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Obtaining Produced Fluid Samples From Subsea Wells Tied Back To An OBO Platform

IP.com Disclosure Number: IPCOM000244505D
Publication Date: 2015-Dec-17
Document File: 4 page(s) / 384K

Publishing Venue

The IP.com Prior Art Database

Abstract

For subsea developments in which the wells are tied back to an operated-by-other (OBO) production platform, obtaining regular samples of the produced fluids from each of the individual wells can be challenging because the operator of the platform has the final decision on when and how often the fluids from a competitor's wells can be routed into their test separators for sampling. In this scenario it would be advantageous to collect the fluid samples directly at the individual wellheads or at the subsea manifold and transport these samples to the sea surface for collection. Currently, it is possible to take fluid samples at a subsea wellhead using a remote operated vehicle (ROV) if the wellhead contains an ROV-accessible fluid sampling port. This method of sampling requires a number of ROVs to be in service at the times when the samples are desired. Alternatively, if the subsea wellhead or manifold contained sample containers that could be released to float to the surface when filled and be retracted into place after the fluids are collected at the surface, the dependence on the OBO platform or ROVs is removed. The inventions in this disclosure would permit fluid sampling at a subsea wellhead or manifold either using dedicated sampling lines or risers that connect to a convenient sample collection location at the sea surface, or using fluid sample containers on the wellhead or manifold that are released to float to the sea surface and be retrieved there.

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Obtaining Produced Fluid Samples From Subsea Wells

Abstract

For subsea developments in which the wells are tied back to an operated-by-other (OBO) production platform, obtaining regular samples of the produced fluids from each of the individual wells can be challenging because the operator of the platform has the final decision on when and how often the fluids from a competitor's wells can be routed into their test separators for sampling. In this scenario it would be advantageous to collect the fluid samples directly at the individual wellheads or at the subsea manifold and transport these samples to the sea surface for collection. Currently, it is possible to take fluid samples at a subsea wellhead using a remote operated vehicle (ROV) if the wellhead contains an ROV-accessible fluid sampling port. This method of sampling requires a number of ROVs to be in service at the times when the samples are desired. Alternatively, if the subsea wellhead or manifold contained sample containers that could be released to float to the surface when filled and be retracted into place after the fluids are collected at the surface, the dependence on the OBO platform or ROVs is removed.

The inventions in this disclosure would permit fluid sampling at a subsea wellhead or manifold either using dedicated sampling lines or risers that connect to a convenient sample collection location at the sea surface, or using fluid sample containers on the wellhead or manifold that are released to float to the sea surface and be retrieved there.

Main Body

The proposed invention is illustrated in Figures 1 and 2 below and involves placing fluid sample containers onto subsea production equipment, such as a wellhead or manifold, that can be opened on demand to collect a produced fluid sample from an individual well and when filled is released to float to the sea surface and be collected there. In one embodiment, the sample container is attached to cables on a winch so that a new, clean sample container can be retracted into place after the previous sample container has been collected at the sea surface. This embodiment is shown in the top left of Figure 2 below. In another embodiment shown at the bottom left of Figure 2, a set of several sample containers is in place with one container connected to the fluid sampling valve. When the active container is filled, it is released to float untethered to the surface, and the next sample container is mechanically moved into place over the fluid sampling valve. After all the sample containers in the set have...