Method and multi-purpose apparatus for dispensing and circulating fluid in wellbore casing

FIELD OF THE INVENTION

This invention relates generally to equipment used in drilling and completion of underground wellbores, and more particularly to the filling and circulating of drilling fluids in a casing sequence as well as the pumping of cement into the casing to locate the casing within the wellbore ,

BACKGROUND

The method of drilling underground wells to extract oil and gas from reservoirs consists of drilling a hole in the ground down to the petroleum pool and installing a pipeline from the reservoir to the surface. A housing is a protective tubular liner within the wellbore that is cemented in place to ensure a pressure tight connection to the oil and gas reservoir. The housing runs as a single connection at the time it is lowered into the wellbore. Occasionally, the housing jams and is unable to be lowered further down the wellbore. When this occurs, a load must be applied to the housing string to force the housing into the wellbore or a drilling fluid must be circulated down the inside diameter of the housing and out of the housing into the annulus, around the housing from the wellbore to free. In order to do this, it has traditionally been the case that a special rack is installed to apply an axial load to the casing string or to facilitate circulating the drilling fluid.

When the housing is running, drilling fluid is added to each section as it enters the borehole. This action is necessary to prevent the housing from collapsing due to high pressures within the borehole. The drilling fluid acts as a lubricant, facilitating lowering of the housing into the wellbore. As each section of the housing is added to the sequence, drilling fluid is displaced from the wellbore. The prior art discloses hose assemblies, housings connected to the uppermost part of the housing, and tools suspended from a drill hook for filling the housing. These prior art devices and arrangements have been labor intensive to install, have required multiple such devices for a variety of housing sequence sizes, have not sufficiently minimized the loss of drilling fluid and have not been suitable for a multiple purpose. Furthermore, disengagement of this prior art device from the inside of the housing has been problematic, resulting in tool damage, increased down time, loss of drilling fluid, and personal injury.

Circulation of the fluid is sometimes necessary when resistance occurs when the housing is lowered into the wellbore. To circulate the drilling fluid, the top of the housing must be sealed so that the housing can be pressurized with drilling fluid. Because the housing is under pressure, the integrity of the seal is critical to safe operation and to minimize the loss of expensive drilling fluid. Once the housing reaches the bottom, circulating the drilling fluid again is necessary to test the surface piping system to condition the drilling fluid in the hole and to flush wall mass and drilling material from the hole. Circulation continues until at least a quantity of drilling fluid has been replaced equal to the volume of the inside diameter of the housing and the wellbore. After the drilling fluid has been sufficiently circulated, the housing can be cemented in place.

The purpose of cementing the housing is to seal the housing to the well formation. To cement the housing within the wellbore, the assembly to fill and circulate drilling fluid is generally removed from the drilling rig and a cementing head apparatus is installed. This process is time consuming, requires manpower, and subjects the crew of the drilling rig to potential injury if the additional equipment is handled and installed to flush out the mud with water prior to the cementing step. A special cementing head or plug container is installed at the upper portion of the housing, which is held there by a lift. The cementing head includes connections for the discharge line of the cementing pumps and typically includes a bottom wiper plug and a top wipe plug. Since the housing and borehole are full of drilling fluid, it is first necessary to inject a spacing fluid to segregate the drilling fluid from the cement that follows. The cementing plugs are used to strip the inner diameter of the housing and serve to separate the drilling fluid from the cement as the cement is guided down the casing string. When the calculated volume of cement required to fill the annulus has been pumped, the top plug is released from the cementing head. Drilling fluid, or any other suitable fluid, is then pumped behind the top plug, thus entraining both the plug and the cement contained between the plugs to a device at the bottom of the housing, known as a float collar ), transported. When the bottom plug seals the bottom of the housing, the pump pressure increases, tearing a diaphragm in the bottom of the plug. This allows the calculated amount of cement to flow from the inner diameter of the housing to a certain level within the annulus being cemented. The annulus is the space within the wellbore between ID of the wellbore and OD of the casing string. When the top plug comes in contact with the bottom plug, the pump pressure increases, indicating that the cementing process has been completed. Once the pressure within the housing is lowered, a special floating collar valve closes, which keeps the cement flowing from the outside diameter of the housing back into the inside diameter of the housing.

A housing circulator and method of operating it is disclosed in US-A-5191939, by means of which fluid can be introduced into the uppermost end of a string engaged by a lift held on a walking block.

Further, US-A-5501280 discloses a housing filling and circulating device having a flow passage therethrough and a shut-off valve disposed within the flow passage for preventing spillage and preventing fluid backflow through the device when the housing string enters a borehole is descended possesses. The apparatus also includes a pressure relief seal means which relieves pressure from the housing prior to separation of the apparatus therefrom by reflux through the apparatus to thereby prevent spillage of fluid.

