Mud bucket with integral fluid storage

A system including a mud bucket with a clam shell enclosure and a storage tank. The clam shell enclosure can have a first portion and a second portion, with the second portion being rotationally coupled to the first portion, where the first portion and the second portion are configured to form a sealed chamber around a joint of a tubular string when the second portion is rotated into engagement with the first portion, where the sealed chamber is configured to receive expelled fluid from the tubular string when the joint is unthreaded, and the storage tank is configured to receive and store the expelled fluid from the sealed chamber while the mud bucket is located at the well center.

TECHNICAL FIELD

The present invention relates, in general, to the field of drilling and processing of wells. More particularly, present embodiments relate to a system and method for significantly preventing spillage of operational fluids (e.g., drilling mud) when joints of a tubular string are disconnected during subterranean operations.

BACKGROUND

During subterranean operations (e.g., drilling operations) tubular strings may need to be “tripped out” of a wellbore to replace equipment, retrieve sensor data collected downhole, replace tubular segments, inspect equipment, etc. While tripping a segmented tubular string from the wellbore, tubular segments are disconnected from the remaining tubular string and moved from the well center to a storage location (e.g., horizontal or vertical storage). When the tubular segment is disconnected from the tubular string containment systems may be used to capture operational fluids (e.g., drilling mud) contained in the tubular segment being disconnected. The fluids may be captured by a device known as a “mud bucket” and drained off to a remote storage tank. Current mud buckets surround the tubular joint being disconnected to receive the fluids expelled from the tubular segment and a drain hose carries the expelled fluid to a remote collection chamber (mud storage, mud pit, moon pool, etc.). The hose can be coupled to a pump which can pump the expelled fluids to the remote collection chamber. Improvements in these fluid reclamation and containment systems are continually needed.

SUMMARY

In accordance with an aspect of the disclosure, a system is provided for conducting a subterranean operation, the system including a mud bucket that can include a clam shell enclosure comprising a first portion and a second portion, with the second portion rotationally coupled to the first portion, where the first portion and the second portion are configured to form a sealed chamber around a joint of a tubular string at a well center of a rig when the second portion is rotated into engagement with the first portion, with the sealed chamber being configured to receive expelled fluid from the tubular string when the joint is unthreaded; and a storage tank that is configured to receive and store the expelled fluid from the sealed chamber while the mud bucket is located at the well center.

In accordance with another aspect of the disclosure, a method is provided for conducting a subterranean operation that can include the operations of sealing a mud bucket around a joint of a tubular string extending from a drill floor; unthreading the joint; capturing fluid expelled from the tubular string in a sealed chamber of the mud bucket as the joint is being unthreaded; and storing the fluid in a storage tank of the mud bucket.

DETAILED DESCRIPTION

The use of “a” or “an” is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise.

The use of the word “about”, “approximately”, or “substantially” is intended to mean that a value of a parameter is close to a stated value or position. However, minor differences may prevent the values or positions from being exactly as stated. Thus, differences of up to ten percent (10%) for the value are reasonable differences from the ideal goal of exactly as described. A significant difference can be when the difference is greater than ten percent (10%).

FIG. 1is a representative view of a rig10that can be used to perform subterranean operations. The rig10is shown as an offshore rig, but it should be understood that the principles of this disclosure are equally applicable to onshore rigs as well. The example rig10can include a platform12with a derrick14extending above the platform12from the rig floor16. The platform12and derrick14provide the general super structure of the rig10from which the rig equipment is supported. The rig10can include a horizontal storage area18, pipe handlers30,32,34, a drill floor robot20, an iron roughneck40, a crane19, and fingerboards80. The equipment on the rig10, can be communicatively coupled to a rig controller50via a network54, with the network54being wired or wirelessly connected to the equipment.

Some of the equipment that can be used during subterranean operations is shown in the horizontal storage area18and the fingerboards80, such as the tubulars60, the tools62, and the bottom hole assembly (BHA)64. The tubulars60can include drilling tubular segments, casing tubular segments, and tubular stands that are made up of multiple tubular segments. The tools62can include centralizers, subs, slips, adapters, etc. The BHA64can include drill collars, instrumentation, and a drill bit.

FIG. 2is representative perspective view of some robots that can be used on a drill floor16of a rig10during subterranean operations.FIG. 2shows a drill floor robot20gripping a tool62at the top end of the tubular string66. The gripper22can engage the tool62and spin it off the top of the tubular string66in preparation for installing a tubular60to the end of the tubular string66. The pipe handler32can engage a tubular60with the grippers36and move the tubular60from a storage location or the pipe handler30to a well center82where the pipe handler32can thread the tubular60onto the tubular string66. The iron roughneck40can then torque the joint via torque wrench42and backup tong44.

When tripping the tubular string66from the wellbore, the iron roughneck40can be used to break lose the joint via the wrenches42,44. The drill floor robot20(or other transport means, such as a mobile cart, robotic arm attached to drill floor16, etc.) can also be used to move a mud bucket100between a storage location and a deployed location. For example, the gripper22of the drill floor robot20can be removed and the drill floor robot20connected, via tool interface, to a mud bucket100for collecting expelled fluid when a tubular joint is disconnected.

FIG. 3is a representative side view of a drill floor robot20carrying a mud bucket100toward a tubular string66. This example shows a drill floor robot20that includes a support platform24mounted on a drill floor16, with a base25that can move along the platform24. A body26of the drill floor robot20can include control for positioning on the platform24and the positioning of the robotic arms27and28. The robotic arm27is pivotably connected to the base26and to the robotic arm28. The robotic arm28can be a multiple segment arm that provides for a wide range of motion. The robotic arm28can be coupled to the mud bucket100via a tool interface130.

The mud bucket100can include a clam shell enclosure110and a storage tank150integrally connected to the clam shell enclosure110. The clam shell enclosure110can have a central longitudinal axis90that extends through the storage tank150. The clam shell enclosure110can be configured to seal around a joint in the tubular string66. When the tubular string66is being tripped out, the tubular string66can be pulled out of the wellbore at the well center82enough to present a joint connection between the pin end69of the tubular60and the box end67of the top end of the tubular string66. The tubular string66can have a longitudinal axis92that extends through the tubular60and into the tubular string66.

