Slotted Liner Shoe Extension for Deep Well Cementing
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Solution Overview
Problem
In geothermal and oil wells, the completion technique using a slotted or perforated liner complicates stimulation of deeper zones due to limited hydraulic pressure and cement intrusion into permeable zones, which impairs production and reduces the economic value of the asset.
Innovation Solution
A system and method involving the injection of a low-density material into a slotted liner to create a solid cemented casing string at a desired depth, using a low-density material to prevent cement intrusion and enhance hydraulic pressure for stimulation without damaging the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a slotted or perforated liner is used to reduce pressure drop and improve production, then fluid flow rate is increased, but hydraulic pressure is limited and stimulation of deeper zones is hampered
Solution Approach 1:
The wellbore is divided into two distinct sections: an upper open annulus section for production with the slotted liner, and a lower cemented section for high-pressure stimulation. The slotted liner acts as a segmentation boundary that allows fluid communication in the upper section while the cement plug in the lower section enables pressure buildup for stimulation operations.
Solution Approach 2:
A cement plug is introduced as an intermediary element between the open annulus and the formation zones requiring stimulation. This cement plug serves as a pressure barrier that allows hydraulic pressure to build up in the stimulation zone without being dissipated through the slotted liner openings, enabling effective stimulation of deeper zones.
2Reliability
If cement is pumped into the liner above the packer to seal zones, then zone isolation is achieved, but cement flows down the annulus and enters permeable zones impairing production
Solution Approach 1:
A low-density material is used as a counterweight element to offset the downward flow of dense cement. The low-density material is pumped first to occupy the lower annulus space, creating a density barrier that prevents the heavier cement from flowing down and entering the permeable production zones, while still allowing effective zone isolation.
Solution Approach 2:
The low-density material is pumped into the annulus before the cement to pre-occupy the space and establish a density barrier. This preliminary action ensures that when cement is subsequently pumped for zone isolation, it cannot flow down into the permeable zones, preventing formation damage before it occurs.
3Productivity
If the open annulus is left open to maximize production area, then pressure drop is reduced and flow rate increases, but work on the well behind the liner becomes difficult and impossible
Solution Approach 1:
The wellbore is segmented into an upper open production section and a lower workable section. The slotted liner maintains the open annulus for production while the cement plug creates a separate lower section where isolation and stimulation operations can be performed, enabling both high productivity and ease of operation.
Solution Approach 2:
The cement plug acts as an intermediary that separates the production zone from the work zone. This allows conventional stimulation and isolation tools to be deployed in the lower cemented section without interfering with the open annulus production configuration, making well operations feasible while maintaining high flow rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method increases the maximum surface pressure for stimulation, effectively deepening the last casing depth without formation damage and seals off undesirable zones, improving fluid production and reducing cement intrusion risks.
Implementation Method 1
a low density material is injected into a liner having a plurality of openings... The low density material extrudes through a lower portion of the liner into an annulus between the liner and the wellbore
Implementation Method 2
A cement is circulated into the Liner above the low density material. The cement extrudes through an upper portion of the liner into the annulus between the liner and the wellbore
Implementation Method 3
a low density material is injected into a liner... to prevent cement intrusion into permeable zones
Data Source
AI summary
A system and method for extending a slotted liner shoe is disclosed. According to one embodiment, a low density material is injected into a liner having a plurality of openings. The liner is suspended below a cemented casing in a wellbore of a well in a subterranean formation. The low density material extrudes through a lower portion of the liner into an annulus between the liner and the wellbore. A cement is circulated into the liner above the low density material. The cement extrudes through an upper portion of the liner into the annulus between the liner and the wellbore. Water is displaced from the wellbore, and a solid cemented casing string is formed at a desired depth.