Rock Fragment Characterization via Segmentation and XRF Analysis
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Solution Overview
Problem
Characterizing subterranean reservoir formations accessed by wellbores is challenging due to the small size and contamination of rock fragments obtained during drilling, making it difficult to accurately estimate hydrocarbon amounts and accessibility without core samples or appropriate tool insertion.
Innovation Solution
A method involving the separation and analysis of rock fragments using a sample splitter and handheld micro X-ray fluorescence (XRF) devices to create consistent samples for bulk and individual analysis, processing measurements to determine elemental composition, and ranking fragments for representative properties like porosity and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rock fragments are used for formation characterization, then cost and accessibility are improved, but measurement precision deteriorates due to small size and contamination
Solution Approach 1:
The rock fragment sample is divided into multiple subsamples, with each subsample analyzed separately. This segmentation allows statistical representation of the formation while working with small, contaminated fragments rather than requiring a single large core sample
Solution Approach 2:
Drilling fluid is used as an intermediary to transport rock fragments from the formation to the surface. While this causes contamination, it enables the retrieval of fragments without requiring core sample extraction tools to be inserted into the wellbore
2Measurement precision
If core samples are used for accurate formation characterization, then measurement precision is improved, but device complexity and operational difficulty worsen due to tool insertion requirements
Solution Approach 1:
Rock fragments are extracted from the formation using the drilling process itself, eliminating the need to insert specialized core sampling tools into the wellbore. The fragments are naturally brought to surface in the drilling fluid
Solution Approach 2:
Multiple small rock fragment subsamples serve as copies that collectively represent the formation characteristics, replacing the need for a single large core sample that would require complex retrieval tools
3Ease of operation
If rock fragments are used instead of core samples, then ease of operation is improved, but reliability deteriorates due to contamination by drilling fluid
Solution Approach 1:
Multiple subsamples are collected and analyzed rather than relying on a single contaminated sample. This excessive sampling approach ensures that even with drilling fluid contamination, reliable formation characteristics can be determined through statistical analysis of multiple fragments
Solution Approach 2:
Drilling fluid is discarded as a contaminant, but the rock fragments suspended within it are recovered and separated for analysis. The valuable information carrier (rock fragment) is separated from the harmful medium (drilling fluid)
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 cost-effective characterization of wellbore depth intervals with high confidence, allowing for accurate estimation of hydrocarbon reserves and formation properties even when core samples are not feasible, and providing data for pilot well validation and reserve estimations.
Implementation Method 1
handheld micro X-ray fluorescence (XRF) devices to create consistent samples for bulk and individual analysis
Data Source
AI summary
Methods and systems for characterizing a wellbore depth interval from rock fragments, including a method that includes converting measurements of a bulk rock fragment sample and of individual rock fragment samples to a concentration percent, computing a normalization deviation for each of the individual rock fragment samples relative to the bulk rock fragment sample (said normalization deviation being derived from the concentration percent of the bulk and individual rock fragment samples) and ranking the individual rock fragment samples based on a corresponding normalization deviation. The method further includes selecting one or more individual rock fragment samples based on a corresponding ranking, characterizing the properties of the wellbore depth interval from which the bulk and individual rock fragment samples originated using measured properties of at least some of the selected individual rock fragment samples and presenting to a user the characterized wellbore depth interval.