FIG. 4Ais a representative side view of a drill floor robot20carrying a mud bucket100that is sealed around the joint in the tubular string66. The drill floor robot20can manipulate the mud bucket100such that the longitudinal axis of the clam shell enclosure110and the longitudinal axis92of the tubular60are aligned (or at least substantially parallel) with each other. This alignment of the two axes90,92can occur when the clam shell enclosure110is in an open position allowing the tubular string66to enter through a side of the mud bucket100. Once the axes90,92are aligned (or substantially aligned), the clam shell enclosure110can be actuated to close around the tubular string66, thereby sealing the clam shell enclosure110above and below the joint of the tubular string66. With the clam shell enclosure110sealed around the tubular string66, the tubular60can be unthreaded (e.g., via a pipe handler, top drive, spinner, etc.) from the tubular string66allowing operational fluid (e.g., drilling mud, water, production fluid, treatment fluid, etc.) contained in the tubular60to be released into the clam shell enclosure110and collected in the storage tank150. The storage tank150may not include a hose for draining the fluid from the storage tank150into a collection chamber positioned away from the well center82.

The storage tank150includes sufficient capacity to receive all the operational fluid expelled from the tubular60(which is being disconnected from the tubular string66) and store the expelled fluid in the storage tank150until the mud bucket100is removed from the well center82. When the mud bucket100is transported away from well center82to a remote location (such as at an inlet to a collection chamber), the outlets of the storage tank150can allow the expelled fluid contained in the storage tank150to be released into the collection chamber to substantially empty the storage tank150in preparation for the next time a tubular60is disconnected from the tubular string66. When substantially emptied, the mud bucket100is again ready to repeat the process to capture the expelled operational fluid from the next tubular60when it is disconnected from the tubular string66. This process can continue until all desired tubulars60are removed from the tubular string66.

FIG. 4Bis a representative functional diagram of a drill floor robot20carrying a mud bucket100and engaging a docking station250after the mud bucket100has captured the expelled fluid from the tubular60when the joint of the tubular string66was unthreaded. As seen inFIG. 4A, the mud bucket100is sealed around a joint of the tubular string66. When the tubular60is unthreaded from the tubular string66, fluid contained in the tubular60can be expelled into the sealed chamber200of the clam shell enclosure110. The expelled fluid240, as explained in more detail below, can be collected from the sealed chamber200and held in the storage tank150until the mud bucket100is moved away from the well center82(and the tubular string66) and engaged with the docking station250. The clam shell enclosure110can be open or closed when the mud bucket100is engaged with the docking station250. However, it may be preferred to have the clam shell enclosure110closed to reduce necessary clearances when moving the mud bucket100across the drill floor16.

The docking station250can include an inlet254that can engage an outlet154aof the storage tank150when the mud bucket100engages the docking station250. Engaging the inlet254to the outlet154acan actuate a valve in the storage tank150and cause the expelled fluid240contained in the storage tank150to be released (or discharged) into the docking station250chamber251. A one-way valve252(e.g., a flapper valve) can be coupled to the inlet254and allow the expelled fluid240to enter the chamber251, but prevent fluid (e.g., liquid or gas) from the chamber251from flowing back into the storage tank150or into the atmosphere when the mud bucket100is not engaged with the docking station250. This can prevent unintended escape of fluid from a collection chamber260(e.g., a mud pit).

The docking station250can couple to an inlet258of a collection chamber260for flowing the expelled fluid240from the chamber251into the collection chamber260as collection fluid262. A valve256can be coupled to the inlet258to allow fluid to flow from the chamber251into the collection chamber260as collection fluid262. The valve256can also be a one-way valve allowing flow in one direction (i.e., fluid262) and preventing flow through the valve256in an opposite direction. However, it should be understood that the docking station250may not include a chamber251, where the expelled fluid240that flows through the inlet254and through the one-way valve252flows directly (howbeit possibly through some conduit) into the collection chamber260(e.g., mud pit). The fluid in the collection chamber260can then be used to resupply operational fluid264to the rig system. The side outlet154bof the storage tank150can be connected to a hose through which the expelled fluid can be discharged from the storage tank150. For example, when the mud bucket100cannot be transported (e.g., via the drill floor robot20) to the docking station250, then the side outlet154bcan be used to for draining the expelled fluid from the storage tank150in preparation for maintenance operations.

FIG. 5is a representative perspective rear view of the mud bucket100, according to certain embodiments. The clam shell enclosure110can include a stationary portion112that can be rotationally fixed to the storage tank150and does not move relative to the storage tank150, and a portion114that is rotationally attached to the stationary portion112and can be rotated (arrows89) about axis96between open and closed positions.FIG. 5shows the clam shell enclosure110in an open position with the portion114rotated away from the portion112to allow a tubular60to enter through a side of the clam shell enclosure110. With the longitudinal axis92of the tubular60(and tubular string66) substantially aligned with the longitudinal axis90of the clam shell enclosure110, the clam shell enclosure110can be closed around the tubular60(or tubular string66) to form a sealed chamber200within which can be positioned the joint of the tubular string66that is prepared for disconnecting.

As used herein, a “sealed chamber” refers to a chamber that may be in pressure communication with an environment external to the clam shell enclosure110and can be in fluid communication with the external environment at some points along the perimeter seal between the portions112,114. Therefore, a “sealed chamber” refers to a chamber that substantially prevents spillage of fluid at well center82when the tubular60is disconnected from the tubular string66. For example, a top seal assembly210may only need to provide a splash guard for containing the expelled fluid within the clam shell enclosure110, and not a pressure seal. Further stated, if the clam shell enclosure110were rotated upside down, the expelled fluid within the clam shell enclosure110might leak out through the seal assembly210, but when the clam shell enclosure110is upright and the seal assembly210is positioned at the top of the clam shell enclosure110, most (if not all) of the expelled fluid can be successfully contained within the clam shell enclosure110until the expelled fluid is released into an inlet of a collection chamber251or260(e.g., a mud pit), the inlet being spaced away from the well center82. With that said, the bottom seal assembly220(not shown, seeFIG. 9C) may require a more robust seal around the tubular string66to prevent the expelled fluid contained within the clam shell enclosure110from being forced past the bottom seal assembly220when the fluid from the tubular60is drained into the storage tank150. Therefore, the “sealed chamber” can include a top seal that can be more of a splash guard and a bottom seal that can form a tight seal with the tubular string66and substantially prevent leakage of the fluid through the seal or between the seal and the tubular string66when the clam shell enclosure110is engaged with the tubular string66.

The portion112can have one or more structural supports115arranged on a perimeter of the portion112which can provide support for a rotational connection to one or more supports116on a perimeter of the portion114. Each of the supports115can be rotationally coupled to a respective support116at a pivot128. It should be understood that the supports115,116are not required, since the portions112,114can be configured to support a pivot128connection between the portions112,114. The pivot128can be formed in the portions112,114to allow the portion114to be rotated relative to the portion112.