The prior art discloses separate devices and arrangements for (1) filling and circulating drilling fluid, and (2) cementing operations. The prior art devices for filling and circulating drilling fluid disclose a closure tube that requires a separate activation step once the tool is positioned within the housing. The closure tubes are known in the art to be malfunctioning due to clogging, leakage, and the like, resulting in downtime. As any writing in the wellbore drilling process is potentially hazardous, time consuming and labor intensive and therefore expensive, a need remains in the art to minimize any downtime. There remains a need in the art to minimize tool replacement and component part installations.

Therefore, a need remains in drilling subterranean wells for a tool that can be used for drilling fluid, filling and circulating, and cementing operations.

For the foregoing reasons, there is a need for a drilling fluid refilling, circulating and cementing tool that can be quickly installed during drilling operations:

For the foregoing reasons, there is a need for a drilling fluid filling, circulating and cementing tool that seals against the inner diameter of a housing having an energy-applying feature.

For the foregoing reasons, there is a need for a drilling fluid filling, circulating and cementing tool that minimizes the waste of drilling fluids and allows for controlled pressure relief of the system.

For the foregoing reasons, there is a need for a drilling fluid filling, circulating and cementing tool that can be used for any housing size.

For the foregoing reasons, there is a need for a drilling fluid filling, circulating and cementing tool that allows additional axial loads to be applied to the housing string, if necessary.

The present invention provides, according to claim 1, a filling and circulating tool operable to charge a housing and circulate fluid in the housing, the filling and circulating tool comprising: a body having a flow path therethrough; a seal for sealing with the housing; the body having at least a first outlet for selectively communicating between the flowpath and the inside of the housing, the at least one first outlet being controllable between open and closed positions to allow fluid flow from the flowpath into the housing via the at least one first outlet in the open position, and for preventing fluid flow through the at least one first outlet and into the housing in the closed position, the body having at least a second outlet for selective communication between the flowpath and the inside of the housing, the at least one second outlet being between a first outlet open and a closed position is controllable, for allowing fluid flow from the flow path into the housing via the at least one second outlet in the open position, and for preventing fluid flow through the at least one second outlet and into the housing in the closed position.

The present invention further provides an apparatus suspended from a barrel block for cementing operations in a wellbore casing, the apparatus comprising: an upper drive frame assembly adapted to be raised and lowered by the run block; a cementing head assembly connected to the upper drive rack assembly; a filling and circulating tool according to claim 1, which is connected to the cementing head assembly; and a wiper plug assembly comprising a plurality of releasable wiper plugs connected in series with the fill and circulate tool for releasing into the housing to seal the bottom of the housing string.

Another aspect of the present invention is to provide a method of filling and circulating fluid into a well casing suspended from a rig floor and for cementing the casing string in the well bore of any one of claims 1 to 18, the method comprising Connecting a filling and circulating tool to the frame assembly of the upper drive; Lowering the upper drive rack assembly so that the fill and circulating tool is positioned above an upper end of the casing depending from the bottom of the drill rig;

Pumping fluid through the top drive through the fill and circulate tool and into the housing string; Installing a cementing head assembly and a wiper plug assembly on the filling and circulating tool; and pumping a calculated volume of fluid through the cementing head assembly to activate the wiper plug assembly to urge a wiper plug into the housing string to facilitate cementing the housing into the wellbore.

The present invention is directed to a method and apparatus that meets the above requirements. A drilling fluid loading, circulating and cementing tool incorporating features of the present invention may be used on racks with conventional rotary type upper drive drilling systems and rack configurations. The tool can be quickly and easily installed in an upper drive or a rotating-type rack assembly. The filling and circulating tool of the present invention includes a mandrel having a central, axial bore extending therethrough. An upper subassembly comprising a series of threaded connections and spacers, bolted to the upper end of the mandrel, is provided to provide suitable spacing of the tool within the frame assembly. The lowermost portion of the mandrel includes a plurality of apertures that allow drilling fluid to flow from the bore and through the apertures, and circulate fluid during drilling. A locking sleeve is disposed about the outside diameter of the mandrel and is positioned to cover the mandrel openings during the fill mode of operation. A retaining spring is disposed on the outside diameter of the mandrel to bias the locking sleeve between the filling and circulating positions. A reverse drill string seal cap is fixedly connected at one end to the outside diameter of the lock sleeve. The opposite end of the cap extends radially outwardly and away from the outside diameter of the locking sleeve and is adapted to automatically seal against the inside diameter of the housing string when the cap is inserted into the housing. A mud safety valve and nozzle assembly is connected to the lower end of the mandrel. The mud safety valve is actuated to the open position by an increased fluid pressure from above and regulates the flow of fluid from the tool. A nozzle is attached to the outlet of the mud safety valve to facilitate entry of the tool into the top of the housing string. This configuration is used in a top drive configuration. When the tool is used in a rotary-type configuration, a bayonet adapter is installed at the inlet of the mandrel and is adapted so that fluid can be pumped directly to the tool. The tool may also be configured in a cementing and drilling fluid filling and circulating arrangement. The cementing and drilling fluid filling and circulating assembly includes a cementing head assembly connected to the top of the mandrel. This configuration allows the tool to be used first to fill in drilling fluid and first to circulate, and then by simply removing the mud safety valve and nozzle and installing the cement scraper plug assembly in place to begin cementing operations to cement the housing in place. can be used. The filling and circulating tool of the present invention, as well as other such tools capable of being inserted into the housing, may be configured with a pressure plate assembly to transfer the weight of the bogie assembly and / or the upper drive to the housing string. to push the string into the hole.

