Patent Application
20190055798
Oil and gas drilling operations use drilling fluid or drilling mud to lubricate, cool, and circulate fluid in the well. A regular occurrence is the formation of gumbo, which is a generic term for soft, sticky, swelling clay formations that are frequently encountered in surface holes offshore or in sedimentary basins onshore near seas. Gumbo fouls drilling tools and plugs piping. Possum bellies are tools used to separate gumbo from drilling mud; however, conventional designs are inefficient and are themselves prone to clogging, sometimes requiring an operator to manually clear gumbo from the possum belly.
Embodiments of the present disclosure are directed to a possum belly that can be used to separate unwanted material from a fluid flow. The possum belly can include a filter having a plurality of slats forming an apex and sloped sides. The slats form a first layer. The possum belly also includes a second layer movable relative to the first layer from a first position to a second position. In the first position the slats are aligned with openings in the second layer and the filter is closed. In the second position the openings in the second layer are positioned at least partially between the slats and the filter is at least partially open. The possum belly also includes a trough positioned relative to the filter to receive material deposited onto the filter from above that does not pass through the filter, and a lower collection area below the filter and being configured to receive material deposited onto the filter from above that passes through the filter. The slats can form a cone-shaped filter and wherein the second layer is rotatable relative to the first layer. The slats form a pyramid and wherein the second layer moves linearly relative to the first layer.
Other embodiments of the present disclosure are directed to an integrated possum belly including a filter unit having sloped sides, an apex, and a plurality of closable openings. The filter is configured to receive a fluid deposited onto the apex from above. The integrated possum belly also includes a first receiving chamber configured to receive material that does not fit through the closable openings, and a second receiving chamber configured to receive material that fits through the closable openings. There can also be one or more sensors configured to monitor the presence of material on the filter, and a controller configured to receive information from the sensors indicating the presence of material on the filter and to actuate the filter to open or close the closable openings in response to the information from the sensors.
Further embodiments of the present disclosure are directed to a method of filtering material from a fluid flow. The method includes depositing the fluid flow onto a raised portion of a filter, the filter having sloped sides configured to direct the fluid flow at least approximately equally in two or more lateral directions, and actuating the openings in the filter to accommodate a predetermined size of material to filter out the material from the fluid flow. The method also includes collecting the material separate from the filtered fluid.
Below is a detailed description according to various embodiments of the present disclosure.
In some embodiments the slats of the first and second layer have the same width and the same number of slats. As such, the layers can be rotated relative to one another (with one or the other or neither being fixed) between a fully open position in which the slats overlap and a fully closed position in which the slats of the second layer bridge the spaces between slats of the first layer. Other configurations are possible as well including having slats of different sizes in the first layer and the second layer. For example, the slats and spaces of the first layer can be larger than the slats and spaces of the second layer. In this formation, the slats of the second layer are not large enough to fully close the cone 22, but in a fully open position with the slats of the second layer smaller than and covered by the slats of the first layer, the cone 22 may perhaps be able to withstand a higher fluid flow rate by covering the slats of the second layer. In still further embodiments the slats and spaces of either the first or second layer can be irregular. The layers can rotate relative to one another more than a single slat width, and in some cases can include a fully 360 degree rotation of the layers. The irregularity of the slats and spaces and the full rotational capability of this configuration allows for more precise customization of the size and orientation of the spaces.
The possum belly 20 also includes a plurality of conduits 28 which are coupled to the cone 22 and are configured to receive fluid passing through the cone 22. The drum 24 has a lower portion 30 which can be tapered to conduct the received drilling fluid. There is a lower pipe 32 and a valve 34 which operate to conduct the drilling fluid away from the possum belly 20 for reintroduction into a drilling operation or for other processing.
The tray 42 has a plurality of ports 54 which can be selectively opened or closed to permit the material and fluid in the tray 42 to be disposed of. The ports 54 can be connected to conduits or other delivery or collection means including shakers. The ports 54 and the openings in the pyramid filter 48 can be integrated with a controller 56 which can be configured to operate the ports 54 and the pyramid filter 48. The possum belly 40 can also include a plurality of sensors 58 positioned around the tray 42, in the trough portion 46, on the pyramid filter 48, and in other suitable positions on the possum belly 40. The sensors and the controller can work together to operate the possum belly in an automated fashion. The sensors 58 can determine if there is gumbo in the flow. If there is no gumbo, the pyramid filter 48 can open fully to allow the drilling fluid to move through the pyramid filter 48 as quickly as possible. If there is gumbo, the sensors 58 can detect it and the controller 56 can actuate the pyramid grate 48 to open fully or partially according to the size of the gumbo or other debris in the flow. There can be sensors below the pyramid filter 48 which are in the clean portion of the flow. If these sensors detect that gumbo or some other unwanted material is in this flow, the controller 56 can close the pyramid filter 48 further and can issue a warning to alert an operator to the situation. The ports 54 can also be opened to varying degrees to allow material of greater or lesser size to pass through as the case may require. The sensors 58 can also detect if the gumbo or other unwanted material in the tray 42 is collecting in an uneven fashion with more at one port and less at another. The ports 54 can be opened or closed to even out the fluid.
The filter 64 can be positioned in a fully open position with the spaces in the first and second layers being aligned, a fully closed position in which slats 70 of the first layer 72 are aligned with spaces in the second layer 74, or any intermediate position where the slats 70 of the first layer are partially aligned with spaces of the second layer 74. There can be discrete positions such as 0%, 25%, 50%, 75%, and 100% open, or another suitable selection of positions between open and closed. The further open the filter 64 is, the larger particle, debris, or gumbo is permitted to pass through the filter 64. The tray 82 includes a trough portion 80, side walls 82, a lower collection area 89, and a plurality of ports 84. The tray 82 operates in a manner generally analogous to the tray 42 shown in
The configuration of the present disclosure allows for an even distribution of fluid throughout the possum belly 60, without clogging one port earlier than another. It is to be appreciated that the filter 62 can have more sides and that the angle of the sloped sides 66 can vary as needed for a particular application. There can be a varying number of ports 84 to deliver the material collected to various destinations. The possum belly configurations shown and described in the present disclosure have been described with respect to drilling fluid and using primarily gumbo and other debris as the unwanted material to be filtered out; however, it is to be appreciated that the apparatuses and techniques of the present disclosure can be used with any other fluid to be filtered or otherwise treated.
Opening and closing of the filter 62 and the ports 84 can be controlled by a controller (not pictured) that is electrically coupled to these components. Sensors can be deployed throughout the possum belly 60 and can be used to deliver information relating to the status of the possum belly 60. If there is a need to open or close the filter 62 or the ports 84, 90, the controller can receive this information from the sensors and can execute some logic to actuate the filter 62 or the ports 84, 90. In some embodiments these systems are integrated together such that the possum belly 60 can operate with minimal intervention, eliminating the need for an operator to manually clear gumbo, and preventing clogs which prevents system downtime.
