PRESSURE SENSITIVE CENTRALIZER
FIELD OF THE INVENTION The present invention relates to systems and methods for controlling the pressure in the wells.
BACKGROUND AND SUMMARY OF THE INVENTION
Background: Pressure in the Well. The accumulation of annular pressure inside wells has been recognized in the oil and gas industry for many years as a serious problem. Fluids blocked in a well or annular space in a well will expand with a corresponding increase in temperature leading to an increase in volume and an increase in the force they exert on the surrounding area. It has been known that this pressure is a significant factor in the failure of subsea wells, including well A-2 of the Marlin development program of British Petroleum 1999 in the deepwater program of the Gulf of Mexico. A relevant article is Practical and Successful Prevention of Annular Pressure Buildup on the Marlin Project, SPE International 77473, 2002, Richard F. Vargo, Jr., et al, and which is incorporated herein by reference in its entirety.
Background: Annular Pressure Accumulation The annular pressure accumulation ("APB") is the pressure generated by the thermal expansion of blocked fluids when heated. When fluids in a well are heated and expanded in a closed system, the expansion produces high induced pressures. Most locations on land and on many coasts can purge this pressure through equipment of accessible wellheads on the surface. At submarine sites, the primary ring between the pipe and the production casing may be the only accessible ring. Consequently, it may not be possible to purge the other rings. Therefore, when there is a risk of underwater APB, well designers should seriously consider appropriate mitigation as part of the fundamental well design. Oil recovery operations on the coasts are moving more and more towards deeper waters and more remote places. Satellite wells are often completed at the bottom of the sea and linked to remote platforms or other facilities through extensive subsea pipelines. Some of these pipes extend through the water thousands of feet deep, where the temperature of the water near the bottom of the sea is in the range of about 4.4 ° C (40 ° F). The
Hydrocarbon fluids, usually produced along with some water, reach the bottom of the sea at higher temperatures, characteristic of the depths of thousands of feet below the bottom of the sea. For a well to experience APB, two conditions must generally be present. First, there may be a sealed region, typically a ring, where pressure can accumulate. Second, an increase in temperature is generally associated with the increase in pressure. Background: APB Mitigation Techniques General There are several solutions that have been presented in the past literature. These solutions include: o cement deficit (leave some cement from a previous emptying); or provide a leak path or purge hole; or compressible, syntactic foam coating; or compressible fluids placed in the blocked ring to absorb volume; or heavy-weight and / or high-performance casing (design of casing
improved); I cemented full height (filled with cement from the entire ring.) Those can be incorporated into drilling plans to mitigate the risks of APB in some circumstances.A good starting point is to try to ensure that the ring is not blocked. possible, a cement deficit is usually designed, which assumes that the cement heights will be below the footing of the previous casing and that the condition of the blocked ring may not occur, however, the cement may still be channeled Due to the poor displacement of the mud, these displacement problems are caused by a poor eccentricity of the casing or by a poor erosion capacity of the well fluids during the primary cementing operation., the drop of barite after perforation can produce a blocking condition. A blocking condition can occur either by cementitious materials or due to sedimentation of heavy mud materials. In many cases, subsea wells are drilled and subsequently completed due to the time required for other components of the production infrastructure, ie pipelines, etc. Over time, the solids in the mud can
sediment, creating a blocking condition. Later when the well is completed, the locked ring condition and the resulting APB may not be displayed until a failure occurs. A second APB prevention technique consists of attaching a compressible syntactic foam liner to the casing. The syntactic foam contains small hollow glass spheres filled with air at atmospheric pressure. When the APB reaches a certain level, the hollow spheres collapse. This collapse results in a corresponding increase in the volume available to thereby decrease the pressure. The data demonstrates the volume required for an effective solution of about 2% to about 8% of the ring volume. Another form of prevention of APB is the use of compressible fluids in the blocked ring to absorb the volume increases when heating occurs. A final way to mitigate APB is by using improved casing products. A coating APB with greater capacity can accommodate a greater degree of pressure buildup without damaging effects to the casing or the well. Extensive work has been applied here that also involves properties
of improved probabilistic performance of the target casing pipes. Pressure Sensitive Centralizer System The present inventions describe methods and systems for controlling pressure and volume variations in orifices. For example, in one embodiment a novel centralizer comprising a centralizing structure with at least one sealed hollow structural component where a rupture disk is capable of breaking in response to sufficient pressure. The present invention further teaches a method for effecting a volumetric change in response to excess pressure within a well comprising at least one hollow structural component. The novel systems and methods herein may be used to avoid loss of production due to damage to the well or the need to restrict the flow of hydrocarbon in an effort to keep the production temperature below dangerous levels. Another advantage of the described centralizer is the ability to be connected to the drilling and production equipment in a number of ways. The centralizer can be equipped with a rupture component that is part of the centralizer, screwed into the bottom of the centralizer by means of threads inside the centralizer.
centralizer, or connected by some other means. It should, of course, be understood that the description is only illustrative and that various modifications and changes in the described structure can be made without departing from the spirit of the invention.
