Study On Marine Seismic Streamer Resistance

Marine seismic streamer is one of the key equipment in the marine oil and gas resources survey system.The resistance of seismic streamer is one of the important problems that people care about,which has a great influence on the efficiency and quality of exploration and the security of whole system.So it is necessary to study the factors that influence the resistance of seismic streamer.Based on the research before,the three-dimensional mathematical model of marine seismic streamer is established.Considering the general conditions,the movement can be simplified to two-dimensional space,and one-dimensional control equations is carried out to describe the movement.All these works give a theoretical basis of numerical simulation and experimental study.To analyze the influence that speed has on the resistance of seismic streamer,numerical simulation is carried out and the resistance of model seismic streamer under different speed is given out.The result shows that the resistance of streamer is proportional to the square of towing speed.To measure front-end tension on streamer exactly,based on strain gauge testing,a high sensitivity sensor is designed.Finite element analysis and calibration experiment are done to this sensor.The result shows that the sensor has good linearity and sensitivity and it satisfies the requirement of experiment.The design of sensor can be a reference for similar experiment later.Based on the signal from experiment and the sensitivity calculated above,the resistance of model seismic streamer without interference under different towing speed is calculated,and by comparing it with the results of numerical simulation,the correctness of the numerical simulation and the reliability of towing experiment can be confirmed.The result shows that the resistance of streamer is proportional to the square of towing speed and it can be further demonstrated by numerical simulation.By using dimensional analysis,four dimensionless numbers are given to describe the resistance.A new method based on this is put forward to forecast the resistance of real marine seismic streamer,and the prediction formula is given in this paper.At the same time,the paper also studies the resistance of streamer when there is a transverse excitation.The result shows that the resistance of streamer can be regarded as superposition of a balance force and a sin-wave force.When excitation frequency is confirmed,the ratio of balance force to sin-wave force is almost constant.The formula is also given to forecast the resistance of real marine seismic streamer when there is a transverse excitation.