Patent Application
20160177632
The field of the invention is string mounted tool operating devices and more particularly an accessory device that prevents tool operation on initial landing on the tool or its operator.
Production packers are typically provided with barrier valves or zone isolation valves. Typically these valves have an associated operator that is engaged by a cooperating tool such that when running in the valve is opened and when pulling back through the valve, the valve closes. One such valve is shown in U.S. Pat. No. 8,443,894. Other shifting tools are illustrated in U.S. Pat. Nos. 5,636,694; 5,765,640; 7,562,703; 7,556,102; 5,678,633; 5,636,694; 5,549,161; 4,928,772; 4,917,191.
One potential issue with such tools is that situations can occur when the string needs to be cut with shear rams in a blowout preventer such as in occasions when the rig has to move off an offshore wellhead in an emergency situation. When that happens the string is allowed to fall when it is cut. If the operating tool on the string is above the barrier valve operator then the barrier valve could potentially be operated to open upon contact of the operating tool that is on the string with the operator for the barrier valve. Since there is already an emergency condition that has caused this sequence of events, it would be undesirable to open the barrier valve which can magnify the potential dangers at such a time. What is needed and provided by the present invention is a device that prevents actuation of the tool on initial contact and allows subsequent tool operation by manipulation of the string to reconfigure the newly added tool to the string in a manner that will then allow the downhole to be selectively operated. In the preferred embodiment a j-slot indexing tool in tandem with associated travel stops is incorporated into the string that stops initial contact with the tool to be operated at a point short of tool operation. In this configuration a pin is in a short slot and an operating tool for the barrier valve actuator comes up short of the actuator when supported by the packer or polished bore receptacle. A subsequent picking up and setting down puts a pin in a longer slot and allows additional travel for the operating tool to reach the barrier valve actuator for opening the valve. Having this indexing tool as part of the string prevents inadvertent opening of a barrier valve if the string is cut by rams and allowed to drop. The cut string can later be fished with the barrier valve closed. While application to a barrier valve associated with a production packer is the preferred application, other applications where an emergency situation could result in a string being dropped in the hole and a tool in the hole being inadvertently operated are other applications that can benefit from the present invention. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be found in the appended claims.
An indexing tool is incorporated into a tubular string. The indexing tool is intended to function as a variable travel stop so that on initial landing other tools associated with the string will not extend to an operating position for tools that would otherwise operate on contact with relative movement. The indexing device can prevent a shifting device from engaging a valve operator when the index device initially lands on a support either during normal operation or in an emergency such as when shear rams have cut the string to allow it to fall so that a blowout preventer can be operated to engage opposed rams. In such an emergency the barrier valve operator will not be actuated and the string is later fished with the barrier valve closed. A pickup and set down force then allows the barrier valve to open when desired.
Referring to
Those skilled in the art will appreciate that the objective of prevention of operation of a tool on initial landing of a string can be accomplished in other ways than a continuous j-slot as described in detail above. A single pin in an l-shaped slot or a slot with multiple turns can be used and can then be operated with a combination of setting down weight and rotation. Another alternative can be a variable volume chamber that is filled with an incompressible fluid and a metered outlet so that initial setting down will also not operate the subterranean tool but if the set down weight is maintained there would then be a predetermined time before sufficient travel has occurred to operate a tool such as a barrier valve. In another variation a variable volume reservoir can be isolated with a rupture disk to prevent continued movement after landing on a travel stop until enough set down weight is applied to build pressure to break the rupture disc. The objective in each case is to make sure that upon initial landing the tool to be operated is in fact not initially operated. Instead, it takes further action or movement of the associated string to get the barrier valve or the tool in question operated. In essence, there is a temporary mechanism or feature that prevents tool actuation on initial setting down weight but thereafter enables such operation by string manipulation, pressure application or some other means to change the amount of available movement so that the subterranean tool that previously was not operated with the initial landing can then be operated. This device is particularly useful if the string has to be cut by shear rams in an emergency and then allowed to fall with the tool operator located at the leading end of the falling string. With this tool, upon initial impact with the travel stop further movement of the components of the device is arrested so that, in the case of a barrier valve, there is no opening of the valve. The string can later be fished out with the barrier valve closed for an added safety feature.
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:
