Real-Time Time-Depth Modeling From Drill-Bit Seismic Data
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Solution Overview
Problem
Traditional methods for determining the depth of geological features in a subterranean region using surface seismic surveys require drilling to pause and result in low-resolution time-depth models, making it difficult to re-evaluate the wellbore path during drilling.
Innovation Solution
A method and system that utilize a drill bit as a seismic source to generate seismic waves, process the resulting seismic dataset to determine a coherency map, and use an objective function to calculate unique seismic velocities and travel times, generating a time-depth model in real-time to guide wellbore path adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional surface seismic survey methods are used to determine geological feature depths, then the wellbore path can be revised after drilling pauses, but the acquisition time increases and the resolution of the time-depth model decreases
Solution Approach 1:
The drill bit generates seismic waves in real-time during the drilling process, allowing the time-depth model to be determined before the wellbore reaches its final position. This preliminary action enables continuous guidance without requiring drilling pauses for traditional seismic surveys.
Solution Approach 2:
The drilling process itself serves dual purposes: both drilling the wellbore and generating seismic data simultaneously. The drill bit acts as both the drilling tool and the seismic source, eliminating the need to stop drilling for seismic data acquisition and maintaining continuous productive action.
2Ease of operation
If traditional surface seismic survey methods are used, then geological features can be identified, but the wellbore path cannot be re-evaluated during drilling
Solution Approach 1:
The real-time generation of seismic waves during drilling provides immediate feedback about geological features encountered. This feedback loop allows the wellbore path to be dynamically adjusted during the drilling process itself, rather than requiring post-drilling analysis and re-planning.
Solution Approach 2:
Geological information is gathered in advance during the drilling process before the wellbore is completed, enabling real-time path adjustments. The drill bit generates seismic data as it penetrates the formation, providing preliminary geological intelligence for immediate operational decisions.
3Productivity
If the drill bit is used as a seismic source to generate real-time seismic data, then acquisition time is reduced and resolution is improved, but the complexity of processing the seismic dataset increases
Solution Approach 1:
The drill bit serves multiple functions simultaneously: it drills the wellbore and generates seismic waves for geological imaging. This multi-functionality eliminates the need for separate seismic sources and receivers, reducing overall system complexity while improving productivity.
Solution Approach 2:
The drilling operation and seismic data acquisition are merged into a single simultaneous process. The drill bit's mechanical action during drilling directly generates the seismic waves, combining two previously separate operations into one integrated process that improves efficiency.
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 determination of geological feature depths, reducing acquisition time and cost, and allowing for precise wellbore path re-evaluation during drilling, thereby improving drilling efficiency and accuracy.
Implementation Method 1
generating seismic waves that propagate into the subterranean region of interest. The seismic waves may be recorded as seismic traces.
Data Source
AI summary
Systems and methods are disclosed. The method includes drilling, using a drill bit, a wellbore to a sequence of drilling depths within a subterranean region of interest. The method further includes, for each drilling depth, obtaining a seismic dataset generated by the drill bit, determining a coherency map using the seismic dataset, a range of seismic velocities, a range of vertical traveltimes, and a geological model, determining a locus from the coherency map, defining an objective function based on the locus, and determining a unique seismic velocity and a unique vertical traveltime based on an extremum of the objective function. The method further still includes generating a vertical traveltime, depth model using the unique seismic velocity and the unique vertical traveltime for each drilling depth, obtaining a time-domain surface seismic dataset, and determining a depth-domain surface seismic dataset using the time-domain surface seismic dataset and the vertical traveltime, depth model.