Patent Application
20140048269
1. Field of the Invention
This invention relates generally to the injection of fluid into oil and gas wells. In particular, this invention relates to the delivery of fluid to a well through a production tree mounted on the well, by injecting the fluid through a mandrel in the production tree.
2. Brief Description of Related Art
The production of oil and gas from some wells may lead to contact between compounds in hydrocarbon rock formations, and those present in oilfield process fluids, such as, for example, seawater. This contact may lead to the formation of “scale”, or salts that clog the formation and inhibit hydrocarbons in the formation from entering the well. Accordingly, scale inhibitors are sometimes introduced into a well to control or prevent scale deposition. In some cases, scale inhibitors may be combined with fracture treatments, whose purpose is to crack the formation and facilitate the release of hydrocarbons into the well.
The fluids used to inhibit scaling and to cause fracturing (hereinafter referred to as scale squeeze fluid, or just fluid) are typically introduced to the well through the choke of a production tree attached to the well. From the choke, the fluid may enter the production bore of the tree, the production tubing of the well, and ultimately the formation in need of de-scaling/fracturing. However, there are problems associated with introducing the fluid through a choke on the production tree.
For example, when the fluid is introduced through the choke, the capacity of the choke to carry out other functions, such as managing pressure within the well, may be reduced or eliminated. In addition, introduction of the fluid through the choke requires a special choke insert adapted for interface with a landing module that delivers the fluid. Retrofitting the choke to accept the special choke insert can be a complicated process that requires multiple steps. The steps include running guide posts, running a remote component replacement (RCR) tool to remove any old choke inserts, running an RCR tool to insert the special choke insert, running a scale squeeze module, injecting the scale squeeze fluid, recovering the module, and capping the scale squeeze adapter.
Accordingly, there is a need for a fluid injection system and process that overcomes the disadvantages of the prior art.
Disclosed herein is a fluid injection system in which the fluid is injected not into the choke of a production tree, but directly into a mandrel at the top of the tree. A pathway is provided within the production tree for the fluid to travel from the mandrel to the production bore within the tree, and then into the production tubing of a well.
Also disclosed herein is a process for injecting fluid into a well by injecting the fluid. directly into the mandrel at a production tree mounted to the well. The process includes attaching a fluid supply line to the mandrel of the production tree with a connector. In one embodiment, all of the components necessary to connect the fluid supply line to the mandrel, and to control the flow of fluid through the fluid supply line, are included in one package, so that installation of the fluid injection system requires only one trip to deliver the package and install the components of the system at the production tree.
The present invention will be better understood on reading the following detailed description of nonlimiting embodiments thereof, and on examining the accompanying drawings, in which:
The system and method of the present disclosure will now be described more fully with reference to the accompanying drawings, in which example embodiments are shown, and wherein like reference numerals refer to like elements throughout. The subject matter of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It is to be understood that the subject of the present disclosure is not limited to the exact details or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there are disclosed illustrative embodiments of the subject disclosure and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
Referring to
The crossover port 12 provides a pathway from the annulus wing block to a production wing block through a crossover valve 16. The crossover port 12 intersects the production bore 4 at a location between a production wing valve 18 and a production master valve 20. The production wing valve 18 separates the crossover port 12 from the portion of the production bore upstream of the production wing valve 18. Each of the valves disclosed herein may be controlled by known methods. For example, the valves may be hydraulically controlled. Alternatively, the valves may be mechanically or electrically controlled.
One advantage to the production tree configuration shown in
As shown in
One advantage to the fluid injection system shown in
With the structure of the production tree 2 and fluid injection system as shown in
Another embodiment of the invention includes a method of injecting fluid into the production tubing of a well by introducing the fluid through a mandrel at the top of a production tree. First, the production tree is positioned at the top of the well, so that the production bore of the tree is in fluid communication with the production tubing in the well. In one embodiment, the production tree is designed as described above in reference to
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. For example, in addition to the parts of the production tree specifically discussed above, other known tree components may be included in the tree. For example, the tree may include chokes, hydraulic or electric control tines for the valves, etc. Similarly, this system can be integrated with other deep water packages. Furthermore, it is to be understood that the above disclosed embodiments are merely illustrative of the principles and applications of the present invention. Accordingly, numerous modifications may be made to the illustrative embodiments and other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