In this embodiment, the portions112,114are rotationally connected at pivots128which are positioned at a location in the supports115,116. Linkage assemblies111can be used to couple the supports115,116together at respective points in the supports115,116that are spaced away from the pivots128. Each linkage assembly111can include links118and122. The link118can be rotationally attached at one end to the link122at pivot119and rotationally attached at an opposite end to the support116at pivot117. The link122can be rotationally attached at one end to the link118at pivot119and fixedly attached at an opposite end to a drive shaft120. The drive shaft120can be rotationally attached to the supports115and driven by an actuator124. The actuator124can comprise a worm gearbox that can provide a self-locking mechanism when the portion114is in the closed position.

As the drive shaft120is rotated by the actuator124in one direction (arrows88about axis94), the links122can move toward the portion114which moves, via the link118, toward a closed position. As the drive shaft is rotated by the actuator124in an opposite direction (arrows88about axis94), the links122can move away from the portion114which moves, via the link118, toward an open position. The actuator124can be coupled to a tool interface130that can receive rotational drive from an external piece of equipment (e.g., drill floor robot20, mobile cart, etc.) and transfer the rotational drive from the tool interface130to the actuator124, thereby rotating the drive shaft120to actuate the portion114between closed and open positions. A support126may be included in the mud bucket100assembly to provide additional support between the tool interface130and the mud bucket100. It should be understood that any other suitable means for actuating the portion114between closed and open positions can be used.

It is not a requirement that the portion114be actuated between closed and open positions by the rotational drive assembly described in this embodiment. The tool interface130should at least be configured to translate an applied force at the tool interface130to a rotational force at the actuator to actuate the portion114toward a closed or open position. The time needed to open or close the clam shell enclosure110can be less than 10 seconds, less than 9 seconds, less than 8 seconds, less than 7 seconds, less than 6 seconds, less than 5 seconds, less than 4 seconds, less than 3 seconds, or less than 2 seconds. A closing force applied to the portion114in the closed position should be greater that a hydrostatic pressure of the fluid contained in the sealed chamber200plus the force needed to sufficiently compress the seals between the portions112,114.

A storage tank150can be fixedly attached to the portion112and the support126. The storage tank150can include an internal chamber sized to receive the expelled fluid when the tubular60is disconnected from the tubular string66. The storage tank150can include an outlet152extending from the top of storage tank150to maintain pressure equalization between the internal chamber and the external environment. As the expelled fluid is drained into the storage tank150, air can escape from the outlet152to prevent pressurizing the internal chamber. The storage tank150can include outlets154a,154bto drain the internal chamber when the mud bucket100is moved away from the well center82.

FIG. 6is a representative perspective view of the tool interface130of the mud bucket100, according to certain embodiments. A conveyance (e.g., drill floor robot, mobile cart, robotic arm attached to drill floor, etc.) can engage the tool interface130to move the mud bucket100to and away from the well center82. In this disclosure, the drill floor robot20may be used in the description as an example of the conveyance to describe the interaction between the conveyance and the mud bucket100. However, it should be understood that it is not a requirement that the drill floor robot20described in this disclosure be the only conveyance means suitable for conveying the mud bucket100about the drill floor16. For example, a mobile cart with a complimentary tool interface can engage the mud bucket100to convey it toward and away from the well center82. Additionally, a robotic arm rotationally attached to a drill floor16can be used to manipulate the mud bucket100around the drill floor16.

This tool interface130can be any shape and configuration to engage the conveyance. However, at least one exemplary tool interface130is described in this disclosure. Referring toFIG. 6, the tool interface130can include a tool engagement structure132that can be engaged by a complimentarily configured conveyance interface. The tool interface130can receive rotational force (or torque) from the conveyance at either or both of the drive gears134,136. These drive gears134,136can be rotated about axis98independently of each other (arrows84and86) and can be rotated in opposite directions if desired. Once the tool interface130is engaged with the conveyance, then the conveyance can manipulate the mud bucket100via the tool interface130through multiple axes of movement. For example, the conveyance can tilt the mud bucket100forward and backward (arrows74), rotate the mud bucket100left and right (arrows72), and move the mud bucket100up and down (arrows70). These movements can be used to substantially align the longitudinal axis90of the clam shell enclosure110with the longitudinal axis92of the tubular string66and with the joint to be disconnected. Once engaged with the tool interface130, the conveyance can move the mud bucket100about the drill floor as needed to position the mud bucket100around a tubular string66at the well center82, or at a fluid discharge location that is remotely positioned away from the well center82, or to other desired locations on the rig10.

FIG. 7is a representative perspective front view of the mud bucket100, in accordance with certain embodiments. The clam shell enclosure110is shown in an open position with a tubular60received through the side entrance opening206of the clam shell enclosure110into the recess or cavity202of the clam shell enclosure110. Seal assemblies210and220can be used to seal around the tubular string66above and below the joint connecting the tubular60to the tubular string66. Seals212,214,216,218can be used to seal along a perimeter between the portions112,114when the clam shell enclosure110is in the closed position. Openings230at the bottom of a chamber200can allow the expelled fluid to drain into the storage tank150when the clam shell enclosure110is closed around the tubular string66and the tubular60is disconnected from the tubular string66. The walls of the storage tank150can form a recess (or cavity)202that provides clearance for the tubular string66through the storage tank when the tubular string66is aligned with the longitudinal axis90of the mud bucket100.

FIG. 8is a representative front view of the mud bucket100with the tubular60and the tubular66positioned in the mud bucket100, in accordance with certain embodiments. The mud bucket100is shown in an open position with the expelled fluid already drained into the storage tank150via openings230, and the tubular60disconnected from the tubular string66. The top seal assembly210can include two halves210a,210bpositioned at the top of the portions112,114, respectively. When the clam shell enclosure110is closed, the halves210a,210bcan form a splash shield around the tubular60. The diameter D1is indicated as the outer diameter of the body of the tubular60. The diameter D2is indicated as the outer diameter of the pin end69of the tubular60. The diameter D3is indicated as the outer diameter of the box end67of the tubular string66. The diameter D4is indicated as the outer diameter of the body of the tubular string66. It should be noted that the tubular60can be extracted from the mud bucket100before the clam shell enclosure110is opened if the seal assembly210is sized to allow the outer diameter D2of the pin end69to move through the seal assembly210.

