Patent Application
20160258261
This invention discloses a pumping unit for oil drilling with a movement control mechanism within a rotating head. More specifically, it comprises a device applied on a pumping unit that automatically sets-off the position of the load at each shifting of the course, providing an automatic adjustment mechanism for the halter, and thus avoiding the need to stop the pumping unit.
Artificial elevation processes are used in the event the reservoir lacks sufficient pressure so as to lift those fluids to the surface. The most common ones in the oil industry are: mechanical pumping, progressive cavity pumping, submerged centrifugal pumping, hydraulic pumping and pneumatic lifting or gas-lift.
Mechanical pumping is based on the transfer of rotating movement to linear vertical movement, using pumping units which promote artificial lifting of the oil deposited in the reservoirs.
Mechanical pumping with stems or rods was the first lifting method used in the oil industry. Its relevance is reflected in the number of this type of facilities in the world, 87% being equipped for mechanical pumping production (Nascimento, João Maria Araujo computational simulator for oil wells with artificial lift methods for mechanical pumping 2005. 114 f Dissertation Master of Science: . . . Federal University of Rio Grande do Norte, Natal, 2005).
The pumping unit is placed on a base, on it are placed a reduction gear box and an engine, a rod and a crank used for transmitting movement to the transversal beam supported on a tripod, whose head supports a polished stem by means of steel cables (halter) which, due to the geometry of the pumping unit head causes the polished stem to perform its movement vertically inside the well, thus reducing stress and friction.
Counterweights are used on the crank or walking beam so that on the upward course the counterweights may descend, reducing the required engine power, and on the downwards course the engine must provide energy so as to lift the counterweights. Therefore, this balancing may only be achieved if adjusted to the position and number of counterweights within the pumping unit.
The course of the polished stem is determined by the distance of the crank axle to the rod bearing support. If the position where the rod is fixed to the crank is altered, this course may be changed.
When the crank turns (1), it moves the rod (2), causing the transversal beam (3) to rise on one side and go down on the other side, like a swing. When this occurs, the head (110) of the pumping unit (100) accompanies the displacement of the transversal beam (3), moving the load (A) on a vertical direction from a position 1, as seen in (A) towards a position 2, as seen in (B). Thus, pumping occurs when the load (A) is lifted. When the load (A) goes down, new oil is sucked and so henceforth, going up and down from 5 to 16 times per minute.
If the rotation radius (R) of the crank (1) is altered, the direction is altered and the radius (r) is then altered.
The new higher position of the load (A) (position 1.1) will now not be as high as the previous one (position 1) and the new position (position 2.1) will not be as low as the previous one (position 2). This results in that the course under this condition is smaller than the previous condition one, pumping a smaller volume of oil on each pumping. This alteration is called “shifting of pumping course”.
This change generates pumping issues, since the pump used is unable to work properly if its lower position (position 2) should be moved up (position 2.1).
Theoretically, the pump should always keep the same lower position (which is shown as an example in position 2), even if the course is altered.
Currently, for each “shifting of pumping course” a trained team must turn off the pumping unit—automatic or not—and reposition the load fixing height (A), which causes production losses for the well.
In this way, in order to avoid stopping the pumping unit for automatic set-off of the load position (A) at each “shifting of pumping course”, the purpose of this invention is a hydraulic device fitted on the stem of the oil well, where such device alters the height of the oil well stem, decreasing or increasing same so as to set-off when the “shifting of pumping course” takes place, without the need to stop the pumping unit when this is equipped with an automatic course regulation device.
The movement control mechanism of a mobile body within a rigid head of a pumping unit comprises a device composed of a fixed portion and a mobile portion.
The fixed portion comprises a set composed of a reducer, differential gear box and its motor, and a control system.
The mobile portion comprises a mobile bodyfa fitted on a rotating head, a worm gear, a master gear, transfer gears and a movement system.
The reducer rotates the mobile portion completely by means of the axle, and rotates together driving the differential through the transfer gears. The differential transfers the rotation to a gear rotating in the same direction as the gear.
The worm gear is not fixed to the axle, but only transmits traction to the transfer gear, which, through the movement system moves the mobile body. When the differential engine is turned off, the master gear and worm gear rotate at the same rate and in the same direction, so that the gear and the system are not driven at the same time and the mobile body does not move on the rotating head.
When the differential engine is turned on, the mobile body will not be displaced along the rotating head, either when the mobile portion is rotating or when still.
