized fuel-air spray into said combustion chamber though said opened side, which when combusted results in a substantially horizontal combustion flow into said combustion chamber; a primary air system for supplying a first pressurized air flow to each of said burner assemblies, wherein said primary air system comprises a blower pump fluidly connected to a primary air inlet of each of said plurality of burner assemblies, said blower pump comprising a positive displacement rotary blower; and a secondary air system for supplying a second pressurized air flow to said firebox, wherein said helical tubular coil of said first heat exchanger unit includes a plurality of traversing lateral tubes which substantially enclose said combustion chamber on a side opposing said opened side, wherein at least one of said traversing lateral tubes is configured directly in line with said substantially horizontal combustion flow; and wherein said second pressurized air flow increases the convective heat transfer of thermal energy from said combustion flow to said treatment fluid as said fluid is pumped through its respective heat exchanger unit by said supply pump.