CT Index Corrects Petrophysical Measurements for Cemented Formations
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Solution Overview
Problem
Current methods for determining petrophysical properties in oil wells are inaccurate due to unaccounted grain density variations and diagenetic cementation, leading to sub-optimal reservoir characterization and well design.
Innovation Solution
A computer-aided tomography index is used in conjunction with geochemical log measurements to correct petrophysical property calculations, integrating CT scan data with elemental concentration values to improve grain density calculations and enhance reservoir modeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional grain density calculation methods are used, then the petrophysical property measurement process is simple, but the measurement precision deteriorates due to unaccounted cement phases and additional solid material
Solution Approach 1:
The patent introduces computer-aided tomography (CT) scanning as an intermediary tool to visualize and quantify cement phases and additional solid material within rock samples. The CT scan serves as a mediator between the traditional grain density measurement and the complex reality of cemented formations, enabling correction of petrophysical properties by accounting for the presence and distribution of cement phases that would otherwise be overlooked in conventional measurements
Solution Approach 2:
The patent applies parameter changes by using CT scan data to calculate correction factors that modify traditional grain density measurements. By changing the measurement approach from direct traditional density measurement to CT-based volumetric analysis, the system can accurately quantify the volume of cement phases and adjust petrophysical properties accordingly, transforming inaccurate measurements into corrected and reliable values
2Reliability
If conventional petrophysical property determination methods are used, then the analysis process is straightforward, but the reliability deteriorates due to errors from unaccounted cementation and sampling inconsistencies
Solution Approach 1:
The patent implements feedback mechanisms by using CT scan results to correct and refine traditional petrophysical property measurements. The CT analysis provides feedback information about cement phase distribution and volume, which is then fed back into the calculation of grain density and other petrophysical properties, creating an iterative correction process that improves reliability by continuously refining the measurements based on actual formation characteristics
Solution Approach 2:
The patent applies preliminary action by performing CT scanning and cement phase quantification before finalizing petrophysical property calculations. This preliminary analysis of the rock sample's internal structure and cement content allows for proactive correction of measurement errors before they propagate through subsequent reservoir modeling and well design processes
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 approach provides more accurate petrophysical property measurements, leading to improved well design, enhanced 3D geological models, and better reservoir management by accounting for variations in grain density and cement phases.
Implementation Method 1
obtaining a computer-aided tomography index measured on a core sample relating to the well
Data Source
AI summary
method for characterizing an oil well may include obtaining measurements of petrophysical properties relating to the oil/gas or water well, obtaining a computer-aided tomography index measured on a core sample relating to the well that is matched to geochemical concentration from geochemical logs or rock-analysis, correcting the measurements of petrophysical properties as a function of the computer-aided tomography index, and developing a model of a subterranean formation using the measurements that were corrected.