Zone selection with smart object selectively operating predetermined fracturing access valves

An intelligent dart or ball or other shape is dropped or pumped into a borehole that has multiple valves for access to the formation through which fractures are initiated. The intelligent object engages with the valves as it passes with retractable engagement dogs that are outwardly biased but not to the degree needed to find support unless the valve in question is the one that needs to be operated. In that event the dogs become supported and pressure is applied to the object to shift the valve to the open position. The object can be released at a later time remotely or can be milled out. Subsequent objects can be landed in the same sleeve after the initial object is released to close it or to close the open port by moving a second sleeve against a first sleeve. Fracturing in any order is envisioned.

FIELD OF THE INVENTION

The field of the invention is hydraulic fracturing and more particularly smart object that can be preconfigured to operate a predetermined valve in an array of valves to fracture in any desired order.

BACKGROUND OF THE INVENTION

Fracturing can be accomplished using a series of valves that each have ball seats. The ball seats get progressively larger going uphole and progressively larger balls are launched or dropped to sequentially open the fracturing valves in a bottom up direction. As one zone is fractured the next ball isolates the already fractured zone and opens the next valve going in an uphole direction. The problem with this system is there is a limit to how many balls of different sizes can be accommodated in a borehole of a given size. Another problem is that the balls have such small size difference to accommodate as many zones as possible that surface personnel can inadvertently grab the wrong ball. Organizers for such ball arrays are shown in U.S. Pat. No. 8,157,090. Despite the use of organizers to keep track the wrong ball can still be inadvertently picked.

One offered solution to the progressively larger ball seats in a bottom up fracturing operation has been offered in U.S. Pat. No. 7,322,417. Here the same ball is used and all but the initial ball seat are retracted. Once the first ball lands and opens a fracturing valve, it also extends the next ball seat up to accept the same size ball. Here the offered advantage is that all the balls are the same size. The limitations are that the actuation order is still fixed from bottom up and the mechanism that connects the shifting of one ball seat to the extension of a ball seat above can be quite complex and expensive to build or operate.

The present invention seeks to optimize a fracturing operation by using intelligent objects such as balls or darts that keep track of how many valve assemblies have been passed by the object so that the mechanism of the object can be reconfigured at the desired valve for latching and ultimately shifting the valve with applied pressure in the borehole. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention can be determined from the appended claims.

SUMMARY OF THE INVENTION

An intelligent dart or ball or other shape is dropped or pumped into a borehole that has multiple valves for access to the formation through which fractures are initiated. The intelligent object engages with the valves as it passes with retractable engagement dogs that are outwardly biased but not to the degree needed to find support unless the valve in question is the one that needs to be operated. In that event the dogs become supported and pressure is applied to the object to shift the valve to the open position. The object can be released at a later time remotely or can be collected or “fished” or can be milled out. Subsequent objects can be landed in the same sleeve after the initial object is released to close it or to close the open port by moving a second sleeve against a first sleeve. Fracturing in any order is envisioned.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1shows one of several variations for the fracturing sleeve valve10that can open the ports12in housing14. A seat16engages dogs18that are biased out radially by springs20. Dogs18are connected by a schematically illustrated link22best seen inFIG. 9. Link22can be connected to a rotating circular ratchet24that turns in a single direction each time the dogs18get pushed against springs20. Ratchet24rotates on shaft26and the amount of rotation is sensed by the processor28. The processor28is programmed to sense a predetermined amount of rotation at which time it can extend a schematically illustrated lock pin or pins30into the ratchet24so that the dogs cannot retract. Once the dogs18land on the next seat16they will support the object32onto the seat16so that pressure against seal assembly34moves sleeve36to open ports12. The locking of the dogs18in the extended position can occur after a predetermined number of cycles of retraction and extension measured by a processor40that can then move a support under the dogs18to prevent their retraction as illustrated inFIG. 10. This form of locking can be triggered electromagnetically, electromechanically or with a pressure switch to name a few examples. The seal assembly34can be adjacent packer cups42and44or they can be spaced further apart in an alternating pattern with rows of dogs46,48and50as shown inFIG. 4.

The preferred order of operation of sleeves36is bottom up so that each landed object that shifts a given sleeve can isolate zones below that have already been fractured. However other orders of sleeve operation are possible. For example, if the sleeves36had two landing locations that straddled the ports12than the initial object could shift sleeve36a first time and another object32can land on another seat that would be above the now open ports12so that pressure could again be built up to move the same sleeve a second time and blank off ports12. In this case the sleeve36would be configured with wall ports that align with ports12in the open position and a blank section that comes into alignment with the ports12for the closed position. Another way to be able to open the ports12and then close them would be to use two adjacent sleeves36and15. The first sleeve36can be as shown inFIG. 1and the second sleeve15can be identical to it and simply push the first sleeve36enough to place the second sleeve that is adjacent in line with the ports12to close them.

Another feature can be a remote release for the object32using the processor28or40so that after shifting a sleeve such as36the object32is released to go the hole bottom or a catcher that is not shown. Alternatively the various landed objects32on the various sleeves36can be simply milled out or flowed out of the well when production starts after a bottom up sequence for fracturing.

The objects32can all be identical and just be programmed to engage specific seats in specific sleeves in a predetermined order. They can have external indication of how many cycles they will undertake before locking the dogs so that the next sleeve is landed on. The ratchet mechanism can be linear or circular. Any locking feature that can be actuated after a predetermined moving of the dogs in and out can be employed. In this manner the landing location for each object is predetermined. The exterior shape of the object can vary from spherical to an elongated shape. The internal components such as the processor28can be cushioned with springs such as60or62. Those skilled in the art will appreciate that the present invention involves programmable objects to land on predetermined sleeves to facilitate bottom up fracturing. With some modification to the sleeve design or by using sleeve pairs the ports to the formation that are opened can also thereafter be closed. This feature can allow re-fracturing only specific zones by closing the remaining sleeves. The objects can be remotely triggered to release from a shifted sleeve. Optionally the sleeves can communicate data on their movement or lack thereof in real time to a surface location using a variety of signaling techniques to the surface such as acoustic, mud pulses, RFID or other types of known telemetry techniques. Of course a pressure buildup at the surface is another signal that an object has landed on a sleeve.

Another alternative can be electronic, or proximity or over the air or fluid signaling from each sleeve as the object goes by it. After the predetermined number of signals are detected then the dogs can be extended to land on the very next sleeve for operating the sleeve with applied pressure. In that manner the dogs do not need to physically engage a profile on each sleeve as that sleeve is passed. Release of the objects after landing can be accomplished with pressure application and removal cycles that eventually allow the support for the dogs to be undermined so that pressure in the borehole can displace the object from the supported location.