The Resistivity Response of Mud Invasion in Fractured Reservoir and Its Correction Method

Zhao, J.; Gu, L.; Liu, J., and Zhou, M., 2015. The resistivity response of mud invasion in fractured reservoir and its correction method.

Resistivity logging data is crucial in reservoir evaluation. However, during the well drilling, it's difficult to obtain the true resistivity of the formation, which is due to the impact of mud invasion in permeable formations and its complex invasion mechanism and influencing factors. This affects the accuracy of reservoir divided, the identification of oil/gas/water zone and calculation of saturation. To solve this problem, the author conducted a experiment which is called “Core Resistivity at Different Fracture Width Experiment”, then, combining the imaging and conventional logging data to study the resistivity response mechanism of mud invasion; ultimately, fitting the correction model for reservoir resistivity which is affected by the development of fracture. By comparing the results of the logging data interpretation, we found that the reservoir resistivity have been effectively corrected, furthermore, the oil saturation increased by 5.6% to 12%, the average increase reached 7.5%.