Design Of The Down Hole Instruments Of Multiplexed Logging System And Research On The Data Compression Of DHV Logging System

Several logging instruments can be flexibly assembled in a Multiplexed Logging System, through which many kinds of petroleum logging data can be acquire when it is put in petroleum wells. This technique can increase greatly the efficiency and reducee the cost of petroleum logging. DHV is an another applicable technique of logging. It is a kind of optics televiseion that is used in the field of logging. Pictures, which show the exactly conditions in well, can be acquired by a down hole camera and transmited to the devices on the ground. These pictures are displayed lively, accurately and vividly on the screen of a monitor on the ground.The design of the down hole instruments of a Multiplexed Logging System are introduced in this thesis. Four instruments include temperature measurement device and nature gamma measurement device and so on are concentrated. In this system, signal can be transmitted in the form of analog or digital data. The two kinds of system are both explained. Another kind of Multiplexed Logging System produced by other company is analyzed, which is expected to help us in our future work.Another subject in this thesis is the data compression of DHV logging system. There are two vital difficulties in the system. One is the extreme condition in the petroleum wells. Since the temperature and pressure are very high and there is no light in the well, pictures are hardly gained through a camera. The other difficulty is that the transmitssion over a logging cable is slow, but the data of pictures are very large. The algorithm based on DCT is simple and easy to be implemented. The way to implement this algorithm has been presented in detail in the thesis.