| 摘要 |
<p>A method of surveying a wellbore is disclosed which utilizes a sensor array located within a drillstring within said wellbore, comprising measuring magnetic and gravitational fields with said sensor array at a particular depth and at a particular tool face orientation, utilising measurements of said magnetic and gravitational fields to calculate directly, algebraically, and non-iteratively at least one wellbore orientation indicator which is free of magnetic field biasing errors, either axial or transverse or both. The method may include angularly displacing the drillstring to at least one other tool face orientation and repeating the measuring step. Intermediate calculations may be carried out including comparing measurements of the magnetic field with expected values.</p> |
