Research On High-precision On-line Monitoring Method Of Wellhead Sand Based On Erosion Model

Sand production is a common phenomenon in the development and production of unconsolidated sandstone oil and gas fields.Excessive sand production can have a serious impacts on development and production,such as clogging of pipelines,erosion of equipment,and even the scrapping of production wells.High-precision sand production monitoring can not only ensure the maximum production efficiency of oil and gas well development,but also effectively avoid the harm of sand production to the entire project.In order to improve the accuracy of sand production online monitoring,this paper mainly studies the high-precision wellhead sand content online monitoring method based on erosion model.Firstly,the vibration and erosion model of wellhead sand on-line monitoring system based on ultrasonic signal is established and analyzed,and a high precision online monitoring method of sand production based on erosion model is proposed.On this basis,an on-line monitoring system of wellhead sand production based on ultrasonic wall thickness measurement and ultrasonic phased array vibration detection is designed,including ultrasonic array probe,wall thickness measurement module,multi-channel array data acquisition module based on NI-6361 and data transmission module.The system uses ultrasonic phased probe to transmit and receive ultrasonic signals in a preset area,and combines the erosion and wear of sand particles on the pipe wall at 90°bend.The mass flow rate of sand particles in the pipe is obtained from the wall thickness loss of the pipe and the specific erosion and wear equation.In addition,a high precision on-line monitoring software for wellhead sand production based on Lab VIEW is designed and developed,which can realize real-time data acquisition,cumulative sand production and instantaneous sand production processing and calculation.Finally,the performance of the loop and sand production monitoring system was tested and improved,and verified by field measurement.The results of loop test and real-time measurement of wellhead sand production show that the high-precision wellhead sand content online monitoring system based on erosion model can automatically calculate the instantaneous sand production and cumulative sand production.The monitoring process does not require long-term uninterrupted monitoring of wellhead sand production signals,and is not affected by single error and cumulative error in the testing process.The sand production monitoring indicators meet:1)monitoring sand particle size≥50μm;2)monitoring minimum sand production rate0.01g/s;3)monitoring error is less than 10%.