CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. The present application claims priority benefit of U.S. Provisional Application No. 62/877,667, filed July 23, 2019, the entirety of which is incorporated by reference herein and should be considered part of this specification.

BACKGROUND

Field

[0002] The present disclosure generally relates to valves for use in gas lift systems in oil and gas wells.

Description of the Related Art

[0003] Oil and gas wells utilize a borehole drilled into the earth and subsequently completed with equipment to facilitate production of desired fluids from a reservoir. Subterranean fluids, such as oil, gas, and water, are produced from the wellbore. In some cases, the fluid is produced to the surface naturally by downhole formation pressures. However, the fluid must often be artificially lifted from wellbores by the introduction of downhole equipment. Various types of artificial lift are available. In a gas lift system, a compressor is located on the surface. The compressor pumps gas down the casing tubing annulus. The gas is then released into the production tubing via gas valves that are strategically placed throughout the production tubing. The gas that is introduced lightens the hydrostatic weight of the fluid in the production tubing, allowing the reservoir pressure to lift the fluid to surface.

SUMMARY

[0004] In some configurations, a valve includes a seat, a stem, and a ball. The ball is separate from the stem and configured to seal against the seat when the valve is in a closed position.

[0005] The stem can include a ball support portion and a stem portion. A first end of the ball support portion is configured to contact the ball. The stem portion extends from a second, opposite end of the ball support portion. The ball support portion can have a lumen therethrough extending from the first end to the second end. In some configurations, an inner surface of the ball support portion defining the lumen is angled relative to a longitudinal axis of the valve. The angled inner surface can be configured to inhibit or prevent washout in use.

[0006] The ball is configured to rotate freely relative to the stem such that the ball has multiple sealing surfaces for sealing with the seat. The valve can further include a spring, which biases the ball against the seat in the closed position. The spring can be disposed about the stem, for example, about the stem portion. The valve can be used in a gas lift system.

BRIEF DESCRIPTION OF THE FIGURES

[0007] Certain embodiments, features, aspects, and advantages of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:

[0008] Figure 1 illustrates a portion of an example of a gas lift system;

[0009] Figure 2 illustrates an example gas lift valve;

[0010] Figure 3 illustrates an example of a gas lift valve according to the present disclosure; and

[0011] Figure 4 illustrates the gas lift valve of Figure 3, showing a flow path through the valve.

DETAILED DESCRIPTION

[0012] In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims. [0013] As used herein, the terms“connect”,“connection”,“connected”,“in connection with”, and“connecting” are used to mean“in direct connection with” or“in connection with via one or more elements”; and the term“set” is used to mean“one element” or“more than one element”. Further, the terms“couple”,“coupling”,“coupled”,“coupled together”, and“coupled with” are used to mean“directly coupled together” or“coupled together via one or more elements”. As used herein, the terms "up" and "down"; "upper" and "lower"; "top" and "bottom"; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point at the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.

[0014] Figure 1 illustrates a downhole portion of an example gas lift system 140. The gas lift system 140 includes a compressor located at the well surface. In use, the compressor pumps gas down the annulus between the casing 102 and the tubing 104, as indicated by arrow 142. The gas is then released into the tubing 104 via one or more gas valves 144 that are strategically placed throughout the tubing 104. The gas lessens the hydrostatic weight of the fluid in the tubing 104, allowing the reservoir pressure to lift the fluid to the surface, as indicated by arrow 146.

[0015] Figure 2 illustrates an example of currently available valves 144 that may be used in a gas lift system 140. As shown, the valve 144 includes a check bushing 152, a check dart 154, and a spring (positioned at location 156) disposed in an outer housing 150. The check dart 154 has a hemispherical head 158 and a stem 160 extending away from the head 158. The spring can be disposed about the stem 160. In a closed position, the hemispherical head 158 of the check dart 154 seals against the check bushing 152. The spring can bias the check dart 154 toward the closed position when no pressure is applied to the valve 144. When pressure is applied, e.g., by gas flow along direction 142, the spring is compressed and the check dart 154 moves away from the check bushing 152, thereby opening the valve 144.

[0016] An example of a valve 244 according to the present disclosure is shown in Figure 3. The valve 244 can be used in a gas lift system 140 and/or other types of artificial lift or other systems. As shown, the valve 244 includes a seat 252, a ball 258, a stem 260, and a spring 256. In the illustrated configuration, the ball 258 is separate from the stem 260. The ball 258 and seat 252 can be made of or include different metals and/or combinations of metals. The spring 256 at least partially surrounds the stem 260.

[0017] The stem 260 has a ball support portion 262 and a stem portion 264. A first end of the ball support portion 262 is configured to contact the ball 258. The first end of the ball support portion 262 can have a curvature or shape selected to correspond to the curvature of the ball 258. The stem portion 264 extends from a second end of the ball support portion 262 opposite the first end. The ball support portion 262 has a lumen therethrough extending from the first end to the second end. An inner surface of the ball support portion 262, which defines the lumen, can be angled relative to a longitudinal axis of the valve 244 as indicated by angle Q in Figure 4. Angle Q can be in the range of about 0° to about 45°. As shown, the inner surface can be angled such that the lumen has a greater diameter at the first end than the second end. The angled inner surface of the ball support portion 262 can help prevent washout and/or provide a directed flow path when the valve 244 is open.

[0018] In a closed position, the ball 258 seals against the seat 252. The seat 252 can be generally cylindrical. A sealing surface of the seat 252 configured to contact and seal with the ball 258 can have a lap or bevel having a contour that matches or corresponds to the curvature of the ball 258. The valve 244 can close when pressure in the tubing 104 exceeds pressure in the casing 102 outside the tubing 104. The spring 256 can bias the stem 260 against the ball 258 and the ball 258 against the seat 252 when no pressure is applied to the valve 244. When pressure is applied, e.g., by gas flow along direction 142, the spring 256 is compressed and the stem 260 and ball 258 move away from the seat 252, thereby opening the valve 244. When the valve 244 is open, fluid can flow through the valve 244 along a flow path as indicated by arrows 270 in Figure 4. The angled inner surface of the ball support portion 262 of the stem 260 can help direct flow through the stem 260 and can help prevent or inhibit washout.

[0019] As the ball 258 can freely rotate or pivot relative to the seat 252 and/or steam 260, the separate, fully spherical ball 258 advantageously provides multiple sealing surfaces for the ball 258 with the seat 252. Providing multiple sealing surfaces can advantageously improve the operating life of the valve 244.

[0020] In some configurations, the valve 244 is designed to withstand operating loads up to around 2500 psi. In some configurations, the valve 244 is designed to withstand loads up to around 10 ksi. [0021] Language of degree used herein, such as the terms“approximately,”“about,” “generally,” and“substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms“approximately,”“about,”“generally,” and“substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and/or within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms“generally parallel” and“substantially parallel” or “generally perpendicular” and “substantially perpendicular” refer to a value, amount, or characteristic that departs from exactly parallel or perpendicular, respectively, by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

[0022] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments described may be made and still fall within the scope of the disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosure. Thus, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above.