Deformable Cementing Plugs for Tapered Casing Strings
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Solution Overview
Problem
Conventional cementing plugs are complex, expensive, and difficult to use, especially in tapered casing strings, due to their bulkiness and the need for specialized designs to handle varying pipe diameters, which increases manufacturing costs and drilling time, and can cause premature tool activation when passing through internal restrictions.
Innovation Solution
A catcher tube assembly with deformable devices that can translate and deform to fit within the catcher tube, allowing for multiple fluid separations and wiping of varying casing diameters, reducing the need for specialized plugs and minimizing pressure increases during cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cementing plugs with wiper fins are used to wipe large diameter casing strings, then effective fluid separation is achieved, but the plugs become heavy, bulky, expensive to manufacture, and time-consuming to drill out
Solution Approach 1:
The patent employs a flexible wiper element made of elastomeric material that can conform to the inner surface of the casing. This flexible film approach replaces the rigid, bulky wiper fins of conventional plugs, achieving effective wiping action while significantly reducing the plug's overall size, weight, and complexity. The flexible element can adapt to varying casing diameters without requiring specialized designs for each diameter.
Solution Approach 2:
The patent utilizes a frangible diverting element that is designed to be ruptured during operation. This disposable approach allows the use of simpler, less expensive materials that can be discarded after a single use, eliminating the need for durable, complex structures that must withstand repeated use. The frangible nature enables the plug to be broken down easily after serving its purpose.
2Adaptability or versatility
If conventional cementing plugs are designed to handle varying pipe diameters in tapered casing strings, then adaptability is improved, but manufacturing costs and drilling time increase
Solution Approach 1:
The patent employs a dynamic, flexible wiper element that can adapt its shape and size to match the casing inner diameter. Rather than using fixed, rigid structures designed for specific diameters, the flexible element dynamically conforms to the casing surface, providing effective wiping action across varying diameters without requiring multiple specialized plug designs.
Solution Approach 2:
The patent creates a universal plug design that can function effectively across a range of casing diameters. The combination of a flexible wiper element and frangible diverting element provides a multi-functional solution that handles both wiping and fluid separation tasks in various casing configurations, eliminating the need for specialized plugs for each diameter.
3Reliability
If pump pressure is increased to rupture the frangible device in the bottom plug, then cement composition flow through the float valve is achieved, but premature tool activation may occur when passing through internal restrictions
Solution Approach 1:
The patent utilizes a frangible diverting element with specific pressure-sensitive properties that change its state at a predetermined pressure threshold. The element remains intact during normal pumping and passage through restrictions, then ruptures when the pump pressure reaches the level required to open the float valve. This parameter-based control ensures reliable flow activation at the correct moment without premature tool activation.
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
The deformable device system allows for efficient fluid separation and wiping across multiple diameters, reducing the need for expensive combination plugs and minimizing the risk of premature tool activation, making the process more cost-effective and user-friendly for both conventional and tapered casing strings.
Implementation Method 1
a deformable device. The deformable device may be any device capable of deforming to fit into the catcher tube
Implementation Method 2
The wiper element may be comprised of, for example, an elastomeric material and may function to wipe the inner surface of the casing string
Implementation Method 3
Operations personnel then increase the pump pressure to rupture a frangible device, within the bottom plug
Data Source
AI summary
Methods and devices useful in stage cementing operations are provided. One example of an apparatus may comprise a catcher tube assembly and a deformable device. One example of a method is a method of stage cementing a casing string comprising: positioning a catcher tube on top of a float collar; pumping a first fluid through the casing string; placing a first deformable device in the casing string; and pumping a second fluid through the casing string, thereby causing the first deformable device to translate downward in the casing string and into the catcher tube.