Drilling Fluid Conditioning Device Shear Thinning
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Solution Overview
Problem
The existing methods for conditioning drilling fluids are inefficient, particularly in milling operations, where the high viscosity and gel strength of the fluid lead to prolonged circulation times and increased energy costs, and can result in equipment damage due to blockages and misjudged conditions, especially when using extendable cutters.
Innovation Solution
A drilling fluid conditioning device is integrated into the tubular string to induce shear thinning of the fluid, allowing for faster conditioning and reducing the load on circulation apparatus, with a bypass tool facilitating initial circulation without activating the cutting tool, enabling higher flow rates and quicker heating of the fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drilling fluid is circulated through the tubular string without a conditioning device, then the circulation system is simpler and the load on pumps is lower, but the fluid viscosity and gel strength remain high causing prolonged circulation times and inadequate conditioning for milling operations
Solution Approach 1:
The conditioning device is installed in the tubular string before milling operations begin to pre-condition the drilling fluid by inducing shear thinning. This preliminary action reduces the fluid's viscosity and gel strength in advance, allowing the fluid to be adequately conditioned before it needs to carry metal swarf, thereby reducing circulation time without requiring complex post-conditioning systems
Solution Approach 2:
The conditioning function is segmented as a separate removable device within the tubular string rather than being integrated into the pump system or drill bit. This allows the conditioning action to be isolated to specific sections of the circulation path, enabling efficient fluid conditioning while keeping the overall circulation system relatively simple and modular
2Reliability
If the drilling fluid is thick and viscous to provide adequate gel strength for cutting operations, then the fluid can carry metal swarf effectively, but much energy is required to pump it at high speeds and the mud pumps reach pressure limits
Solution Approach 1:
The conditioning device changes the rheological parameters of the drilling fluid by inducing shear thinning, which reduces viscosity and gel strength temporarily during circulation. This parameter change allows the fluid to be pumped at lower pressures and higher flow rates, reducing energy consumption while maintaining adequate swarf carrying capability when needed
Solution Approach 2:
The drilling fluid's viscosity is made dynamic rather than static through shear thinning induced by the conditioning device. The fluid adapts its viscosity based on flow conditions - thinner during high-speed circulation to reduce pumping energy, and can regain higher gel strength when flow velocity decreases, ensuring reliable swarf transport without constant high energy input
3Productivity
If tight nozzles are used in the drill bit to jet the mud at the cutting face, then the rate of drilling penetration is improved, but the pressure and power requirements for the mud pumps increase significantly
Solution Approach 1:
The conditioning device acts as an intermediary between the mud pumps and the tight nozzles by pre-conditioning the fluid to reduce its viscosity. This intermediary action reduces the resistance to flow before the fluid reaches the nozzles, allowing the nozzles to operate at required pressures for high penetration rates without requiring the pumps to work against the full viscosity of unconditioned fluid, thereby reducing overall power requirements
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 solution significantly reduces the time required to condition the drilling fluid, potentially from 18 hours to 6 hours, saving rig time and preventing equipment damage by ensuring the fluid is adequately thinned for milling operations, while minimizing the load on pumps and equipment.
Implementation Method 1
A drilling fluid conditioning device is integrated into the tubular string to induce shear thinning of the fluid
Implementation Method 2
a bypass tool facilitating initial circulation without activating the cutting tool, enabling higher flow rates
Implementation Method 3
the drilling fluid acts like a heat exchanger between the hot rock and the cold surface temperature
Data Source
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AI summary
A method for facilitating a downhole cutting operation comprises providing a drilling fluid conditioning device in a surface portion of a tubular string providing mounting for a cutting tool on a downhole portion of the string. Initially, drilling fluid is circulated through the conditioning device and the tubular string to condition the drilling fluid. The drilling fluid conditioning device is then removed from the string and the conditioned drilling fluid circulated through the tubular string and the cutting tool.