Azimuthal Gamma Ray Density Estimation During Drilling
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Solution Overview
Problem
During drilling operations at oil and gas reservoirs, well log samples may not be available at all intervals, limiting the accuracy of density measurements and porosity estimation.
Innovation Solution
A computer-implemented method using a bit tool with a gamma ray detector and magnetometer to obtain azimuthal gamma ray measurements, derive bulk density estimates, and synthesize a density log, which can be used to estimate porosity and adjust drilling operations, even in the absence of core samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If well log samples are used for density measurement, then measurement accuracy is improved, but availability is reduced since samples are not available at all intervals
Solution Approach 1:
The patent creates a synthetic density log by copying the information content of physical core samples through azimuthal gamma ray measurements. The system synthesizes density values at depths where no physical samples exist, effectively creating virtual copies of the density information that would be obtained from actual core samples, thereby extending measurement coverage to all depth intervals.
Solution Approach 2:
The patent introduces azimuthal gamma ray measurements as an intermediary between the unavailable core samples and the needed density information. These gamma ray measurements serve as a mediator that can be obtained continuously during drilling and are then converted into synthetic density values, bridging the gap where direct sampling is impossible.
2Measurement precision
If core samples are collected for density measurement, then measurement accuracy is improved, but drilling time and cost increase
Solution Approach 1:
The patent enables continuous density measurement throughout the entire drilling process by using azimuthal gamma ray detectors that operate continuously during drilling operations. This eliminates the discontinuous, stop-and-go nature of core sampling, where drilling must pause to collect and analyze physical samples, thereby maintaining uninterrupted drilling progress while obtaining density data at all depths.
Solution Approach 2:
The drilling system performs its own density measurement function using the bit tool's integrated azimuthal gamma ray detector during the drilling process itself, without requiring separate core sampling operations. The system serves its own measurement needs by utilizing the drilling operation's own progress and the detector's continuous data collection capability.
3Device complexity
If traditional gamma ray measurements are used, then device complexity is reduced, but measurement precision deteriorates due to lack of azimuthal resolution
Solution Approach 1:
The patent segments the gamma ray measurement process into multiple azimuthal sectors around the borehole, with detectors positioned at different angular locations. This segmentation allows the system to capture density information from different directions, improving the precision of bulk density estimation by accounting for lateral variations in formation properties while maintaining a relatively simple tool design.
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 method enables accurate bulk density and porosity estimation across varying lithologies, enhancing geosteering, well placement, and reservoir characterization, while reducing the need for core samples and improving drilling efficiency.
Implementation Method 1
a bit tool with a gamma ray detector and magnetometer to obtain azimuthal gamma ray measurements
Implementation Method 2
a bit tool with a gamma ray detector and magnetometer to obtain azimuthal gamma ray measurements
Data Source
AI summary
The present disclosure provides a method computer-implemented method for conducting a measurement while drilling (MWD) operation in a wellbore of a reservoir, the method comprising: accessing data encoding measurements obtained from a bit tool during the MWD operation in the wellbore of the reservoir, wherein the bit tool includes a gamma ray detector and a magnetometer; extracting, from the measurements, recordings of a gamma ray detector, wherein the recordings comprise gamma ray measurements taken from more than one azimuthal sectors of a depth location in the wellbore; estimating a bulk density at the depth location in the wellbore using the gamma ray measurements from the more than one azimuthal sectors; and based on, at least in part, the estimated bulk density, adjusting the MWD operation.