Research On Downhole Communication Technology For Intelligent Layered Oil Production With Cable

The reservoir storage types in China are complex and diverse,and the heterogeneity between layers is serious.With the continuous deepening of oilfield development,most oilfields have entered the period of high water cut for exploration and development.In order to improve the stability and reliability of oilfield development,intelligent analysis layer injection mining technology came into being.In actual logging operations in oilfields,single-core cables are widely used as carriers for communication between wells and grounds due to their simple structure,low price,convenient maintenance and high transmission rate.In the process of layered injection and production in smart wells,the single-core steel pipe cable must not only supply power for downhole instruments,but also serve as a carrier for the interaction of downhole reservoir monitoring information and surface control command data.This paper introduces the single-core cable communication method based on DC carrier,analyzes the transmission characteristics of the signal in the single-core steel pipe cable,and establishes the data transmission model of the cabled intelligent stratified oil production communication system for the permanent intelligent well monitoring system.The hardware circuit of a multi-layer half-duplex communication system based on a single-core steel tube cable is presented.On this basis,according to the data transmission characteristics of the single-core steel pipe cable of the permanent intelligent well monitoring system,a two-way communication protocol for the downstream command and the upstream data of the hierarchical injection-production system is designed.The influencing factors of bit error rate in the interaction of downhole reservoir monitoring data and surface control command data are studied.Aiming at the problem of instability of data transmission between wells and grounds,a data adaptive decoding algorithm and long-time data adaptive transmission method for cabled intelligent layered oil production system are designed.The gain and filter coefficient of the system can be adjusted in real time according to the bit error rate of signal transmission to realize adaptive and efficient data transmission.Finally,based on the overall optimization of the system circuit,a large number of experiments have been carried out.The experimental results shown that the system can quickly establish stable data communication between wells and ground,and adjust adaptively according to the bit error rate of the transmitted data,which effectively improves the efficiency and stability of data interaction of the cable intelligent stratified oil production system,which is of great significance to the stable development of the oil field.