Wells – Processes – With indicating – testing – measuring or locating
Patent
1999-05-10
2000-10-03
Bagnell, David
Wells
Processes
With indicating, testing, measuring or locating
16625007, 7315229, E21B 4700
Patent
active
061259349
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a downhole flow monitoring tool, and concerns in particular a tool for the downhole injection of one or more tracer or marker materials into a flowing multiphase fluid in a hydrocarbon well, for subsequent detection downstream of the injection point.
BACKGROUND OF THE INVENTION
When a well, specifically an oil or gas well, has been completed and is yielding the desired product it is necessary to monitor the well's performance to ensure that it is behaving as expected. In particular, it is desirable to measure the rate at which the well's products--in an oil well, for example, these would be oil, water, gas or a combination, even a mixture, of all three--are flowing along the borehole and up to the surface, and it is generally desirable to monitor the flow velocities actually down the well itself rather than merely when they reach the surface. Many types of method and apparatus have been proposed for this purpose; two typical such involve firstly the use of a mechanical "spinner" and secondly the use of tracer or marker materials. In the spinner case a wireline-supported tool carrying a small propeller- (or turbine-) driven dynamo is placed in the flowing fluid so that the propeller is turned around by it, and the dynamo's output indicates the flow velocity. In the tracer/marker case there is used an injector/detector tool, by which a suitable material--for example, a detectable chemical or a radioactive substance--is injected into the fluid, and its arrival time at a downstream detector station is noted, giving the flow velocity by a simple distance-over-time calculation. Spinners work satisfactorily in borehole sections that are vertical, but not nearly so effectively in sections which are horizontal--it is common these days for a well to include a section driven horizontally through the underground geological formation delivering the sought-after product--for in such a section the well fluid is liable to be stratified into individual component layers (with the heaviest, such as water/brine, on the bottom, the lightest, such as methane gas, on the top, and any others, such as oil, in the middle), and these layers are not necessarily flowing at the same speed. A spinner placed in the borehole across two differently-flowing layers is therefore likely to output a signal which is at best some sort of average, and is at worst quite meaningless. For fluid flow velocity measurement in horizontal wellbore sections, therefore, it has been suggested that there should be employed tracer/marker materials and the appropriate injector/detector tools, and it is with this that the present invention is concerned.
There are many specific techniques utilising tracer/marker materials. For example, in a group of methods that might be referred to as "nuclear" there can be involved: radioactive substances, and detecting the radiation they emit; activatable substances, that on exposure to a radiation source become unstable, and detecting their decay products; neutron-absorbing substances, and detecting the fall in received neutrons from a source as the tracer passes by; and X-ray-absorbing (that is, dense) substances, and detecting the way they modify the radiation received from some appropriate X-ray source. Numerous techniques and materials have been previously proposed in the literature for use in monitoring flows in oil wells, and reference is made to the patents and technical literature.
However, regardless of what specific technique is employed, there remains the problem of measuring the flow velocity of the desired component of the wellbore fluid, and in part this is usually done simply by preparing the tracer/marker material that is significantly more soluble--or, at least, more miscible--in the chosen component than it is in the other(s). Thus, for monitoring a well's water/brine output the selected material is conveniently formulated as an aqueous solution, while an oil-miscible composition is used if it is the well's oil output that needs to be observed. All that is then left is for the tr
REFERENCES:
patent: 2564198 (1951-08-01), Elkins
patent: 2738019 (1956-03-01), Atkinson
patent: 4166215 (1979-08-01), Anderson
patent: 4166216 (1979-08-01), Cubberly, Jr.
patent: 4223727 (1980-09-01), Sustek, Jr. et al.
patent: 4622463 (1986-11-01), Hill
patent: 4805450 (1989-02-01), Bennett et al.
patent: 4861986 (1989-08-01), Arnold
patent: 4966233 (1990-10-01), Blount et al.
patent: 5047632 (1991-09-01), Hunt
patent: 5282492 (1994-02-01), Angeli
patent: 5306911 (1994-04-01), Hunt
patent: 5441110 (1995-08-01), Scott, III
patent: 5543617 (1996-08-01), Roscoe et al.
patent: 5631413 (1997-05-01), Young et al.
Lenn Christopher Peter
Roscoe Bradley Albert
Bagnell David
Batzer William B.
Dougherty Jennifer R
Schlumberger Technology Corporation
LandOfFree
Downhole tool and method for tracer injection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Downhole tool and method for tracer injection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Downhole tool and method for tracer injection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-186390