Untitled record

Multi-Point Chemical Injection System

Background of the invention

In many types of wells, different treatment applications are used to ultimately improve well productivity. Treatment applications often involve injecting fluids at desired locations along the wellbore. For example, chemicals may be injected into the surrounding reservoir in one or more areas of the well. Generally, a process pipe string is connected down the drill hole to the wellbore so that process fluids can be delivered to the desired position or positions.

Treating more than one well area can cause problems because of the need to deliver the process fluid to more than one location. In some applications, the process string can be released and moved to the next well zones, but installing and releasing the process string is difficult in many environments. In other applications, several separate control lines are extended from the surface with each control line directed to a single injection site. However, using multiple control lines requires multiple bypass ports through various system components, such as the wellhead and production pad (buffer). In other applications, a single control line is generally extended from the surface in order to inject a chemical into the production piping from a single point or location. However, injecting a chemical at multiple points into multiple tanks from a single control line extended from the surface can cause a volume of fluid to be injected into each area that is different from the others. The areas with the lowest tank pressure will acquire the largest volume of fluid, while the areas with the greatest tank pressure will acquire the smallest volume of fluid. A depleted area can capture all the fluid.

This defeats the purpose of injecting chemicals into the production steam. Therefore, it is desirable to have a chemical injection system that allows chemicals to be delivered at multiple points in multiple areas of uniform size, or in other desirable proportions, from a single control line extended from the surface.

General description of the invention

In general, the present disclosure provides a technique for injecting chemicals into a well. A multi-point chemical injection system is connected and deployed along a wellbore.

The multi-point chemical injection system is designed to deliver a chemical treatment along the wellbore to multiple injection zones, including injection into the pipe group as well as the annular space.

A single control line is extended from a surface position down through the wellbore to the multiple zones, and a single control line is used to deliver the treatment chemical to each zone.

Brief explanation of the drawings

Below certain embodiments of the invention will be described by reference to the attached figures, wherein similar reference numbers refer to similar elements, and:

Figure 1 is a schematic illustration of an example of an injection system for use in a well, according to one embodiment of the present invention;

Figure 2: An upper front view of an example of an injection system placed in a wellbore, according to one embodiment of the present invention;

Figure 3: A vertical projection of a most effective example of a valve system for injecting a chemical substance that can be used in an injection system to deliver a chemical treatment substance to an injection area, according to one embodiment of the present invention;

Figure 4: A view of both ends of the valve system for injecting a chemical shown in Figure 3, according to one embodiment of the present invention;

Figure 5: A cross-sectional view taken along line 5-5 shown in Figure 4, according to one embodiment of the present invention;

Figure 6: A cross-sectional view taken along line 6-6 shown in Figure 5, according to one embodiment of the present invention;

Figure 7: A vertical projection of an example of a downward valve system for chemical injection used at the lower end of the injection system to deliver a chemical treatment to the furthest down injection zone, according to one embodiment of the present invention;

Figure 8 is a cross-sectional view similar to that shown in Figure 5 but showing the inferior valvular system for injecting the chemical, according to one embodiment of the present invention; And

Figure 9 is a cross-sectional view similar to that shown in Figure 6 but showing the inferior valvular system for injecting the chemical, according to one embodiment of the present invention.

Detailed description

In the following description, many details are given to provide a good understanding of the present invention. However, those of ordinary skill in the art should realize that the present invention can be applied in practice without these details and that many changes or modifications can be made to the embodiments described.

In general, the present invention includes a system and method for well treatment operations involving the injection of chemicals at separate locations of the well. The system and method greatly simplify and improve the efficiency of the processing process. Generally, the technology uses a multipoint injection system (i.e., at least two) that delivers treatment chemicals to several areas of the well, such as production zones. The system can be used to deliver treatment chemicals to well areas on a regular basis or according to other desired ratios via a single control line extended from the surface.

According to one embodiment, the multipoint injection system includes a plurality of valve systems for injecting a chemical dispersed at desired locations along a wellbore. Valve systems for injecting chemicals are connected to a single control line extending from the surface, and a portion of the chemical treatment material is calibrated at the outlet of each valve system for injecting a chemical. For example, a portion of the reagents is calibrated at the outlet of a first valve injection system and the remaining reagents are passed to a next valve injection system. This process can be repeated for each successive zone until the treatment chemical is introduced into the desired number of well zones along the wellbore.

