Fundamental Research On Azimuth Density Logging While Drilling

Approach of azimuth density logging while Drilling could be possible to provide the 16 positions density image of formation material around the well, which has provided conveniently for geological contact surface occurrence's computation across the bore hole. When the logging instrument works, the survey density and the photooptical data are saved in 16 sectors around the bore hole. The sector data divides into 4 quadrants (top, bottom, left and right). The instrument revolving probe head which surveys in 4 quadrants can form the density result 360°image to reflect information of formation. In these 16 sectors, we can obtain the data of azimuth through calculating the density and the electro-optical coefficient. These azimuth's data can give the qualitative image formation chart. In this paper, based on the peculiarity of the method of LWD density logging, the models of density logging were built. The response of density logging, as well as the influence factors of their measurement, including azimuth, quarters, different formation density, detection interface, the size of the well bore, formation thickness and dip angle, were simulated by using Monte Carlo method. And we gain the gamma field distribution under different formation condition, which simulated from (137)~Cs radioactive source. At the same time we also had informed the instrument's survey window and size of the source-detector separation. The gamma ray count rate of the far detector and the near detector decreases with the stand-off increasing under the different standoffs, and at the same time, the gamma ray count ratio of the far and near detector increases. And aims at its influence, this paper conducted preliminary study on the three detectors to compensate the sandoff's influence. Meanwhile the gamma count rate of the near detector in the LWD logging decreases with the thickness of the formation increasing. In the slanting stratum, I studied its response relation by changing different dipping formation's angle, and used the data to gain the 360°image of formation, and obtained the processing method from image formation chart. It can help us obtaining parameters stratum density, dip angle, stratum depth, and so on. Which have built the foundation for real-time geology guidance function. This response of the LWD density logging and the influencing factors of the horizontal well were studied, therefore this lay the foundation for the LWD density logging interpret.