Intra-drill pipe microwave communication distance calculation and optimum frequency point determination method

Abstract

The invention discloses an intra-drill pipe microwave communication distance calculation and optimum frequency point determination method. Drill pipes are converted into stepped microwave waveguides; the microwave power transmission coefficient of a single drill pipe under a master mode working condition is calculated according the inner wall structure of the drill pipe; and the optimum number of connection drill pipes between two relays is calculated according to the maximum output power of a transmitting relay and the minimum receiving power of a receiving relay. According to the method, the microwave power transmission coefficient of the single drill pipe under the master mode working condition can be calculated according the inner wall structure of the drill pipe; the microwave transmission performance of the drill pipe can be known; the principle is simple; the operation amount is low; moreover, the optimum number of the drill pipes between the two relays can be calculated through the maximum output power of the transmitting relay and the minimum receiving power of the receiving relay, thereby providing guiding significance for drill column design of gas drilling, and construction design of microwave measurement while drilling.

Description

technical field [0001] The invention relates to the field of oil and gas exploitation, and to the gas drilling downhole monitoring process while drilling, in particular to a method for calculating microwave communication distance in a drill pipe and determining an optimal frequency point. Background technique [0002] In oil and gas drilling engineering, in order to achieve safe, fast and high-quality drilling, it is necessary to carry out downhole monitoring while drilling, so as to accurately and timely grasp the downhole formation fluid, formation lithology, reservoir physical properties and the working status of the drill bit. The acquisition of these information is mainly achieved by installing various sensors on the drill bit and drill string, and using signal transmission technology to transmit the signals output by the sensors to the ground. In gas drilling construction, downhole information can be transmitted by transmitting microwave signals in the drill string. Th...

AI Technical Summary

Problems solved by technology

However, in the drilling construction process, there are various combinations of drill strings, and the structure of the drill string is complex and changeable. The communication distance of 200 meters is often not the most suitable communication distance. and unable to carry out

However, this parameter is an important parameter for the design of the gas drilling microwave monitoring while drilling system. If the communication distance is shorter than the optimal value, the number of relays will be large, that is, there will be redundant relays, which will greatly increase the difficulty and risk of gas drilling construction; If the communication distance is longer than the optimal value, the signal may be unstable or even interrupted, which will greatly reduce the reliability of downhole monitoring while drilling

The drilling site has also adopted the method of real-time monitoring of the microwave signal strength during the drilling process to determine whether to install a new relay into the well, but this method is not predictable, which greatly increases the workload and construction difficulty of the monitoring while drilling process. It is difficult to meet the requirements of gas drilling

Images