For example, each chemical valve injection system may include a valve mandrel with a housing containing a valve for metering a fluid positioned in an interstitial flow path, as described in more detail below. One or more throttle valves may be located in the interstitial flow path to allow the process chemical to pass while preventing backflow of tank fluids to the single control line. Fluid metering valves are used in chemical valve injection systems to deliver uniform amounts (or other desired amounts) of treatment chemicals to each production zone, other areas in the well, or at multiple points in a single production zone.

Furthermore, fluid metering valves can be used synergistically to compensate for variations in reservoir pressures at different well zones and to compensate for any pressure loss associated with restrictions and/or friction between the treatment chemical and the control line to ensure that a desired amount, e.g. a uniform amount, is delivered. of chemical to every area in the well. For example, if the reservoir pressure at a second well zone is greater than at a first well zone, the fluid metering valve in the first well zone creates a flow restriction that compensates for the higher pressure in the lower second well zone. This compensation allows uniform amounts of treatment chemicals to be delivered to each area of the well. The compensation process is considered an autonomous process capable of continuously adjusting the properties of the tank to ensure regular delivery of chemical treatment materials. In one embodiment, the fluid metering valves include variable position throttle valves designed to compensate for variations in tank pressures.

Referring generally to Figure 1, an example of a well system 20 that can be used to inject chemical treatment materials at desired locations in a well is shown as a schematic diagram. In this example, the well system 20 includes a multipoint chemical injection system 21 comprising at least two chemical valve systems 22 positioned at desired positions unique to the injection system in the well. For illustrative purposes, a well system 20 is illustrated that includes three independent valve systems for injecting a chemical 22; However, other numbers of chemical valve injection systems can be used depending on the number of well areas to be treated. The chemical treatment material is introduced into the system 20 and delivered to multiple chemical valve injection systems 22 via a single injection/control line 24. At each valve system 22, a portion of the chemical treatment material, as indicated by arrow 26, is injected into a surrounding well area 28, such as a production area. The remaining portion of the treatment chemical is passed to the next valve chemical injection system until the lowest valve chemical injection system is reached.

It should be noted that System 20 can be used in horizontal wells, where in this case the word "minimum" refers to the valve chemical injection system located at the farthest distance, often towards the front end of the horizontal wellbore. In this final example, the upper valve chemical injection systems are those located before the lower system and farthest at the leading end of the wellbore. Apart from this, the single control line 24 works in conjunction with the valve systems 22, a simplified system and method for directing controlled flows of the treatment chemical to several areas in the well. The design also enables the simultaneous injection of the chemical treatment agent into several areas in the well to be treated.

In Figure 2, a more preferable example of a 20 well system is shown according to one embodiment of the present invention. In this example, a multipoint injection system 21 is deployed in a wellbore 30 drilled in a subterranean formation that includes multiple well zones 28. The well treatment system 20 may also include a wellhead 32 located above the wellbore 30 at a shallow position 34.

In the example shown, the well system 20 includes a treatment chemical delivery system 36, such as a pumping system, designed to deliver a chemical treatment fluid downhole through the single control line 24. As shown, the single control line 24 can be routed through the wellhead 32 via a port Single-pass 38. Likewise, the single-pass control line 24 may be routed through an upper (isolating) grout 40, such as a production grout, through a single-pass port in the grout 42. Other isolation means 44 may be used, such as gaskets to isolate areas of the wellbore 30, such as Associated with each area of well 28. In some applications, the single control line 24 is also routed through these buffers 44 via single passthrough ports.

Chemical valve injection systems 22 are connected to a well tubing string 46 and deployed along the wellbore 30 at desired positions in the valve system. In some applications, the well tubing string 46 includes a tubing string that can be used to deliver production fluids, such as hydrocarbon-based fluids, up the wellbore to a surface position 34 of each well zone 28. Valve injection systems can be connected to a chemical 22 by sections of piping, production components, and other downhole equipment that space the valve injection systems to deliver the treatment chemical to desired areas in the well. It should be noted that a variety of completion components and other downhole equipment may be included in the well tubing series 46 and the well system as a whole 20 .