When the clam shell enclosure110is closed, the halves220a,220bcan form a fluid seal around the tubular string66below the box end67. This seal assembly220can substantially prevent spillage of the fluid from the bottom of the chamber200. A pipe handler (e.g., pipe handler32, top drive, spinner, etc.) can be used to rotate the tubular60(arrows83) about the axis92for unthreading the tubular60from the tubular string66. The height L1of the clam shell enclosure110can include the heights of the pin and box ends69,67, the longitudinal separation between the pin and box ends69,67when they are unthreaded, a desired longitudinal separation between the pin end69and the top of the enclosure110, and a desired longitudinal separation between the box end67and the bottom of the enclosure110. As way of an example, the length L1can be 1380 mm. The height L2of the storage tank150may be determined by the volume of fluid that is needed to be stored in the storage tank150. The volume of fluid to be stored in the storage tank can be multiples (1×, 1.1×, 1.2×, 1.3×, 1.4×, 1.5×, 2.0×, etc.) of the volume of fluid contained in the tubular60before it is to be disconnected from the tubular string66. For example, the tank150may need to store up to 750 liters. In this example, the height L2can be 723 mm.

FIG. 9Ais a representative perspective front view of the clam shell enclosure110of the mud bucket100, according to certain embodiments. The clam shell enclosure110is shown in an open position without the storage tank150attached. As described above, the seal assemblies210,220are used to seal around the tubular string66, with the seal assembly210used as more of a splash guard as opposed to fluid tight sealing around the tubular string66. The seals (e.g.,212,214,216,218, including seals not shown) around the perimeter of the interface between the portions112,114can provide fluid tight sealing between the portions112,114at the perimeter seals.

FIG. 9Bis a representative perspective view of the upper seal assembly210of the mud bucket100, according to certain embodiments. The two halves210a,210bcan form the seal assembly210when the portions112,114are in the closed position. The seal assembly210can form an opening234through the center of the seal assembly210with a diameter D5. The diameter D5can vary to accommodate tubulars60of different outer diameters D1and D2. The seal assembly210can include multiple arcuate resilient seal segments232a,232bwhich may overlap its neighbor (i.e., adjacent segments) to minimize gaps as the segments are flexed to accommodate the tubular60.

FIG. 9Cis a representative perspective view of the lower seal assembly220of the mud bucket100, according to certain embodiments. The two halves220a,220bcan form the seal assembly220when the portions112,114are in the closed position. The seal assembly220can form an opening236through the center of the seal assembly220with a diameter D6. The diameter D6can vary as the seal assembly220is compressed against the tubular string66. However, to accommodate various diameters of tubular strings66, the seal assembly may be replaced with different halves210a,210b. The outer diameter D7of the seal assembly220remains substantially constant, but the inner diameter D6can vary between different sets of seal halves220a,220bto accommodate tubular strings66with varied outer diameters.

FIG. 10is a representative partial cross-section view of the clam shell enclosure110of a mud bucket100, according to certain embodiments. The clam shell enclosure110is shown in a closed position without the storage tank150attached. The portion114has been rotated into engagement with the portion112, causing the seal assembly210to seal around the tubular60above the joint and the seal assembly220to seal around the tubular string66below the joint. These seal assemblies210,220as well as the perimeter seals (e.g.,212,214,216,218) can form a sealed chamber200within the clam shell enclosure110that can contain and direct expelled fluid from the tubular60into the storage tank150through the openings230.

When the clam shell enclosure110is closed around the tubular string66(including the tubular60), the joint connecting the tubular60to the tubular string66may have been untorqued by a roughneck (or other suitable tool) before the mud bucket100is moved to the well center82. With the joint untorqued, but not yet unthreaded, the mud bucket100can be sealed around the joint of the tubular string66. When the clam shell enclosure110is closed around the tubular string66, a pipe handler (e.g., pipe handler32, top drive, spinner, etc.) can begin unthreading the pin end69from the box end67. At some point during the unthreading of the joint, fluid240,242contained in the tubular60can be released or expelled from the tubular60. Gravity can cause the fluid240,242to flow from the tubular60, into the chamber200and down through the openings230into the storage tank150(not shown).

Openings230may only exist at the bottom of the portion112which is fixed to the storage tank150. Since the portion114rotates relative to the storage tank150, it is preferred that no openings230are at the bottom of portion114. Fluid242that is expelled from the tubular60into the portion112, can travel directly through the openings230into the storage tank150. Without openings230in the bottom of the portion114, the fluid240that is expelled into the portion114will be directed to the openings230in the portion112. To facilitate faster draining of the fluid240into the storage tank150, an inclined surface238can be disposed at the bottom of the portion114. The inclined surface238can be inclined toward the openings230and over a lip239. The lip239provides a shallow dam for retaining fluid in the portion112at the completion of draining the fluids240,242into the storage tank150, where a small portion of the fluids240,242may remain at the bottom of the portion112. This lip239helps prevent spillage of the fluid240,242that remains in the portion112, when the clam shell enclosure110is opened. By having the inclined surface238deliver the fluid240over the lip239, then a minimal amount of the fluid240,242remaining in the portion112will be retained by the lip239and the seal half220a.

The fluid240,242can be expelled from the tubular60and stored in the storage tank150in less than 15 seconds, less than 14 seconds, less than 13 seconds, less than 12 seconds, less than 11 seconds, less than 10 seconds, less than 9 seconds, less than 8 seconds, less than 7 seconds, less than 6 seconds, or less than 5 seconds.

FIG. 11Ais a representative perspective rear view of a clam shell enclosure110of a mud bucket100in a closed position, according to certain embodiments.FIG. 11Bis a representative top view of the clam shell enclosure110ofFIG. 11Ain the closed position, according to certain embodiments. To close the clam shell enclosure110, the tool interface130(not shown) can drive the actuator124through a coupling, which in this example includes drive shafts146,148and a gear box140. With the tool interface130rotating the drive shaft146in an appropriate direction (arrows76), the drive shaft148can be rotated in a desired direction (arrows78) via the gear box140which can transfer the torque from the drive shaft146to the drive shaft148. Torque from the drive shaft148can be received by the actuator124, which can cause the drive shaft120to rotate in a clockwise direction (arrow88about axis94), thereby extending the linkage111against the portion114and rotating the portion114in a clockwise direction (arrow89about axis96) into engagement with the portion112forming the sealed chamber200around a tubular string66.

FIG. 12Ais a representative perspective rear view of a clam shell enclosure110of a mud bucket100in an open position, according to certain embodiments.FIG. 12Bis a representative top view of the clam shell enclosure110ofFIG. 12Ain the open position, according to certain embodiments. To open the clam shell enclosure110, the tool interface130(not shown) can drive the actuator124through a coupling, which in this example includes drive shafts146,148and a gear box140. With the tool interface130rotating the drive shaft146in an appropriate direction (arrows76), the drive shaft148can be rotated in a desired direction (arrows78) via the gear box140which can transfer the torque from the drive shaft146to the drive shaft148. Torque of the drive shaft148can be received by the actuator124, which can cause the drive shaft120to rotate in a counter-clockwise direction (arrow88about axis94), thereby retracting the linkage111and rotating the portion114in a counter-clockwise direction (arrow89about axis96) away from engagement with the portion112.

