||Temperature in well is useful in control of drilling properties, design of cement slurry, design of casing and of bore hole tools. It is more important in wells because of high temperature encountered than in oil The elusive temperature in a well is the temperature durin drilling operations. Some people intended to collect data on the maximum temperature in a well (1). Since a number of good theoretical on determining circulating temperatures have been written, they ave been applied to oil well problems (2 to 6). There are apparent difference in thermal situation between geothermal fields and oilfields, and some examples are as follows: (1) In oil country, geothermal temperature gradient is generally constant and geothermal temperature increases 1 with depth. In geothermal fields, geothermal temperature rises rapidly toa high at a shallow depth, and thereafter increases gradually with depth. Patterns of distribution of temperature are dependent upon particular wells. (2)In oil country, types of rocks encountered are usually sedimentary rocks, but in geothermal fields, volcanic and rocks are mainly encountered and sedimentary rocks are intervened sometimes. It is, therfore, important that oil well practices are not directly appl to geothernwl 1 practices.. Our work consists of two simulation of temperature distribution in a well, and measurement of conductivity of cuttings. As for measurement of thermal conductivity of divided bar method using cores is standard method. But in drilling of development wells, cores are taken rarely for point of In that case, are used instead of cores. There were sane works on of conductivity of cuttings (7 and 8). Needle probe method is adopted in this work for the of measurement.