Patent Application
20070284109
These drawings illustrate certain aspects of some of the embodiments of the present invention, and should not be used to limit or define the invention.
The present invention relates to methods and devices for treating multiple interval well bores and more particularly, the use of an isolation assembly to provide zonal isolation to allow selected treatment of productive or previously producing intervals in a multiple interval well bore.
The methods and devices of the present invention may allow for reestablishing zonal isolation of producing intervals, bypassed, or non-producing intervals, or previously producing intervals in multiple interval well bores through the use of an isolation assembly. In certain embodiments, isolation assemblies of the present invention may comprise a liner and a plurality of swellable packers, the swellable packers being disposed about the liner at selected spacings.
To facilitate a better understanding of the present invention, the following examples of certain embodiments are given. In no way should the following examples be read to limit, or define, the scope of the invention.
In particular,
In certain embodiments, liner 110 may be installed permanently in a well bore, in which case, liner 110 may be made of any material compatible with the anticipated downhole conditions in which liner 110 is intended to be used. In other embodiments, liner 110 may be temporary and may be made of any drillable or degradable material. Suitable liner materials include, but are not limited to, metals known in the art (e.g. aluminum, cast iron), various alloys known in the art (e.g. stainless steel), composite materials, degradable materials, or any combination thereof. The terms “degradable,” “degrade,” “degradation,” and the like, as used herein, refer to degradation, which may be the result of, inter alia, a chemical or thermal reaction or a reaction induced by radiation. Degradable materials include, but are not limited to dissolvable materials, materials that deform or melt upon heating such as thermoplastic materials, hydralytically degradable materials, materials degradable by exposure to radiation, materials reactive to acidic fluids, or any combination thereof. Further examples of suitable degradable materials are disclosed in U.S. Pat. No. 7,036,587, which is herein incorporated by reference in full.
Swellable packers 120 may be any elastomeric sleeve, ring, or band suitable for creating a fluid tight seal between liner 110 and an outer tubing, casing, or well bore in which liner 110 is disposed. Suitable swellable packers include, but are not limited, to the swellable packers disclosed in U.S. Patent US 2004/0020662, which is herein incorporated by reference in full.
It is recognized that each of the swellable packers 120 may be made of different materials, shapes, and sizes. That is, nothing herein should be construed to require that all of the swellable packers 120 be of the identical material, shape, or size. In certain embodiments, each of the swellable packers 120 may be individually designed for the conditions anticipated at each selected interval, taking into account the expected temperatures and pressures for example. Suitable swellable materials include ethylene-propylene-copolymer rubber, ethylene-propylene-diene terpolymer rubber, butyl rubber, halogenated butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene, styrene butadiene, ethylene propylene monomer rubber, natural rubber, ethylene propylene diene monomer rubber, hydragenized acrylonitrile-butadiene rubber, isoprene rubber, chloroprene rubber, and polynorbornene. In certain embodiments, only a portion of the swellable packer may comprise a swellable material.
As is evident from
The swelling of plurality of swellable packers 220 may cause an interference fit between liner 210 and casing string 205 so as to provide fluidic isolation between selected intervals along the length of the well bore. The fluidic isolation may provide zonal isolation between intervals that were previously not fluidly isolated from one another. In this way, integrity of a previously perforated casing may be reestablished. That is, the isolation assembly can reisolate intervals from one another as desired. By reestablishing the integrity of the well bore in this way, selected intervals may be treated as desired as described more fully below.
The swelling of the swellable packers may be initiated by allowing a reactive fluid, such as for example, a hydrocarbon to contact the swellable packer. In certain embodiments, the swelling of the swellable packers may be initiated by spotting the reactive fluid across the swellable packers with a suitable fluid. The reactive fluid may be placed in contact with the swellable material in a number of ways, the most common being placement of the reactive fluid into the wellbore prior to installing the liner. The selection of the reactive fluid depends on the composition of the swellable material as well as the well bore environment. Suitable reaction fluids include any hydrocarbon based fluids such as crude oil, natural gas, oil based solvents, diesel, condensate, aqueous fluids, gases, or any combination thereof. U.S. Patent Publication 2004/0020662 describes a hyrdocarbon swellable packer, and U.S. Pat. No. 4,137,970 describes a water swellable packer, both of which is hereby incorporated by reference. Norwegian Patent 20042134, which is hereby incorporated by reference, describes a swellable packer, which expands upon exposure to gas. The spotting of the swellable packers may occur before, after, or during the introduction of the isolation assembly into the well bore. In some cases, a reservoir fluid may be allowed to contact the swellable packers to initiate swelling of the swellable packers.
After fluidic isolation of selected intervals of the well bore has been achieved, fluidic connectivity may be established to selected intervals of the well bore. Any number of methods may be used to establish fluidic connectivity to a selected interval including, but not limited to, perforating the liner at selected intervals as desired.
