Steerable Drill Bit Pads for Rate of Penetration Estimation
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Solution Overview
Problem
Deploying sensors close to the drill bit in oil well drilling is challenging due to space constraints in the lower BHA, which can compromise the integrity of drilling and steering tools, leading to inaccurate formation and wellbore property measurements.
Innovation Solution
Incorporating a rotary steerable tool or steerable drill bit with extendable and retractable pads that measure radial displacements to compute parameters like wellbore caliper, rate of penetration, and formation index, allowing for real-time data collection close to the drill bit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are deployed close to the drill bit, then measurement precision is improved, but device complexity increases due to space constraints in the lower BHA
Solution Approach 1:
The patent combines the sensor deployment function with the existing pad structure of the rotary steerable tool. The pads, which are already present for steering functions, serve dual purposes by housing sensors for measuring wellbore caliper, rate of penetration, and formation properties. This merging eliminates the need for separate sensor deployment mechanisms that would compromise BHA integrity.
Solution Approach 2:
The pads in the rotary steerable tool are designed to perform multiple functions: steering control, sensor housing, and data collection. By making the pads universal components that serve both mechanical steering and measurement functions, the patent avoids adding separate dedicated sensor components that would increase device complexity and compromise BHA integrity.
2Measurement precision
If sensors are deployed at or near the drill bit, then measurement precision is improved, but reliability deteriorates due to compromised BHA integrity
Solution Approach 1:
The patent merges sensor functionality into the existing pad structure, eliminating the need for separate sensor components that would compromise BHA integrity. The pads themselves serve as both steering elements and sensor housings, maintaining structural integrity while enabling precise measurements.
Solution Approach 2:
The rotary steerable tool's pad system serves itself by using the same mechanical components for both steering and sensing functions. The pads inherently provide the structural framework needed for sensor deployment without requiring additional support structures that would weaken BHA integrity.
3Productivity
If pads are closely spaced near the drill bit, then productivity is improved by reducing latency, but device complexity increases
Solution Approach 1:
The patent utilizes the dynamic rotation of the drill string to bring multiple pads into position for measurement. The pads are axially spaced and circumferentially distributed, and their relative positions are dynamically adjusted during rotation to enable close spacing near the bit while maintaining manageable complexity through the rotary mechanism.
Data Source
AI summary
A method for drilling a subterranean wellbore includes rotating a drill string in the subterranean wellbore to drill the wellbore. The drill string includes a rotary steerable tool or a steerable drill bit including at least first and second axially spaced pads configured to extend radially outward from a tool body and engage a wall of the wellbore. Radial displacements of each of the first and second axially spaced pads are measured while drilling. The measured radial displacements are processed to compute a rate of penetration of drilling.