FIG. 13Ais a representative perspective front view of a storage tank150for a mud bucket100, according to certain embodiments. The storage tank150can include a top162, a front164, a right side166, a rear168, a left side170, and a bottom172. An outlet152(e.g., a gas vent) can extend from the top162of the storage tank150. A recess202can be formed in the storage tank150with access through an opening206in the front164. The opening206allows a tubular string66to enter the recess202through the opening206. The opening160in the top162can align with the openings230in the bottom of the portion112, where the expelled fluids240,242flow into the storage tank150. The storage tank150can have a length L4, a width L3, and a height L2. These dimensions can be adjusted when the storage tank150is formed to accommodate various desired tank volumes. As way of an example, with a desired capacity of 750 liters, the height L2can be equal to 723 mm, the length L4can be equal to 920 mm, and the width L3can be equal to 1290 mm. A storage tank150built per this embodiment and with these dimensions can at least 750 liters of fluid240,242.

FIG. 13Bis a representative perspective rear view of a storage tank150for a mud bucket100, according to certain embodiments. Two outlets154a,154bare shown that can be used to drain fluid from the storage tank150. One outlet154acan exit the bottom172. This outlet154acan have a valve (not shown) coupled to it, with the valve actuated between closed and opened positions when engaged with a docking station250or other suitable actuator. When it is desirable to drain the fluid from the storage tank150, the conveyance (e.g., drill floor robot20) can move the mud bucket100away from the well center82and the tubular string66to a location (e.g., a docking station250) that can receive the fluid from the storage tank150. When positioned at the desired discharge location, the valve can be actuated to discharge the fluid240,242from the storage tank150into a collection chamber (e.g., mud pit). The valve can be actuated via wired or wireless control, mechanically actuated (e.g., flapper valve, a poppet valve), hydraulically actuated, or pneumatically actuated. For this example, at least 750 liters of fluid240,242contained in the storage tank150can be drained from the storage tank150through the outlet154awithin 50 seconds, within 45 seconds, within 40 seconds, within 35 seconds, within 30 seconds, or within 25 seconds.

The discharge location can be a docking station250for the mud bucket100, where the mud bucket100can be disengaged from the conveyance (e.g., drill floor robot20) while the fluid is being drained from the storage tank150into the collection chamber. It is not a requirement that the mud bucket100be disengaged at the docking station250, just that it can be disengaged from the conveyance if desired. This can free up the conveyance to perform other rig tasks while waiting for the fluid to drain and waiting for the next joint in the tubular string66to be in position for disconnection during a trip out procedure. The collection chamber can be a mud pit, a temporary storage chamber that can pump the expelled mud to mud pit for reuse later, or any other location that can receive the expelled fluid and save it until it is needed again for other subterranean operations. The docking station250can have a flapper valve that is opened only when the fluid is being discharged from the storage tank150. This will help prevent any release of fluid from the collection chamber (e.g., release any gas drafts from a mud pit).

Alternatively, or in addition to, another outlet154bcan be formed in a side (e.g., left, right, front, or back) and can be used to drain the fluids from the storage tank150into a hose that may be connected to the outlet. The hose can be coupled to the outlet154bduring the mud bucket100operations, or the hose can be connected to the outlet154bat other locations when the mud bucket100is moved to that location. The outlet154bcan also be controlled by a valve that can be actuated via wired or wireless control, mechanically actuated (e.g., flapper valve, a poppet valve), hydraulically actuated, or pneumatically actuated. The fluid240,242contained in the storage tank150can be drained from the storage tank150through the outlet154bwithin 50 seconds, within 45 seconds, within 40 seconds, within 35 seconds, within 30 seconds, or within 25 seconds. It may be preferable for the outlet154bto be manually operated to drain the fluid in the storage tank150when the mud bucket100cannot be delivered to the docking station to drain fluid through the opening154a. The outlet154bcan be used as an emergency drain to empty the storage tank150in the event the robot handling the mud bucket100breaks down or otherwise fails to deliver the mud bucket100to the docking station.

FIG. 13Cis a representative perspective rear translucent view of a storage tank150for a mud bucket100, according to certain embodiments. The sides of the storage tank150are shown as being translucent to allow viewing of the internal features of an example of the storage tank150. Baffles180can be installed in an interior chamber204of the storage tank150. These baffles180can prevent sloshing of the fluid contained in the storage tank150to reduce dislocation of a center of gravity of the storage tank150as it is being moved around on the rig floor16. It is preferred that a gap L5be provided between the top of the baffles180and the top162of the storage tank150to prevent gas from being trapped by the baffles180in the storage tank150. It is also preferred that a gap L6be provided between the bottom of the baffles180and the bottom172of the storage tank150to prevent (or at least reduce) relocation of a center of gravity of the storage tank150when it contains fluid and is moved around the rig10.

FIGS. 14A and 14Bare representative perspective views of a mud bucket100, according to certain embodiments. Much like the mud bucket embodiments shown inFIGS. 2thru12B, the portion112remains stationary relative to the storage tank150, with the portion114being rotationally attached to the portion112at the axis96. Rotating the portion114(arrows89) about the axis96can open or close the clam shell enclosure110. This clam shell enclosure110has additional link assemblies111that can link the drive shaft120to the portion114. Rotational drive from the tool interface130can be coupled to an actuator (not shown) that can rotate (arrows88) the drive shaft120about the axis88. The sealed chamber200can be formed when the portions112,114are engaged with each other in a closed configuration around the tubular string66. The recess202is formed differently than the previously described example, but the storage tank150can still provide access through a side of the storage tank150to allow entrance of the tubular string66into the recess202and the clam shell enclosure110.

FIG. 15is a representative side view of a drill floor robot20engaging a mud bucket100(as shown inFIGS. 14A, 14B) with a tubular string66, according to certain embodiments. The conveyance (e.g., the drill floor robot20in this example) can manipulate the mud bucket100to align the center longitudinal axis90of the clam shell enclosure110with the longitudinal axis92of the tubular string66. The portion114can be rotated to the closed position sealing around the joint of the tubular string66. The tubular60can then be unthreaded from the tubular string66expelling fluid contained in the tubular60into the chamber200and through openings160,230into the storage tank150. When the expelled fluid is captured in the storage tank150, the portion114can be rotated to the open position, the mud bucket100can be moved away from the tubular string66and moved to a discharge location (e.g., a docking station250) to empty the storage tank150into a collection chamber.

