EP2877683B1

EP2877683B1 - System and method for fracturing of oil and gas wells

Info

Publication number: EP2877683B1
Application number: EP13766030.4A
Authority: EP
Inventors: Kristian Brekke
Original assignee: Flowpro Well Technology As
Current assignee: Flowpro Well Technology As
Priority date: 2013-09-20
Filing date: 2013-09-20
Publication date: 2019-09-04
Anticipated expiration: 2033-09-20
Also published as: CA2886434C; CN104854301A; AU2013394347A1; EA029721B1; BR112015011565B1; CN104854301B; WO2015039698A1; EA201590099A1; BR112015011565A2; AU2017232094B2; CA2886434A1; MX2015000912A; AU2017232094A1; EP2877683A1

Description

BACKGROUND

This disclosure relates to a fracturing system and method for acquiring oil and gas.
The demand for natural gas and oil has significantly grown over the years making low productivity oil and gas reservoirs economically feasible, where hydraulic fracturing plays an important part in these energy productions throughout the world. For several decades different technology has been used to enhance methods for producing resources from oil and gas wells. Long horizontal wellbores with multiple fractures is one commonly used process to enhance extraction of oil and gas from wells. This process starts after a well has been drilled and the completion has been installed in the wellbore. Multi-stage fracking is a method that involves pumping large amounts of pressurized water or gel, a proppant and/or other chemicals into the wellbore to create discrete multiple fractures into the reservoir along the wellbore.
One of the technologically advanced methods being used today is simultaneous proppant fracturing of up to thirty fractures in one pumping operation. This method involves usage of proppant to prevent fractures from closing. However, this practice can usually cause an uneven distribution of proppant between the fractures, which will reduce the efficiency of the fracture system. As a result, this practice can also cause fractures to propagate in areas that are out of the target reservoir. Thus, such method can be inefficient and unsafe.
Additionally, proppant fracturing usually involves multiple steps and requires several tools in order to be performed successfully. Such practice that will allow even distribution of proppant between fractures highly depends on setting, plugs between the fracture stages or using frac balls of increasing sizes. In these methods, plugs are either set after each fracture has been perforated and pumped, or frac balls are dropped from the surface to successively open fracturing valves placed along the well. For each stage, balls of different diameters are dropped into the well corresponding to a specific fracturing valve's seat. At a point in the well, the ball will no longer pass through due to a decrease in well diameter. Once the ball is in place, fracturing can take place. After fracturing, the plugs must be drilled out and the balls must be recovered. With each fracturing stage while setting plugs, much time and energy is expended in tripping out of the hole between the stages and drilling out the plugs. Moreover, land-based rigs are usually rented per day basis, and so any delays can be quite expensive. Also, only about 12 different fracture stages are possible with the ball method before a restriction in flow area due to small ball diameter, which makes fracturing difficult due to large pressure losses.
US 2012/0305265 A1 describes cluster opening sleeves for wellbore, allowing for isolation of segments of a wellbore for sequential treatment of the isolated segment.
US 2004/163820 A1 describes a bi-directional ball seat system for controlling flow in hydrocarbon wells.
WO 2013/169790 A1 relates to a seat assembly with counter for isolating fracture zones in a well. The seat assembly are provided with a rotary indexing system allowing a predetermined number of plugs to pass through the assembly.
As such it would be useful to have an improved system and method for fracturing oil and gas wells.

SUMMARY

According to a first embodiment, the present invention relates to a well fracturing system according to claim 1.
According to another aspect, the invention relates to a method of fracturing a well according to claim 12. Preferred embodiments are respectively disclosed in claims 2-11 and 13-14.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1A illustrates a side view of a base pipe.
Figure 1B illustrates a view of a base pipe.
Figure 1C illustrates a cross sectional view of a base pipe.
Figure 2A illustrates a sliding sleeve.
Figure 2B illustrates a view of a sliding sleeve.
Figure 2C illustrates a cross sectional view of a sliding sleeve.
Figure 2D illustrates a cross sectional view of a sliding sleeve that further comprises a fixed sleeve, and an actuator.
Figure 3A illustrates a peripheral view of outer ring.
Figure 3B illustrates a view of an outer ring.
Figure 4A illustrates a valve casing.
Figure 4B illustrates a fracturing port of a valve casing.
Figure 4C illustrates a production port of a valve casing.
Figure 5 illustrates a fracturing valve in fracturing state.
Figure 6 illustrates an impedance device in between fracturing port.
Figure 7 illustrates fracturing valve in production state.

