Cementing a wellbore casing

Abstract

A method of cementing a casing in a wellbore includes lowering the casing in the wellbore. The casing includes multiple pipes each of progressively smaller diameters, and a transition point where a first pipe overlaps a second pipe. The method also includes flowing cement into the casing and deploying, by fluidic pressure, a wiper plug assembly in the casing upstream of the cement to push downhole the cement with the wiper plug assembly. The wiper plug assembly includes a hollow wiper plug and a solid wiper plug releasably coupled to the hollow wiper plug. The deploying includes applying fluidic pressure until the hollow wiper plug reaches and is retained at the transition point and the solid wiper plug is released from the hollow wiper plug to flow downhole in the casing to a downhole end of the casing and push the cement out of the casing.

What is claimed is: 
     
         1 . A method of cementing a casing in a wellbore, the method comprising:
 lowering the casing in the wellbore, the casing comprising a plurality of pipes of progressively smaller diameters, the casing comprising a transition point where a first pipe of the plurality of pipes overlaps a second pipe of the plurality of pipes that extends beyond the first pipe, the first pipe defining a first inner diameter and the second pipe carried by the first pipe and defining a second inner diameter smaller than the first inner diameter;   flowing cement into the casing; and   deploying, by fluidic pressure of a fluid, a wiper plug assembly in the casing upstream of the cement to push downhole the cement with the wiper plug assembly, the wiper plug assembly comprising i) a hollow wiper plug that allows the fluid to flow across the hollow wiper plug and ii) a solid wiper plug releasably coupled to the hollow wiper plug and configured to separate the cement from the fluid, wherein deploying comprises applying fluidic pressure until the hollow wiper plug reaches and is retained at the transition point and the solid wiper plug is released, under fluidic pressure, from the hollow wiper plug to flow downhole in the casing to a downhole end of the casing and push the cement out of the casing.   
     
     
         2 . The method of  claim 1 , wherein deploying comprises cementing the wellbore in one trip by pushing, under fluidic pressure of the fluid, a last portion of the cement out of the casing into an annulus of the wellbore as the solid wiper plug travels along a last pipe of the casing to a downhole end of the last pipe where the solid wiper plug is retained. 
     
     
         3 . The method of  claim 2 , wherein deploying comprises pushing the last portion of the cement as the solid wiper plug fluidly isolates the last portion of the cement from the fluid in the last pipe. 
     
     
         4 . The method of  claim 3 , wherein the second pipe is the last pipe of the plurality of pipes. 
     
     
         5 . The method of  claim 1 , wherein the hollow wiper plug comprises a first wiper configured to wipe the first pipe and the solid wiper plug comprises a last wiper configured to wipe a last pipe of the plurality of pipes, the method further comprises wiping, with the wiper plug assembly pushing the cement, the casing. 
     
     
         6 . The method of  claim 5 , wherein the last wiper comprises an outer diameter smaller than an outer diameter of the first wiper, and the wiping comprises wiping the first pipe with the first wiper and wiping the last pipe with the last wiper. 
     
     
         7 . The method of  claim 1 , wherein the wiper plug assembly further comprises an intermediate hollow wiper plug disposed between and releasably coupled to the hollow wiper plug and the solid wiper plug, the casing comprising a second transition point where the second pipe overlaps a third pipe of the plurality of pipes that extends beyond the second pipe, and deploying comprises applying fluidic pressure until the hollow wiper plug is retained at the transition point and the intermediate hollow wiper plug is released, with the solid wiper plug coupled to the intermediate hollow wiper plug, from the hollow wiper plug, and deploying further comprises applying fluidic pressure until the intermediate hollow wiper plug is retained at the second transition point and the solid wiper plug is released, under fluidic pressure, from the intermediate hollow wiper plug. 
     
     
         8 . The method of  claim 1 , wherein the first pipe is a surface pipe extending from or near a terranean surface of the wellbore, and lowering the casing comprises setting the first pipe on or near the terranean surface of the wellbore with the second pipe suspending from the first pipe. 
     
     
         9 . A method, comprising:
 flowing cement into a casing, the casing disposed within a wellbore and comprising a first pipe and a second pipe carried by and extending downhole from the first pipe, the first pipe defining a first inner diameter and the second pipe defining a second inner diameter smaller than the first inner diameter; and   deploying, under fluidic pressure of a fluid, a wiper plug assembly in the casing and upstream of the cement to push the cement out of the casing, the wiper plug assembly comprising a first wiper plug and a second wiper plug releasably coupled to the first wiper plug, the first wiper plug configured to allow fluid to flow across the first wiper plug and the second wiper plug configured to fluidly isolate the cement from the fluid in the casing, wherein deploying comprises applying fluidic pressure until the first wiper plug reaches and is retained at an inlet of the second pipe and the second wiper plug is released, under fluidic pressure, from the first wiper plug to flow downhole in the casing to a downhole end of the casing and push the cement out of the casing.   
     
