Author: M.Gürhan YALÇIN, Zeynep ŞAHİN
Publishing Date: 2005
Volume 20 Issue 4
Drilling wells are classified upon the purpose, depth, location, and the matter of material to be explored. Drilling methods also vary. One of which is rotary drilling method. The aim of this study is to outline the processes during the rotary drilling utilized for the extraction of CO2 gas. The problems encountered during and after drilling were identified and solution schemes were proposed. As a practical application, the drilling activities in Kemerhisar district were chosen. The drilling operations through the CO2 bearing formation of Kemerhisar district was followed in a particular borehole, down to the depth of 220 m, and the fragments coming from the bottom of the hole were logged on a one-meter basis detail. During drilling operation, the performance of equipment were monitored and such properties as drilling speed, drilling fluid properties, gas emissions and water intakes were recorded. Upon those, well design and development were carried out. An appropriate drilling rig was set and the CO2 gas was securely extracted. The well yield was evaluated to be 15 % water and 85 % gas. An increase with CO2/water ratio was observed deeper than 100 m. CO2 content reaches maximum level in the alternating layers of limestone and mudstone, between the depths 0f 165 m and 205 m. In conclusion barite added drilling mud as well as safety values would be needed where the pressures are really high. Gas emission with high pressures would be able to control by such a heavy drilling mud. This would certainly prevent the cease of pump, sudden gas ejections, and the collapse of the borehole perimeter. Needless to say, it would ensure the working safety for the crew as well.
Key Words: Natural gas; CO2; drilling mud; drilling; Kemerhisar; Niğde.