The Study Of Signal Detection And Processing Technology On Relief-well

In recent years,many drilling accidents,such as blowout or overflow,happening in both domestic and overseas have represented a serious threat to people's life and safety.However,there is no viable rescue system in our country up to now.Combined with the National Key S&T Special Project and the National Natural Science Foundation Project,we carry out distance and azimuth detection work of accident wells,aiming at providing basis for the intersection of relief wells and accident wells in order to plug the accident well and rescue as soon an possible.In the rescue scheme presented in this paper,we set electrode and inject current into strata to generate gathering current on the accident well casing.Then,we use fluxgate to detect the secondary magnetic field to detect the distance and azimuth of accident well.Finally,the paper concludes a detecting method and develops a principle prototype of accident well which is detecting and locating.According to the theory of electromagnetic detection,we can determine the physical parameters,including magnetic intensity and acceleration,which are required for position detecting of relief well.There into,The magnetic intensity is the one which is formed by the gathering current on the accident well casing,and the acceleration field is the gravity acceleration field.And we locate for the accident well combined with the two parameters.Based on the above ideas,we design and develop a system prototype for detecting of the relief-well signal.The prototype uses fluxgate sensor and gravity acceleration sensor to detect the signal of the secondary magnetic field and acceleration field respectively,and it is combined with high-precision analog-digital conversion chip to complete data aquisition of the two fields.Meanwhile,we completed the signal processing of the two fields by the LabVIEW.And we get the distance and azimuth between sensing point and accident well through the relief-well location algorithm.The result is timely displayed on the LabVIEW interface by both time domain waveform and frequency domain wave.While developing the software and hardware of electromagnetic exploring system,we have constructed the indoor and outdoor simulation test system.After analyzing a large number of experimental data,we draw the following conclusion that we can accurately measure the distance and azimuth between the detection point and gathering current source.Detection point and gathering current source represent the detection point in relief well and thegathering current on accident well casing respectively.Thus we can measure the distance and azimuth between relief wells and accident wells.Above work has provided rescue methods and reference technical basis for the processing of drilling accident.