Experiment Researches Of Overflow And Leakage In Mpd Drilling Based On Dual-point Measurement System

Since the formations of high temperature high pressure and narrow safe density window became the main battlefield of oil and gas exploration and development,drilling engineering are now encountering with many obstacles such as deep-buried reservoir,rocks with intricate properties,sensitive formation and etc.,as a result the managed pressure drilling come into significant use.Conventional MPD applies single point measurement to collect information near the bit,however,the information collected by single point are not accurate and reliable enough to predict and solve the complicated drilling conditions.By adding an extra measurement point above the former one and comparing the information of dual point measurement can real-time detect the abnormal drilling conditions near the bit,meanwhile,the outcomes can be delivered to the ground.This essay established the simulation experiment system for gas kicking and leakage,including simulation wellbore and devices for pressure signal.To improve the experiment,the similarity analysis and the CFD simulation are computed.The essay also establish the analysis model for dual-point experiment on the basis of digital signal analysis theory,which can improve the accuracy of estimate of drilling condition.According to the results of this essay,the pressure and velocity gradient between the bit and leaking point,the pressure fluctuation comparison of this area and outer area is valuable for early detection.In the gas kicking simulation,pressure fluctuates violently between the ground and kicking point,as a result the pressure signal analysis from this part should be put into emphasis.In the analysis section,the results of frequency analysis among the gas kicking data are overt,there are much more lower-frequent signals in the gas kicking condition comparing to the normal one.In the leakage simulation,there are more low-frequent signals while the leaking quantity is smaller.