Research On Testing System Of Oil Down-hole Pressure And Dynamic Uncertainty

Perforation and fracture is a key technology in the process of oil exploration and development, perforation and fracture instantaneous dynamic pressure parameters provide a theoretical basis for evaluating of perforating and fracturing effecting, deepen the mechanism of perforation and fracture process and new perforation product development. In order to test the dynamic pressure signal when perforation and fracture, developed a dynamic pressure tester (P～t tester) for harsh environment of the oil down-hole, and capture the dynamic pressure signal successfully in perforation and fracture many times. To clear the quality of test results, based on the existing theory of uncertainty, research on the dynamic uncertainty principle of assessment based on error sources, evaluate dynamic uncertainty caused by pressure testing system, quantitative descript the quality of test results.This article focuses on the following four aspects:Firstly, analysis reasons of the previous generation product test failure, with the measured signal characteristics, clear the system testing requirements, gives the overall system design and some of the hardware circuit, analyze in detail the key technologies of test system, such as conversion sampling strategy to determine the trigger point, isolating vibration and shock of test system.Secondly, study on dynamic response characteristics the test system, calibrate dynamic characteristics of the sensor using shock tube as the excitation source, clear the frequency band of the sensor, and basis on this, do quasi-static calibration to the sensitivity of the system with a drop hammer, analyze the measured data.Thirdly, research on the dynamic uncertainty principle of assessment based on error sources, on the basis of GUM uncertainty principle, with the characteristics of test system dynamic measurement errors, study the sources and characteristics of dynamic uncertainty, give a assessment method to dynamic uncertainty. Finally, according to uncertainty evaluation methods, set up a mathematical model for underground pressure testing system, and evaluate component of dynamic uncertainty, give expansion standard uncertainty of testing system.