Numerical Simulation of Logging-While-Drilling Azimuth Density Measurement

A numerical simulation of logging while drilling density (LWD) is investigated by using Monte-Carlo (MC) method. The response of azimuth imaging is performed with in a highly deviated well with 60 degree slope. And then, the influence of counting rates of detectors was discussed due to characteristics of the inhomogeneous stratum. The numerical result shows that the azimuthal density image can intuitively display the characteristics of metrical stratum. Moreover, it can really display the thickness and location of the reservoir when drilling. The density image visually realized the visualization of the results and achieved application of geo-steering while drilling in theory. A further numerical study was carried out by using a Spine-and-Rib plot and the Far Detector Count Rate Compensation to analyze the influence of the standoff distances. And the numerical simulation results were analyzed with different Be-windows design parameters. The numerical result shows that the compensated density can satisfy the precision requirement with the two methods when the standoff distance is less than a predetermined value. Otherwise, just the far detector count rate can be compensated the stratum density with the cone-shape Be-windows.