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Choked Washpipe to improve Gravel Packing Quality in Long Horizontal Wells

IP.com Disclosure Number: IPCOM000192072D
Publication Date: 2010-Jan-19
Document File: 1 page(s) / 26K

Publishing Venue

The IP.com Prior Art Database

Abstract

Gravel Packing operations involve pumping slurries of gravel and a carrier fluid into the annulus around a screen assembly. The gravel is deposited as carrier fluid leaks into the formation or circulates back to surface through a wash pipe inside the screens and a tubing workstring. In a horizontal well application, the low side of a borehole packs first until gravel reaches the far end of a section, also called the toe, or until gravel forms a bridge because of formation collapse or high fluid leakoff. When it is the second scenario, the section behind the bridge will remain unpacked and thus a poor packing job is resulted. In the conventional set-up, carrier fluid starts to leak through the very first screen into the annulus space between the screen and wash pipe. This one contribution to the fluid leakoff is even worse when gravel packing is done in a long horizontal section and make it easier for a bridge to form. To address the above discussed problem and lower the risk of bridging, a new gravel packing system with choked washpipe is propsed in Figure #2. A choke will be installed inside the wash pipe, as well as perforations are to be made through the wash pipe at the upstream of the choke. Both features will be located under the first several screen sections. There are a couple of benefits associated with this concept. Firstly the choke will force part of the returning fluid out the wash pipe through the perforations to fill the screen/wash pipe annulus, thus eliminates fluid leaking from the pumping slurries through the screens; Secondly the fluid being forced out from the wash pipe will flow out the screens to add directly into the slurries to ensure enough fluid to carry gravel further toward the toe; In addition, from the flow dynamics point of view, the fluid sweating out of the screens is in a transverse direction to the slurries, which will in turn increase the turbulent intensity of the slurries and prevents gravel from settling down prematurely. A pair of seals can be installed on the OD of the wash pipe to straddle the perforations, such as the fluid being forced out by the choke can specifically flow out the certain screen sections.

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Gravel Packing operations involve pumping slurries of gravel and a carrier fluid into the annulus around a screen assembly. The gravel is deposited as carrier fluid leaks into the formation or circulates back to surface through a wash pipe inside the screens and a tubing workstring. In a horizontal well application, the low side of a borehole packs first until gravel reaches the far end of a section, also called the toe, or until gravel forms a bridge because of formation collapse or high fluid leakoff. When it is the second scenario, the section behind the bridge will remain unpacked and thus a poor packing job is resulted. In the conventional set-up, carrier fluid starts to leak through the very first screen into the annulus space between the screen and wash pipe. This one contribution to the fluid leakoff is even worse when gravel packing is done in a long horizontal section and make it easier for a bridge to form. To address the above discussed problem and lower the risk of bridging, a new gravel packing system with choked washpipe is propsed in Figure #2. A choke will be installed inside the wash pipe, as well as perforations are to be made through the wash pipe at the upstream of the choke. Both features will be located under the first several screen sections. There are a couple of benefits associated with this concept. Firstly the choke will force part of the returning fluid out the wash pipe through the pe...