Referring generally to Figure 3, one embodiment of a valve system for injecting a chemical 22 is illustrated. In this example, the valve system 22 is an upper valve system of a type that can be used before the lower valve system. As shown, the valve chemical injection system 22 includes a valve mandrel 48 that includes a mandrel housing 50 that has a diagonally extending portion 52. As also shown in Figure 4, the mandrel housing 50 includes a primary passage path 54 that can be coupled to tubular segments, production components and/or other downhole equipment for drill pipe series 46. In some applications, the primary passage path 54 is used to direct a flow of producing fluids up the wellbore to a shallow position. In the illustrated embodiment, the diagonally extending portion 52 of the mandrel housing 50 is designed to accommodate the flow of chemical process materials directed down the wellbore through the single control line 24. As shown, the diagonally extending portion 52 also includes a cavity 56 that can be used to accommodate other types of equipment Which is placed or directed down the wellbore along the well pipe string 46.

As also shown in Figures 3 and 4, the single control line 24 may be coupled to a forward side of the valve chemical injection system 22 via a coupler 58. The coupler 58 extends from a longitudinal end ahead of the diagonally extending portion 52 in order to facilitate coupling of the valve system 22 to a line Single control 24. Likewise, a second coupler 60 is mounted on a dimension side of the diagonally extended portion 52 in order to facilitate coupling of the single control line 24 between the valved chemical injection system 22 shown and the next valved system located thereafter. For example, the couplings 58, 60 may include dry hydraulic mating couplings of the type used to make control line connections.

A portion of the treatment chemical is injected into the well area 28, eg to the wellbore and/or reservoir, surrounding the valve chemical injection system 22, and the remaining portion is passed to the next valve chemical injection system. An example of the components that can be used to provide injection and passing functions is shown in Figure 5. In the illustrated embodiment, the interstitial flow path 62 extends through the mandrel housing 50, specifically through the diagonally extending portion 52, to facilitate the injection of the treatment chemical into the area surrounding the valve chemical injection system 22. The single control line 24 is connected to the interstitial flow path 62 via a lead coupling 58 It delivers the treatment chemical to flow through the passage path 62 and is distributed to the surrounding well area 28 through a fluid metering valve 64, such as a Flosert-type fluid metering valve.

The fluid metering valve 64 controls the amount of fluid that is injected into the surrounding area. In one example, the fluid metering valve 64 includes a variable position throttle valve 66 that can efficiently restrict or throttle the amount of process chemical that can move along the interstitial flow path 62 to the surrounding area. As described in more detail below, the remaining portion of the processing chemical traverses the interstitial flow path 62 and is directed to the next valve chemical injection system 22 .

In the example shown in Figure 5, the coupling 58 is mounted on the diagonally extending portion 52 of the mandrel housing 50 via an adapter plug 68. The coupling 58 can be engaged via threaded threads with the adapter plug 68 via an area equipped with threaded threads 70 and leakage between it and the The adapter plug 68 is connected by one or more seals. Likewise, the adapter plug 68 can be engaged by threaded threads with the diagonally extending portion 52 within the interstitial flow path 62 through an area equipped with threaded threads 74. Leakage between the adapter plug 68 and the mandrel housing 50 is prevented by using one or more suitable seals 76, such as a sealing ring. However, it should be noted that a variety of coupling and sealing mechanisms other than the threaded engagements and seals shown can be used.

In the interstitial flow path 62, one or more non-return valves may be used to allow afterflow of the process chemical while preventing backflow of tank fluid from the surrounding environment. In the example shown, the valve chemical injection system 22 includes a pair of non-return valves 78 mounted on opposite sides of a dual-engagement adapter 80. As better illustrated in Figure 6, the interstitial flow path 62 is also in fluid communication with a bypass path My side 82. In this example, the bypass path 82 is coupled to the interstitial flow path 62 at a position between the adapter plug 68 and the non-return valves 78. The fluid metering valve 64 restricts the amount of treatment chemical being injected into the surrounding well area 28 and this causes the remaining portion of the treatment fluid to move In the bypass path 82 and exits the chemical injection system valve 22 via the coupling 60.

As with the coupling 58, the coupling 60 may be coupled to the mandrel housing 50 on either side of the diagonally extended portion 52. The coupling 60 may be coupled to the diagonally extended portion 62 via a suitable coupling mechanism, such as an engagement area with threaded threads 84 whereby the coupling engages 60 by means of threads along an inner surface of the bypass path 82. Leakage between the coupling 60 and the diagonally extending portion 52 may be prevented by using one or more suitable sealant fluids 86. A portion of the single control line 24 is used to couple the coupling 60 with the pre-coupling 58 of the following valve chemical injection system 22.

