Development And Application Of The Eight Sector Logging Tool For Cement Density And Casing Wall Thickness

With the development of setting up of Daqing one-hundred-year oil field and insistant production of forty million tons,infill well and around well will be more and more in old areas. The figure of wells which need to check the quality of cement bond in oil field is becoming larger and larger every year.The efficient evaluation to the quality of cement bond is important process which can make sure the follow-on production of oil field. The tool which is used for checking the quality of cement bond is CF^T-100 logging tool which was introduced from russia by DLTS,But the tool costs so much that limits the number of introduction.Furthermore,the problem which the repairing parts can’t be received in time influenced the logging timeliness.Therefore,we need to develop national related logging tool eagerly.The logging tool which is designed by my issue can measure sector cement sheath density and the average density of cement sheath by using Gamma ray scattering method at the same time. And it can also be used for measuring casing wall thickness and casing eccentricity.200mCi137Cs is used as the Gamma ray source of Gamma rays in this tool. The Nal(T1) crystal far detector which has eight same sources and circumference arrangement and Nal(T1) crystal near detector are used as receiving scattering of Gamma rays. The tool can be used in universal 140mm casing well of Daqing. It can be applied in many ways, such as confirming the height of cementing cement roof and free pipe position, evaluation of the quality of cement consolidation, measurement of eccentricity of pipe related to well shaft, checking of the damage of pipe and collar position, and so on.Many topics are discussed in my issue,such as the basic working principle of eight sector cement density and casing wall thickness logging tool,machine design,circuit design,signal transmission way. Complete machine and main parts are included in the machine design; 2kv/2w high-power switching power supply, the signal processing circuit and the data collection & transmission circuit are included in circuit design; signal transmission wayis 5.729kb/s normal Manchester code transmission. The ways of power supply and signal transmission can be compatible with Daqing producing logging surface system. The tool can be connected to universal ground equipment directly to logging, and data can be done with by Russian MAK-9 explanation platform.The tool has reached the standard of 125℃/60Mpa temperature resistance and pressure according to indoor experiment. Another hand, the precision of tool has been in accord with expected requirements. The function of tool has got a further inspection by field test of five wells. The tool has good reliability, repeatability,consistency,which can evaluate the quality of cement consolidation effectively in Daqing oil field.