Research On Down-hole Flow Control Valve Based On Fiber Bragg Grating Detection

With the rapid development of economic in recent years, our country needs more and more oil. But domestic oil fields have been locating in the post-mining:the high water cut stage. So we need to make full use of each oil layers and increase the oil recovery ratio. At present, China mainly utilizes slice mining technology. It includes the mechanical slice mining technology and microcontroller slice mining technology. The drawbacks of mechanical slice mining technology are complex structure, cumbersome working process, low efficiency, no flow control system and low recovery ratio. The microcontroller control slice mining technology can not measure the flow accurately. And signal interference is so serious that the communication between the surface and down-hole is difficult. Because of the use of the flow control system for flow control, it improves recovery ratio evidently.In this background, because of the inaccuracy of flow control and the difficult of message transmission, the paper brought forth the opening detection system of down-hole flow control valve based on fiber Bragg grating sensing. The system utilizes fiber Bragg grating sensing technology to realize interference-free signal transmission, get real-time information of the underground flow, reduce traditional routine task. The detailed content of this paper shows as follows:1. This paper gives the background of down-hole flow control valve both at home and abroad, and it also proposes the good application prospect of down-hole flow control valve based on fiber Bragg grating sensing.2. This article introduces the basic principle of fiber grating sensor and fiber Bragg grating strain measurement, and to determine the advantages of a fiber Bragg grating for the opening detection system of the down-hole flow control valve based on fiber Bragg grating structure design.3. It analyzes the operating requirements of down-hole flow control valve, and gets the overall program of down-hole flow control valve. We design the down-hole flow control valve for easy flow control and do some researches and simulations on important structure.4. According to the design features of the down-hole flow control valve, we design the opening detection system. The system is used to detect the displacement of the inner sleeve, and gets the relative displacement of the inner and outer sleeve. After calculation, it gets the size of the available flow. In addition, we make some theoretical analysis of the system, choose and simulate a key component.5. Do some displacement detection laboratory experiments of the opening detection system, and proved by experiments that the fiber grating can be accurate, reliable measurement of valve opening, realize the flow detection. So this thesis provides a new effective method for down-hole flow control.