BRIEF DESCRIPTION OF THE FIGURES The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification thereof as a reference, where: FIGURES la and lb show a preferred embodiment of a centralizer. FIGURE 2 shows a preferred embodiment of a centralizer. FIGURE 3 shows a preferred embodiment of a centralizer configuration using an "articulated" array within a borehole. FIGURE 4 shows a production system using a centralizer with hollow rupture components. FIGURE 5 shows a preferred embodiment of a centralizer with multiple break components. FIGURE 6 shows a preferred embodiment of a pressure sensitive system with a centralizer and
Multiple rupture components. FIGURE 7 shows a preferred embodiment of a hollow rupture component. FIGURE 8 shows a preferred embodiment of a centralizer where an empty rupture component is attached to the main centralizer chamber.
DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The numerous innovative teachings of the present application will be described with particular reference to the currently preferred mode (by way of example, and without limitation). The described inventions take advantage of a new way in which the pressure in perforations can be controlled. In one embodiment, a centralizer is combined with a rupture disk to allow the release of excess pressure from a well. The hollow components in this embodiment contain a bursting disc or rupture disc, which are selected to rupture at a predetermined pressure according to what is required by the well hydrostatic pressure and other factors. The internal and external diameters of the centralizer preferably provide effective centering of the casing in the bore or outer casing. The number of
Struts or braces and bursting or bursting discs can be adjusted in such a way as to meet specific pressure and volume needs of a specific project. For example, in one embodiment, there may be six struts or braces with a rupture disc in each strut or brace. In another modality, there may be four struts or braces with two rupture discs in each strut. In another embodiment, a centralizer is combined with a purge valve to allow the release of excess well pressure. The hollow components in this embodiment contain a purge valve that is selected to open at a predetermined pressure as required by the well hydrostatic pressure and other factors. A purge valve is sometimes that which is not destroyed when it is opened. A hollow structural component is a rigid prefabricated structure capable of allowing a volumetric expansion. In yet another embodiment, the rupture disk is sealed in such a manner that it "explodes" at a predetermined pressure to facilitate the production of hydrocarbons. This invention avoids the loss of production due to damage to the well due to excess pressure and the need to restrict the flow of hydrocarbons in an effort to maintain the temperature
of production below dangerous levels. In a further embodiment, the centralizer may also comprise at least one centralization structure and includes at least one breakable structural component that can respond to increasing pressure arising. The breakable structural component may collapse, burst, or rupture to provide a change in volume in response to excess pressure. An advantage of this mode is that the pressures accumulated within perforations can be alleviated. Another advantage is that the volume in a well can be controlled in such a way that production within a well is optimized. FIGURE shows a preferred embodiment of the centralizing unit 100. This is a side view of the centralizing unit itself, which does not show the casing which, once the centralizer 100 has been installed, will normally pass through. of the axial central cavity 130. The struts 110 of the centralizer 100, in this embodiment, run parallel with the well 140. One or more rupture discs (not shown in this figure) are located on one or more of the struts. These struts are hollow structural components. In this mode, the centralizer is made of stainless steel. It can be used in your
Place carbon steel, chrome-moli, or titanium or other materials. FIGURE lb shows a preferred embodiment of one of the struts 110 of the centralizing unit 100. This is a profile formed of tubular steel, having a hollow center (not visible in this figure). A rupture disk 112 locks the single opening towards the hollow center of the strut 110. (Preferably a hole is drilled and bifurcated in the strut 110). In this embodiment, the end of the strut 110 is joined to a circumferential element 120 by means of welding 114, which also serves to close the gap inside the strut 110. In this embodiment, the centralizer is made of stainless steel. It can be used in its place carbon steel, chrome-moli, or titanium or other materials. FIGURE 2 shows a preferred embodiment sample of the pressure sensitive system using the centralizing unit 200. This is a side view of the centralizing unit itself, which does not show the casing which, once it has been installed. centralizer 200, would normally pass through axial central cavity 230. The struts 210 of the centralizer, in this embodiment, run parallel with well 240. One or more rupture discs (not shown).
