Fracture Density Calculation from Borehole Image Logs
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Solution Overview
Problem
Accurate determination of rock fracture density is challenging due to varying fracture densities and angles, leading to inefficiencies in borehole drilling and hydrocarbon production, as existing methods rely on apparent fracture density calculations that are angle-dependent and prone to overcorrection.
Innovation Solution
The method calculates fracture density as the ratio of intersecting fracture surface area to volume, providing an angle-independent measurement using image data from borehole walls, allowing for precise determination and informing formation-related actions such as drilling and production strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If apparent fracture density calculation methods are used, then the process is simple, but the measurement precision deteriorates due to angle-dependency and overcorrection errors
Solution Approach 1:
The patent transitions from two-dimensional apparent fracture density calculations to three-dimensional fracture surface area measurements within a defined volume surrounding the borehole. By using image data from multiple depths and calculating the actual surface area of fractures intersecting a volumetric region, the method eliminates angle-dependency and provides accurate fracture density measurements without overcorrection errors.
2Productivity
If fracture density determination is performed without accurate methods, then resource allocation is inefficient, but implementing accurate methods increases computational complexity
Solution Approach 1:
The patent uses image data from borehole wall scans as a digital representation (copy) of the actual formation structure. By processing these optical copies through automated image analysis algorithms, the system calculates three-dimensional fracture surface areas and densities without requiring physical core samples or complex laboratory analysis, thus improving productivity while managing computational complexity through efficient image processing techniques.
3Device complexity
If conventional apparent fracture density methods are used, then the device complexity is low, but the reliability deteriorates due to angle-dependent errors
Solution Approach 1:
The patent replaces mechanical/physical measurement methods (such as core sampling and manual fracture counting) with optical imaging and computational analysis. By using borehole wall image data and applying three-dimensional geometric calculations, the system reliably determines fracture density independent of fracture orientation, eliminating the angle-dependent errors that plague conventional methods while keeping the measurement system relatively simple.
Data Source
AI summary
A method for performing a formation-related physical action includes: receiving image data of a wall of a borehole penetrating a formation, the image data having image data of fractures intersecting the wall of the borehole; and defining a volume surrounding the borehole. The method also includes determining a surface area of each fracture intersecting the volume at each defined depth in a plurality of depths and calculating a fracture density for each defined depth based on the surface area of each fracture intersecting the volume at each defined depth in a plurality of depths and a size of the volume. The method further includes performing the formation-related physical action based on the fracture density for each defined depth using apparatus configured to perform the formation-related physical action.