Wells – Means for forming filter beds
Reexamination Certificate
2001-08-03
2002-12-17
Will, Thomas B. (Department: 3672)
Wells
Means for forming filter beds
C166S227000, C166S278000, C166S334400
Reexamination Certificate
active
06494256
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to tools used to complete subterranean wells. More particularly the present invention describes a means of completing two zones within a single wellbore with the capability of isolating one of the zones.
2. Description of Related Art
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.
Sand or silt flowing into the wellbore from unconsolidated formations can lead to an accumulation of fill within the wellbore, reduced production rates and damage to subsurface production equipment. Migrating sand has the possibility of packing off around the subsurface production equipment, or may enter the production tubing and become carried into the production equipment. Due to its highly abrasive nature, sand contained within production streams can result in the erosion of tubing, flowlines, valves and processing equipment. The problems caused by sand production can significantly increase operational and maintenance expenses and can lead to a total loss of the well. One means of controlling sand production is the placement of relatively large sand (i.e., “gravel”) around the exterior of a slotted, perforated, or other type liner or screen. The gravel serves as a filter to help assure that formation fines and sand do not migrate with the produced fluids into the wellbore.
In a typical gravel pack completion, a screen is placed in the wellbore and positioned within the unconsolidated formation that is to be completed for production. The screen is typically connected to a tool that includes a production packer and a cross-over, and the tool is in turn connected to a work or production tubing string. The gravel is mixed and pumped in a slurry down the tubing and through the cross-over, thereby flowing into the annulus between the screen and the wellbore. The liquid forming the slurry leaks off into the formation and/or through the screen, which is sized to prevent the gravel in the slurry from flowing through. The liquid that passes through the screen flows up the tubing and then the cross-over directs it into the annulus area above the packer where it can be circulated out of the well. As a result of this operation, the gravel is deposited in the annulus area around the screen where it forms a gravel pack. The screen prevents the gravel pack from entering into the production tubing. It is important to size the gravel for proper containment of the formation sand, and the screen must be designed in a manner to prevent the flow of the gravel through the screen.
In wellbores that penetrate more than one productive zone it is often desired to complete and produce more than one zone. In some cases more than one zone can be completed and produced together. This is often referred to as commingled production. In other cases, often due to differing reservoir characteristics such as formation pressures, two zones will be completed, but will be separated and produced through separate production strings. This is often referred to as a dual completion.
A common problem encountered when completing a well as a dual completion is a temporary commingling of the separate zones and the loss of substantial amounts of completion fluids into one or both of the formations, resulting in possible formation damage and requiring multiple trips into the wellbore to perform remedial treatments. The multiple trips and the remedial actions needed to reduce or remove formation damage can significantly increase the time and expense of dual well completions.
At times it is desirable to complete a zone and then isolate the zone until production is initiated or resumed at a later date. An example of this is when work is to be performed on the lower zone in a dual completion well; it may be beneficial to isolate the upper zone while the work is performed on the lower zone, both to increase safety during the well work and to reduce the chances of formation damage to the upper zone due to fluid loss. Zonal isolation systems are used to isolate and selectively produce oil or gas from separate zones in a single well. U.S. Pat. Nos. 5,579,844; 5,609,204 and 5,988,285 describe systems for the zonal isolation of wells. Often these systems involve multiple trips into the well and significant time and expense to perform. Any reduction in the number of trips required to complete a well or isolate a zone during subsequent operations can result in significant cost savings.
There is a need for improved tool assemblies and methods that enable the completing of a wellbore as a dual completion while reducing the chances of fluid loss into completed zones and enabling subsequent remedial work.
SUMMARY OF THE INVENTION
One embodiment of the present invention is a zonal isolation assembly for completing a first zone in a subterranean wellbore. The zonal isolation assembly comprises an inner housing and a sliding sleeve capable of moving between an open and closed position. The sliding sleeve is disposed within the inner housing. A passageway provides fluid communication between the inside and outside of the inner housing and an isolation tubing element is at least partially disposed within the inner housing and capable of moving between an upper position and a lower position. When the sliding sleeve is in its closed position and the isolation tubing element is in its lower position, fluid communication from the first zone through the isolation assembly is restricted.
The isolation tubing element can be releasably attached to the inner housing. The isolation tubing element can comprise a sealing element adapted to seat within a receptacle attached to a lower packer when the isolation tubing element is in its lower position. The receptacle can be releasably attached to the lower packer.
The assembly can further comprise an upper packer and an outer housing connected to the upper packer and to the lower packer. The outer housing can be connected to the inner housing and comprise a wall having a passageway therethrough, the outer housing and the passageway are located above the inner housing and below the upper packer. A sliding sleeve can be disposed within the outer housing capable of moving between an open and closed position and located above the inner housing. The outer housing can further comprise a sand screen located below the inner housing. The inner housing, isolation tubing element and receptacle can each be releasable disposed within the outer housing.
When the isolation tubing element is in its upper position, the isolation tubing element is capable of providing fluid communication between the area within the inner housing and the sand screen. When the isolation tubing element is in its lower position, the isolation tubing element is capable of providing fluid communication between the area within the inner housing and the area below the lower packer. When the isolation tubing element is in its lower position and the sliding sleeve disposed within the inner housing is in its closed position, fluid communication through the sand screen is restricted. When the isolation tubing element is in its lower position and the sliding sleeve disposed within the inner housing is in its closed position, the isolation tubing element is capable of providing fluid communication between the area within the outer housing located above the inner housing and the area below the lower packer.
When the sliding sleeve disposed within the outer housing is in its open position, fluid communication is capable through the passageway in the outer housing, and when the sli
Achee, Jr. Timothy T.
Dufrene Kerby J.
Hayes Joseph E.
Wenner James
Beach Thomas A.
Griffin Jeffrey E.
Jeffery Brigitte L.
Schlumberger Technology Corporation
Will Thomas B.
LandOfFree
Apparatus and method for zonal isolation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for zonal isolation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for zonal isolation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2997423