Wells – Submerged well – Riser
Patent
1998-09-11
2000-08-29
Taylor, Dennis L.
Wells
Submerged well
Riser
166344, 166360, 166368, E21B 1701
Patent
active
06109353&
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a riser system particularly, but not exclusively, for use with sub-sea intervention work.
Existing riser systems for use in interventions are dual bore: there is a main bore and an annulus bore. The main bore allows full access to the well and is typically 5" diameter and the annulus bore, which is 2" diameter, allows control of the annulus pressure so that pumping or stimulation operations can be performed and fluid returns monitored and controlled at surface. The annulus bore also allows pressure testing of the annulus and also pressure testing of a tubing hanger located in, for example, a casing lined borehole and from which tubing such as a liner may be hung.
Existing dual bore riser systems typically involve two sets of tubing; a 5" tubing and a 2" tubing which are coupled together at surface to a downhole tool, such as a tubing hanger or tubing hanger running tool, or a 5".times.2" completion tree, such as disclosed in applicant's U.S. Pat. No. 5,873,415. In addition, the dual bore riser may use a main bore consisting of high quality pipe and an annulus bore made of coiled tubing as disclosed in applicant's U.S. Pat. No. 5,960,885.
With a dual bore riser system it is necessary to run both the main bore tubing and the annulus tubing at the same time and to clamp the tubes together at regular spaced intervals along their lengths which is relatively time consuming.
Furthermore, after a pressure test of the tubing hanger is carried out it is necessary to run separate 5" and 2" wireline plugs. This further adds to the time taken to run which results in increased expense.
An object of the present invention is to provide an improved riser system which obviates or mitigates at least of the aforementioned disadvantages.
A further object of the present invention is to provide a single bore riser system in which a single umbilical can be used which allows pressure testing to be carried out and also wireline plugs to be set without the need to run a separate dual bore riser.
This is achieved by using a dual bore completion tree and coupling an eccentric sub to the top of the tree which may be sealed by BOP pipe rams and also by storing a wireline plug in the annulus bore which has a by-pass and which allows communication to provide annulus control and which may be remotely actuated to plug the annulus bore.
The principal advantage of this arrangement is that it provides a single bore riser system which allows the running of a single tubing offering major savings in terms of time and cost. A further advantage is that the modified completion tool can be used to retrieve wireline plugs from the main bore and the annulus bore and also allows the testing of the annulus and tubing hanger.
According to a first aspect of the present invention there is provided a single bore riser system comprising: completion tree coupled to the bottom of the offset sub whereby the offset sub is coupled to the main bore of the sub-sea test tree which is off centre from the main axis of the completion subsea tree, through-bore, at least one valve element located in the main bore and at least one valve element located in the annulus bore, said valve elements being operable to move between an open and a closed position whereby when the valves are in an open position there is communication through the main bore and through said annulus bore and when said valves are in the closed position, there is no communication through the main bore or said annulus bore, a wireline plug located in the annulus bore downstream of said valve element, said wireline plug being moveable between a first position whereby communication is permitted past said plug and through said annulus and a second position whereby said plug is moveable into the tubing hanger to seal said annulus.
Preferably, there are two valves in said main bore, said valves being connected in series. Conveniently, said valves are ball valves. Alternatively, said valves may be roller valves, gate or flapper valves.
Preferably also, the valve in the annulus bor
REFERENCES:
patent: 3189099 (1965-06-01), Otteman et al.
patent: 3376923 (1968-04-01), Bullard
patent: 3536344 (1970-10-01), Nelson
patent: 3710859 (1973-01-01), Hanes et al.
patent: 4126183 (1978-11-01), Walker
patent: 4331203 (1982-05-01), Kiefer
patent: 4585369 (1986-04-01), Manesse et al.
patent: 4848472 (1989-07-01), Hopper
patent: 5161620 (1992-11-01), Ritter
patent: 5377762 (1995-01-01), Turner
patent: 5535826 (1996-07-01), Brown et al.
patent: 5544707 (1996-08-01), Hopper et al.
patent: 5873415 (1965-06-01), Edwards
patent: 5884706 (1999-03-01), Edwards
Edwards Jeffrey Charles
Morgan Michael Graham
Expro North Sea Limited
Taylor Dennis L.
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