Wellbore Plug Isolation System and Method

Abstract

A wellbore plug isolation system and method for positioning plugs to isolate fracture zones in a horizontal, vertical, or deviated wellbore is disclosed. The system/method includes a wellbore casing laterally drilled into a hydrocarbon formation, a wellbore setting tool (WST) that sets a large inner diameter (ID) restriction sleeve member (RSM), and a restriction plug element (RPE). The RPE includes a first composition and a second composition that changes phase or strength under wellbore conditions. After a stage is perforated, RPEs are deployed to isolate toe ward pressure communication. The second composition changes phase to create flow channels in the RPE during production. In an alternate system/method, the second composition changes phase or strength thereby deforming the RPE to reduce size and pass through the RSM's. The RPEs are removed or left behind prior to initiating well production without the need for a milling procedure.

1 . A restriction plug element (RPE) in a wellbore system comprising:
 (a) first composition; and   (b) second composition   wherein   said first composition and said second composition are proximal to each other;   said second composition is configured to change a physical property at a predetermined temperature expected to be encountered in said wellbore without chemically reacting with wellbore fluids in said wellbore; and said physical property selected from a group consisting of: phase, strength, and elasticity.   
     
     
         2 . The restriction plug element of  claim 1  wherein said first composition at least partially surrounds said second composition. 
     
     
         3 . The restriction plug element of  claim 1  wherein said second composition at least partially surrounds said first composition. 
     
     
         4 . The restriction plug element of  claim 2  wherein as said second composition changes physical property, said second composition exits said restriction plug element to form at least one flow channel in said restriction plug element. 
     
     
         5 . The restriction plug element of  claim 2  wherein as said second composition changes physical property, said restriction plug element deforms such that said restriction plug element passes through a restriction sleeve member in said wellbore. 
     
     
         6 . The restriction plug element of  claim 3  wherein as said second composition changes physical property, said restriction plug element reduces size to enable it to pass through a restriction sleeve member in said wellbore. 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . The restriction plug element of  claim 2  wherein said second composition is in further direct contact with a third composition. 
     
     
         11 . The restriction plug element of  claim 10  wherein said second composition at least partially surrounds a solid core of said third composition. 
     
     
         12 . The restriction plug element of  claim 10  wherein said second composition at least partially surrounds a cavity of said third composition. 
     
     
         13 . The restriction plug element of  claim 2  wherein as said second composition changes physical property, said second composition exits said restriction plug element through a passage in said first composition. 
     
     
         14 . The restriction plug element of  claim 4  wherein said flow channels are configured to enable substantially unobstructed fluid flow during production. 
     
     
         15 . The restriction plug element of  claim 4  wherein at least some of said flow channels are aligned with each other. 
     
     
         16 . The restriction plug element of  claim 4  wherein said flow channels further comprise a piston, wherein said piston is configured to slide from a first position to a second position to enable fluid flow through said flow channels. 
     
     
         17 . The restriction plug element of  claim 1  wherein said first composition is selected from a group comprising plastics, non-degradable or long term degradable. 
     
     
         18 . The restriction plug element of  claim 1  wherein said second composition is selected from a group comprising eutectic metals, non-eutectic metals or thermoplastics. 
     
     
         19 . The restriction plug element of  claim 1  wherein said first composition controls a rate of temperature change of said second composition. 
     
     
         20 . The restriction plug element of  claim 1  wherein said second composition is selected to change phase under wellbore temperature conditions. 
     
     
         21 . The restriction plug element of  claim 1  wherein said change in physical property of said second composition is temperature dependent. 
     
     
         22 . The restriction plug element of  claim 1  further comprises a heating element, said heating element upon activation accelerates said change in physical property of said second composition. 
     
     
         23 . The restriction plug element of  claim 1  wherein said first composition surrounds a solid spherical core of said second composition. 
     
     
         24 . The restriction plug element of  claim 1  wherein said first composition surrounds a hollow spherical core of said second composition. 
     
     
         25 . The restriction plug element of  claim 1  wherein said first composition surrounds a solid cylindrical core of said second composition. 
     
     
         26 . The restriction plug element of  claim 1  wherein said first composition partially surrounds a hollow cylindrical core of said second composition. 
     
     
         27 . A wellbore plug isolation system comprising:
 (a) restriction sleeve member (RSM); and   (b) restriction plug element (RPE)   wherein   said RSM is configured to fit within a wellbore casing;   said RSM is configured to be positioned at a wellbore location by a wellbore setting tool (WST);   said RPE is configured to position to seat in said RSM;   said RPE comprises a first composition and a second composition;   said first composition and said second composition are in direct contact with each other;   said second composition is configured to change a physical property at a predetermined temperature expected to be encountered in said wellbore casing without chemically reacting with wellbore fluids in said wellbore; and said physical property selected from a group consisting of: phase, strength, and elasticity.   
     
     
         28 . A wellbore plug isolation method, said method operating in conjunction with a restriction plug element (RPE), said restriction plug element comprising:
 (a) first composition; and   (b) second composition   wherein   said first composition and said second composition are in direct contact with each other;   said second composition is configured to change a physical property at a predetermined temperature expected to be encountered in said wellbore without chemically reacting with wellbore fluids in said wellbore; and said physical property selected from a group consisting of: phase, strength, and elasticity.   wherein said method comprises the steps of:   (1) checking if a restriction sleeve member (RSM) is present, if so, proceeding to step (3);   (2) setting a restriction sleeve member at a wellbore location in a wellbore casing;   (3) perforating a hydrocarbon formation with a perforating gun string assembly;   (4) deploying said restriction plug element into said wellbore casing to isolate toe end fluid communication and create a hydraulic fracturing stage;   (5) controlling a contact temperature of said restriction plug element to maintain said physical property of said second composition;   (6) fracturing said fracturing stage with fracturing fluids;   (7) controlling a contact temperature of said restriction plug element to enable said second composition to undergo a change in said physical property;   (8) checking if all hydraulic fracturing stages in said wellbore casing have been completed, if not so, repeating steps (1) to (7); and   (9) enabling fluid flow in production direction.   
     
     
         29 . The wellbore plug isolation method of  claim 28  wherein said first composition at least partially surrounds said second composition. 
     
     
         30 . The wellbore plug isolation method of  claim 28  wherein said second composition at least partially surrounds said first composition.