Patent Application
20080083530
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Referring to
Referring now to
Frac heads 100 and 100′ include main body portions 140 and 140′ (also referred to in the art as “goat heads”) having a plurality of side ports 142. The exemplary embodiments shown include three (
With reference now to
With continued reference to
Side ports 142 are preferably symmetrically arranged around main body 140 or 140′ (e.g., three side ports located at 120 degree intervals about main body 140 or four side ports located at 90 degree intervals about the main body 140′). Such an arrangement advantageously reduces lateral fluid flow and therefore tends to advantageously reduce frac head erosion. It is also preferable for side ports 142 to terminate at substantially the same longitudinal position in the frac head (e.g., the same vertical distance from vortex 168) such that lateral flow from one side port tends to counteract lateral flow from an opposite side port. In the exemplary embodiments shown, side ports 142 are at an angle of about 45 degrees with respect to longitudinal axis 110, although the invention is not limited in this regard. Side ports 142 are also shown welded to body portions 140 and 140′. The invention is, of course, not limited in this regard.
While the invention is not limited to embodiments having multiple body portions (such as 120, 140′, and 160 described above), such a construction provides certain advantages. One such advantage is a reduction in manufacturing complexity and cost. Another advantage is that damaged body portions may be replaced individually without requiring replacement of the entire frac head. The modular configuration of frac heads 100 and 100′ also endows functional advantages. For example, the modular configuration shown on
Another functional advantage of the modular configuration is that conventional wireline and/or slick line tool assemblies may be mounted atop frac heads 100 and 100′. This obviates the need to remove the frac head from the well head prior to wireline and/or slick line operations and thereby saves valuable rig time. For example, in one exemplary embodiment, top port 122 may be configured to include a conventional Otis or Bowen connector. A conventional lubricator (not shown) may then be coupled to the top port. As is known to those of ordinary skill in the art, a typical slick line tool assembly includes a slick line routed through a conventional stuffing box, which is mounted atop the aforementioned lubricator. A typical wireline tool assembly includes a wireline routed through a conventional grease injection head, which is mounted atop a lubricator. In such operations, the slick line and/or wireline tool may be advantageously lowered down through frac head 100 or 100′ into the wellbore.
Frac head 100′ further includes a longitudinal through bore from top port 122 down through the lower end of the tool. The longitudinal through bore includes at least three sections, a first bore section 148 having an inner diameter ID1, which is located upstream of a second section, tapered section 168, which is in turn located upstream of a third bore section having an inner diameter ID2. Tapered section 168 has a reduced diameter at the downstream end thereof, reducing the inner diameter of the bore from ID1 at the upstream end of the tapered section 168 to ID2 at the downstream end of the tapered section 168 in the exemplary embodiment shown. First bore section 148 includes a mixing chamber 145 located at the lower end thereof, downstream of side port bores 144 and upstream of the tapered bore 168. As shown, mixing chamber 145 has a length d and an inner diameter ID1. The combination of the mixing chamber 145 and the tapered vortex 168 has been found to advantageously reduce erosion in frac head 100′. It is believed that the presence of mixing chamber 145 above vortex 168 serves to redirect fluid flow downhole with minimal turbulence and associated lateral fluid flow. Stated another way, the mixing chamber 145 and vortex 168 are believed to “straighten out” the fluid prior to its entry into the smaller diameter bore 164.
With continued reference to
In the exemplary embodiment shown (
The exemplary embodiments shown on
It will be appreciated that the top port 122 and/or the side ports 142 may optionally each include a wear resistant sleeve (or tube) deployed therein as is well known to those of ordinary skill in the art. Such sleeves, when utilized, are intended to minimize erosion in the top and/or side ports.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alternations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