When the engine is turned on, the worm gear rotates at a different rate than the master gear, so that this rate difference moves the gear which through the movement mechanism displaces the mobile body along the rotating head. By inverting the direction in which the mobile body engine rotates, the mobile body will be displaced in the opposite direction. This displacing occurs both with the mobile part is in rotation and when it is still.
The function of the differential gear box is to transfer the rotation of its engine completely if the mobile portion is still. If the mobile portion is rotating under the action of the reducer, the function of the differential will be to set-off the rotation of the engine by adding to or subtracting from the rotation of the mobile portion, so that the displacing of the mobile portion is always performed at the same rate. The differential sets-off the rotation by receiving the rotation of the gear that is being moved by the master gear.
Lastly, the control system records the relative position of the mobile body reporting to the engine when it is time to stop and the necessary rotation direction for achieving another desired position.
The pumping unit for oil drilling, object of this invention, comprises an automatic halter adjustment mechanism fitted on the oil well stem (120), which changes the length of such stem (120), decreasing or increasing same so as to set-off the shifting of course of the pumping unit (100), keeping the stem (120) top always in the same position, and avoiding the need to stop the pumping unit (100) when it is equipped with automatic course regulation at each shifting of the course, as necessary.
The halter adjustment mechanism applied to a pumping unit for oil extraction comprises a fixed body (10) fitted with a peripheral support for fixing the steel cables (11) that are coupled to the head (110) of the pumping unit (100).
On the periphery of the fixed body (10) there are guides (12) where the peripheral support is displaced, with a position sensor (121) being provided on the top end of such guide (12).
A telescopic mobile body (13) on the inner part of the fixed body has a course that is defined according to the movement of the pumping unit (PU) head (110), and moves in the same proportion as the movement of said head (110), the movement of said mobile body (13) being actuated by an electrical-hydraulic unit (20).
When the pumping course is changed, an electronic system detects the new position that the mobile body (13) needs to achieve so as to set-off the movement, and activates the electrical-hydraulic unit (20) which commands the movement of the mobile body (13) so as to displace the same towards the desired position as identified by the position sensor (121).
As shown in
The movement control mechanism of a mobile body within the rigid head of the pumping unit, which is the object of this invention, comprises a device composed of a fixed portion (31) and a mobile portion (36).
The fixed portion (31) comprises a reducer set (32), with a differential gear box (33) and its engine (10) and a control system (38).
The mobile portion (36) comprises a rotating head (35) over which a mobile body (39) is attached (39), a worm gear (37), a master gear (34), transfer gears (11), (12) and (13) and a movement system (14).
The reducer (32) rotates the mobile portion (36) entirely on the axle (15), the gear (34) is fixed on the axle (15) and rotates together by driving the differential (33) through the transfer gear (12). The differential (33) transfers the rotation to the gear (11), which rotates in the same direction as the gear (12).
The worm gear (37) is not fixed to the axle (15), but merely transmits traction to the transfer gear (13) which, through the movement system (14) moves the mobile body (9). When the differential (33) engine (10) is turned off, the master gear (34) and the worm gear (37) rotate at the same rate and in the same direction, in this way, the gear (13) and the system (14) are not activated and the mobile body (39) does not move over the rotating head (35).
While the engine (10) of the differential (3) is not turned on, the mobile body (39) will not be displaced along the rotating head (35), when the mobile portion (36) is either rotating or still.
When the engine (10) is turned on, the gear (11) rotates at a different rate than the gear (12), causing the worm gear (37) to rotate at a different rate than the master gear (34), so that this rate difference moves the gear (13), which through the movement system (14) displaces the mobile body (39) along the rotating head (35). Inverting the direction of the engine rotation (10) the mobile body (39) will be displaced in the opposite direction. This displacement occurs, both when the mobile portion (36) is rotating and when it is still.
The function of the differential gear box (33) is to transfer the rotation of its engine (10) completely if the mobile portion (36) is still. If the mobile portion is rotating under the action of the reducer (32), the function of the differential (33) will be to set-off the rotation of its engine (10) adding to or subtracting from the rotation of the mobile portion (36) so that the displacement of the mobile body (39) is always performed at the same rate. The differential (33) sets-off the rotation by receiving the rotation of the gear (12) that is being moved by the master gear (34).
Lastly, the control system (38) records the relative position of the mobile body (39) and reports to the engine (10) when it is time to stop and the necessary direction of the rotation for achieving another desired position.
