Drilling Apparatus Using Suspended Pilot Bit for Vertical Accuracy
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Solution Overview
Problem
Current drilling technologies for vertical holes are complex and expensive, relying on sophisticated rotary steerable systems, which are not efficient in maintaining accurate verticality, especially in directional drilling where deviations and doglegs can lead to increased torque and casing wear.
Innovation Solution
A drilling apparatus comprising a pilot bit and a hole-opening bit assembly, where the pilot bit is suspended from the drill support, allowing it to act as a pendulum, maintaining vertical orientation with reduced weight-on-bit, and a method involving a pilot hole-drilling assembly and a hole-opening assembly, where the pilot bit drills at a lower unit loading, enabling faster penetration and minimizing deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sophisticated rotary steerable technology is used, then vertical drilling accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The drilling system is divided into two separate functional components: a pilot hole-drilling assembly that creates the initial vertical hole, and a hole-opening assembly that enlarges the hole. This segmentation allows the pilot assembly to focus solely on maintaining verticality with simple suspended geometry, while the hole-opening assembly handles the enlarging operation, eliminating the need for complex rotary steerable systems.
Solution Approach 2:
The pilot hole-drilling assembly uses a simple suspended bit geometry that is inexpensive and can be easily replaced. This simple, low-cost pilot assembly drills a small pilot hole that guides the subsequent hole-opening operation, replacing the need for expensive, complex rotary steerable technology with a disposable, simple alternative.
2Manufacturing precision
If high weight-on-bit is applied to maintain verticality, then vertical drilling accuracy is improved, but rate of penetration decreases
Solution Approach 1:
The drilling process is segmented into two stages with different weight-on-bit requirements: the pilot hole-drilling stage uses low WOB with the suspended pilot assembly to maintain verticality, while the hole-opening stage applies higher WOB to the opening assembly to achieve fast penetration. This segmentation allows each stage to be optimized independently for its specific function.
Solution Approach 2:
The pilot hole acts as an intermediary element that establishes the vertical trajectory. By first creating this guiding pilot hole with minimal WOB, the system enables subsequent high-WOB hole-opening operations to follow the established vertical path, achieving both accuracy and high productivity.
3Manufacturing precision
If pilot bit is suspended to act as pendulum, then vertical orientation is maintained, but weight distribution becomes complex
Solution Approach 1:
The suspended pilot bit assembly utilizes the gravitational force acting on the pilot assembly itself as a counterbalancing mechanism. The pilot assembly hangs from the drill string, and its weight creates a natural pendulum effect that stabilizes vertical orientation. This self-balancing approach eliminates the need for additional complex counterweight mechanisms or active control systems.
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
Enables accurate and efficient vertical drilling with reduced operational complexity and cost, maintaining verticality while allowing high rates of penetration and minimizing casing wear by utilizing the pendulum effect and adjustable stabilizers to manage weight distribution.
Implementation Method 1
the pilot bit is suspended from the drill support, allowing it to act as a pendulum, maintaining vertical orientation
Implementation Method 2
As the pilot bit is suspended from the drill support, a portion of the drill support will be in tension. This portion will typically be located below the hole-opening bit.
Data Source
AI summary
Drilling apparatus comprises: a body; a pilot hole-drilling assembly (14) mounted to the body for drilling a pilot hole of a first diameter; and a hole-opening assembly (16) mounted to the body for opening the pilot hole to a larger second diameter. The apparatus is configured such that the pilot hole-drilling assembly (14) will drill at a faster rate than the hole-opening assembly (16) for a given unit loading. As the pilot hole-drilling assembly (14) has the capability to drill at a faster rate than the hole-opening assembly (16), the pilot hole-drilling assembly will tend to experience relatively low weight-on-bit (WOB). The pilot hole-drilling assembly (14) will thus tend to maintain a vertical orientation. The hole-opening assembly (16) will follow the path of the pilot hole, while opening the hole to the required diameter.