Wells – Processes – Repairing object in well
Reexamination Certificate
2001-11-21
2004-03-02
Neuder, William (Department: 3672)
Wells
Processes
Repairing object in well
C166S278000, C166S207000
Reexamination Certificate
active
06698517
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods and apparatus for use in a wellbore; more particularly the invention relates to methods and apparatus for expanding tubulars in a wellbore and specific applications for the expanded tubulars.
2. Background of the Related Art
The drilling, completion and servicing of hydrocarbon wells requires the use of strings of tubulars of various sizes in a wellbore in order to transport tools, provide a path for drilling and production fluids and to line the wellbore in order to isolate oil bearing formations and provide support to the wellbore. For example, a borehole drilled in the earth is typically lined with casing which is inserted into the well and then cemented in place. As the well is drilled to a greater depth, smaller diameter strings of casing are lowered into the wellbore and attached to the bottom of the previous string of casing. Tubulars of an ever-decreasing diameter are placed into a wellbore in a sequential order, with each subsequent string necessarily being smaller than the one before it. This process of casing and cementing is commonly referred to as “completing” the well. In each instance, a sufficient amount of space must exist in an annular area formed between the tubulars in order to facilitate the fixing, hanging and/or sealing of one tubular from another or the passage of cement or other fluid through the annulus. Typically, when one tubular is hung in a wellbore, a slip assembly is utilized between the outside of the smaller tubular and the inner surface of the larger tubular therearound. One such assembly includes moveable portions, which are driven up cone-shaped members to affix the smaller tubular to the larger tubular in a wedging relationship.
Many of the above drilling and completion methods are also applicable for water wells. Typically, water wells are shallower than hydrocarbon producing wells, encounter lower formation pressures, and are budgeted for drilled and completed at costs significantly less than hydrocarbon producing wells.
Increasingly, lateral wellbores are created in wells to more fully or effectively access hydrocarbon bearing formations. Lateral wellbores are formed off of a vertical wellbore and are directed outwards through the use of a diverter, like a whipstock. After the lateral wellbores are formed, they are typically lined with a tubular creating a junction between the tubulars lining the vertical and lateral wellbores. The junction must be sealed to maintain an independent flow path in and around the wellbores. While prior art technologies have effectively provided means for forming and lining the lateral wellbore, operational effective and cost effective apparatus and methods for completing these wellbores are scarce or, in some situations, nonexistent. Conceptually, lateral water well boreholes can be drilled and completed, but costs are usually out of a normal budget range designated for typical water wells.
Multiple vertical and/or lateral wellbores are typically drilled into a hydrocarbon producing formation in a producing oil or gas “field”. Early in the life of the field, fluids are typically produced from all wells. The produced fluid is typically a combination of hydrocarbon and water. As the field matures, the fraction of water in the produced fluid (typically referred to as the “water cut”) increases as the level of the water-hydrocarbon interface within the formation increases, and internal formation pressures decrease. Eventually, it is not commercially feasible to produce high water cut wells, even though other wells within the field are producing fluids with commercially acceptable water cuts. In many cases, high water cut wells are converted from producing wells to “injection” wells. Another approach is to drill additional wells specifically for injection wells. Since these wells do not produce hydrocarbons, cost of drilling and especially cost of completion is a prime economic consideration. A variety of fluids, or combinations of fluids, are injected into the producing formation through injection wells. This injected fluid sweeps through the permeable producing formation to drive remaining hydrocarbons toward the wellbores of the field's producing wells. Injected fluids can comprise water, gas, hydrocarbons, surfactants, and a variety of combinations and injection sequences of these and other fluids. This process is broadly referred to as “enchanced” recovery.
In producing wells, whether hydrocarbon or water, it is highly desirable to control entry of particulate mater, such as sand, into tubulars within the producing wellbore. Particulates are typically filtered from produced fluids using a variety of screens, slotted liners and other tubular filtering means. These filtering means, which are typically set in other tubulars but which can also be set in uncased or “open” well boreholes, are known in the art. Conversely, in enhanced recovery injection wells, it is highly desirable to control entry of particulate mater into the formation since particulates tend to clog formation pore space and pore throats connecting the pore space thereby reducing formation permeability. A reduction in permeability decreases the efficiency of the enhanced recovery operation. Prior art teaches the use of various screens, slotted liners, gravel packs and the like to control movement of particulates in a dynamic wellbore fluid flow. All of these prior art methods result in operational and economic disadvantages as will be discussed in subsequent sections of this disclosure.
Economics also play an important role in the completion of hydrocarbon and water wells. As mentioned previously, formations penetrated by a borehole are hydraulically sealed from each other and from the borehole by cement, which is pumped into the casing-borehole annulus. Any means that can reduce the volume of this annulus reduces the required amount of cement which, in turn, reduces the cost of well completion. The cost of completion is further reduced if a hydraulic seal can be obtained directly between the outer surface of casing and the borehole wall, thereby eliminating the need for cementing. Gravel packs have been used to control inclusion of particulates in injection or water wells, especially when these wells are drilled into unconsolidated formations. Gravel packs are expensive and add significantly to the completion cost of the well. Sand screens have been used to control the flow of particulates, but are prone to collapse, especially when the pressure differential across the sand screen is directed alternately from borehole to formation and then from formation to borehole, as the case in “huff and puff” operations known in the art.
There is a need for apparatus and methods to quickly and easily position tubular filtering means in targeted formations within vertical and lateral wellbores. There is also a need for apparatus and methods to quickly and easily expand a tubular in a wellbore to a given diameter. There is a further need for apparatus and methods which position and expand tubular filters in boreholes to filter particulate material from fluid flowing between a formation of interest and the well borehole. There is yet a further need for methods and apparatus for expanding tubulars in a wellbore, which permit one tubular to be expanded into an opening formed in another tubular to create a filter for fluids flowing through the opening. There a further need for methods and apparatus permitting a tubular to be expanded within a well borehole thereby reducing the volume of an annulus formed by the outer surface of the tubular and the borehole wall thereby reducing cement volume required in completing the well. There is still a further need for methods and apparatus permitting a tubular to be expanded into an opening in a larger tubular or well borehole, wherein the expanded tubular will withstand pressures created by fluid injected into the larger tubular or borehole, through the expanded tubular, and into an earth formation penetrated by the boreh
Hopmann Mark
Simpson Neil A.A.
Moser, Patterson & Sheridan L.L.P.
Neuder William
Weatherford / Lamb, Inc.
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