In accordance with the method of the present invention, when the assembly is used to fill and circulate drilling fluid within the housing string, the assembly is first positioned on the top drive or rotary-type unit and then positioned above the housing to be filled. The assembly is then lowered until the hose extension is within the upper end of the housing string without engaging the seal cap with the inside of the housing. In this position, the openings at the lowermost portion of the mandrel are covered by the locking sleeve. The drilling fluid pumps are then started, causing the drilling fluid to flow through the assembly, and open, creating sufficient fluid pressure that flows through the mud safety valve and out of the nozzle into the housing.

To begin the drilling fluid circulation mode, the assembly is further lowered into the housing string to cause the drill string seal cap to automatically engage and seal against the inside diameter of the housing, generally the drill string seal cap and sliding sleeve in place with respect to the housing Housing fixed. Further lowering of the assembly causes the mandrel to move axially downward, causing the mandrel openings to be exposed by the sliding sleeve. With sufficient fluid pressure from the pumps, fluid from the tool enters the housing via the openings and over the nozzle. Continued fluid flow through the tool and into the housing pressurizes the drilling fluid and sufficient pressure causes the fluid to circulate from the inside diameter of the housing into and out of the annulus to expose or remove the housing from the wellbore ,

When the housing has run to the desired depth and drilling fluid loading and circulation is no longer required, the arrangement for the cementing operation can be configured. The drilling fluid lines are separated and replaced by the cement pumping lines. After the drilling fluid flow is stopped, the device is withdrawn from the housing to expose the mud safety valve and hose extension assembly. The mud safety valve and hose extension assembly can be easily tapped from the lower housing or body of the apparatus and the cement scraper plug assembly can be installed. The device with the cement plug assembly and cement pump lines installed are then drained back into the housing. When the drill string seal cap is automatically engaged with the housing, the cementing process begins. The plug release mechanism may be initiated at appropriate times during the cementing operation to release the cement scraper plugs. The present invention can be used in upper-drive or rotary-type racks. Unlike prior art devices, this invention allows the same basic tool to be used for all housing diameters. The only difference is in the selection of the diameter of the drill string seal cap assembly. As a result, the need to have multiple tools on hand for multiple housing diameters is eliminated. This feature is much safer, saves set-up time as well as equipment rental costs for each housing installation. The same base assembly can be used to cement the housing within the wellbore, which in turn saves setup time and equipment rental. In addition, the assembly may be configured to fill in drilling fluid and only to circulate. The prior art does not disclose a single assembly that can be used to fill and circulate drilling fluid, pressurize the housing, fill and circulate cement to place the housing in place.

In order that the invention may be well understood, some embodiments thereof are given by way of example, with reference to the accompanying drawings, in which:

Fig. 1 illustrates an upper drive rack assembly according to the present invention;

Fig. 2 illustrates a conventional bogie assembly used in accordance with the invention;

3 is a side view of the fill and circulate tool in the fill mode, and configured for a top drive rack assembly; group;

FIG. 4 illustrates a side view of the fill and circulate tool in the fill mode and configured for a conventional bogie assembly; FIG.

FIG. 5 illustrates a side view of the fill and circulate tool in the cementing mode and configured for a top-drive rack assembly; FIG. and

FIG. 6 illustrates a side view of the filling and circulating tool configured with the pressure plate assembly. FIG.

Figure 1 illustrates a top drive rig 3. Figure 1 also illustrates the housing fill and circulating tool 46 in the top drive configuration, which is described more fully below. Those skilled in the art will recognize that a hook 2 is suspended from the walking block 1 on a drilling rig. The upper drive unit 3 is suspended from the hook 2. Pressurized fluid is supplied from the drilling fluid pumps 8 via a hose 4 directly to the upper drive unit 3. An upper lower box connection assembly 6 is bolted at one end to the upper drive shoulder 5 to receive the fill and circulate tool 46. The opposite end of the upper sub-box connection assembly is threadedly connected to the housing filling and circulating tool 46. A tool grasping plate 7 may be fixed to the upper lower box connection assembly 6 as a stopper which will engage against the uppermost part of the housing when the tool is released from the upper drive unit 3. An elevator 14 is suspended from hangers 3a and 3b attached to the upper drive unit 3. It should be apparent to those skilled in the art that a connection of the housing 32 under the upper drive unit can be positioned to allow the upper end of the housing to be gripped by the elevator 14 to thereby provide the filling and circulating tool 46 partially insert within the housing 32. The housing 32, suspended from the elevator 14, then via rotary table carriage or Slide members 10 are lowered on the rig floor and the turntable 11 below the rack floor and into the wellbore 12. When the housing 32 is lowered, it may be filled with drilling fluid from the fill and circulate tool 46, the entire operation of which is described more fully below. Once the housing 32 is lowered so that the elevator 14 is nearly in contact with the turntable sliding members 10, the slide members 10 are then brought into engagement with the housing 32 to hold it in position above the shelf to secure the next connection of the rack Housing 32 record. The process is repeated until the entire housing sequence is lowered into the borehole 12.