in this figure) are located on one or more of the props. In this mode, the centralizer is made of stainless steel. Can be used in its place carbon steel, chrome-moli, or titanium or other materials. In this embodiment, a centralizer is attached to the threads using the rupture component 260. FIGURE 3 shows a preferred embodiment of the centralizing unit 300. This is a side view of the centralizing unit itself, which does not show the pipeline. of coating, in which, once the centralizer 300 has been installed, it would normally pass through the axial central cavity 330. The struts 310 of the centralizer, in this mode, run parallel with the well 340. One or more disks of rupture (not shown in this figure) are located on one or more of the struts. In this mode, the centralizer is made of stainless steel, but of course carbon steel or chrome-moli, or titanium or other materials can be used. In this embodiment, the centralizer is attached to a rupture component using hinges or joints 360. FIGURE 4 shows a production system 400 using a centralizer 410 with the hollow rupture component 420 surrounded by the well 440. A casing used to move the desired hydrocarbons or other material is illustrated by 470 in which the
Hydrocarbons or other desired products can be moved from the well to some type of recovery equipment located at 480. FIGURE 5 shows a centralizer system 500 with multiple rupture components 510, 520, and 530. The rupture components 510, 520 and 530 are attached to the centralizing component 540. The centralizing component 540 is joined to the hollow struts 550. The breaking components 510, 520 and 530 can be of different pressure sizes and sensitivities. FIGURE 6 shows a combination of casing pipe with centralizer and hollow rupture components. A hollow component 600 contains multiple rupture components 610 and 630. Within the walls of the hollow components 640 an orifice is drilled and the first rupture component is placed in 610. A second rupture component 630 is held in place by elements within the hollow component at 620. FIGURE 7 shows a hollow rupture component 700. A ring 710 separates the sealed discoidal components 720 and 730. The hinges 740 can attach the hollow rupture component to the centralizing system. The hollow rupture component can also be attached by means of the threads found at 750. FIGURE 8 shows a centralizing system
800 with a rupture component 810 located at either end of the centralizing system 850 and 860. The additional breaking components can be placed at 820, 830 and 840. The struts supporting the structural centralizer 850 are placed along the hole. In one example, the innovations herein are enabled as a method to avoid excess pressure in a borehole, comprising the actions of opening a hollow structural component sealed within the borehole to relieve or purge the excess pressure thereby of the volumetric expansion towards a hollow structural component that is claimed. In another example, the innovations herein are provided as a method of avoiding excess pressure to a borehole, comprising the options of relieving pressure within a bore by collapsing at least part of a hollow structural component and creating a volumetric expansion. as is also claimed. In another example, the innovations herein are provided as a method of relieving excessive pressure in a bore comprising inserting a hollow structural component into a bore and increasing the pressure within the bore and relieve
the excess pressure in the perforation creating the available volume in the perforation through a change of the hollow structural component as it is also claimed. Nothing in the description of the present application should be read as implying any particular element, step or function as an essential element to be included in the scope of the claims: THE SCOPE OF THE PATENTED OBJECT MATTER IS DEFINED ONLY BY THE PROVIDED CLAIMS.
Modifications and Variations As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and vary over a tremendous range of applications, and consequently the scope of the patented subject matter is not limited by any exemplary teaching. specific given. The pressure sensitive system can be made from any number of materials, including, but not limited to, stainless steel, carbon steel, titanium, or any number of other materials. In addition, the number of struts, rupture discs and purge or relief valves may vary from mode to mode. The chain down the hole can be in different forms, including, but not limited to, a chain of
tubular perforation or coating chain. A variation includes replacing rupture discs with purge or relief valves or other structures that allow the volume locked up opens at a predetermined pressure. A particular advantage of the hollow chamber (at atmospheric or pressurized pressure) to be transported down a perforation with a rupture disc is that it can be designed to break at a predetermined stage of operations. Note that the pressure required for the rupture will correspond directly to the internal design of the centralizer and the pressure with which it is sealed. The hollow structural component can be physically part of the centralizer, or be connected to it, or it may be separate from the centralizer itself. Nothing in the description of the present application should be read as implying any particular element, step or function as an essential element to be included in the scope of the claims: THE SCOPE OF THE PATENTED OBJECT MATTER IS DEFINED ONLY BY THE PROVIDED CLAIMS.