Depending on the specific downhole injection application, the bypass path 82 may also be connected to an emergency release system 88 so that the treatment chemical can be released into the surrounding well area in the event that fluid flow through the chemical injection system is obstructed by a valve 22. In this example, the system 88 includes On a firing path 90 in which a crushing member 92 is mounted, such as a shredding disc, or other mechanism suitable for pressure firing.

Upon operation, a fluid containing the chemical treatment enters the chemical injection system valve 22 through the single control line 24 and then passes through the non-return valves 78. The fluid metering valve 64 restricts the flow of the chemical treatment fluid so that only a portion of the fluid is directed to the well area Surrounding 28. The remaining portion of the process chemical fluid moves around the non-return valves 78 and the fluid metering valve 64 via the bypass path 82. The bypass path 82 is coupled to the following valve chemical injection system 22 via a portion of the single control line 24. The following valve chemical injection system 22 performs the same function of injecting a portion of the process chemical fluid and bypassing the remaining portion. This process is repeated downward until the lower valve 22 chemical injection system is reached, which does not require a bypass path. Thus, chemical valve injection systems 22 allow simultaneous injection of the treatment chemical into a group of well zones using a single hydraulic line 24.

Fluid metering valves 64 may be selected for the chemical injection valve system group 22 to deliver a desired amount of chemical treatment fluid at each area of the well. In addition, the fluid metering valves 64 provide the desired flow restrictions in a way that the valves 64 are used in conjunction with each other to compensate for differences in reservoir pressures at different well zones 28. Fluid metering valves 64 may also be designed to compensate for any pressure loss associated with restrictions and/or friction between the chemical treatment fluid and the control line to ensure that a uniform (or other desired) amount of chemical treatment fluid is delivered to each zone.

Referring generally to Figure 7, an example of a chemical injection valve system 22 that can be used at the inferior/post injection site is illustrated. In this embodiment, the valve chemical injection system 22 includes a connection 58 located at an inlet side of the chemical process agent, but connection 60 is not necessary because there is no need to side-pass a portion of the chemical process fluid.

For example, the lower valve chemical injection system 22 may form an interstitial flow path 62 with the fluid metering valve 64, non-return valves 78, and coupling 58 mounted on the diagonally extended portion 52 by means of an adapter plug 68, as shown in Figure 8. With However, the bypass path 82 is excluded, as best illustrated in Figure 9. Furthermore, the emergency release system 94 may be connected to the interstitial flow path 62 via the exit port 96. In the example shown, the outlet port 96 is positioned between the fluid metering valve 64 and the non-return valves 78 to allow the release of the treatment chemical into the surrounding well area if fluid flow through the lower valve chemical injection system is obstructed.

For example, the release system 94 may include a release path 98 in fluid communication with the exit port 96. A crushing member 100, such as a shredding disc, or other suitable release mechanism may be installed under pressure along the flow path 98 to allow the process material fluid to be released Chemicals under pressure, when necessary. For example, the fracturing member 100 may be used as an emergency means of delivering process chemicals to the lower well area 28 in the event that the fluid metering valves 64 become clogged with debris. In this case, the pressure in the single control plane 24 can be increased to fracture the crushing member 100 and to allow the treatment chemical to be injected into the surrounding well area 28.

The total well system 20 can be designed to accommodate a variety of injection applications in a variety of well environments. Accordingly, the number, type and design of components and systems in the overall system can be adjusted to accommodate different applications. For example, the size and design of the valve mandrel and its housing 50 can be changed. Furthermore, the interstitial flow path can be directed and passed through the mandrel housing at several different positions. The type of fluid metering valve and non-return valves used in the interstitial flow path can also be changed. In addition, the type of single flow line 24 can be changed, and the method of coupling the single flow line 24 to each chemical valve injection system 22 can rely on several different types of couplings. Likewise, other downhole equipment types and arrangements used in the well tubing series 46 are selected according to the particular well application in which chemical injection capabilities are being used.

Although only a few embodiments of the present invention have been described in detail above, those with experience in the art can easily recognize that many modifications can be made without being physically removed from the information disclosed in this invention. As an example only, although injection into the annular space has been described here, it is conceivable that the injection area could also be a region in the tubing group. Accordingly, the intention is to include such modifications within the scope of this invention as defined in the elements of protection.