Bi-frustoconical Cementing Tool for Lost Circulation Control
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Solution Overview
Problem
Cementing processes in wellbores often fail to ensure complete protection due to lost circulation zones, where cement slurry is sucked into formations, leaving areas above such zones unprotected, and traditional top jobs are ineffective in controlling cement loss.
Innovation Solution
A bi-frustoconical cementing tool with a collar is positioned in the annulus between the casing and wellbore, loaded with cement slurry to form a seal, and additional cement is added until the top reaches a predetermined height, forming a column that hardens to create a seal between the casing and wellbore wall, using a cement basket to anchor the tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement slurry is pumped down the casing and into the annulus to fill it completely, then complete cementing of the casing is achieved, but cement slurry is sucked into lost circulation zones, leaving areas above unprotected
Solution Approach 1:
The plug is installed in advance at a predetermined position in the annulus before cementing operations. This preliminary placement creates a physical barrier that prevents cement slurry from being sucked into lost circulation zones below, while allowing cement to be pumped above the plug level to achieve complete protection.
Solution Approach 2:
The plug acts as an intermediary element between the cement slurry and the lost circulation zone. It intercepts the cement flow and redirects it, preventing direct contact between the cement and the formation that would cause losses, thereby enabling complete cementing without cement loss.
2Reliability
If a top job is performed to bring the top of cement to the surface, then the annulus is filled with cement, but cement loss from the annulus cannot be controlled
Solution Approach 1:
The plug is pre-positioned in the annulus before the top job operation. This preliminary action establishes a controlled barrier that allows cement to be pumped to the surface level without uncontrolled losses into lost circulation zones, making the top job operation successful and controllable.
3Ease of manufacture
If the bottom of the casing is set above a lost circulation zone, then cementing can proceed, but cement slurry is sucked into the formation, leaving the area above unprotected
Solution Approach 1:
The plug serves as a mediator that decouples the casing position from the cementing effectiveness. Even when the casing bottom is positioned above the lost circulation zone, the plug creates a barrier that prevents cement losses, allowing complete protection to be achieved regardless of the exact casing placement.
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 method effectively prevents cement loss into lost circulation zones by forming a stable column of cement that seals the annulus, ensuring complete cementing and protection of the wellbore.
Implementation Method 1
pumping cement slurry down the interior of the casing and allowing the cement slurry to flow out of the bottom of the casing
Implementation Method 2
forming a column that hardens to create a seal between the casing and wellbore wall
Data Source
AI summary
A method of cementing a casing in a wellbore extending from an Earth's surface into a subsurface includes providing a tube having a bi-frustoconical shape. The bi-frustoconical shape is defined by an upper tube part having an inverted frustoconical shape, a lower tube part having a frustoconical shape, and a waist intermediate between the upper tube part and the lower tube part. The tube is positioned in an annulus formed between the casing and a wall of the wellbore from a surface opening of the annulus. The tube is urged in a direction down the annulus and along the casing until the tube lands on a collar radially projecting from an outer surface of the casing into the annulus.