Subsea production system
AssigneeAker Kvaerner Subsea AS
InventorGeir Inge Olsen
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Abstract
Methods and arrangements for production of petroleum products from a subsea well. The methods comprise control of a downhole separator, supplying power fluid to a downhole turbine/pump hydraulic converter, performing pigging of a subsea manifold, providing gas lift and performing three phase downhole separation. Arrangement for performing the methods are also described.
Claims50
Method of controlling a downhole separator, for separating hydrocarbons and water, the hydrocarbons leaving the separator flowing through a x-mas tree and a first header in a manifold, wherein a power fluid is used to drive a downhole turbine/pump hydraulic converter, the pump in the downhole turbine/pump hydraulic converter pumping separated water, characterized in that the power fluid for the downhole turbine/pump hydraulic converter is fed through a second header in the manifold, a adjustable valve and a x-mas tree to the turbine in the downhole turbine/pump hydraulic converter, the rate of pumping being controlled by the rate of power fluid based on measures of water level in the separator, flow-split or oil and/or water entrainment of the separated phases.
Method of supplying power fluid to a downhole turbine/pump hydraulic converter, characterized in that the method comprising the steps of:
- providing a manifold having a first and a second header,
- providing communication between the first header and a well fluid line in the well bore.
- providing communication between the second header and the turbine of the downhole turbine/pump hydraulic converter, and
- supplying power fluid to the turbine through the second header.
The method of any of the preceding claims, characterized in that surrounding seawater is used as power fluid and is either injected into the reservoir together with the separated produced water or returned to the seabed and discharged to the surrounding sea.
The method of any of the preceding claims, characterized in that the power fluid is extracted form a formation and is free flowing from an aquifer to the seabed or pumped to the seabed using a downhole electrical operated pump or a downhole turbine/pump hydraulic converter.
The method of claim any of the preceding claims, characterized in that the power fluid is circulated in a closed loop with pressure increase by use of a seabed located charge pump and that the power fluid is returned to the manifold in a third header.
A subsea petroleum production arrangement for producing hydrocarbons from a plurality of wells, comprising a manifold having a first and a second header and isolating valves for isolating the first or the second header from the respective wells, at least the first header being in selective fluid communication. via a respective adjustable valve and a respective x-mas tree, with respective hydrocarbon transporting lines in the wells, for transportation of hydrocarbons, at least one of the wells having a downhole separator for separating hydrocarbons and water and a downhole turbine/pump hydraulic converter for pumping separated water, characterized in that the second header is in communication with a power fluid supply and via a power fluid adjustable valve in further communication with a turbine in the downhole turbine/pump hydraulic converter.
The arrangement of claim 154, characterized in that the discharge side of the turbine and the pump of the downhole turbine/pump hydraulic converter is in communication with an injection zone in a formation being injected with water.
The arrangement of any of the preceding claims, characterized in that isolation valves are provided to isolate the second header from the power fluid lines and open communication between the second header and the hydrocarbon transporting lines, thereby enabling transportation of hydrocarbons in both headers.
The arrangement of any of the preceding claims, characterized in that isolation valves are provided to isolate the power fluid lines from the second header, open communication between the first header and the power fluid lines, isolate the hydrocarbon transporting lines from the first header and open communication between the hydrocarbon transporting lines and the second header, to enable hydrocarbon transport in the second header and power fluid transport in the first header or vice versa.
A method for performing pigging of a subsea manifold, the manifold comprising a first and a second header being in selective communication with each other at a first respective end, characterized in that a single flowline is in selective communication with the first and the second header at a second respective end, wherein a pig is fed into the flowline and directed into the first header. the pig is thereafter led into the second header and subsequently led into the flowline.
A subsea petroleum production arrangement, comprising a subsea manifold having a first and a second header in selective communication with each other at a first respective end, characterized in that a single flowline is in selective communication with the first and the second header at a second respective end.
An arrangement for controlling a downhole separator, for separating hydrocarbons and water, comprising a manifold having a first and a second header and isolating valves for isolating the first or the second header from the respective wells, at least the first header being in selective fluid communication, via a respective adjustable valve and a respective x-mas tree, with respective hydrocarbon transporting lines in the wells, for transportation of hydrocarbons, at least one of the wells having a downhole separator for separating hydrocarbons and water and a downhole turbine/pump hydraulic converter for pumping separated water, characterized in that the second header is in communication with a power fluid supply, and via a power fluid adjustable valve in further communication with a turbine in the downhole turbine/pump hydraulic converter.
A subsea petroleum production arrangement for producing hydrocarbons from a plurality of wells, comprising a manifold having a first and a second header and isolating valves for isolating the first or the second header from the respective wells, at least the first header being in selective fluid communication, via a respective adjustable valve and a respective x-mas tree, with respective hydrocarbon transporting lines in the wells, for transportation of hydrocarbons, at least one of the wells having a downhole turbine/pump hydraulic converter, characterized in that the second header is in communication with a power fluid supply, and via a power fluid adjustable valve in further communication with a turbine in the downhole turbine/pump hydraulic converter and that the pump of the turbine/pump hydraulic converter is pumping well fluid or production fluid.
A method for providing downhole three phase separation, characterized in that at least a part of the gas in a well fluid is extracted from the wellfluid in a downhole gas-liquid separator and transported in a separate line passed a downstream liquid-liquid separator.
A subsea petroleum production arrangement for producing hydrocarbons, characterized in that the arrangement further comprising a downhole gas-liquid separator for separating at least partly gas from the well fluid, the separator being in communication with a gas line extending passed a liquid-liquid separator.
A subsea petroleum production arrangement for producing hydrocarbons, characterized in that the arrangement further comprising a downhole gas-liquid separator placed in a substantially horizontal section of the well, for separating at least partly gas from the well fluid, the separator being in communication with a gas line communication with a gas scrubber at an elevated position in a vertical or deviated section of the well.
A subsea petroleum production arrangement for producing hydrocarbons from a plurality of wells, comprising a manifold having a first and a second header and isolating valves for isolating the first or the second header from the respective wells, at least the first header being in selective fluid communication, via a respective adjustable valve and a respective x-mas tree, with respective hydrocarbon transporting lines in the wells, for transportation of hydrocarbons, and the first header being in communication with a first flowline, the second header being in communication with a second flowline, characterized in that the arrangement further comprising a third header, the third header being in communication with the second flowline, for supply of gas from the second flowline to the third header, for artificial lift of production fluid.
Dependencies are inferred from the claim text.