Method and Apparatus for Multi-Zone Stimulation

Abstract

Methods of treating a well bore in a single trip are provided. A tubing string may be inserted into a subterranean formation having a well bore, where the tubing string has a locking device on an end. A workover tool may be positioned in a first zone of the subterranean formation, where the workover tool engages the locking device. One or more perforations may be created or enhanced in a first zone of a subterranean formation using the workover tool, and the tubing string may be positioned in a second zone of the subterranean formation. A fracturing fluid may be introduced into the first zone of the subterranean formation at a rate and pressure sufficient to create or enhance one or more fractures in the subterranean formation. The first zone of the subterranean formation may be isolated from the second zone of the subterranean formation and one or more perforations in the second zone of the subterranean formation may be created or enhanced using the workover tool.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to stimulation of subterranean formations, and more particularly, to a novel apparatus and methods of multi-zone stimulation of subterranean formations, in particular, at least in some embodiments, in high temperature, high pressure wells.[0002]Treatment fluids may be used in a variety of subterranean treatments, including, but not limited to, stimulation treatments and sand control treatments. As used herein, the term “treatment,” or “treating,” refers to any subterranean operation that uses a fluid in conjunction with a desired function and / or for a desired purpose. The term “treatment,” or “treating,” does not imply any particular action by the fluid or any particular component thereof.[0003]One common production stimulation operation that employs a treatment fluid is hydraulic fracturing. Hydraulic fracturing operations generally involve pumping a treatment fluid (e.g., a fracturing fluid) into a well bore that penet...

AI Technical Summary

Benefits of technology

[0032]In an embodiment, the apparatus of the present disclosure may comprise a downhole tool system disposed on tubing string with an interchangeable set of tools for performing treatment operations.

[0033]In one embodiment, the present invention provides a downhole tool system comprising: a profile nipple disposed on a tubing string, wherein the profile nipple comprises a locking receptacle; and a tool assembly, wherein the tool assembly has a locking lug, wherein the locking lug engages the locking lug receptacle, wherein the tool assembly may be passed through the tubing string to engage the profile nipple. In some embodiments, the tool assembly comprises at least one tool selected from the group consisting of: a perforating gun, and a washing tool. In some embodiments, the tool comprises a hydrajetting tool. In some embodiments, the hydrajetting tool comprises dual check valves. In some embodiments, the tool assembly may be engaged and retrieved by a wireline, a slickline, or coiled tubing. These embodiments are discussed below.

[0034]In an embodiment, a locking device may be disposed on the end of a tubing string within a subterranean formation. A variety of tools utilizing locking lugs for engaging the locking device may be used to treat the formation by passing the tools through the interior of the tubing string until they lockingly engage the locking device on the end of the tubing string. In an embodiment, a hydraulic workover unit may be utilized to allow the treatment operations to proceed while the well is under pressure. The downhole tool system and the various tools that may be used are described in more detail below.

[0035]In an embodiment, the apparatus of the present disclosure may be used in a well bore disposed in a subterranean formation. In an embodiment shown in FIG. 1, a well bore 10 may be created so as to extend into a subterranean formation 22. A casing 12 may be disposed within the well bore and cement 14 may be introduced between the casing 12 and the well bore 10 walls in order to hold the casing 12 in place and prevent the migration of fluids between the casing 12 and the well bore 10 walls. A tubing string 16 may be disposed within the casing 12. In an embodiment, the tubing string 16 may be jointed tubing, coiled tubing, or any other type of tubing suitable for use in a subterranean well environment. Suitable types of tubing and an appropriate choice of tubing diameter and thickness may be known to one skilled in the art, considering factors such as well depth, pressure, temperature, chemical environment, and suitability for its intended use. In an embodiment, a hydraulic workover unit 20 may be disposed at or near the top of the tubing string 16, the casing 12, or both. The hydraulic workover unit 20 may allow for tubing and o

Problems solved by technology

Certain subterranean formations, however, have properties that may make stimulation operations difficult, time consuming, and/or expensive.

For example, high-temperature high-pressure (“HTHP”) wells may present operating difficulties.

For these deep wells, a single trip with

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