Cement Retainer for Continuous Drilling Without Tripping
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Solution Overview
Problem
Conventional well construction in open water environments is time-consuming and costly, with significant losses of drilling fluid and potential well instability due to the need to trip the drilling string in and out of the wellbore, which also results in inefficient use of resources.
Innovation Solution
A system and method that utilize a cement retainer within the casing string to allow drilling and cementing without tripping the drilling string, using a cement retainer that can be in a partially open or closed configuration to manage fluid flow and prevent cement from flowing back into the casing string, enabling continuous drilling operations without removing the drilling string from the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drilling string is tripped in and out of the wellbore for each drilling section, then the casing string can be installed and cemented, but the drilling time and operational cost increase significantly
Solution Approach 1:
The cement retainer is installed in the casing string before the drilling string is placed in the wellbore. This preliminary positioning allows the cement retainer to be ready to receive and retain cement behind the drilling string, eliminating the need to trip the drilling string out for cementing operations. The drilling string remains in place continuously while cement is pumped behind it, resolving the time loss associated with tripping operations.
2Ease of manufacture
If the drilling string is removed from the wellbore for cementing, then the casing string can be cemented, but the exposed formations may flow and cause well loss
Solution Approach 1:
The cement retainer acts as an intermediary device that enables cementing operations without removing the drilling string. It receives cement pumped behind the drilling string and retains it in the annulus behind the drill collar, allowing cementing to proceed while the drilling string remains in place to maintain wellbore stability and prevent formation flow.
3Productivity
If the drilling string is tripped out of the wellbore, then the next section can be drilled, but drilling fluid is lost through the pump and dump technique
Solution Approach 1:
The system enables continuous drilling operations where the drilling string remains in the wellbore throughout the entire process. Cement is pumped behind the drilling string and retained by the cement retainer, eliminating the need to trip the drilling string out. This continuous operation prevents the loss of drilling fluid that occurs during tripping and pump-and-dump operations.
4Loss of time
If a cement retainer is installed in the casing string, then continuous drilling without tripping is enabled, but the device complexity increases
Solution Approach 1:
The cement retainer is designed as a segmented structure with multiple components including a body, a movable element, and a sealing element. The movable element can shift between positions to open or close flow paths, allowing the device to control cement flow while maintaining a relatively simple overall structure that integrates into the existing casing string.
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 approach reduces the time and cost of drilling operations, prevents fluid loss, and allows for quicker and more efficient deepwater well construction by eliminating the need for multiple trips of the drilling string, thereby enhancing operational efficiency and reducing expenses.
Implementation Method 1
The cement retainer may comprise and/or consist of a valve disposed within the casing string
Data Source
AI summary
A portion of a wellbore is drilled in a subterranean formation, using a drilling string (140) disposed within a casing string (130) and extending through a cement retainer (150) disposed within the casing string. The drilling string can be retracted into the casing string to a location fully above the cement retainer, and subsequently the casing string can be cemented in the wellbore whereby maintaining the drilling string inside the casing in the wellbore.