FIG. 16is a representative perspective bottom translucent view of a storage tank150of a mud bucket100, according to certain embodiments. Gears182can be disposed in the interior chamber of the storage tank150. The gears182can couple the rotational drive from the tool interface130to the drive shaft120which rotates about the axis94(arrows88). Various other gear configurations can be used to couple the rotational drive from the tool interface130to the drive shaft120for rotating the portion114between open and closed positions. A poppet valve174can be operated to empty the fluid240,242from the storage tank150at the discharge location. A structure at the discharge location can be used to move the poppet valve away from the opening176to release the fluid240,242from the storage tank150into an inlet of the collection chamber.

FIG. 17is a representative side view of a manually operated mobile cart190that can be used as an alternative to the previously described drill floor robot20. The mobile cart190can engage the mud bucket100at the tool interface130and thereby attach the mud bucket100to the mobile cart190. The mobile cart190can be operated by rig personnel194via a control console192. The control console192can be on the mobile cart190or positioned at a remote location where the rig personnel194can safely operate it. The mobile cart190can convey the mud bucket100to and from the well center82to collect the expelled fluid from the tubular60and discharge the fluid from the storage tank150at a discharge location remote from the well center82.

FIG. 18is a representative side view of a drill floor robot20carrying a mud bucket100, in accordance with certain embodiments. This mud bucket100is similar to the previously described mud bucket100embodiments. It should be understood that the previous description also applies to this mud bucket100except were specifically shown and described below to be different.

FIGS. 19A, 19B, 20Aare representative perspective views of a mud bucket100with an integral storage tank assembly270(which includes the integral storage tank150), in accordance with certain embodiments. Similar to previously described embodiments, the mud bucket100can include a clam shell enclosure110with portions112,114. The clam shell portion112can be removably attached to a storage tank assembly270, and rotationally fixed to the storage tank assembly270. The portion114can be rotationally coupled to the portion112, such that the portion114can rotate relative to the portion112and relative to the storage tank assembly270between closed, open and partially open configurations. The storage tank assembly270, can include a frame300and the storage tank150, with the frame300providing structural support for the storage tank150. The frame300can be removably attached to a rear portion of the storage tank150as shown inFIGS. 19A, 19B, 20A.

The storage tank150can include the opening206that allows tubulars to enter the mud bucket100from the front side164of the storage tank150. An outlet154bcan be used to drain fluid from the storage tank150whenever the main outlet154ais unavailable, such as when the mud bucket100is not resting in the docking station250. Of course, the outlet154bcan be used at any appropriate time, but it is preferred that it be used as an emergency outlet for draining the storage tank150A when the mud bucket100is immobile. The tool interface130can be used to interface a drill floor robot20to the mud bucket100for manipulation and control of the mud bucket100, as described in more detail regarding previously described embodiments. A shield138can be used to reduce or prevent debris from entering the coupling of the tool interface130to the drill floor robot20.

Access doors310provide access to various compartments within the storage tank150to facilitate maintenance and cleaning of the internal chambers of the storage tank150. These access doors310are latched and sealed during operation. A fluid level indicator302can be used to measure and monitor a fluid level within the storage tank150by visual inspection. However, the fluid level indicator302is not required and the mud bucket150can be provided without the fluid level indicator302. The fluid level indicator302can include a clear tube in fluid communication between the top and bottom of the storage tank150. This allows the fluid level in the fluid level indicator302to mimic the fluid level in the storage tank150.

The outlet152, in this configuration, is a straight pipe section extending from the top surface162of the storage tank150. Since the outlet152is below and covered by the shield138, it does not need to be like the U-shaped versions as in previous embodiments.

The support126provides structural support for the portions112,114, the tool interface130, the storage tank assembly270, the actuator124, the drive shaft120, and the link assemblies111. The seals210a,210b,220a,220bsealingly engage a tubular string when the tubular string66is positioned within the chamber200of the clam shell enclosure110.

FIG. 20Bis a representative top view of the seal assembly210of the mud bucket ofFIG. 20A, in accordance with certain embodiments. The two halves210a,210bcan form the seal assembly210when the portions112,114are in the closed position. The seal assembly210can form an opening234through the center of the seal assembly210with a diameter D5(seeFIG. 9B). The difference between the seal assembly210ofFIG. 9Band this seal assembly210is that the assembly210inFIG. 20Bcovers most if not all of the top of the clam shell enclosure110. The diameter D5can vary to accommodate tubulars60,66of different outer diameters D1and D2. The seal assembly210can include multiple arcuate resilient seal segments232a,232bwhich may overlap its neighbor (i.e., adjacent segments) to minimize gaps as the segments are flexed to accommodate the tubular60,66.

FIG. 20Cis a representative partial cross-sectional view of a lower seal assembly220of the mud bucket100ofFIG. 20A, in accordance with certain embodiments. The lower seal assembly220can include seals220a,220b.FIG. 20Cshows the portion114rotated to engage the portion112to form the sealed chamber200. The resilient ends of the seal220aengage the resilient ends of the seal220bto seal between the seals220a,220b. The resulting curved inner surface of the seal assembly220can engage a tubular to prevent fluid from passing between the seal assembly220and the tubular string66when the portion114is engaged with the portion112in the closed position of the mud bucket100.

The seals220a,220bform a seal assembly220with an inner diameter of D6. This diameter D6can vary incrementally when the seal assembly engages and disengages the tubular string66. Various diameters of tubular strings66can be accommodated by replacing the seals220a,220bwith other seals220a,220bthat adjust the diameter D6to a desired diameter. The seals220a,220bcan be mounted from below into a cavity formed in each portion112,114, with fasteners (e.g., nuts) coupled to protrusions (e.g., threaded studs) that protrude from the top of the seals220a,220bthrough holes in the top of the cavities in the portions112,114. A seal308can be used to seal between edges of the portions112,114when the mud bucket100is in the closed position.

FIG. 20Dis a representative partial cross-sectional view of an interface between the clam shell enclosure110and a storage tank150of the mud bucket ofFIG. 20A, in accordance with certain embodiments. The extension304extends from the opening230of the portion112and can protrude through the opening160in the storage tank150to provide sealing between the portion112and the storage tank150when the mud bucket100is assembled. A seal306positioned around the opening160engages an outer surface of the protrusion304to prevent fluid from spilling out of the opening160during operation.

