Direct Heating of Drill Cuttings in a Low-Oxygen Drying Atmosphere
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Solution Overview
Problem
Current methods for disposing of drill cuttings contaminated with drilling fluid are inefficient, leading to significant loss of fluid and increased costs, as they focus on post-drilling cleanup rather than prevention, and indirect heating methods pose risks of uncontrolled reactions.
Innovation Solution
Direct heating of drill cuttings using a low-oxygen, inert gas, such as nitrogen, at elevated pressures to evaporate drilling fluid, allowing for its recovery and safe handling, with a two-stage combustion process to manage oxygen levels and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indirect heat is used to dry cuttings, then the risk of uncontrolled exothermic reaction is reduced, but the heating efficiency and drying speed are limited
Solution Approach 1:
The patent introduces heated air as an intermediary medium to transfer thermal energy to the cuttings. The hot air flows through the cuttings bed, providing indirect heating that reduces explosion risk while maintaining efficient heat transfer. This mediator approach allows thermal energy transmission without direct contact between heating source and combustible material.
Solution Approach 2:
The patent creates a controlled atmosphere by limiting oxygen availability during the drying process. By conducting drying in a low-oxygen environment and controlling air flow rates, the system prevents conditions necessary for uncontrolled exothermic reactions while still enabling effective heat transfer to evaporate drilling fluid from cuttings.
2Productivity
If direct heat is used to dry cuttings, then heating efficiency and drying speed improve, but the risk of uncontrolled exothermic reaction increases
Solution Approach 1:
The patent employs an inert or low-oxygen atmosphere during direct heating to eliminate the oxygen necessary for uncontrolled exothermic reactions. By controlling the gas composition and limiting oxygen presence while applying direct heat, the system achieves high drying efficiency without the safety risks associated with conventional direct flame heating.
3Loss of substance
If drilling fluid is not recovered, then disposal costs increase and environmental impact worsens, but the process complexity and operational requirements increase
Solution Approach 1:
The drying system is designed to perform multiple functions simultaneously: it dries the cuttings to prevent caking and removes drilling fluid through evaporation and condensation. By integrating fluid recovery capability into the drying process, the system eliminates the need for separate recovery operations, reducing overall process complexity while achieving both drying and recovery goals.
Solution Approach 2:
The patent implements a condensation system that captures evaporated drilling fluid and condenses it back to liquid form for recovery and reuse. This approach transforms what would be lost vapor into recoverable liquid, enabling drilling fluid to be discarded from the cuttings and recovered for future use, thereby reducing disposal costs and environmental impact.
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 recovers drilling fluid and reduces the risk of explosions, enhancing operational efficiency and cost-effectiveness by minimizing fluid loss and ensuring safe handling of drill cuttings.
Implementation Method 1
combusting a rich air-fuel mixture at a rich combustion temperature, thereby producing a generally low oxygen, inert rich exhaust
Implementation Method 2
providing the rich exhaust to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least a portion of drilling fluid is evaporated therefrom
Implementation Method 3
at least a portion of drilling fluid is evaporated therefrom
Implementation Method 4
condensing at least a portion of the evaporated drilling fluid to produce condensed drilling fluid
Data Source
AI summary
Systems and methods for removing drilling fluid from wet drill cuttings are described. According to some embodiments, the method comprises, at a pressure above atmospheric pressure: combusting a rich air-fuel mixture at a rich combustion temperature, thereby producing a generally low oxygen, inert rich exhaust; providing said rich exhaust to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least a portion of the drilling fluid is evaporated therefrom and at least some dry solid drill cuttings remain; condensing at least a portion of the evaporated drilling fluid to produce condensed drilling fluid; and separately recovering the condensed drilling fluid and the dry solid drill cuttings.