Not applicable
The present invention relates to deep well operations controlled or initiated by free falling tool subs.
A cone of flexible material is secured within one or both of the centering spring cages of a free falling well tool connected to or part of a perforating gun, tubing cutter or well logging sensor or similar well tool. In a first operational mode, the invention is preferably utilized to regulate the descent rate of the free falling tool in substantially vertical segments of a well length. In a second operational mode, the invention is a process and tool for driving a well tool along deviated and horizontal segments of a well length where gravity forces are insufficient to sustain displacement. In the second mode, the cone opens against up-hole fluid pressure to drive the tool along deviated, substantially horizontal length segments of a well. The second mode cone also collapses to permit the free by-pass flow of standing well fluid when free falling in vertical length segments of the well.
The invention is hereafter described in detail and with reference to the drawings wherein like reference characters designate like or similar elements throughout the several figures and views that collectively comprise the drawings. Respective to each drawing figure:
As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly“, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate. Moreover, in the specification and appended claims, the terms “pipe”, “tube”, “tubular”, “casing”, “liner” and/or “other tubular goods” are to be interpreted and defined generically to mean any and all of such elements without limitation of industry usage.
A basic utility of the present invention, as practiced, for example, upon a drill string cutting operation, is represented by the six views, A through F of
The
Referring to the sectioned view of
With the thin wall section 30 of the sacrificial mandrel 20 severed,
In detail, the drop sub embodiment 22 illustrated by
Referring to
As illustrated by
Fluid supplies into most deep well service operations are provided by positive displacement pumps that discharge a known volume of fluid for each revolution or cycle of the pump. This known discharge volume into the closed volume of a downhole pipe 10 bore may be translated to a known axial displacement distance of the drop sub assembly 22 along the pipe 10 length for each pump cycle when the cone 50 within the lower centering spring 47 opens to substantially prevent bypass flow around the cone. Consequently, a well operator may determine the exact position of a drop sub assembly 22 with reasonable precision by simply counting the number of pump revolutions.
As used herein, the term “fluid barrier” to describe the cone 50 fabrication material is to be interpreted in a sense that the well fluid of a specific application does not pass freely through it. Hence, the term must be interpreted in the context of the physical characteristics of the fluid in which it is to be immersed. This would include a range of materials from membranes that are substantially impermeable to water or gas to strong, loosely woven fabrics immersed in a viscous, high gravity drilling mud.
Other preferable material characteristics of cone 50 are such as to readily collapse away from the centering springs 47 when the drop sub assembly 22 is free falling by gravity to permit fluid standing within the pipe 10 bore to bypass the drop sub. Depending upon the well fluid conditions such as pressure, depth, acidity, viscosity density, rheology and other factors, the material may be a polymer impregnated fabric, reinforced rubber, or woven fiberglass as examples.
Although the
The invention embodiment of
The cone 52 functions as a brake to retard and slow the gravity driven freefall descent of the drop sub assembly 22. The viscosity and specific gravity of fluid in a pipe pore is highly variable depending on particular well circumstances. In many cases, the fluid may be air or some inert gas, especially in the upper zone of a well, which offers little resistance to the sub assembly descent. Gaseous fluids allow the sub assembly 22 to acquire excessive speed along the pipe string bore thereby jeopardizing the integrity of the attached tool 28 and/or its operation. For example, a severe shock upon landing against the plug seating aperture 24 may prematurely release the fluid pressure actuated firing pin mechanism within pipe stem 42. The cone 52 opens like a parachute to retard the drop sub descent rate.
In the case of the present invention, fluid bypass apertures 54 into the bore of stem tube 42 above the cone 52 cooperate with the valve actuating apertures 43 to provide a restricted fluid flow path past the cone 52 as a descent rate control device. Further control is enabled by a sleeve valve 56 which may be selectively positioned along stem tube to close one or more of the apertures 43.
This combined assembly of
As described with respect to the
It will also be obvious to those of ordinary skill that the materials used for the construction of cones 50 and 52 need not be the same nor even similar. There may be considerable differences in operational stress imposed on the respective cones.
While the foregoing description has focused on the preferred embodiments of the invention as for controlling the placement of free-falling or unattached well tools, it will also be appreciated that the invention principles may be applied to pipe and coiled tubing attached tools. In particular, the piston configuration of the invention embodied in cone 50 may be effectively engaged to draw a long string of coiled tubing along a horizontal segment of deviated well.
Although the invention disclosed herein has been described in terms of specified and presently preferred embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto. Alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the invention are contemplated which may be made without departing from the spirit of the claimed invention.
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Number | Date | Country | |
---|---|---|---|
20130341007 A1 | Dec 2013 | US |