Method and apparatus for single-trip wellbore treatment

Abstract

The apparatus consists of a tubular housing carried into the well on a workstring. A series of spaced isolation modules is provided for each zone and carried into the well on a tubular conduit. The first, or most downstream module includes first and second sealing mechanisms to isolate the first zone to be treated. A full bore valve is provided that is activated to closed position by an activating component in response to a source of a first level of pressure to isolate the first zone from other parts of the well bore. A port within the housing is initially blocked but selectively opened concurrently with the activation of the first sealing means to manipulate the second sealing mechanism to fully isolate the selected zone and the module. As the module is activated, a second full bore valve is activated to seal the interior of the housing upstream of the first module by manipulation of the tubular string.

Description

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY[0001]This is a utility application claiming priority from U.S. provisional patent application No. 61 / 305,621, filed Feb. 18, 2010, entitled “Method and Apparatus For Single-Trip Wellbore Treatment”, Gregg W. Stout, inventor.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to apparatus and methods for oil and gas wells to enhance the production of subterranean wells, either open hole or cased hole, and more particularly to improved multizone stimulation systems.[0004]2. Brief Description of the Prior Art[0005]Wells are drilled to a depth in order to intersect a series of formations or zones in order to produce hydrocarbons from beneath the earth. The drilled wells are cased and cemented to a planned depth and then may cased and cemented or a portion left open hole. Producing formations intersected with the well bore in order to create a flow path to the surface. Stimulation proce...

AI Technical Summary

Benefits of technology

[0013]A single trip multizone well treating method and apparatus provides a means to progressively stimulate individual zones through a cased or open hole well bore. The need to drop and mill balls and seats for each zone or run hydraulic control lines from the surface to actuate a series of isolation devices has been eliminated. Also, the I.D. restriction created by balls and seats has been eliminated to provide a full bore completion. The full bore completion allows use of larger perforating guns when thru-tubing perforating is desired. A unique feature of this system is that the operator can progressively treat each zone up the hole by moving the workstring up and down a short distance to release a flapper valve selectively for each zone. Applied pressure to the flapper both opens a sliding sleeve and sets a packer and then shifts the flapper below the frac port so a pumping treatment can commence. The apparatus is presented as a “Frac Module” that consists of three major components, a packer, a sliding sleeve, and a workstring actuated fluid isolation device which are integrated together in an assembly that would be shorter in length for closely placed zones. One Frac Module is used per zone and the frac module is stacked with tubing spacers through all zones that need treatment and zonal isolation.

[0015]This invention provides an improved multizone stimulation system to improve the conductivity of the well formations with reduced rig time and no milling. The equipment for all zones can be conveyed in single workstring trip and frac units can stay on location one time to treat all zones.

Problems solved by technology

This means you can't get adequate pressure to frac the zone or the ball is so weak, the ball blows through the seat.

Furthermore, the small ball seats reduce the I.D. of the production flow path which creates numerous other problems.

The size of the ball seats and related balls limits the number of zones that can be treated in a single trip.

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