Selected intervals may then be treated with a treatment fluid as desired. Selected intervals may include bypassed intervals sandwiched between previously producing intervals and thus packers should be positioned to isolate this interval even though the interval may not be open prior to the installation of liner 210. Further, packers may be positioned to isolate intervals that will no longer be produced such as intervals producing excessive water.
As used herein, the terms “treated,” “treatment,” “treating,” and the like refer to any subterranean operation that uses a fluid in conjunction with a desired function and/or for a desired purpose. The terms “treated,” “treatment,” “treating,” and the like as used herein, do not imply any particular action by the fluid or any particular component thereof. In certain embodiments, treating of a selected interval of the well bore may include any number of subterranean operations including, but not limited to, a conformance treatment, a consolidation treatment, a sand control treatment, a sealing treatment, or a stimulation treatment to the selected interval. Stimulation treatments may include, for example, fracturing treatments or acid stimulation treatments.
Liner 310 may be introduced into well bore 340 by any suitable method for disposing liner 310 into well bore 340 including, but not limited to, deploying liner 310 with jointed pipe or setting with coiled tubing. If used, any liner hanging device may be sheared so as to remove the coiled tubing or jointed pipe while leaving the previously producing intervals isolated. Optionally, liner 340 can include a bit and scraper run on the end of the liner for the purpose of removing restrictions in the casing while running liner 310. In certain embodiments, liner 310 may be set on the bottom of well bore 340 until swellable packers 320 have swollen to provide an interference fit or fluidic seal sufficient to hold liner 310 in place. Alternatively, liner 310 may set on bridge plug 355 correlated to depth, or any suitable casing restriction of known depth. Here, liner 305 is depicted as sitting on bridge plug 355, which may be set via a wireline. In this way, bridge plug 355 may serve as a correlation point upon which liner 310 is placed when it is run into the casing. In certain embodiments, liner 310 may a full string of pipe to the surface, effectively isolating the entire casing string 310, or in other embodiments, liner 310 may only isolate a longitudinal portion of casing string 310.
As previously described, once liner 310 is in place and the swellable packers have expanded to provide fluidic isolation between the intervals, selected intervals may be isolated and perforated as desired to allow treatment of the selected intervals. Any suitable isolation method may be used to isolate selected intervals of the liner including, but not limited to, a ball and baffle method, packers, nipple and slickline plugs, bridge plugs, sliding sleeves, particulate or proppant plugs, or any combination thereof.
Before treatment of selected intervals, liner 310 may be perforated to allow treating of one or more selected intervals. The term “perforated” as used herein means that the member or liner has holes or openings through it. The holes can have any shape, e.g. round, rectangular, slotted, etc. The term is not intended to limit the manner in which the holes are made, i.e. it does not require that they be made by perforating, or the arrangement of the holes.
Any suitable method of perforating liner 310 may be used to perforate liner 310 including but not limited to, conventional perforation such as through the use of perforation charges, preperforated liner, sliding sleeves or windows, frangible discs, rupture disc panels, panels made of a degradable material, soluble plugs, perforations formed via chemical cutting, or any combination thereof. In certain embodiments, a hydrajetting tool may be used to perforate the liner. In this way, fluidic connectivity may be reestablished to each selected interval as desired. Here, in
In certain embodiments, sliding sleeves 360 may comprise a fines mitigation device such that sliding sleeve 360 may function so as to include an open position, a closed position, and/or a position that allows for a fines mitigation device such as a sand screen or a gravel pack to reduce fines or proppant flowback through the aperture of sliding sleeve 360.
Certain embodiments may include umbilical line, wirelines, or tubes to the surface could be incorporated to provide for monitoring downhole sensors, electrically activated controls of subsurface equipment, for injecting chemicals, or any combination thereof. For example, in
Although liner 310 and swellable packers 320 are shown as providing isolation along casing string 305, it is expressly recognized that liner 310 and swellable packers 320 may provide isolation to an openhole without a casing string or to a gravel pack as desired. Thus, casing string 305 is not a required feature in all embodiments of the present invention. In other words, the depiction of casing string 305 in the figures is merely illustrative and should in no way require the presence of casing string 305 in all embodiments of the present invention.
As selected intervals are appropriately isolated and perforated using the isolation assembly, selected intervals may be treated as desired.
Examples of suitable treatments that may be apply to each selected interval include, but are not limited to, stimulation treatments (e.g. a fracturing treatment or an acid stimulation treatment), conformance treatments, sand control treatments, consolidating treatments, sealing treatments, or any combination thereof. Additionally, whereas these treating steps are often performed as to previously treated intervals, it is expressly recognized that previously bypassed intervals may be treated in a similar manner.
Once attachment 575 is sheared or otherwise disconnected, hydrajetting tool 585 may be lowered to a well bore interval to be treated, in this case, first well bore interval 591 as illustrated in
After removal of the excess proppant, hydrajetting tool 585 may be used to perforate casing string 505 and initiate or enhance perforations into second well bore interval 592 as illustrated in
As a final step in the process the tubing may be lowered while reverse circulating to remove the proppant plug diversion and allow production from the newly perforated and stimulated intervals.
Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.