Fig. 2 illustrates a conventional drilling frame with a rotating-type frame assembly with the housing circulating tool installed. 46. Those skilled in the art will recognize that a hook 2 is suspended from the walking block on the rotary-type frame configuration. The hook 2 comprises two eyes 2a and 2b arranged on each side of the hook 2 and used to connect a pair of hangers 13a and 13b and a lift 14 thereunder. The lower end of the hanger 13a and 13b is connected to the eyes 14a and 14b of the elevator 14. The hook 2 also hangs on a guide plate 15, connected to a U-shaped screw ring 16, which is secured to the guide plate 15 with nuts 16 a and 16 b. The U-shaped screw ring 16 extends through openings 15 c and 15 d in the guide plate 15. The hangers 13a and 13b extend through two openings 15a and 156 in the guide plate 15, so that a horizontal movement of the hangers 13a and 13b, the elevator 14 and the filling and circulating tool 46 is limited. A locking block 18 having a central axial bore is welded at one end to the bottom surface 15e of the guide plate 15. The locking block 18 includes at least one opening 18a that extends through the wall of the locking block 18 to receive a spring pin 18b. The spring pin 18b is adapted to releasably extend through the locking block opening 18a and to engage the channel 17a in the upper end of the bayonet adapter 17 on the filling and circulating tool 46. The spring pin 18b is inserted through the opening 18 and into the channel 17a to retain the bayonet adapter 17 within the locking block 18, thereby suspending the filling and circulating tool 46 from the guide plate 15. To supply fluid to the housing, the drilling fluid pump 8 is activated, which discharges drilling fluid into the tube 4 and into the filling and circulating tool via the nozzle 17b on the bayonet adapter 17, which supplies the drilling fluid to the filling and circulating tool 46 and transported into the housing 32 inside. Alternative embodiments of the locking block and the bayonet adapter are provided by the present invention. For example, the locking block 18 may include an internally threaded cylinder and the bayonet adapter with a screw threaded end so as to be bolted to the locking block. In a second alternative embodiment, the locking block 18 has a cylinder with two openings extending through the wall of the cylinder at 180 ° to the upper end of the bayonet adapter, which has a cylinder with two openings extending through the wall of the cylinder extend 180 ° from the cylinder, with an outer side diameter slightly smaller than the inner diameter of the locking block. The upper end of the bayonet adapter is inserted into the inside of the locking block with the openings in alignment with each other. A pin would then be inserted over the openings to retain the bayonet adapter, and therefore the filling and circulating tool.

Figure 3 illustrates the preferred embodiment of the fill and circulate tool in the top-drive configuration and in the fill position. Those skilled in the art will recognize and understand that each component in the flow path includes an inlet and an outlet. The tool consists of a mandrel 19 having a central, axial bore defining a flow path 19a through which fluid flows through the tool. A plurality of openings 19c located near the outlet of the mandrel 19 allow fluid to flow through the openings 19c during the circulation mode of the tool 46, as described more fully below. To elongate the mandrel to expand the tool to any desired length on the frame, the upper subassembly is connected to the inlet of the mandrel 19. The upper subassembly consists of an upper base 20, a first spacer 21, a connector coupling 22, a second spacer 23, an upper collar 24 connected in series to extend over the entire length of the tool as well as the flow path 19a extend. Any number of couplings and spacers or lengths of spacers may be used to achieve proper spacing on the upper drive or conventional bogie configuration. Once the spacing requirements have been determined, the upper subassembly connected to the upper collar 24 at the inlet of the mandrel 19 is configured.

A spring 25 is disposed about the outer surface 19b of the mandrel 19. The upper end 25a of the spring 25 is in engaging contact with and below the lower surface 24a of the upper collar 24. A sliding sleeve 26 in engaging contact with the lower end 25b of the spring 25 is disposed about the upper surface 19b of the mandrel 19. *** " A spring stop 25 c is disposed within the annular space between the spring 25 and the outer surface 19 b of the mandrel 19. The spring stopper 25c is provided to prevent the spring from being damaged by excessive compression. The spring 25 biases the sliding sleeve 26 so that in the filling mode of the tool 46, the sliding sleeve 26 covers the mandrel openings 19 c, which causes fluid to flow exclusively through the outlet of the mandrel 19.

