Patent Application
20170107781
The field of this invention is removable borehole barriers and more particularly barriers that can be used in plug and perforate systems involving an expandable ratcheting sleeve with an integrated ball seat.
Fracturing using a plug and perforate method is well known. In this method barriers are delivered with a perforating gun and after the barrier is set the gun is repositioned and fired followed by a pressure treatment against the barrier. This process is repeated in an uphole direction until the entire zone of interest is treated. After that the plugs are generally drilled out. The process of drilling out the plugs is time consuming and the cost of the plugs can be substantial depending on the size of the borehole and how many plugs are required for the interval to be treated.
Ratchet mechanisms have been used in the past for allowing relative movement in a single direction. Some devices in the past have used ball seats in tools as distinct structures from ratchet rings. Generally ratchet rings are internal tool components that permit unidirectional relative movement between parts. Some examples are: U.S. Pat. No. 7,861,781; U.S. Pat. No. 6,116,336 (FIG.9); U.S. Pat. No. 8,887,818 (
What is needed and provided by the present invention is an economical way to provide barriers in the borehole coupled with a way they can be rapidly removed such as by drilling out or by other means such as disintegration. The barriers have a scroll shape to allow for radial expansion with one or opposed ratchet features to lock the enlarged dimension against a surrounding borehole. The scroll exterior can have hard facing or carbide or other materials that preferably penetrate the inside wall of the surrounding tubular for additional support. Expansion can be with a subterranean tool such as an inflatable, or potential energy trapped in the scroll can be released or the scroll can be made of a shape memory alloy that grows to meet the surrounding borehole when exposed to well temperatures above the critical temperature of the material. The scroll is flexible to tolerate some out of roundness of the surrounding tubular and the built in seat at an end allows a ball to land to stop most of the flow so pressure can build up for the treatment of the formation. In many applications complete sealing is not needed as long as high flows under high pressure can enter the formation. 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 recognizing that the full scope of the invention is to be determined from the appended claims.
A borehole barrier comprises a scroll where the overlapping parts have a ratchet for radial expansion against a surrounding tubular with the ratchet controlling springing back. The outer surface can have carbide or other hard particles to penetrate the surrounding tubular for fixation. The end of the scroll forms a tapered ball seat. Expansion into place can be with a tool, or by releasing potential energy in the scroll or by using a shape memory alloy that enlarges at above its critical temperature. The scrolls can be removed by milling or allowed to dissolve or disintegrate with exposure to well fluids. The scroll design is quickly deployed and removed and is far more economical than known plugs that have the traditional seal and slip design. The balls can be milled out with their associated scrolls or flowed to the surface with produced fluids.
The barrier 10 has a tubular shape with a passage 12 therethrough. Surrounding the passage 12 is a tapered surface that can act as a ball seat 14 that can accept an object such as a ball that is not shown. In
The barrier 10 has an elongated tab 26 with an end 28 and a ratchet profile 30 visible on the left side of
The barrier 10 can be made of soft drillable materials such as metals or composites and in some applications plastics may be used. The increase in diameter can be 50% or more meaning that inventory can be kept low to handle a broad range of surrounding tubular inside diameters. Edges 28 and 34 preferably abut in the run in position of
The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anti-corrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc. Another operation can be production from said zone or injection into said zone.
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:
