The Research Of Downhole Video Technology

Along with the development of oil and gas resources, the technology of stratum testing is more and more important in increasing the recovery ratio. The downhole video technology plays an important role in the test of cased well and naked well. By using the downhole television, we can directly observe the intricate phenomenon of downhole and get some visible information which is impossible to capture by conventional test method. The downhole video imaging technology improves the diagnostic ability of oil and gas well. According to the processing of image information, we can know the rule of seepage and diagnose the structure of stratum and the distribution of oil layer. In a word, this kind of technology has a good prospect in oil field.The major purpose of this dissertation is to study a downhole video imaging system which transmits video digital image signal. It can resist the high temperature, high pressure and erosion. The major content and outcome is listed as follows.1. The designing and debugging of downhole television system. The ADV611/612 acts as the hardcore of image signal compress and decompress chips. The DSP chips TMS320F240 are used to initialize and control the SAA7113 chip (which decomposes image format), the ADV7175 chip (which compose image format) and the ADV611/612 chip. The modularization method is adopted in the design of software.2. The design and test of digital transmission system. The signal is transmitted from downhole to ground based on the variety of frequency. The digital system is presented the first time in the world. When we conduct the transmission on the 3000 meters long single core of cable, the transmit speed amounts to 1Mbit per second.3. The studies of resistance of High temperature, high pressure and dirt. Pinhole camera is used in this system and the defense device is built in. The introduction of isolated layer make the pinhole camera departs from high temperature and high pressure. Special active velamen is added to the camera to keep it clean and resist the dirt.