Drilling operations have begun on the Koctepe-1 well in the Diyarbakir Petroleum District of South Eastern Turkey. All pre drilling activities were completed during the first week of July and the well is currently drilling at a depth of just over 100 meters. Located on the Hoto prospect in License 3784, the well will be drilled by partner Aladdin Middle East with their Wilson 75 rig, which has a depth capacity of 2700 meters. The Koctepe-1 well is expected to be drilled to a total depth of 1680 meters which is expected to be reached by mid-August. Tethys Oil will have a 45 percent interest in the license after completion of the well and Aladdin (the Operator) a 55 percent interest.
The Koctepe-1 exploration well is targeting a limestone reservoir of Cretaceous age, called the Karababa formation. Estimated depth to this potential oil-bearing zone at the well location is slightly more than 1500 meters. A secondary target is for dolomite reservoirs in the Derdere formation at slightly less than 1650 meters.
Background - Drilling Operations
A number of tasks must be completed before actual drilling of the hole begins. These tasks are divided into three operations: location construction, mobilization, and rig-up. The first operation, after the location was surveyed, was to make level an area of 100 by 100 meters. Within that area a cement pad was poured for the rig to sit on and a reserve mud pit was dug and lined.
The second operation was to mobilize and set up living quarters for the 45 workers who will be there. Next drilling materials were moved in and stacked. This includes 300 pieces of 10 meter long casing (steel pipes) weighing in total 128 metric tons, 1200 sacks of drilling mud, and over 1000 sacks of cement at 50 kilograms each. Altogether this required almost 60 truckloads to arrive on location including mobilizing the rig. The last pre-drilling operation is to ?Rig-up?, which means putting all of the pieces together.
Initial steps of spudding the well (?spud? means to start drilling, originally the word described a small digging tool) are as follows: mix drilling mud of freshwater and bentonite clay, drill a 67 centimeter diameter hole to about 10 meters, put in it a 51 cm diameter pipe and cement around it from top to bottom. Next the blowout preventer is installed to control any flow of mud, oil or gas out of the hole. After this operation, the hole is ready to be deepened with a 31 cm drill bit to a depth of 328 meters where a 24 cm casing will be cemented into the bottom of the hole. Finally the hole will be drilled to a total depth of 1680 meters with a 22 cm drill bit.