The upper end of the sliding sleeve 26 includes a flange portion 26a, the upper surface of which is in engaging contact with the lower end 25b of the spring 25 and the lower surface thereof is in mating contact with a spacer ring 27. *** " The lower surface of the spacer ring 27 is in engaging contact with a ferrule 28. The ferrule 28 is adapted to hold the upper end 29a of a drill string sealing cap 29 against and between the lower surface of the ferrule 28 and the outer surface of the sliding sleeve 26 near the upper end 26b. The spacer ring 27 minimizes the potential for deflection of the ferrule 28 when subjected to fluid pressure, forcing the drill string seal cap 29 and ferrule 28 upwardly and outwardly. A locking sleeve 30 is disposed about the sliding sleeve 26 and is in contact with the lower end 26b of the sliding sleeve 26. The upper end 30a of the locking sleeve 30 is in engaging contact with the upper end 29a of the drill string sealing cap 29 to further secure the drill string sealing cap 29 within the Clamp 28 and to hold against the outer surface 26 b of the sliding sleeve 26. The drill string sealing cap 29 hangs downwardly with respect to the upper end 29 a of the drill string sealing cap 29 to bulge radially outwardly and away from the sliding sleeve 26 so as to form a cone defining an annular space between the inner surface of the drill string sealing cap 29 and the Sliding sleeve 26 forms. The outside diameter of the bottom end 29b of the drill string sealing cap 29 is at least equal to the inside diameter of the housing 32. The lower end 29b is further adapted to be inserted into the housing and to automatically engage the inside diameter of the housing 32 upon insertion and to form a leakage seal. The drill string sealing cap 29 is formed of a flexible, elastomeric material such as rubber, however, other materials or a combination of materials are provided by the present invention. For example, in an alternative embodiment, the upper end 29a of the drill string seal cap 29 is made of steel while the lower end 29b is made of rubber or some other elastomer.

The outlet of the mandrel 19 is connected to the inlet of a lower housing or body 31. The lower housing or the lower body 31 limits the course of the sliding sleeve 26 down. In the filling mode of the tool 46, the spring 25 biases the sliding sleeve downward so that the bottom surface of the sliding sleeve 26 is in engaging contact with the upper surface of the lower body 31. The lower body 31 is also provided with a channel connection between the mandrel 19 and the mud safety valve 34. A guide ring 33 is connected to the outer surface of the lower body 31 and arranged therearound. The guide ring 33 serves as a guide to center the tool 46 within the housing 32 as it is being discharged. The outlet of the lower housing 31 is threadedly connected to a mud safety valve and nozzle assembly. The mud safety valve and nozzle assembly includes a mud safety valve 34 and a nozzle 35. The preferred embodiment includes a mud safety valve 34 having threads on the outer surface of the valve inlet and internal threads on the inner surface of the valve outlet. The mud safety valve 34 is connected to the tool 46 by being bolted to the housing extension 36 at the mud safety valve 34 connected to the inlet of the outlet of the lower body 31. With this in mind, the housing extensions and a portion of the lower body 31 define the housing and an annular space for the mud safety valve 34 inside. A housing seal 36a having an O-ring is formed within a channel formed in the outer surface of the upper end of the housing extension 36, against the outlet of the inner surface of the lower body 31 and against the pressurized fluid leaking at the connection leakage seal. Starting with the interior parts of the mud safety valve 34 at the outlet area, a choke 37 is connected to a choke extension 38 for regulating fluid flow from the tool 46. The choke extension 38 and the housing extension 36 are adapted to retain a piston spring 39 within the space defined by a portion of the inner surface of the housing extension 36 and the outer surface of the choke extension 38. A piston 40 having a central, axial bore is connected to the upper end of the choke extension 38. The piston 40 includes a centrally located projecting annular portion 41 which is in sliding, mating contact with the inner surface of the valve housing 42. A piston seal 40 a having an O-ring is disposed within the channel formed in the annular portion 41 to form a leak-tight seal against the valve housing 42. The upper end of the piston 40 includes a plurality of openings 40b to allow fluid to flow into and into the bore of the piston 40 out of the choke 37. A plunger tip 40c is adapted to achieve a fluid tight seal against a piston seat 43a. The piston spring 39 biases the piston 40 to thereby exert an upward force on the choke extension 38 and therefore on the piston 40 so that the piston tip 40c engages and forms a fluid-tight seal against the piston seat 43a. A fluid pressure exerted on the piston tip 40c will cause the piston spring 39 to compress, creating an opening that allows fluid to flow through the mud safety valve 34 through the nozzle 35 and into the housing 32. The valve housing 42 is disposed between the piston 40 and the lower housing 31 and in an engaging contact therewith. A housing seal 42 a having an O-ring is disposed within a channel formed in the outer surface of the valve housing to achieve a leak-tight seal against the lower housing 31. A seat ring 43 having a central, axial bore is in engaging contact with the uppermost inner portion of the lower body 31 and is disposed within and in mating contact with the valve housing 43 and the upper body 37. A seal 31a of the lower body having an O-ring is disposed within a channel formed in the lower case 31 to achieve a leakproof seal against the seat ring 43. The outlet of a centrally located bore within the seat ring 43 defines the piston seat 43a. The piston seat 43a is adapted to sealingly receive the piston tip 40c. The seat ring 43 further includes a plurality of spring-loaded shut-off valves 44 received within vertical cavities 43b. An opening 43c extends from each of the cavities 43b so as to provide fluid communication between the seat ring bore and the cavities 43b. If the pressure below the seat ring 43 exceeds the pressure above the seat ring 43, fluid will push through the check valves 44 and the openings 45 until an equilibrium pressure is reached above and below the seat ring 43. The check valves 44 therefore operate as safety relief valves to ensure that fluid under high pressure is not trapped underneath the tool, which could cause the tool 46 to be uncontrollably ejected from the housing 43 when it is removed, or could become one uncontrolled, pressurized flow of the fluid from the housing 32 when the tool is removed. It will be apparent to those skilled in the art that the uncontrolled pressurization of the fluid could result in substantial downtime due to loss of fluid, equipment damage, and personal injury. The mud safety valve 34 also functions as a check valve to open when the fluid pressure reaches a desired pressure point of about 21 bar (300 psig). As the fluid pressure rises above 21 bar (300 psig), the piston 40 is compressed against the spring 39, lifting the piston 40 from the piston seat 43, allowing fluid to flow through the tool 46 and into the housing 32. As the fluid pressure drops below about 21 bar (300 psig), the piston spring 39 biases the piston 40 upwardly, causing the piston tip to abut against the seat ring 43. As a result, the mud safety valve 34 retains fluid that would otherwise be drained and wasted by the tool 46. The nozzle 35 is connected to the outlet of the sludge safety valve 34. The nozzle 35 is generally conical to facilitate insertion into the housing and includes an opening 35a, all of which allow fluid to escape from the tool 46 into a region of substantially laminar flow. Several configurations of mud safety valve 34 and nozzle 35 are provided by the present invention. For example, a hose may be connected between the mud safety valve 34 and the nozzle 35, or a hose may be connected between the lower housing 31 and the mud safety valve 34.