     
         10 . The method of  claim 9 , wherein deploying comprises pushing, under fluidic pressure of the fluid, a last portion of the cement out of the casing into an annulus of the wellbore as the second wiper plug travels along a last pipe of the casing to a downhole end of the last pipe where the second wiper plug is retained. 
     
     
         11 . The method of  claim 10 , wherein the first wiper plug comprises a first annular wiper configured to wipe the first pipe and the second wiper plug comprises a second annular wiper configured to wipe the last pipe, the method further comprises wiping, with the wiper plug assembly pushing the cement, the first pipe and the last pipe. 
     
     
         12 . The method of  claim 11 , wherein the second annular wiper comprises an outer diameter smaller than an outer diameter of the first annular wiper, and the wiping comprises wiping from cement the first pipe with only the first annular wiper and wiping the last pipe with only the second annular wiper. 
     
     
         13 . The method of  claim 9 , wherein the wiper plug assembly further comprises an intermediate hollow wiper plug disposed between and releasably coupled to the first wiper plug and the second wiper plug, the casing comprising a third pipe carried by and extending downhole of the second pipe, and deploying comprises applying fluidic pressure until the hollow wiper plug is retained at the inlet of the second pipe and the intermediate hollow wiper plug is released, with the second wiper plug coupled to the intermediate hollow wiper plug, from the first wiper plug, and deploying further comprises applying fluidic pressure until the intermediate hollow wiper plug is retained at an inlet of the third pipe and the second wiper plug is released, under fluidic pressure, from the intermediate hollow wiper plug. 
     
     
         14 . A cementing wiper plug assembly, comprising:
 a first wiper plug defining a bore configured to direct fluid from an inlet to an outlet of the first wiper plug; and   a second wiper plug releasably coupled to the first wiper plug, the second wiper plug comprising a solid body configured to fluidly isolate, when disposed within a casing of a wellbore, a first portion of the casing downhole of the wiper plug assembly from a second portion of the casing uphole of the wiper plug assembly, the casing comprising a first pipe and a second pipe carried by and extending downhole from the first pipe, the first pipe defining a first inner diameter and the second pipe defining a second inner diameter smaller than the first inner diameter, wherein the first and second wiper plugs are configured to flow together to an inlet of the second pipe and the second wiper plug is arranged to be released, under fluidic pressure, from the first wiper plug to flow downhole in the casing to a downhole end of the casing and push cement out of the casing, with the first wiper plug retained at the inlet of the second pipe.   
     
     
         15 . The cementing wiper plug assembly of  claim 14 , wherein the solid body of the second wiper plug is configured to sit and be retained at a downhole end of a last pipe of the casing. 
     
     
         16 . The cementing wiper plug assembly of  claim 14 , wherein the second wiper plug is releasably attached, by a joint comprising a shear pin, to the first wiper plug. 
     
     
         17 . The cementing wiper plug assembly of  claim 16 , wherein one of the first wiper plug or second wiper plug comprises a first inner tube comprising an aperture and inserted into a second inner tube of the other one of the first wiper plug or second wiper plug, the second inner tube comprising a shear pin inserted, with the first wiper plug and second wiper plug attached, into the aperture of the first inner tube. 
     
     
         18 . The cementing wiper plug assembly of  claim 14 , wherein the first wiper plug comprises a first annular wiper configured to wipe the first pipe and the second wiper plug comprises a second annular wiper configured to wipe a last pipe of the casing. 
     
     
         19 . The cementing wiper plug assembly of  claim 18 , wherein the second annular wiper comprises an outer diameter smaller than an outer diameter of the first annular wiper. 
     
     
         20 . The cementing wiper plug assembly of  claim 14 , further comprising an intermediate wiper plug defining a second bore configured to direct fluid from an inlet to an outlet of the intermediate wiper plug, the intermediate wiper plug disposed between and releasably coupled to the first wiper plug and the second wiper plug, the casing comprising a third pipe carried by and extending downhole of the second pipe, wherein the cementing wiper plug assembly is configured to flow to the inlet of the second pipe and the intermediate wiper plug is arranged to be released, with the second wiper plug attached to the intermediate wiper plug, from the first wiper plug to flow downhole in the casing to an inlet of the third pipe, and the second wiper plug is arranged to be released, under fluidic pressure, from the intermediate wiper plug to flow downhole in the casing to an outlet of the casing.