Patent Application
20120285684
The field of the invention is tubular cutters that grip before the cut to put the string in tension and more particularly a resettable tool with the ability to isolate the tubular with a seal by closing a seal bypass while leaving the bypass open for circulation as the tubular is cut.
When cutting and removing casing or tubulars, a rotary cutter is employed that is driven from the surface or downhole with a downhole motor. The cutting operation generates some debris and requires circulation of fluid for cooling and to a lesser extent debris removal purposes. One way to accommodate the need for circulation is to avoid sealing the tubular above the cutter as the cut is being made. In these cases also the tubular being cut can be in compression due to its own weight. Having the tubing in compression is not desirable as it can impede the cutting process making blade rotation more difficult as the cut progresses. Not actuating a seal until the cut is made as shown in U.S. Pat. No. 5,101,895 in order to allow for circulation during the cut leaves the well open so that if a kick occurs during the tubing cutting it becomes difficult to quickly get control of the well. Not gripping the cut casing until the cut is made so that the cut is made with the tubular in compression is shown in U.S. Pat. No. 6,357,528. In that tool there is circulation through the tool during cutting followed by dropping an object into the tool that allows the tool to be pressured up so that the spear can be set after the cut is made.
Sometimes the casing or tubular is cut in a region where it is cemented so that the portion above the cut cannot be removed. In these situations another cut has to be made further up the casing or tubular. Some known designs are set to engage for support with body lock rings so that there is but a single opportunity to deploy the tool in one trip. In the event the casing or tubular will not release, these tools have to be pulled from the wellbore and redressed for another trip.
While it is advantageous to have the opportunity for well control in the event of a kick the setting of a tubular isolator has in the past presented the associated problem of blocking fluid circulation as the cut is being made.
Another approach to making multiple cuts is to have multiple assemblies at predetermined spacing so that different cutters can be sequentially deployed. This design is shown in U.S. Pat. No. 7,762,330. It has the ability to sequentially cut and then grip two cut pieces of a tubular in a single trip and then remove the cut segments together.
U.S. Pat. No. 5,253,710 illustrates a hydraulically actuated grapple that puts the tubular to be cut in tension so that the cut can be made. U.S. Pat. No. 4,047,568 shows gripping the tubular after the cut. Neither of the prior two references provide any well control capability.
Some designs set an inflatable packer but only after the cut is made so that there is no well control as the cut is undertaken. Other designs are limited by being settable only one time so that if the casing will not release where cut, making another cut requires a trip out of the well. Some designs set a packer against the stuck portion of the tubular as the resistive force which puts the tubular being cut in compression and makes cutting more difficult. Some designs use a stop ring which requires advance spacing of the cutter blades to the stop ring. In essence the stop ring is stopped by the top of a fish so that if the fish will not release when cut in that one location, the tool has to be tripped out and reconfigured for a cut at a different location.
The latter design is illustrated in
Some designs allow a grip in the tubular to pull tension without the use of a stop ring but they can only be set one time at one location. Some examples are U.S. Pat. Nos. 1,867,289; 2,203,011 and 2,991,834. U.S. Pat. No. 2,899,000 illustrates a multiple row cutter that is hydraulically actuated while leaving open the mandrel for circulation during cutting.
What is needed and provided by the present invention is the ability to make multiple cuts in a single trip while providing a spear that mechanically is set to grab inside the tubular being cut above the cut location. Additionally the packer can be already deployed before the cut is started to provide well control while also providing a bypass to allow circulation through the tool while cutting to operate other downhole equipment. The tubular to be removed is engaged before the cut and put in tension while the cut is taking place. These and other features of the present invention will be more apparent to those skilled in the art from a review of the detailed description and the associated drawings while understanding that the full scope of the invention is to be determined from the appended claims.
A cut and pull spear is configured to obtain multiple grips in a tubular to be cut under tension. The slips are set mechanically with the aid of drag blocks to hold a portion of the assembly while a mandrel is manipulated. An annular seal is set in conjunction with the slips to provide well control during the cut. An internal bypass around the seal can be in the open position to allow circulation during the cut. The bypass can be closed to control a well kick with mechanical manipulation as the seal remains set. If the tubular will not release after an initial cut, the spear can be triggered to release and be reset at another location. The mandrel is open to circulation while the slips and seal are set and the cut is being made. Cuttings are filtered before entering the bypass to keep the cuttings out of the blowout preventers.
Referring to
Ports 44 lead to an annular space 50 that extends to ports 52 which are shown as closed in
Upper drag block segments 86 and lower drag block segments 88 hold the outer non-rotating assembly fixed against an applied force so that mechanical manipulation of the mandrel 32 can actuate the spear S as will be described below. In between the spaced drag block segments 86 is an automatic nut 90 that is also a series of spaced segments that have a thread pattern facing and selectively engaging with a thread 92 on the mandrel 32. The automatic nut 90 is a ratchet type device so that when the mandrel 32 is rotated to the right the segments of the automatic nut just jump over the thread 92. However, if the mandrel 32 is rotated to the left the automatic nut 90 engages the threads 92 and the top sub 82 and sub 58 being constrained by the key 78 from rotation wind up moving axially so that the o-ring seals 54 and 56 no longer straddle ports 52 now shown in the open position in
In order to set the slips 66 and the seal 48 weight is set down during run in so that the castellations 94 engage the castellations 38 and the drive sub is turned to the right about 40 degrees. Using a combination lock/j-slot mechanism 96 these movements enable upon subsequent picking up to bring the cone 64 under the slips 66 with continued pulling force compressing the seal 48 against the surrounding tubular to be cut. At this point the relative motion between the sleeve 59 and the cone 64 are selectively locked. The tensile force on mandrel 32 can be maintained when cutting by turning mandrel 32 to the right when picked up. The ports 52 can be opened before cutting while picked up and turning mandrel 32 to the left. When ports 52 are open the automatic nut 90 is no longer affected by mandrel 32 rotation to the right. As stated before, the ports 52 are closed with setting down weight but the slips 66 and the seal 48 remain set even with the weight being set down to close the ports 52 in the event of a well kick. Eventually the slips 66 and seal 48 can be released by axial opposed movements of the mandrel 32 caused by physical force or pressure cycles that further reconfigures the combination lock/j-slot mechanism 96 so that a setting down force will pull the cone 64 out from under the slips 66 while letting the seal 48 grow axially while retracting radially. The spear S can be reset in other locations in the surrounding tubular to be cut any number of times and at any number of locations.
It should be noted that in
Those skilled in the art will appreciate that the spear S offers several unique and independent advantages. It allows the ability to set and cut in multiple locations with the tubular to be cut under tension while retaining an ability to circulate through the mandrel 32 to power the cutter C or/and to remove cuttings. The tool has the facility to collect cuttings and prevent them from reaching a blowout preventer where they can do some damage. The cuttings can be retained in the
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.