To begin the fluid filling process, the fill and circulate tool 46 is lowered over the housing 32 to be filled. Only the area of ​​the tool 46 below the drill string sealing cap 29 is inserted into the housing 32. The drill pipe sealing cap 29 remains above and outside the housing during the filling process. The filling of fluid is carried out by simply activating the pump 8 to fill, and then by deactivating the pump 8 at the completion. As the fluid pressure within the tool 46 increases, the mud safety valve piston 40 is lifted by the piston seat 43a and fluid is allowed to flow through the fill and circulating tool 46 and into the housing 32 to be filled.

Fig. 4 illustrates the preferred embodiment of the fill and circulate tool in the rotary type configuration. Fig. 4 illustrates a bayonet adapter 17 connected to the first spacer 21 in place of the upper base 20 on the upper subassembly. If the upper subassembly is not needed, the bayonet adapter 17 can be connected directly to the mandrel. The bayonet adapter 17 includes a fluid tube connection 17b adapted to be connected to the fluid tube 4, and a cylindrical column 17c extending from the top of the bayonet adapter 17. The outer diameter of the column 17 c is slightly smaller than the inner side diameter of the locking block, so that the column 17 c can be inserted within the bore of the locking block 18. The outer surface of the upper end of the column 17 includes a channel for receiving a spring pin, allowing the filling and circulating tool 46 to be suspended in a bogie configuration.

FIG. 4 also illustrates the fill and circulate tool 46 in a fluid circulation mode. The fill and circulate tool 46, in the bogie configuration, is shown lowered into the housing 32 such that the drill string seal cap 29 is in sealingly engaging contact with the inside diameter of the drill string Housing 32 is. A flow of fluid from the pump 8 will cause fluid pressure to build up within the housing 32 until the hydrostatic pressure is overcome, thereby resulting in the desired circulation of fluid from within the housing 32 into the wellbore 12. The drill string sealing cap 29 automatically engages against the inside diameter of the housing 32 as it is lowered therein. Therefore, when circulating within the housing is desired (e.g. as the housing grows in the wellbore 12), another downward force is exerted on the tool 47 by lowering the assembly from the walking block 1. This causes the spring 25, disposed about the outside of the mandrel 19, between the upper collar 24 and the flange portion 26a on the sliding sleeve 26 to be compressed. The downward force causes the mandrel 19 to move vertically downwardly relative to the sliding sleeve 26, thereby releasing the lower end of the mandrel 19 and the openings 19c therein. Pressurized fluid from the fluid pump 8 may now follow the flow path 19a through the tool 46 as well as through the openings 19d into the housing 32. As the housing string 32 is filled, the fluid pressure inside the housing increases, further engaging the drill string seal cap 29 against the inside surface of the housing 32. When circulation is no longer needed, the pump 8 is simply stopped. This causes the piston 40 within the sludge safety valve 34 to abut against the piston 43 a again, which stops the flow of fluid from the nozzle 35. The tool 46 is then retracted from the housing 32 by lifting the assembly, suspended or depending from the walking block 1, so that the next connection of the housing 32 can be received, or for preparing the tool 46 for cementing operations.

