Coaxial Coring Device for Horizontal Drilling
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Solution Overview
Problem
Traditional vertical drilling methods face challenges such as insufficient stratum information, low effective drilling length, high costs, and logistical difficulties in high mountain areas, while horizontal directional drilling improves precision and cost-effectiveness but struggles with in-well power supply and ensuring coaxial survey holes.
Innovation Solution
A casing-protective horizontal directional drilling coaxial coring device comprising a casing pipe, a coring tube, and a conversion adapter with a screw motor, allowing the coring tube to move axially within the casing pipe, ensuring concentricity and power accessibility, and featuring centralizers and sealing components for stability and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional vertical drilling survey methods are used, then drilling depth can be achieved, but the effective drilling length is too low, the number of drilling holes is too massive and the cost is too high
Solution Approach 1:
The invention transitions from traditional vertical drilling to horizontal directional drilling, changing the drilling dimension from vertical to horizontal. This allows the drill bit to advance through the ground in a horizontal direction while the casing pipe provides protection, enabling longer effective drilling lengths without requiring multiple deep vertical holes.
Solution Approach 2:
The coring tube is nested within the casing pipe, with the coring tube having an outer diameter smaller than the inner diameter of the casing pipe. This nested structure allows the coring device to operate within the protected space of the casing pipe, enabling continuous coring over long horizontal distances.
2Measurement precision
If horizontal directional drilling technology is applied, then precision and cost-effectiveness are improved, but in-well power supply becomes inconvenient and ensuring coaxial survey holes is difficult
Solution Approach 1:
The power supply system is segmented into an external power source and a flexible cable that can be extended through the drilling apparatus. The cable passes through the conversion adapter and screw motor assembly, allowing power to be delivered to the screw motor located within the wellbore without requiring complex in-well power generation or transmission systems.
Solution Approach 2:
The conversion adapter serves as an intermediary component that facilitates both power transmission and mechanical connection. It has a through-hole that allows the flexible cable to pass through, enabling power supply to the screw motor while also providing a mounting structure for the motor within the casing pipe assembly.
3Manufacturing precision
If horizontal directional drilling is used for coring, then drilling precision is improved, but ensuring the survey hole is concentric and coaxial with the full face drilling hole becomes difficult
Solution Approach 1:
The casing pipe is installed in advance to establish a fixed reference axis before coring operations begin. The first and second centralizers are positioned along the casing pipe to pre-establish alignment references, ensuring that subsequent coring operations maintain concentricity and coaxiality with the original drilling hole without requiring complex real-time alignment adjustments.
Solution Approach 2:
The centralizers change the positional parameters of the coring tube by constraining it to specific radial positions within the casing pipe. This mechanical constraint ensures that the coring tube maintains a fixed offset from the casing pipe center, guaranteeing concentric drilling throughout the coring process.
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 device enables efficient horizontal directional drilling with a high coring rate, easy power access, and prevents hole collapse, maintaining coaxial alignment and reducing costs with a simple and effective structure.
Implementation Method 1
a screw motor is located between the conversion adapter and the coring tube, two ends of the screw motor are fixedly connected with the conversion adapter and the coring tube, respectively; under an action of an external force, the screw motor drives the coring tube to move along an axial direction of the casing pipe
Data Source
AI summary
A casing-protective horizontal directional drilling coaxial coring device for geological investigation includes a casing pipe, a coring tube and a conversion adapter. Both the casing pipe and the coring tube are tubular, and the coring tube is coaxially set within the casing pipe. The conversion adapter, having a cylindrical structure fitted with the casing pipe, is coaxially set at a back end portion of the casing pipe and is slidably connected with an inner wall of the casing pipe. A screw motor is located between the conversion adapter and the coring tube, two ends of the screw motor are fixedly connected with the conversion adapter and the coring tube, respectively. Under an action of an external force, the screw motor drives the coring tube to move along an axial direction of the casing pipe till the coring tube extends out of or retracts into the casing pipe.