Downhole completion system

1. A completion system for connecting several screens into a well tubular structure mounted from base pipe sections, comprising:

a first screen assembly and a second screen assembly, each screen assembly comprising:

a base pipe section mounted as part of the well tubular structure having a longitudinal extension, the base pipe section having an outer face, and

a tubular screen element surrounding and being connected to the outer face of the base pipe section, and

an assembly connection part for connecting an end of the first screen assembly with an end of the second screen assembly,

wherein the completion system further comprises:

a first tubular member having a minimum inner diameter which is equal to or larger than a maximum outer diameter of the tubular screen element, the first tubular member being arranged opposite the assembly connection part so that fluid flowing in through the tubular screen element of one of the screen assemblies flows on the outside of the assembly connection part,

a flow section mounted as part of the well tubular structure for allowing fluid to flow into or out of the well tubular structure, the flow section including a first end mounted to an end of the base pipe section of the second screen assembly, and

a second tubular member arranged opposite the flow section so that fluid flowing in through the tubular screen element of one of the screen assemblies flows on the outside of the base pipe section and in through the flow section.

2. A completion system according to claim 1 , further comprising a first tubular member connector and a second tubular member connector, each tubular member connector having a minimum inner diameter which is equal to or larger than the maximum outer diameter of the tubular screen element, and the first tubular member is maintained in at least the longitudinal extension by the tubular member connectors.

3. A completion system according to claim 2 , wherein each screen assembly comprises a screen element fixation part adapted to fixate the tubular screen element to the base pipe section.

4. A completion system according to claim 3 , wherein the first tubular member connector is arranged so as to at least partly overlap the screen element fixation part of the first screen assembly, and the second tubular member connector is arranged so as to at least partly overlap the screen element fixation part of the second screen assembly.

5. A completion system according to claim 3 , wherein the screen element fixation part has an external thread.

6. A completion system according to claim 2 , wherein the first tubular member connector and the second tubular member connector have internal threads.

7. A completion system according to claim 2 , wherein the first tubular member connector and the second tubular member connector are slidable on the outer face of the base pipe section during assembly of the first screen assembly and the second screen assembly.

8. A completion method for completing the completion system according to claim 2 in a borehole of a well, said completion method comprising:

providing the first screen assembly,

mounting the second screen assembly to the first screen assembly by means of the assembly connection part,

sliding the first tubular member along the tubular screen element of the first screen assembly or the second screen assembly, and

positioning the first tubular member opposite the assembly connection part.

9. A completion method according to claim 8 , wherein the completion system comprises a first tubular member connector and a second tubular member connector, each having an outer diameter which is equal to or larger than the outer diameter of the tubular screen element, and wherein the first tubular member connector and the second tubular member connector are moved along the longitudinal extension towards the first tubular member to fasten the first tubular member opposite the assembly connection part.

10. A completion method according to claim 8 , wherein the completion system further comprises a third screen assembly and a flow section mounted between the second screen assembly and the third screen assembly.

11. A completion method according to claim 10 , wherein the completion system further comprises a second tubular member which is slid along the tubular screen element of the second screen assembly or the third screen assembly, positioning the second tubular member opposite the flow section.

12. A completion method according to claim 8 , wherein the sliding includes:

before the mounting the second screen assembly to the first screen assembly, sliding the first tubular member along the tubular screen element of the first screen assembly to be arranged opposite the tubular screen element of the first screen assembly and away from the end of the first base pipe section of the first screen assembly that is to be connected to the base pipe section of the second screen assembly, and

wherein the positioning the first tubular member opposite the assembly connection part is after the mounting the second screen assembly to the first screen assembly.

13. A completion system according to claim 2 , wherein the first tubular member connector and the second tubular member connector are slidable on the outer face of the base pipe section before and after the ends of the first and second screen assemblies are connected by the assembly connection part.

