Patent Application
20170089781
The present invention is related to devices and methods for determining the traction of several anchoring lines whose function is to maintain stabilized at a certain position, platforms or floating units which are prospecting and producing oil at sea. More particularly to a device that is independent of the anchoring line, i.e., not an integral part thereof. More specifically, to a device which employs a monitoring system in real time.
The oil production on an offshore environment, with increasing water depths, has become a real challenge in order to stabilize through mooring lines, the platforms or the floating units securely in operating position.
This is due not only by its own weight that these mooring lines reach due to the depth, also by all the drag influences they are exposed to because of sea currents, sometimes in different directions according to the depth, as well as by their own swing due by the waves on the sea surface and by the drag by winds acting on the floating unit.
The factors mentioned above as an example, together with the platform operational problems and also by the mooring manufacturing, may cause the breaking of the anchoring lines.
The disruption of one or more anchoring lines can lead the floating unit to a shift in position to beyond the safety margin and can cause very serious problems, particularly relating to the production pipeline connected to it, which may break leading to major environmental disasters as well as risk of death to the crew members.
The main guarantee of the integrity of the entire anchoring system, which maintains a given floating unit in a safe operation, is based on monitoring the tensile force wherein each of the anchoring lines are subjected to.
When they are being constructing, the platforms have as the integrated device, monitoring systems in order to monitor the anchoring lines that will eventually be linked to them. These integrated systems are subjected to the marine environment action which, over time, begin to provide mechanical and electrical failures and start to compromise the security as a whole. It is almost mandatory to use alternative device such that the monitoring of the stress traction in these mooring lines is performed.
It is very old the concern about the integrity of vessels anchoring lines, even with those simpler even with those that doesn't have a greater commitment than that of only to keep the vessel positioned.
The document GB 532 772 A of 1941 is a good example of this type of concern and means of prevention. This document discloses a link-shaped device that becomes part of an anchoring line, constructed with a central element sectioned. Electric contacts are fixed in each end of the sectioned central section of this element, being spaced from one another. These contacts are connected to a module which is laterally fixed to the link and houses batteries and a lamp. When the traction is excessive, the trend is that the chain link suffers an elongation deformation, and the two branches of the central element become in contact closing the electric circuit that lights the lamp and draws the attention of the involved personnel.
Over time the techniques has evolved to a more sophisticated devices, based on calculations made with data derived from correlations with phenomena suffered by a mooring line, for example, the existence of a relationship between the frequency of vibration of a certain line and the active traction force. In this technique, the device measure the natural frequency of a line vibration and the line traction may be calculated using the line specific weight and its free length between two points of support or attachment.
The document PI 0401668-8 A illustrates another tension monitoring mode or the disruption in submerged lines, and in general, among them, the anchoring lines. It comprises a device fixed to a region of a particular line with a sensor that is related to a parameter indicating a variation in the position of this device, and a communication unit for transmitting to a control base a variation that has occurred in said parameter. This method is positional and based on the fact that an anchoring line assume a certain inclination relating to the water line, and its slope is a function of the active tensile force acting on the line.
The acting tractions are obtained by calculations based on the measurement of the angles that are recorded by the sensor.
Another type of device for this purpose is shown in US 2013/0067881 A1 which shows an assembly of a device similar to the shackle, with a body in which one side is in the form of a fixed pin with arms extending in parallel in each end of this fixed pin. On the other ends of each one arms is interposed a pin. In at least one arm, a recess is formed inside which is housed a pressure sensor which acts as tensile meter.
Other examples are based on technical data of deformation or reduction in the width of a given link and on the changing of the steel electromagnetic properties when it is tensioned.
What is important to note is that the solutions presented above are permanently installed or are integrating part of the anchoring lines system, which are used as a component thereof. The technique lacks from a device for monitoring the tension in an anchoring line that is simple in its design, and which is adapted at one point of an anchoring line without being an integral part thereof, and thus, once collected the necessary data, the machine can be dismantled from this line and be mounted on another line, resulting in reduced costs.
It is object of the invention a device to measure and monitor the traction forces acting on the anchoring lines of any floating platform that operates at the oil exploration and production activities at sea.
The device is mounted at a point onto an anchoring line without it becomes as an integral part thereof, such that, once collected the necessary data, this device is dismantled from the first line and is mounted on another line in which it is necessary to make a traction measurement without any special maneuver.
The objective is achieved by designing this device which comprises basically: an upper bar and a lower horizontal bar, which are interconnected at one end by a hydraulic cylinder and at the other end by a solid vertical bar, optionally with an extensometer adapted in this vertical bar and, in another possibility, the solid vertical bar is replaced by a second hydraulic cylinder.
The present invention is relating to a device for measuring and/or to monitor the traction forces acting on an anchoring line at any floating platform that operates in exploration and oil production activities at sea, device which is mounted at a point on that anchoring line without becomes an integral part thereof. Once collected the necessary data, this device can be taken from the first line and mounted on another line in which it is necessary to make a measurement of the traction forces, without any special maneuver.
The anchoring line (LA) mentioned throughout this report is formed by a plurality of links (W).
The device (A) to monitor the traction in an anchoring line can be seen at the
The said vertical bar (4) can be selected from the following configurations:
The mounting of the device (A), best seen in
On applying the hydraulic pressure to the first cylinder (CH1), the piston rod (3) is pushed back causing the side of the hydraulic cylinder (CH1) to become as the same length than that of the vertical bar (4), the second link (W2) and the third link (W3) slacken, and the traction force acting on the anchoring is transferred to the device (A).
On operating the device (A), the upper bar (1) and the lower bar (2) are parallel to each other. When mounting or dismounting, the upper bar is at an angle relating to the lower bar (2) due to the hydraulic cylinder (3) be distended.
The traction measurement transferred from the anchoring line (LA) to the device (A) may be chosen from:
According to the features that were exposed above, it can be safely stated that the device (A) to measure and/or monitoring the tension in an anchoring line (LA) has as its main advantages:
a) it is not necessary to disconnect or handling the anchoring line (LA) in order to get the traction measure;
b) get immediately the traction measure;
c) detect immediately the breaking of an anchoring line (LA);
d) operates in an environment dry or submerged in water;
e) may be maintained permanently mounted to an anchoring line (LA), and is only triggered when it is desired to obtain the traction value on the line, or be removed from a particular line and mounted on another so as to measure the traction effort in all the anchoring lines (LA) of the floating platform;
f) has a simple and flexible operation, and does not interfere with the floating platform operation.
While the invention has been described in its preferred embodiment, the main concept guiding the present invention is a device to monitor the traction on an anchoring line of a floating platform for oil exploration and production at sea, said device being mounted on a point on the anchoring line without becoming an integral part thereof, so that, once collected the necessary data, this device can be dismounted from the first line and be mounted in another line in which it is necessary to make a measurement traction, without any special maneuver, maintaining itself preserved about its innovative character, where those usually skilled in the art may discern and practice variations, modifications, alterations, adaptations and appropriate and compatible equivalents to the concerning working environment without, however, departing from the comprehensiveness of the spirit and scope of the invention that are represented by the claims that follow.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/BR2014/000097 | 3/26/2014 | WO | 00 |
