A mud invasion correction method based on RPM logging

As the actual logging situation is complex, some resistivity curves of mud invasion wells only contain resistivity curve while drilling. And as the mud invasion is not complete during the measurement, conventional mud invasion correction methods can not be applied to the mud invasion correction in this kind of wells. In order to solve this problem, a new correction method is proposed, that is, the water saturation are corrected directly with the relation between water saturation before and after mud invasion according to the improved volume model. The water saturation measured by RPM is corrected directly to effectively avoid the inapplicability of resistivity logging data. Then the correction model is applied to the interpretation of logging data, and it is found that the interpretation conclusion is consistent with the actual outputs. The interpretation results of mud invasion correction by resistivity curves while drilling is corrected, which verifies the feasibility of the correction method. This method provides a new idea for the mud invasion correction.