DETAILED DESCRIPTION

Figure 1A illustrates a side view of a base pipe 100. Base pipe 100 can be connected as a portion of a pipe string. In one embodiment, base pipe 100 can be a cylindrical material that can comprise different wall openings and/or slots. Base pipe 100 wall openings can comprise insert port 101, fracturing port 102, and/or production port 103. Insert port 101 can be made of one or more small openings in a base pipe 100. Fracturing port 102 can also be made of one or more openings. Further, production port 103 can be a plurality of openings in base pipe 100.
Figure 1B illustrates a front view of base pipe 100 further comprising a chamber 104. Chamber 104 can be a cylindrical opening or a space created inside base pipe 100. As such chamber 104 can be an opening that can allow material, such as frac fluid or hydrocarbons to pass through. Figure 1C illustrates a cross sectional view of a base pipe 100. Each wall opening discussed above can be circularly placed around base pipe 100.
Figure 2A illustrates a sliding sleeve 200 connected to a fixed sleeve 205 by an actuator 206, and in line with an outer ring 207. In one embodiment, sliding sleeve 200 can be a cylindrical tube that can comprise fracturing port 102. Thus, fracturing port can have a first portion within base pipe 100 and a second portion within sliding sleeve 200. Figure 2B illustrates a front view of a sliding sleeve 200 further comprising comprising an outer chamber 201. In one embodiment, outer chamber 201 can be an opening larger than chamber 104. As such, outer chamber 201 can be large enough to house base pipe 100.
Figure 2C illustrates a cross sectional view of a sliding sleeve 200. Sliding sleeve 200 can comprise a first sleeve 202 and a second sleeve 203. First sleeve 202 and second sleeve 203 can be attached through one or more curved sheets 204, the spaces between each curved sheet 204 defining a portion of fracturing port 102. Inner surface of first sleeve 202 can have a bottleneck void, or any other void within the inner surface. The void can extend radially around the complete inner diameter of base pipe 100, partially around the inner diameter, or locally. If completely around the inner diameter, the ends of inner surface can have a smaller diameter than the void.
Figure 2D illustrates a cross sectional view of a sliding sleeve 200 further comprising fixed sleeve 205, and actuator 206. In one embodiment, actuator 206 can be a biasing device. In such embodiment, biasing device can be a spring. In another embodiment, actuator can be bidirectional and/or motorized. In one embodiment, second sleeve 203 of sliding sleeve 200 can be attached to fixed sleeve 205 using actuator 206. In one embodiment, sliding sleeve 200 can be pulled towards fixed sleeve 205, thus compressing, or otherwise load actuator 206 with potential energy. Later actuator 206 can be released, or otherwise instigated, pushing sliding sleeve 200 away from fixed sleeve 205.
Figure 3A illustrates a peripheral view of outer ring 207. In one embodiment, outer ring 207 can be a solid cylindrical tube forming a ring chamber 301, as seen in figure 3B. In one embodiment, outer ring 207 can be an enclosed solid material forming a cylindrical shape. Ring chamber 301 can be the space formed inside outer ring 207. Furthermore, ring chamber 301 can be large enough to slide over base pipe 100.
Figure 4A illustrates a valve casing 400. In one embodiment, valve casing 400 can be a cylindrical material, which can comprise fracturing port 102, and production port 103. In one embodiment, fracturing port 102 can be a plurality of openings circularly placed around valve casing 400, as seen in Figure 4B. Furthermore, production port 103 can be one or more openings placed around valve casing 400, as seen in Figure 4C.
Figure 5 illustrates a fracturing valve 500 in fracturing mode. In one embodiment, fracturing valve 500 can comprise base pipe 100, sliding sleeve 200, outer ring 207, and/or valve casing 400. In such embodiment, base pipe 100 can be an innermost layer of fracturing valve 500. A middle layer around base pipe 100 can comprise outer ring 207 fixed to base pipe 100 and sliding sleeve 200, where fixed sleeve 205 is fixed to base pipe 100. Fracturing valve 500 can comprise valve casing 400 as an outer later. Valve casing 400 can, in one embodiment, connect to outer ring 207 and fixed sleeve 205. In a fracturing position, fracturing port 102 can be aligned and open, due to the relative position of base pipe 100 and sliding sleeve 200.
Fracturing valve 500 can further comprise a frac ball 501 and one or more stop balls 502. In one embodiment, stop ball 502 can rest in insert port 101. At a fracturing state, actuator 206 can be in a closed state, pushing stop ball 502 partially into chamber 104. In such state, frac ball 501 can be released from the surface and down the well. Frac ball 501 will be halted at insert port 101 by any protruding stop balls 502 while fracturing valve 500 is in fracturing mode. As such, the protruding portion of stop ball 502 can halt frac ball 501. In this state, fracturing port 102 will be open, allowing flow of proppant from chamber 104 through fracturing port 102 and into a formation, thereby allowing fracturing to take place.
Figure 6 illustrates one example of an impedance device counteracting actuator 206, in an embodiment where actuator 206 is a biasing device, such as a spring. In one embodiment, an erosion device, in the form of a string 601, can be an impedance device. String 601 can connect sliding sleeve 200 with base pipe 100. While intact, string 601 can prevent actuator 206 from releasing. Once the string 601 is broken, broken, actuator 206 can push sliding sleeve 200. One method of breaking string 601 can be by pushing a corrosive material reactive with string through fracturing port, as corrosive material can deteriorate string 601 until actuator 206 can overcome its impedance.
Figure 7 illustrates fracturing valve 500 in production mode. As sliding sleeve 200 is pushed towards outer ring 207 by actuator 206, fracturing port 102 can close and production port 103 can open. Concurrently, frac ball 501 can push stop balls 502 back into the inner end of first sleeve 202, which can further allow frac ball 501 to slide through base pipe 100 to another fracturing valve 500. Once production port 103 is opened, extraction of oil and gas can start. In one embodiment, production ports can have a check valve to allow fracturing to continue downstream without pushing frac fluid through the production port.

