Measuring and testing – Instrument proving or calibrating – Volume of flow – speed of flow – volume rate of flow – or mass...
Patent
1992-12-14
1994-11-22
Williams, Hezron E.
Measuring and testing
Instrument proving or calibrating
Volume of flow, speed of flow, volume rate of flow, or mass...
73168, G01L 2700, G01M 1900
Patent
active
053657691
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method for verifying the correct operation of a safety valve of an oil well.
In accordance with safety standards, a production well head must be fitted with a safety valve disposed in the well approximately 30 meters below the surface of the ground or of the sea bottom. This valve, most of the time hydraulically actuated, is intended to close the well in the case of a serious accident, for example in the case of a blow out.
In general, such a valve is designed to have a closed rest position, the valve being held in an open position under the effect of the hydraulic pressure sent from the surface by a hydraulic line situated along the production string. If required, the hydraulic pressure is stopped, which then leads to closure of the valve. Thus, any incident or destruction at the well head leads in this manner to the automatic closure of the safety valve.
Since such a valve constitutes an essential element for well security, it is necessary to monitor periodically the correct operation of the valve and of the hydraulic control system. However, actuating the valve is not sufficient in the present case because it is not possible to detect with certainty a possible malfunction such as partial opening which could lead, after a period of production, to the valve being rendered inoperative.
SUMMARY OF THE INVENTION
The object of the present invention is therefore a method for verifying the correct operation of a safety valve of a well, after its first positioning and subsequently in order to perform its maintenance as well as possible.
For this purpose, the invention provides a method for verifying the correct operation of an oil well valve situated at depth characterized in that it comprises the following steps: as a function of time or of the volume pumped for a valve in an optimum state prior to installation there of, well, operation or a possible malfunction of the valve situated at depth.
Other characteristics and advantages of the present invention will emerge more clearly on reading the following description which is made with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a device allowing implementation of the method of the present invention; and
FIGS. 2A, 2B, 3A and 3B are curves obtained with the device in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically represents a hydraulic circuit comprising a safety valve 10 intended to be disposed at depth. A positive displacement pump 12 sends a hydraulic liquid 14 through a control line 16 to the valve 10. The hydraulic pressure supplied by the pump 12 is measured by a manometer 18 and the variation of the pressure over time is displayed by means of a recorder 20.
In the example illustrated, the control line has a diameter of 0.6 cm and a length of 120 m. Its control is provided by a Subhydrelf brand oil and a Gilson constant flow rate positive displacement pump. The output is constituted by a paper recorder however, a computer screen or any other display means may also be used.
The method first of all provides for the production, with the help of this device, of a curve P=f(t), P being the hydraulic pressure applied to the valve and t being time. First, after safety valve 10 is closed, the valve is opened, its leaktightness is observed and it is again closed. This prior production may be done in the factory, in the workshop or on site. According to the invention, two curves are then compared, one being obtained by acting on a valve in a known mechanical state and the other being obtained by acting on the same valve in operation at depth in a well. Differences between the two curves then allow diagnosis, when the valve is situated at depth, of a cycling fault as well as any abnormal friction, hard spot, leak, to be made indicating actual or latent malfunction.
FIGS. 2A, 2B, 3A and 3B are explanatory curves of the present method. The pair of curves 2A and 3A represents the evolution of the hydraulic pressure supplied t
REFERENCES:
patent: 3653254 (1972-04-01), Simon
patent: 3799269 (1974-03-01), Brown et al.
patent: 4428223 (1984-01-01), Trevisan
patent: 4448216 (1984-05-01), Speegle et al.
patent: 4527415 (1985-07-01), Chabat-Courede
patent: 4542649 (1985-09-01), Charbonneau et al.
patent: 4694693 (1987-09-01), Gerlowski
patent: 4949288 (1990-08-01), Bookout
Ashraf Nashmiya
Elf Aquitaine Production
Williams Hezron E.
LandOfFree
Method for verifying the correct operation of a safety valve of does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for verifying the correct operation of a safety valve of , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for verifying the correct operation of a safety valve of will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1983405