Determination of borehole azimuth using standoff measurements and tool azimuth measurements

摘要

Borehole azimuth is determined using a measured tool azimuth and a parameter indicative of the displacement between the tool and the borehole wall. The parameter may be a stand off measurement or a known lateral displacement vector. When standoff is used in the determination, measurements of standoff and tool azimuth are acquired 204 using standoff sensors and tool azimuth sensors provided on a downhole tool. The measured stand off and tool azimuth is processed to determine the azimuth of the wellbore 208. The determination may include processing of other parameters such as the lateral displacement vector of the downhole tool, logging measurements, borehole parameter vectors. The azimuthal dependence of a measured borehole parameter is also determined by correlating the calculated borehole azimuth with LWD sensor measurements. This is accomplished by convolving the azimuthally sensitive data using a window function. The azimuthal dependence may be utilised to generate a borehole image 210 having improved image resolution and noise rejection.