Side Pocket Mandrel Flow Blocks Prevent Cement Slurry Settlement
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Solution Overview
Problem
Existing side pocket mandrels in gas lift systems are ineffective in preventing cement slurry contamination during cementing operations in larger diameter production tubing, as the multiple small filler guide sections used in smaller applications are not sufficient to manage cement slurry effectively.
Innovation Solution
A side pocket mandrel design featuring a pair of primary flow blocks that occupy at least 35% of the central portion's length, with elongated flow blocks extending on either side of the tool channel, enhancing fluid turbulence and preventing cement slurry accumulation by minimizing void spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple small filler guide sections are used in side pocket mandrels, then the design works for smaller diameter production tubing, but it is ineffective in preventing cement slurry contamination in larger diameter production tubing
Solution Approach 1:
The invention changes the parameters of the filler guide sections by increasing their length to at least 35% of the central portion length and positioning them to extend beyond the tool channel boundaries. This parameter change makes the filler guide sections effective for larger diameter production tubing while maintaining their function in smaller applications.
Solution Approach 2:
The invention divides the filler guide function into multiple discrete sections positioned at different locations within the central portion. These segmented filler guide sections work together to block cement slurry from entering the tool channel, with each section contributing to the overall blocking effect throughout the length of the central portion.
2Adaptability or versatility
If the central portion of the side pocket mandrel is made longer to accommodate larger diameter tubing, then it can fit larger production strings, but cement slurry has more space to settle and accumulate
Solution Approach 1:
The filler guide sections act as intermediary elements that block the tool channel from the central bore. These sections prevent cement slurry from the central bore from entering and accumulating in the tool channel, effectively mediating between the larger central portion volume and the tool channel that must remain clear for operations.
Solution Approach 2:
The filler guide sections are pre-positioned within the central portion before cementing operations. They create preliminary blockages that prevent cement slurry from entering the tool channel during the cementing process, eliminating the need for post-cementing clearance operations.
3Reliability
If filler guide sections are made longer to block cement slurry, then cement prevention improves, but the risk of wiper plug becoming stuck increases
Solution Approach 1:
The filler guide sections are designed with specific local qualities: they extend beyond the tool channel boundaries to effectively block cement, but their surfaces are configured to be smooth and compatible with wiper plug passage. This local quality differentiation allows them to perform dual functions of cement blocking and wiper plug guidance.
Solution Approach 2:
The invention converts the potential harm of long filler guide sections (wiper plug getting stuck) into a benefit by designing them to actively guide the wiper plug through the central portion. The sections that could potentially trap the wiper plug are instead configured to direct and facilitate its passage while maintaining effective cement blocking.
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 design effectively prevents cement slurry settlement and ensures the functionality of side pocket mandrels in larger diameter production strings by reducing residual cement and facilitating tool installation and removal, improving the efficiency of gas lift operations.
Implementation Method 1
Holt, Jr. also discloses that filler guide sections generate turbulent circulations within the mandrel voids by the working fluid flow behind the wiper plug to further clean slurry debris from the side pocket mandrel.
Data Source
AI summary
A side pocket mandrel for use in a gas lift system is configured to improve the recovery of petroleum fluids from a well. The side pocket mandrel includes an upper assembly joint, a lower assembly joint, and a central portion that has a total length (LT). The side pocket mandrel further comprises a central bore extending through the side pocket mandrel along a central longitudinal axis that extends through the upper and lower assembly joints. The side pocket mandrel further includes a tool channel offset from the central bore and a side pocket tube linearly aligned with the tool channel and configured to receive a gas lift valve. The side pocket mandrel further includes a pair of primary flow blocks that each have a length (LFa) that is at least 35% of the total length (LT) of the central portion of the side pocket mandrel.