FIG. 21Ais a representative partial cross-sectional view of a seal312between the portions112,114of the clam shell enclosure110of the mud bucket100ofFIG. 20A, in accordance with certain embodiments. The seal312can be secured to the edge of the portion112via fasteners316. A flange314can be formed along the edge of the portion114, the flange having a tapered edge that guides the seal312into engagement between the flange314and the edge of the portion112to form sealing engagement between the portions112,114along their edges.

FIG. 21Bis a representative perspective partial front view of a top seal of the mud bucket ofFIG. 20A, in accordance with certain embodiments. The seal assembly210can include multiple arcuate resilient seal segments232a,232bwhich may overlap its neighbor (i.e., adjacent segments) to minimize gaps as the segments are flexed to accommodate the tubular60,66. Due to the length of the resilient seal segments232a,232b, these segments232a,232bmay tend to droop down from the outer edges that are attached to the portions112,114.

This drooping is beneficial, since the drooping causes the seal segments232a,232bto be forced downward when the clam shell portions112,114are in a closed position and engage a tubular60,66. The drooping can be limited by securing a biasing device318a,318bbelow the respective seal segments210a,210b. The biasing device318a,318b(e.g., a spring, a resilient cord, etc.) allows the seal segments210a,210bto droop a desired amount without allowing the segments to droop more than desired. When the seal segments210a,210bengage a tubular60,66, the biasing devices318a,318ballow the seal segments210a,210bto be forced further downward as they engage and seal against the tubular60,66. The biasing devices318a,318bthen return the seal segments210a,210bto the original positions when the portions112,114are opened.

FIG. 21Cis a representative perspective view of a bottom seal220aof the clam shell enclosure110ofFIG. 20A, in accordance with certain embodiments. The bottom seal220acan include a seal carrier221awith protrusions224a(e.g., threaded studs) extending from a top surface of the carrier221a. A seal insert222acan be inserted into the channel of the carrier221ato form the seal220a. Similarly, the bottom seal220bcan include a seal carrier221bwith protrusions224b(e.g., threaded studs) extending from a top surface of the carrier221b. A seal insert222bcan be inserted into the channel of the carrier221bto form the seal220b.

As seen inFIG. 21Dthe seal220acan be assembled into a curved recess in the portion112by extending the protrusions224athrough holes in the portion112and coupling the protrusion224awith a retainer225a(e.g., stud extended through the holes in the portion112with nuts threaded onto the studs to hold the seal220ain place).

FIG. 22Ais a representative perspective front view of a clam shell enclosure110of the mud bucket100ofFIG. 20Ain an open position, in accordance with certain embodiments. The actuator124is operated by couplings to the tool interface130. Rotational force is received at the tool interface130(e.g., from a drill floor robot20) and transferred to the actuator124. The actuator124can rotate the drive shaft120in response to receiving the rotational force. The drive shaft120can rotate (arrows88) about the axis94and cause the linkage assemblies111to rotate the portion114(arrows89) about the axis96. Each linkage assembly111can have adjustable links that provide adjustability of the linkage assembly111.

FIG. 22Bis a representative perspective front view of a clam shell enclosure of the mud bucket ofFIG. 20Ain a closed position, in accordance with certain embodiments. With the drive shaft120rotated to extend the linkage assemblies111and engage the portion114with the portion112, the clam shell enclosure110is in a closed position. The actuator124is self-locking, such that when the actuator124rotates the portion114(via the drive shaft and linkage assemblies) to the closed position, it does not allow rotational forces on the drive shaft120to rotate the actuator. The forces applied to the linkage assemblies111and thus the portion114may not be releasable until the input from the tool interface rotates the actuator124in the reverse direction. To open the clam shell enclosure110, the tool interface is rotated in an opposite direction relative to the direction in which it was rotated to close the clam shell enclosure110. This reverse rotation causes the actuator124to rotate the drive shaft120in an opposite direction and retracts the linkage assemblies111, thereby rotating the portion114to an open position.

FIG. 23Ais a representative perspective view of a tool interface of the mud bucket ofFIG. 20A, in accordance with certain embodiments.FIG. 23Bis a representative side view of the tool interface of the mud bucket ofFIG. 20A, in accordance with certain embodiments. The tool interface130can be mounted to the support structure126above the outlet152and include a shield138that reduces debris and fluids from entering the coupling between the tool interface and the conveyance (e.g., a drill floor robot). The shield138also shields the outlet152from receiving debris and fluids during operation. The shield may not prevent ingress of debris or fluids into the storage tank through the outlet152, but it should minimize it.

FIG. 24Ais a representative partial cross-sectional side view of the tool interface130of the mud bucket100ofFIG. 20A, in accordance with certain embodiments.FIG. 24Bis a representative detailed partial cross-sectional side view of a drive of the tool interface ofFIG. 24A, in accordance with certain embodiments. The tool interface130inFIGS. 24A, 24Bincludes only one drive gear134that can receive rotational forces from a robotic arm or a mobile cart. The drive gear134can rotate (arrows84) about a center axis98and transfer the rotation via a shaft of the drive gear134to a drive gear322on an opposite side of the tool interface130. The shaft of the drive gear134can be rotationally mounted in the tool interface130via bearings324. The drive gear322can be coupled to a drive chain320that can transfer the rotational force to the actuator124.

FIGS. 25, 26are representative perspective rear views of a drive train321for the clam shell enclosure110ofFIG. 20A, in accordance with certain embodiments. The drive train321can include a drive chain320that is coupled to the drive gear322at one end and coupled to a drive gear326at the other end. The drive gear326transfers the rotational force from the drive chain to the actuator124which converts the rotational forces from the drive gear326to rotation of the drive shaft120. The drive shaft120can extend from top and bottom of the actuator124to the respective linkage assemblies111. The top portion of the drive shaft120can include a cardan joint328that allows for misalignments between the actuator124and the top linkage assembly111. The cardan joint328can be protected by a rubber bellow that encloses the joint. The bottom portion of the drive shaft120can include a cardan joint329that allows for misalignments between the actuator124and the bottom linkage assembly111. The cardan joint329can also be protected by a rubber bellow that encloses the joint.

FIG. 27Ais a representative perspective view of a storage tank assembly270for the mud bucket100ofFIG. 20A, in accordance with certain embodiments. The storage tank150is removably installed in the support frame300. The storage tank150can include the emergency outlet154b, the entrance206to the recess (or cavity)202, the outlet152from the top surface162, the opening160with the seal306disposed along the perimeter of the opening160, and access doors310for access to internal chambers of the storage tank150.

