A Study Based On Mud Invasion Experiment And Correction Of Resistivity Logging In Sandstone Reservoir

The invasion of mud and filtrate is a complex physical process.It is very difficult to evaluate the mud invasion process because the reservoir is in a complex formation environment and there are many factors that influence the process of mud invasion.What's more,mud filtrate invasion changed the fluid properties of near wellbore reservoir,resulting in well logging interpretation and evaluation of reservoir distortion;the influence of different physical properties of sandstone reservoir,mud invasion degree,thus affecting the accuracy of reservoir logging evaluation.This paper based on the similarity principle and the corresponding theory of the Dagang Oilfield dense sandstone complex reservoirs.carry out the mud invasion experiments combined with experiments to study the new calculation method of resistivity and invasion depth,and we can provide reference for more accurate evaluation of oil and gas reservoir based on this.The main contents of this paper are as follows:(1)Based on the theoretical basis of mud invasion and the core features of the actual mud system and reservoir petrophysical characteristics and experimental conditions,according to the similarity principle to establish similar conditions and the actual formation simulation experiments,the experimental results are similar to the actual layer formation parameters under the conditions of mud intrusion after the variation of mud invasion.(2)Carry out the mud experiment invasion study under the factors of physical properties,differential pressure and fluid properties.Study the resistivity changes with time dynamic rules and influencing factors are given different conditions of mud invasion and its analysis.(3)On the basis of the experiment of mud invasion,two new resistivity correction methods are explored,and the correction effect is analyzed by combining the traditional calibration method,and the practicability of the method is verified(4)Explore a new method to calculate the depth of invasion based on experimental analysis of mud invasion comparing and analyzing the calculation and the traditional method,the calculation of penetration depth has found a good correspondence,show that the method is feasible and effective.