Design Of Oilfield Pressed Fracture Location Monitoring System

With the rapid development of world economy, oil as the "industrial blood" of the national economy, has gradually developed into an extremely important resource which related to the national security. In China low-permeability reservoir which has a great development potential accounts for two-thirds of the proven oil reservoir and has become the main battlefield of oil and gas exploration. Currently hydraulic fracturing technology is the most widely used exploiting technology for low permeability reservoir. Monitoring and analysis the location of hydraulic fracture is one of the important issues which is going to being solved during the research of oil and gas exploring technology.Based on the analysis and absorption of the existing monitoring theory, a low cost and low power high performance fracture monitoring system, according to the cooperative unit's request, has been developed independently in the paper, which becomes the ideal solution to the monitoring of the oilfield pressed fracture localization.After the comprehensive analysis of oilfield geological parameters and the fracture injected principles, a solution of fracture location monitoring system based on micro-seismic signal detection and remote intelligent monitoring, is proposed in the paper. According to the characteristics of source signals which picked up by the piezoelectric sensor, a micro seismic signal processing circuit is designed to match the goal of the signal buffer amplifier, wireless transmission, rectifier filter, background noise cancellation and so on. Taking AT98S52 MCU as hardware development platform, an event identification processing circuit is designed to collect and save the time difference as well as to transfer data by PC software. Based on TDOA (Time Difference of Arrival) localization theory, the monitoring system is designed by Visual Basic6.0 software development platform, which could help to achieve the goal of precise localization and real-time display of the fracture extending.The fracture location monitoring system which designed in the paper has passed the laboratory testing as well as the debugging and running test in the construction site. And it was proved to fully satisfy the requirements of cooperation unit. Field test results showed that fracture monitoring system can achieve precise localization for more than 6 hours within 1,000 meters around the fractured well.