Patent Application
20130153396
The present invention relates to fracturing and more particularly to the purification of a fluid for example water after fracturing.
Hydraulic fracturing, often called fracking, fracing or hydrofracking, is the process of initiating and subsequently propagating a fracture in a rock layer, employing the pressure of a fluid as the source of energy. The fracturing, known as a frack job (or frac job), is done from a wellbore drilled into reservoir rock formations, in order to increase the extraction and ultimate recovery rates of oil and natural gas.
Hydraulic fractures may be natural or man-made and are extended by internal fluid pressure which opens the fracture and causes it to extend through the rock. Natural hydraulic fractures include volcanic dikes, sills and fracturing by ice as in frost weathering. Man-made fluid-driven fractures are formed at depth in a borehole and extend into targeted formations. The fracture width is typically maintained after the injection by introducing a proppant into the injected fluid. Proppant is a material, such as grains of sand, ceramic, or other particulates, that prevent the fractures from closing when the injection is stopped.
One use of hydraulic fracturing is in stimulating water wells. In that case, the fluid used may be pure water (typically water and a disinfectant such as bleach).
Frac water may be water and various minerals and debris that results from fracturing. The frat water must be processed to eliminate the minerals and debris so that the substantially pure water may be returned to the environment.
An apparatus for treating frac water may include a vacuum container to support a vacuum, a heating device to heat the vacuum container, a spiral auger to rotate to separate the frac water being positioned within the vacuum container, a condenser to condense the water vapor to liquid water, a second vacuum chamber to receive the liquid water and a storage container to store the liquid water.
The vacuum container may maintain a sufficient vacuum to boil water at approximately 100° F. and to form water vapor;
The vacuum chamber may include a substantially circular cross-section.
The vacuum chamber may include a input port to receive the frac water.
The vacuum chamber may include a first output port to discharge the debris.
The vacuum chamber may include a second output port to discharge the water vapor.
A first passageway may connect the vacuum chamber and the condenser chamber.
A second passageway may connect the second vacuum chamber and the condenser chamber.
The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which, like reference numerals identify like elements, and in which:
In operation, a vacuum sufficient to boil water at substantially hundred degrees Fahrenheit is formed within the vacuum cavity 103 and frac fluid which may be frac water enters the input port 119 of the input narrow portion 109. The rotating shaft 105 rotates the spiral auger 107 to help separate the water from the debris and minerals. Additionally, the vacuum encourages the water to enter the vapor state to encourage the separation from the debris and materials. The debris material and minerals and perhaps some water produced output from the vacuum chamber 101 through the first outlet port 131.
The condenser 135 condenses the water vapor to liquid water which now should be substantially pure. The liquid water enters a vacuum chamber 141 by a second transfer passageway 143 which may connect the condenser 135 and the vacuum chamber 141. The substantially pure water may be transferred from the vacuum chamber 141 to a storage container 145 through a third transfer passageway 147. The water may be stored in the storage container 145 until needed.
The pressure inside the vacuum container 101 and the vacuum chamber 141 may be between substantially 0.25 to 2 lbs/inch. The operating temperature of the vacuum container 101 and the vacuum chamber 141 may be between substantially 400 to 500 degrees Fahrenheit. The pressure is equivalent to exposing the frac water to the atmospheric pressure at substantially 50,000 to 80,000 feet above the surface of the earth. At this altitude and correspondingly in the vacuum container 101 and the vacuum chamber 141 water may boil at room temperature and may boil below room temperature. The operating temperature may allow the frac water to flash boil. The agitation of the frac water may compensate for the low pressure within the vacuum container 101 and the vacuum chamber 141 With so little pressure the inside of the vacuum chamber 141 and the vacuum container 101 unit a portion of the heat may need to be transferred by physical contact of the rotating shaft 105. Since the vacuum may provide insulation, the heating requirements may be reduced. The heat may transfer to the frac water by contact with the rotating shaft 105 and the interior surface of the vacuum container 101. This apparatus may facilitate the processing of large volumes of frac water at a constant rate.
The condenser 135 condenses the water vapor to liquid water which now should be substantially pure. The liquid water enters a vacuum chamber 141 by a second transfer passageway 143 which may connect the condenser 135 and the vacuum chamber 141. The substantially pure water may be transferred from the vacuum chamber 141 to a storage container 145 through a third transfer passageway 147. The water may be stored in the storage container 145 until needed.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed.