5 illustrates the filling and circulating tool in the cementing configuration. While FIG. 5 illustrates the preferred embodiment of the filling and circulating tool shown in FIGS. 3 and 4, the present invention provides a filling and circulating tool of other embodiments before and includes these. Accordingly, the discussion that follows where reference is made to the fill and circulate tool 46 is made for illustrative purposes. Furthermore, this configuration can be used either in the upper drive frame or in conventional bogie assemblies. Any filling and circulating tool suitable for insertion into the housing can be quickly and easily switched from a drilling fluid filling and circulating mode of operation to a cementing configuration as shown in FIG. 5. The filling and circulating tool is, in the cementing configuration, connected to the flow path from a cementing head assembly 47 to a stripper plug assembly 52 and extends it. Using the fill and circulate tool 46, as more fully described above, the cementing configuration has a cementing head assembly 47 connected to the first spacer 21 on the upper subassembly and a cement scraper plug assembly 52 instead of the mud safety valve 37 and the nozzle 35. Since the present invention provides and includes filling and circulating tools of various other embodiments, means for securing the upper drive or conventional rotary-type units are provided as required by the particular filling and circulating tool used in the cementing configuration.

The inlet of the cementing head assembly 47 includes a Kelley valve 48. Those skilled in the art will be familiar with the design and operation of a Kelley valve 48 and therefore it is not necessary to discuss the components therein and to describe. The inlet of the Kelley valve 48 is directly connected to the upper drive 3, or a bayonet adapter 17 is connected to the inlet of the Kelley valve, so that the tool (in the cementing configuration) can be hung down from the conventional bogie as it is more fully described above. The Kelley valve 48 is used to isolate the tool 46 from the drilling fluid. Kelley valve 48 also operates to isolate the assembly to rinse back portions of the cementing assembly or flush out portions of the assembly to remove any blocking or flow obstructions. The cementing head assembly further includes a ball drop pump in the tee 49 connected to the outlet of the Kelley valve 48. The ball drop pump in the tee 49 has an inlet nozzle 49a, an outlet nozzle 49b, a pump port 49c, a control ball chamber 50, and a pull pin assembly 51. One or a plurality of control balls 50a is disposed within the control ball chamber. The drawing pin assembly 51 has a pin or Needle nozzle 51a connected at one end to the ball drop pump in the tee 49, an end cap 41b fixedly connected to the opposite end of the nozzle, and a retractable pin 51c connected to and extending through the end cap 51b. The stylus assembly 51 may be manually operated or may be attached to a remote or locally controlled actuator to retract the retractable pin 48h to release the control ball 50a. The outlet nozzle 49b on the ball drop pump in tee 49 is connected to the first spacer 21, the location of which is more fully discussed above.

If the fill and circulate tool 46 is installed with the cementing head assembly 47 and the wiper plug assembly 52, it is preferred to keep cement from flowing through the mandrel openings 19c. If cement is allowed to flow through the mandrel openings 19c, clogging of the openings as well as erosion may occur. To prevent this, the sliding sleeve 26 must be attached to the filling and circulating tool of the present invention so that the mandrel openings 19c remain covered during the cementing operation. To do so, an adjustment screw 27a is disposed within each of a plurality of threaded adjustment screw holes 27b in the outer surface 19c of the mandrel 19 near the mandrel outlet 19c. Preferably, the openings 27d are located a minimum distance above the spring stop 25c so as to fix the sliding sleeve 26 in a position to cover the mandrel openings 27b during the cementing operations. As a result, the cement will not flow from the mandrel 19 through the mandrel openings 19c. It is therefore desirable for the complete flow of cement to follow a flow path 19a so as to ensure proper operation of the ball drop function and to prevent clogging or erosion of the mandrel 19. Those skilled in the art will readily recognize other methods of preventing the sliding sleeve 26 from moving upward to expose the mandrel openings 19d. For example, a tubular member may be disposed above the spring 25 between the upper collar 24 and the sliding sleeve 26, which fixes the sliding sleeve 26 in place.

