Patent Application
20130020091
The invention relates to a plunger lubricator.
During fluid production operations, a plunger lift system is sometimes used when pressure within a wellbore is insufficient to cause fluid to rise naturally. In a plunger lift system, a plunger serves as a mechanical interface between lift gas below the plunger and produced fluid above the plunger. When sufficient lift gas from the reservoir collects below the plunger to provide buoyant lift to the plunger and produced fluid above the plunger, the fluid and plunger are elevated in the wellbore to the surface. At the surface, a lubricator is used to absorb the kinetic energy of the plunger and to recover the plunger from the wellbore. The lubricator has fluid flow ports where produced fluids above the plunger maybe fed to, for instance, a pipeline or collection system.
Canadian patent no. 2,635,993 discloses a plunger lubricator housing, which comprises an elongated tubular body made from a single piece of material. The body has a first end, a second end, an outer surface, an inner surface that defines a plunger receiving interior bore, and radial ports which provide fluid communication between the interior bore and the outer surface. Each of the radial ports 43 has a threaded coupling that is inset from the outer surface of the body 40.
The invention disclosed herein provides for a plunger lubricator.
In accordance with one aspect of the present invention, there is provided a lubricator for receiving a plunger comprising: an outer surface; an inner surface defining a bore; a well head connection at a first end for connecting a well head; a stem connection at a second end for connecting a stem; at least one flow port for connecting a flow line, the at least one flow port being an externally threaded nipple that extends radially outwardly from the outer surface; and a catcher port for catching a plunger.
In accordance with another aspect of the present invention, there is provided a method for connecting a plunger lubricator to a flow line fitting having external threads, comprising: providing an externally threaded nipple that extends radially outwardly from an outer surface of the lubricator; threadedly connecting the externally threaded nipple to a first end of an internally threaded collar; and threadedly connecting a second end of the internally threaded collar to the external threads of the flow line fitting.
Drawings are included for the purpose of illustrating certain aspects of the invention. Such drawings and the description thereof are intended to facilitate understanding and should not be considered limiting of the invention. Drawings are included, in which:
The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
Referring to
Lubricator 10 further includes flow ports 28 for connecting to flow lines (not shown). In one embodiment, flow ports 28 are externally threaded nipples 29 that extend radially beyond outer surface 14. Lubricator 10 may also be provided with other ports 30, which may be used for attaching gauges or sensors, or for injecting chemicals. Lubricator 10 may also comprise a catcher port 34 to catch a plunger at the top of its stroke. Ports 30 and 34 may be external nipples that extend radially outwardly from outer surface 14. In one embodiment, ports 28, 30, and 34 are machined into lubricator 10. In another embodiment, ports 28, 30, and 34 are formed by creating apertures in the body of lubricator 10 and then integrating separate components to the circumference of the apertures, for example, by attaching threadolets by welding. In one embodiment, lubricator 10 includes an equipment attachment which may be used for attaching a sensor to indicate the arrival of a plunger. In another embodiment, other components, such as lifting eyelets, are welded or otherwise attached to lubricator 10.
In one embodiment, lubricator 10 is constructed from a single piece of material as described hereinafter. A single piece of material is machined, forged, or casted to form bore 18 and outer surface 14. The material may be any metal meeting proper specifications for strength, temperature rating, ductility, durability, corrosion resistance, capability of being welded, worked or machined, typically a steel, and preferably 4130 or 4140 carbon steel. Well head connection 20 is machined at the first end, and stem connection 24 is machined at the second end. In one embodiment, outer surface 14 may be machined to form ports 28, 30 and 34. In another embodiment, apertures are created in the body of lubricator 10 and separate threadolet components may be welded to the circumference of the apertures to form ports 28, 30, and 34. In a further embodiment, outer surface 14 is machined to have an increased thickness at various points along the length of the lubricator 10 such that the lubricator 10 may have increased thickness about ports 28, 30 and 34, or at other locations.
Referring to
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.
