| 摘要 |
A method of compensating a density log (D, E, F, figures 2, 4, 5) comprising the step of: compensating a far density (E, figures 2, 4, 5) by adding a correction at a given point in the density log. The correction comprises at least a first correction function, and optionally a second correction function. When the correction includes both the first and second correction functions, the first correction function relates to a correction for slow-moving perturbations such as slow variations of mudcake's thickness 18, and the second correction function relates to fast-moving perturbations at the said given point. Regardless of whether the correction includes the second correction function the first correction function is filtered by a long filter. The first correction function may be defined by (k-1)*(long filtered far density - long filtered near density), and the second correction function may be in the form of (k'-1)*(far density difference- near density difference), where k and k' are the first and second values of the penetration ratio respectively. An example of fast-moving perturbation may be borehole wall 17 irregularities. |