14. A completion system according to claim 1 , further comprising at least one annular barrier assembly comprising:

a base pipe section for being mounted as part of the well tubular structure, the base pipe section comprising an aperture,

an expandable sleeve surrounding the base pipe section and having an inner face facing the base pipe section and an outer face facing a wall of a borehole or another well tubular structure,

each end of the expandable sleeve being connected with the base pipe section, and

an annular space between the inner face of the expandable sleeve and the base pipe section.

15. A production method for producing hydrocarbon-containing fluid from a reservoir into a well tubular structure, comprising:

letting fluid in through a first screen assembly of a completion system according to claim 1 ,

letting the fluid past an annular space between the first tubular member and the assembly connection part,

letting the fluid flow between the tubular screen element and the base pipe section of a second screen assembly, and

letting the fluid flow into an annular space under a second tubular element and into a flow section and into the well tubular structure.

16. The completion system according to claim 1 , further comprising a third screen assembly comprising:

a base pipe section mounted as part of the well tubular structure having a longitudinal extension, the base pipe section having an outer face;

a tubular screen element surrounding and being connected to the outer face of the base pipe section; and

wherein the flow section includes a second end mounted to the base pipe section of the third screen assembly in order to connect the second screen assembly to the third screen assembly.

17. The completion system according to claim 1 , further comprising a flow channel between the base pipe section and the tubular screen element of each of the first screen assembly and the second screen assembly, the flow channel of the first screen assembly and the flow channel of the second screen assembly each extend along a longitudinal length and are each connected to an annular space between the assembly connection part and the first tubular member.

18. The completion system according to claim 1 , wherein at least a portion of an outer surface at the maximum outer diameter of the tubular screen element of the first screen assembly is configured to be an outermost surface of the completion system, and/or at least a portion of an outer surface at the maximum outer diameter of the tubular screen element of the second screen assembly is configured to be an outermost surface of the completion system.

19. The completion system according to claim 1 , wherein the fluid is hydrocarbon-containing fluid that is configured to flow from a reservoir and into the well tubular structure through the tubular screen element of one of the screen assemblies and/or through the flow section.

20. A completion system for connecting several screens into a well tubular structure mounted from base pipe sections, comprising:

a first screen assembly and a second screen assembly, each screen assembly comprising:

a base pipe section mounted as part of the well tubular structure having a longitudinal extension, the base pipe section having an outer face, and

a tubular screen element surrounding and being connected to the outer face of the base pipe section, and

an assembly connection part for connecting an end of the first screen assembly with an end of the second screen assembly,

wherein the completion system further comprises a first tubular member having a minimum inner diameter which is equal to or larger than a maximum outer diameter of the tubular screen element, the first tubular member being arranged opposite the assembly connection part so that fluid flowing in through the tubular screen element of one of the screen assemblies flows on the outside of the assembly connection part,

further comprising a first tubular member connector and a second tubular member connector, each tubular member connector having a minimum inner diameter which is equal to or larger than the maximum outer diameter of the tubular screen element, and the first tubular member is maintained in at least the longitudinal extension by the tubular member connectors.

21. A completion system for connecting several screens into a well tubular structure mounted from base pipe sections, comprising:

a first screen assembly and a second screen assembly, each screen assembly comprising:

a base pipe section mounted as part of the well tubular structure having a longitudinal extension, the base pipe section having an outer face, and

a tubular screen element surrounding and being connected to the outer face of the base pipe section, and

an assembly connection part for connecting an end of the first screen assembly with an end of the second screen assembly,

wherein the completion system further comprises:

a first tubular member having a minimum inner diameter which is equal to or larger than a maximum outer diameter of the tubular screen element, the first tubular member being arranged opposite the assembly connection part so that fluid flowing in through the tubular screen element of one of the screen assemblies flows on the outside of the assembly connection part, and

at least one annular barrier assembly comprising:

a base pipe section for being mounted as part of the well tubular structure, the base pipe section comprising an aperture,

an expandable sleeve surrounding the base pipe section and having an inner face facing the base pipe section and an outer face facing a wall of a borehole or another well tubular structure,

each end of the expandable sleeve being connected with the base pipe section, and

an annular space between the inner face of the expandable sleeve and the base pipe section.