Measuring and testing – Borehole or drilling – Fluid flow measuring or fluid analysis
Reexamination Certificate
1998-03-19
2001-01-23
Williams, Hezron (Department: 2856)
Measuring and testing
Borehole or drilling
Fluid flow measuring or fluid analysis
C073S152290, C073S152420
Reexamination Certificate
active
06176129
ABSTRACT:
The invention relates to a method and to apparatus for acquiring data and intended for use in a hydrocarbon well. More particularly, the method and the apparatus of the invention are designed to monitor production parameters in a hydrocarbon well and to enable diagnosis to be performed in the event of an incident.
To perform monitoring and diagnostic functions in a hydrocarbon well that is in production, a certain amount of data, mainly physical data needs to be acquired. The data relates essentially to the multiphase fluid flowing along the well (flow rate, proportions of the various phases, temperature, pressure, etc.). The data may also concern certain characteristics of the well proper (ovalization, deviation, etc.). Depending on the type of apparatus used, the information collected downhole can be transmitted to the surface either in real time, or in deferred manner. For real time transmission, the transmission can take place via a telemetry system using the cable from which the apparatus is suspended. For deferred transmission, the information collected downhole is recorded within the apparatus and it is read only once the apparatus has been brought back to the surface.
Whatever the way in which data acquired downhole is used (real time or in deferred manner), existing data-acquisition apparatus is always made up of a large number of modules disposed end-to-end. In particular, speed or flow rate measurement is always performed in a module that is different from the module that serves to detect the proportions of the various phases present in the fluid, when such detection is performed. More precisely, speed or flow rate measurement is generally performed in the bottom modules of the assembly, whereas the proportions of the various phases of the fluid are determined, if they are determined at all, in a module placed higher up.
This conventional disposition of data-acquisition apparatus used in hydrocarbon wells is illustrated in particular by document EP-A-0 733 780 (FIG. 7).
In existing apparatuses, this increase in the number of modules that are superposed to perform monitoring and to establish diagnoses in the event of anomalies in the well, poses various problems.
Firstly, the fact of the data being acquired at significantly different levels in the well means that interpretation of the data can lead to errors or inaccuracies.
Also, when it is desired to acquire a large amount of data, the above organization leads to building up an apparatus that is particularly long, heavy, and expensive. Length and weight make handling of the apparatus on the surface much more complicated. In addition, after the apparatus has been raised, it needs to be transferred to the surface through a decompression lock and the cost of such a lock increases with increasing length.
An object of the invention is to enable data to be acquired in a hydrocarbon well over a reduced height.
A further object of the invention is to enable data to be acquired in a hydrocarbon well at a lower cost than with conventional techniques.
Another object of the invention is to facilitate interpretation of the data acquired and reduce the risks of error and uncertainty.
According to the invention, there is provided a method of acquiring data in a hydrocarbon well, comprising the steps of measuring, on the flow section, the flow rate of a multiphase fluid flowing along the well in the central region thereof, and determining, at least in a local region situated at substantially the same level, the proportions of the fluid phases present in said local region.
By convention, the term “local region” designates any region or three-dimensional zone corresponding to a subdivision or to a portion of the flow section of the well. Also, the term “substantially at the same level” means that the levels at which the fluid flow rate is measured and at which the proportions of the phases in the fluid are determined can be identical or slightly different. If they are slightly different, the difference between the levels is much less than the difference that would exist if the two operations were performed on distinct modules, one mounted beneath the other.
Because flow rate is measured and the proportions of the phases of the fluid are determined at substantially the same level, the data acquired in this way can be interpreted more reliably and more accurately than is possible with prior art methods. In addition, the resulting reduction in the length of the corresponding apparatus simplifies handling and reduces cost, in particular by reducing the length required for the decompression lock.
In a preferred implementation of the invention, the proportions of the fluid phases present are determined in a plurality of local regions surrounding a central region of the well.
Advantageously, the proportions of the fluid phases present are then determined in a plurality of local regions that are regularly distributed around the central region and that are situated at substantially equal distances therefrom.
Preferably, the flow rate is determined on the section of the well by measuring the speed of the fluid in said central region and by measuring the diameter of the well substantially at the level of each local region.
In a preferred implementation of the invention, the proportions of the fluid phases present are then determined in four local regions distributed at 90° intervals relative to one another around the central region, and the diameter of the well is measured in two orthogonal directions each passing substantially through two of the local regions.
Preferably, when the well is deviated, a reference vertical direction substantially intersecting the axis of the well is also determined.
The invention also provides an apparatus for acquiring data in a hydrocarbon well, comprising flow rate measuring means on the flow section for measuring the flow rate of a multiphase fluid flowing along the well in the central region thereof, and at least one local sensor situated substantially at the same level as the flow rate measuring means, each local sensor being suitable for determining the proportions of the phases of the fluid in which it is immersed.
In a preferred embodiment of the invention, the flow rate measuring means comprise means for measuring speed. Centering means then automatically hold the speed-measuring means in a central region of the well, with a plurality of local sensors being disposed around the speed-measuring means.
Advantageously, the local sensors are regularly distributed around the speed-measuring means and are situated at substantially equal distances from said means. The centering means comprise at least three arms in the form of hinged V-linkages, a top end of each being pivotally mounted on a central body carrying the speed-measuring means between the articulated arms, and a bottom end of each being hinged to a moving bottom endpiece. Resilient means are interposed between the central body and each of the articulated arms to press the arms against the wall of the well. In addition, each of the articulated arms carries one of the local sensors substantially at the level of the speed-measuring means.
Advantageously, the centering means comprise four arms at 90° intervals relative to another around a longitudinal axis of the central body.
Preferably, the flow rate measuring means further comprise means for measuring the diameter of the well between each diametrically opposite pair of arms about the longitudinal axis of the central body.
In particular, the means for measuring well diameter may comprise two differential transformers supported by the central body.
When the well is deviated, means, likewise supported by the central body, may also be provided to determine a reference vertical direction substantially intersecting the longitudinal axis of the central body.
These means for determining a reference vertical direction advantageously comprise a flyweight potentiometer.
REFERENCES:
patent: 4928758 (1990-05-01), Siegfried, II
patent: 4974446 (1990-12-01), Vigneaux
patent: 5251479 (1993-10-01), Siegfried, II e
Aguesse Laurent J.
Cantin Gilles C.
Parent Philippe R.
Vessereau Patrick P.
Batzer William B.
Cygan Michael
Schlumberger Technology Corporation
Williams Hezron
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