Bit-Rock Interaction Modeling for Real-Time Formation Elasticity
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Solution Overview
Problem
Conventional methods for determining rock elastic properties during wellbore drilling, such as wireline and LWD sonic logging, are costly and lack real-time geosteering capabilities due to separate runs and measurement points behind the drill bit, which can delay informed drilling decisions.
Innovation Solution
A bit-rock interaction model that utilizes passive drilling data, including drill bit vibrations and rate of penetration, to determine rock elastic properties in real-time by establishing a relationship between stress and strain through Hooke's law, allowing for cost-effective and at-bit measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline and LWD sonic logging are used to determine rock elastic properties, then measurement accuracy is improved, but cost increases and real-time geosteering capability is lost
Solution Approach 1:
The drill bit serves dual functions: both drilling the wellbore and measuring rock elastic properties through integrated sensors. The drilling process itself generates the data needed for elastic property determination, eliminating the need for separate logging runs and reducing overall system complexity.
Solution Approach 2:
The patent combines the drilling function with the measurement function into a single integrated system. Sensors are embedded in the drill bit to capture vibrations and acoustic emissions during drilling, merging two previously separate operations (drilling and logging) into one simultaneous process.
2Measurement precision
If separate wireline and LWD runs are conducted to measure rock elastic properties, then measurement accuracy is improved, but time consumption increases
Solution Approach 1:
The measurement process continues uninterrupted during the drilling operation itself. Data collection is continuous and simultaneous with wellbore creation, eliminating the need to stop drilling for separate logging runs and maintaining continuous productive action.
Solution Approach 2:
Rock elastic properties are determined during the drilling process itself, before the wellbore is completed. This preliminary measurement allows real-time geosteering decisions to be made while drilling, rather than after separate logging runs are completed.
3Reliability
If LWD measurement points are positioned behind the drill bit, then measurement reliability is improved, but real-time geosteering capability is reduced due to measurement delay
Solution Approach 1:
The drill bit itself is used as the measurement point, positioned at the very front of the drilling operation. This allows rock properties to be measured at the actual point of rock interaction, providing the earliest possible data for geosteering decisions rather than delayed measurements from behind the bit.
Solution Approach 2:
Sensors embedded in the drill bit act as intermediaries between the rock formation and the measurement system. These sensors directly capture vibrations and acoustic emissions at the bit-rock interface, providing immediate measurement data without the delay of transmitting information from behind the bit.
4Measurement precision
If conventional sonic logging methods are used to determine rock elastic properties, then measurement accuracy is improved, but drilling cost increases
Solution Approach 1:
The drilling operation itself provides the measurement function through integrated sensors. The energy and resources already expended for drilling are sufficient to generate the data needed for elastic property determination, eliminating the need for additional expensive logging operations.
Solution Approach 2:
The drill bit is designed to perform multiple functions simultaneously: drilling the wellbore and measuring rock elastic properties. This multi-functionality eliminates the need for separate specialized logging tools and operations, reducing overall cost while maintaining measurement capability.
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 real-time geosteering and reduces costs by using passive drilling data to determine rock elastic properties, providing accurate and timely insights for drilling parameter adjustments.
Implementation Method 1
The bit-rock interaction model may utilize drilling data obtained while the drill bit drills the wellbore. The drilling data may include drill bit vibrations
Implementation Method 2
the bit-rock interaction model may derive stress representatives from the drill bit vibrations, and the strain representatives from the ROP. In some implementations, the stress representatives and/or strain representatives may then be utilized to determine one or more rock elastic properties of the subsurface formation, such as Young's modulus, Poisson's ratio, etc., according to Hooke's law.
Data Source
AI summary
A method comprises obtaining drilling data of a drill bit while drilling a wellbore in a formation with the drill bit. The method comprises generating stress representatives and strain representatives via a bit-rock interaction model configured with parameters to map the drilling data. The method comprises determining one or more elastic properties of the formation based on the stress representatives and the strain representatives.