Abstract
A new multistage fracturing technology based on Radio Frequency Identification (RFID) was disclosed. It consists of disc spring energy storage system, electric control direction valve, multifunction sliding sleeve, microcomputer control system and battery group, distributed with magnetic field sensor, pressure sensor and RFID antenna. The fracturing process is cooperatively controlled by magnetic tags, RFID tags and pressure wave system. The RFID sliding sleeve system keeps a low-power mode in the ordinary time. In fracturing operations, the magnetic tags should be lowered into the well firstly to activate the electronic control system, and then RFID tags are launched to control the opening and closing of the sliding sleeve in any specific fractured interval. After fracturing, pressure wave is applied to open all the sliding sleeves and the production operation begins. The characteristics of controllable sliding sleeve are as follows: (1) the standby time of controllable sliding sleeve is more than six months. It can offer enough time for the fracturing preparation. (2) The drift diameter of controllable sliding sleeve is constant, as a result, fracturing interval number is not restricted. (3) It has a simple operation process, production operation can implemented directly after fracturing, without running and pulling other strings. Lab tests showed that, every module of controllable sliding sleeve run normally and it can meet the demand of field application.