FIG. 27Bis a representative partial cross-sectional side view of an access door for the storage tank ofFIG. 27A, in accordance with certain embodiments. Each access door310can include a hinge334that is attached to the top surface162of the storage tank150. When the access door310is closed, it covers and seals an opening in the surface162of the storage tank150. A seal332positioned around the underside perimeter of the access door310engages the top surface162when in the closed position. The latch330can be rotated to latch the access door closed as shown inFIG. 27Bor rotated to release the access door310to rotate about the hinge334to an open position.

FIG. 28Ais a representative perspective view of a support frame300for the storage tank150ofFIG. 27A, in accordance with certain embodiments. The support frame300accommodates a sloped bottom surface of the storage tank150by having legs340that extend a distance of L7below the right horizontal support on the right side338of the support frame300. The left side336of the support frame300does not have an extended leg. This creates a downward slope from the right side338to the left side336at the angle of the bottom of the storage tank150.

FIG. 28Bis a representative front view of the storage tank150inFIG. 27A, in accordance with certain embodiments. The bottom surface172of the storage tank150can slope down from the right side166to the left side170a total vertical distance L7which substantially equals the total vertical distance of the slope of the support frame300. The sloped bottom surface172allows for faster draining of the fluid from the storage tank150.

FIG. 29Ais a representative perspective bottom view of the storage tank assembly270for the mud bucket150ofFIG. 20A, in accordance with certain embodiments. The bottom view shows the primary outlet154athrough which fluid can be drained when the mud bucket100is positioned in the docking station250.

FIG. 29Bis a representative partial cross-sectional view of primary outlet154awith a valve350for the storage tank150ofFIG. 29A, in accordance with certain embodiments. The valve350can be actuated by a protrusion at the docking station250that acts to open the valve350and allow fluid in the storage tank150to be drained. The valve350can include a valve body342that can be mounted to the storage tank150via a flange354. The valve body342can include supports344that allow fluid to flow through the valve350while guiding the valve350within the valve body342. When an upward force is applied to the valve350, the valve350disengages from the valve seat352and moves upward between the supports344.

A guide shaft346can extend through the top of the valve body342to guide the valve350up and down (arrows360). A biasing device348can be used to urge the valve350to a closed position (i.e., valve350engaged with valve seat352). Therefore, as an upward force is applied to the valve350, the valve350will move upward within the supports344and extend the guide shaft346upward through the top of the valve body342. The biasing device348will compress as the valve350moves upward. The fluid contained within the storage tank150can flow through the valve350and out of the storage tank150through the outlet154a. When the upward force is removed from the valve350, the biasing device348will urge the valve350back into engagement with the valve seat352, thereby closing the valve350.

VARIOUS EMBODIMENTS

A system for conducting a subterranean operation, the system comprising:

a mud bucket comprising:

a clam shell enclosure comprising a first portion and a second portion, with the second portion rotationally coupled to the first portion, wherein the first portion and the second portion are configured to form a sealed chamber around a joint of a tubular string at a well center of a rig when the second portion is rotated into engagement with the first portion, wherein the sealed chamber is configured to receive expelled fluid from the tubular string when the joint is unthreaded; and

a storage tank that is configured to receive and store the expelled fluid from the sealed chamber while the mud bucket is located at the well center.

The system of embodiment 1, wherein the storage tank is configured to drain the expelled fluid from the storage tank when the mud bucket is moved away from the well center.

The system of embodiment 2, wherein the mud bucket is configured to drain the expelled fluid at a docking station that is positioned away from the well center.

The system of embodiment 2, wherein the storage tank comprises:

an outlet that is configured to drain the expelled fluid from the storage tank, and

a valve coupled to the outlet, wherein the valve selectively permits and prevents drainage of the expelled fluid from the storage tank.

The system of embodiment 4, wherein the mud bucket is configured to drain the expelled fluid at a docking station that is positioned away from the well center, and wherein the docking station operates the valve to an open position when the mud bucket is engaged with the docking station.

The system of embodiment 5, wherein the docking station comprises a fluid inlet to a collection chamber and a one-way valve coupled to the fluid inlet that allows the expelled fluid to be drained into the collection chamber and prevents flow of a collection fluid from the collection chamber, through the one-way valve, and out of the fluid inlet.

The system of embodiment 1, wherein the storage tank holds the expelled fluid as the mud bucket is moved away from the tubular string.

The system of embodiment 1, wherein a conveyance manipulates the mud bucket about a drill floor.

The system of embodiment 8, wherein the conveyance substantially aligns a longitudinal axis of the clam shell enclosure with a longitudinal axis of the tubular string.

The system of embodiment 8, wherein the conveyance comprises a robot or a manually operated cart.

The system of embodiment 10, wherein the robot comprises a drill floor robot or a robotic arm rotationally attached to the drill floor.

The system of embodiment 8, wherein the conveyance couples to the mud bucket via a tool interface on the mud bucket, and wherein the tool interface couples a rotational drive from the conveyance to the clam shell enclosure and rotates the second portion between closed, open, and partially open positions.

A method for conducting a subterranean operation, the method comprising:

sealing a mud bucket around a joint of a tubular string extending from a drill floor;

capturing fluid expelled from the tubular string in a sealed chamber of the mud bucket as the joint is being unthreaded; and

storing the fluid in a storage tank of the mud bucket.

The method of embodiment 13, further comprising:

unsealing the mud bucket from around the joint; and

storing the fluid in the storage tank as the mud bucket is conveyed away from the tubular string.

The method of embodiment 14, further comprising:

conveying the mud bucket to a docking station on the drill floor;

engaging the mud bucket with the docking station; and

discharging the fluid from the storage tank into the docking station.

The method of embodiment 15, further comprising repeating the preceding operations for each desired joint of the tubular string as the tubular string is tripped out of a wellbore.

The method of embodiment 13, wherein the mud bucket further comprises a clam shell enclosure comprising a first portion and a second portion, with the second portion rotationally coupled to the first portion between open, closed, and partially open positions.

The method of embodiment 17, further comprising:

aligning the clam shell enclosure with the tubular string;

rotating the second portion into engagement with the first portion, thereby forming the sealed chamber around the joint;

flowing the fluid from the sealed chamber into the storage tank; and

storing the fluid in the storage tank as the clam shell enclosure is opened by rotating the second portion out of engagement with the first portion.

The method of embodiment 18, further comprising:

conveying the mud bucket to a docking station on the drill floor;

engaging the mud bucket with the docking station; and

discharging the fluid from the storage tank into the docking station.

The method of embodiment 19, wherein engaging the mud bucket with the docking station actuates a valve of the mud bucket that releases the fluid into the docking station.

While the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and tables and have been described in detail herein. However, it should be understood that the embodiments are not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims. Further, although individual embodiments are discussed herein, the disclosure is intended to cover all combinations of these embodiments.