PDC Drill Bit Coring Blade Geometry for Directional Drilling
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Solution Overview
Problem
Current drill bit designs face challenges in efficiently extracting core samples during directional drilling, as tilting the drill bit can lead to premature extraction of core samples due to induced forces, and the process of changing drill bits is time-consuming and costly.
Innovation Solution
The design incorporates a PDC drill bit with coring blades featuring a continuously angled radially interior surface and a conical insert embedded near the bit centerline, allowing for directional drilling without negatively impacting core sample formation, and optimizing core sampling by using non-planar cutting elements with radial offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drill bit is tilted for directional drilling, then directional drilling capability is improved, but core sample extraction is adversely affected due to premature extraction
Solution Approach 1:
The coring blade is segmented into multiple functional zones: a radially interior surface for directional drilling contact, a core sample formation zone with specific geometry, and a core sample extraction zone. This segmentation allows each zone to perform its specific function independently, enabling directional drilling while preserving core sample integrity.
Solution Approach 2:
Different regions of the coring blade are given different geometric properties and functions. The radially interior surface has a specific angle for directional drilling, while the core sample formation area has optimized curvature and spacing. This local differentiation allows the blade to simultaneously accommodate directional drilling tilts and maintain proper core sample formation conditions.
2Productivity
If conventional drill bit designs are used, then drilling operations can be performed, but frequent drill bit changes are required which increases time and cost
Solution Approach 1:
The drill bit design integrates multiple functions into a single tool: it can perform both directional drilling and core sample extraction without requiring bit changes. The coring blade geometry is optimized to handle both operations, eliminating the need to retrieve and replace the drill bit when transitioning between these functions, thereby reducing non-productive time and increasing overall drilling efficiency.
3Adaptability or versatility
If the coring blade has a radially interior surface for directional drilling, then directional drilling is enabled, but core sample length may be compromised
Solution Approach 1:
The coring blade geometry is pre-configured with optimized radial offsets and curvature radii that anticipate the effects of directional drilling tilts. The radially interior surface angle and core sample formation zone geometry are designed in advance to compensate for forces induced during tilted drilling, ensuring that core samples of the desired length are formed even when the bit is tilted for directional drilling.
Solution Approach 2:
The design optimizes specific geometric parameters including the angle of the radially interior surface, the radial offset distances, and the curvature radii of the core sample formation zone. By carefully selecting and adjusting these parameters, the blade maintains its ability to form full-length core samples while accommodating the angular deviations necessary for directional drilling operations.
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 design enables effective core sample extraction during directional drilling by maintaining the core sample length and reducing the need for frequent drill bit changes, thereby improving drilling efficiency and reducing costs.
Implementation Method 1
The cutting elements are designed to shear formations that range from soft to medium hard through abrasion, fracturing, or shearing action
Implementation Method 2
The cutting elements engage the earthen formation causing the bit to cut through the formation material by either abrasion, fracturing, or shearing action
Implementation Method 3
With weight applied to the drill string, the rotating bit engages the earthen formation
Implementation Method 4
tilting the drill bit can lead to premature extraction of core samples due to induced forces
Data Source
AI summary
A drill bit for obtaining core sample fragments from a subterranean formation includes a bit body having a bit centerline and a bit face, a plurality of blades extending radially along the bit face, including a coring blade, a plurality of cutting elements on the blades, and a non-planar insert embedded in the bit body proximate the bit centerline. One of the cutting elements is a first cutting element on the coring blade at a first radial position from the bit centerline, and at least a portion of the coring blade is radially outward from a most radially interior cutting part of the first cutting element.