After the housing sequence has run, it must be cemented into the bottom of the wellbore 12. After the last housing connection has been filled with drilling fluid, a volume of water or flushing fluid is pumped through the assembly and into the housing. The assembly is then removed from the housing sequence to be configured for the cementing mode. The filling and circulating tool is then disconnected from the upper drive or rotary drive unit. The cementing head assembly 47 is connected to the inlet of the tool. In the alternative, the cementing head assembly 47 may be pre-installed with the fill and circulate tool for operation in both the drilling fluid and cementing modes. The next step is to connect the wiper plug assembly 52 to the lower body 31 on the fill and circulate tool 46. First, the mud safety valve 34 and the nozzle 35 are removed from the filling and circulating tool 46. The wiper plug assembly 52 is then installed. The wiper plug assembly 52 has an upper wiper plug 52a releasably connected to a bottom wiper plug 52b. The filling and circulating tool is now in the cementing head assembly and is then reconnected to the upper drive or rotary unit. The next step is to release the bottom plug 48d from the wiper plug assembly 49. In order to release the bottom plug 52b, the first and second control balls 50a must be released from the control ball chamber 50. To release the control ball 50a, the pin 51c is retracted, allowing the ball 50a to descend from the control ball chamber 50 and through the tool 46. The first control ball 50a serves to connect between two wiper plugs 52a and 52b, causing the bottom wiper plug 52b to fall into the housing string 32a. A calculated volume of cement is then pumped through the tool and assembly, driving the bottom wiper plug 52b down along the housing string. As the bottom wiper plug 52b lowers the casing string, it wipes mud away from the inside diameter of the casing. The cement drives the bottom scraper plug 52b to engage the floating collar at the bottom of the housing 32. After the calculated volume of cement has been pumped, a second control ball is released from the ball drop pump in tee 49. The second control ball separates the upper plug 52a from the wiper plug assembly 52 and lowers into the housing sequence. The upper plug 52a is driven downwardly along the housing 52 by pumping drilling fluid or other suitable fluid behind the upper plug 59a, which also strips the cement from the inside of the housing. When sufficient pressure is generated between the two wiper plugs 52a and 52b, a diaphragm is ruptured in the bottom wiper plug 52b, allowing cement between the wiper plugs 52a and 52b from the inside of the housing 32 through the bottom wiper plug 52b and into the annulus flows into it. After the upper plug 52a has come to rest by engagement against the bottom plug 52b, the outlet pressure at the pump begins to increase, indicating that the housing 32 has been successfully sealed against the annulus 12.

Fig. 6 illustrates a pressure plate assembly 53. During housing operations, it may be necessary to apply a downward force to push the housing 32 into the wellbore. This feature allows the weight of the rack assembly to be applied to the top of the housing via the pressure plate assembly 53. While FIG. 6 shows the preferred embodiment of the filling and circulating tool shown in FIG. 3, the present invention provides and incorporates filling and circulating tools of other embodiments. Accordingly, the discussion that follows where reference is made to the fill and circulate tool 46 is for illustrative purposes. Furthermore, this configuration can be used in either the upper drive rack or in conventional bogie arrangements. The pressure plate assembly 53 is disposed between the upper collar 24 and the upper subassembly 20 on the fill and circulate tool 46 and is installed in place with the standard connector coupling 22. The pressure plate assembly 53 includes a coupling 54 having a plurality of J-shaped slots 55 within the outer wall 56 of the coupling 54. A rotatable plate 57 is disposed radially about the coupling 54 and is adapted to be fixed about the coupling 54 with a plurality of pins 58.

To apply a load to the housing string, the plate 57 must first be rotated until the pin 58 is engaged within the horizontal area of ​​the J-shaped slot 55. This locks the plate 57 within the assembly 53 so that a load can then be transferred to the housing sequence. The spider 10 is then engaged against the housing 32 to hold the string in place. The elevator 14 is then released from the housing above the rack floor. The upper drive unit 3 is then lowered by the walking block 1 until the plate 57 is in contact with the top of the housing sequence. The elevator 14 is then attached to the housing 32. The spider 10 is then released. The housing 32 is held only by the elevator 14. Further lowering of the upper drive unit 3 adds a load (the weight of the rack) to the housing string, which pushes the string into the wellbore 12. To release and release the load from the rack, the spider 10 is adjusted against the housing to hold the housing string. The walking block 1 is then raised about 6 inches to hang on the upper drive unit 3 enough to release the plate 57 from the top of the housing 32. The plate 57 is then rotated so that the pins 58 are aligned with the vertical portion of the J-shaped slot. The walking block 1 is then lowered about 6 inches to push on the upper drive unit 3 enough to allow the elevator to be released from the housing sequence. The assembly can now be positioned to receive the next connection of the housing 32 to add to the sequence.

Those skilled in the art will readily recognize how to further modify the present invention. For example, many of the connections shown have been threaded, however, it should be understood that any connection means (thread, weld, O-ring, etc.) that can achieve a leak-tight connection can be used without the subject matter of the present invention Invention as disclosed herein. In addition, the subject matter of the present invention should not be construed as limiting the particular material of construction. Therefore, many construction materials are provided by the present invention including, but not limited to, metals, fiberglass, plastics, as well as combinations and variations thereof.