Loss Early Identification And Location Based On Surface Pressure Fluctuation Detection Identification And Location Research

Well leakage accidents have become the biggest non-productive time problems faced by operators during the drilling process,mainly due to their multiple occurrences and severity of hazards.Usually a well leakage can lead to various downhole accidents and affect normal production.In serious cases,it will endanger personal safety.Therefore,we must pay great attention to leak prevention and take appropriate measures.However,the characteristics of well leakage are: strong concealment,suddenness and intractability.The traditional well-drainage identification method generally uses the difference between the total pool volume and the inlet-outlet flow rate,and then determines the wellbore leakage.However,in the on-site construction,due to the difficulties in the collection and determination of various data,there is a great difficulty in the determination of the leak.In this paper,based on the current situation and problems of well leakage in drilling,based on the uniform and vertical characteristics of the drilling annulus,combined with the detection method of long oil pipeline leakage in the field of oil and gas storage and transportation,a leakage layer based on transient flow frequency domain response is proposed.Detection method.This method is mainly based on the principles of water hammer and water hammer and the transfer matrix method.By analyzing the results of the water hammer and the annulus system,the leak layer is judged.Specifically,the pressure wave generated by the well drain is equivalent to the water hammer wave,and the well pressure wave is taken as the input signal.The leaking annulus is the system.The time domain pressure signal received by the pressure sensor at the outlet of the drilling fluid is the output signal and consists of The difference in the degree of resonance between the fluid and the annular flow channel is obtained by a system frequency response diagram(FRD)that represents the relationship between the frequency of the leaky pressure wave and the head of the frequency domain.The periodic relationship between the odd-order harmonics in the frequency domain head and the FRD is calculated by the transfer matrix method,and the leakage layer is located by analyzing this periodic relationship.In order to verify the accuracy of this method,the model was simulated by MATLAB.For this method,the computer simulation was used.The results showed whether the change of the leakage volume and the change of the pressure wave velocity had no effect on the leak detection result..This verifies the feasibility of the method.In order to ensure the accuracy of the signal processing,the oversampling and de-noising techniques of the collected pressure wave signals are performed,which further improves the accuracy of the results.