Claims

A well fracturing system, comprising a base pipe (100) comprising a fracking port (102) first portion, and a sliding sleeve (200) comprising a fracking port (102) second portion and being arranged around the base pipe, where the sliding sleeve (200) is manoeuvrable into a first and a second position, characterised in
that the base pipe (100) comprises an insert port (101) housing a stop ball (502), said stop ball (502) partially protruding within a chamber (104) of said base pipe (100); and in
that the sliding sleeve (200) comprises a first sleeve (202) and a second sleeve (203), said first sleeve comprising an inner surface, said inner surface comprising a void, wherein said void rests on a surface of said base pipe not comprising said insert port, preventing said stop ball (502) from exiting the chamber (104) of said base pipe (100) when said first sleeve (202) is in its first position, and wherein said void rests over said insert port (101), said stop ball (502) capable of exiting the chamber (104) of said base pipe (100), to enter said void, when the first sleeve is in its second position, and wherein one or more curved sheets (204) connect(s) said first sleeve (202) to said second sleeve (203), the space between said one or more curved sheets (204) being said fracking port (102) second portion.
The well fracturing system of claim 1, further comprising
a fixed sleeve (205) fixed around said base pipe (100) near a first side of said sliding sleeve (200); and
an actuator (206) connecting said fixed sleeve (205) to said sliding sleeve (200), said actuator (206) capable of moving sliding sleeve (200) from said first position to said second position.
The well fracturing system of claim 1 wherein said base pipe further comprises production port (103).
The well fracturing system of claim 1, wherein said sliding sleeve (200) while in said first position, said fracking port (102) first portion aligns with said fracking (102) port second portion; and
in said second position, said fracking port (102) first portion does not align with said fracking port (102) second portion.
The well fracturing system of claim 1, further wherein said sliding sleeve (200) while in
said first position, said second sleeve (203) blocks said production port (103); and
in said second position, said second sleeve (203) does not block said production port (103).
The well fracturing system of claim 4, wherein said sliding sleeve (200) while in said first position, said second sleeve (203) blocks said production port (103); and in said second position, said second sleeve (203) does not block said production port (103).
The well fracturing system of claim 2 wherein said actuator (206) is a spring.
The well fracturing system of claim 2 further comprising an impedance device (601) that impedes biasing device (206) from moving from a first position to a second position.
The well fracturing system of claim 8, wherein said impedance device (601) is a string, the first end of said string connected to said base pipe (100), the second end of said string connected to said sliding sleeve (200), said string within said fracking port (102) first portion and fracking port (102) second portion.
The well fracturing system of claim 2 further comprising an outer ring (207) fixed around said base pipe (100) near a first side of said sliding sleeve (200).
The well fracturing system of claim 3 further comprising a one-way valve at the production port to prevent fracking fluid from exiting said base pipe at said production port.
A method of fracturing a well, characterized in comprising connecting a base pipe (100) within a pipe string, said base pipe (100) comprising a fracking port (102) first portion, and an insert port (101) housing a stop ball (502), said stop ball (502) partially protruding within the chamber (104) of said base pipe (101); actuating a sliding sleeve (200) being arranged around the base pipe (100), from a first position to a second position, said sliding sleeve (200) comprising a first sleeve (202), and a second sleeve (203), said first sleeve (202) comprising an inner surface, said inner surface comprising a void, and where one or more curved sheets (204) are connecting said first sleeve (202) to said second sleeve (203), the space between said one or more curved sheets (204) being said fracking port (102) second portion, said first sleeve being positionable into said first position, wherein said void rests on a surface of said base pipe not comprising said insert port, preventing said stop ball from exiting the chamber of said base pipe; and said second position, wherein said void rests over said insert port, said stop ball capable of exiting the chamber of said base pipe, to enter said void.
The method of claim 12, comprising the preceding step of fracturing a well.
The method of claim 13, comprising the preceding step of pushing a frack ball through said pipe string to said stop balls.