Successfully Drilled 1,300 m Serpentine with STIFF DRILL D

Case Studies - July 2015


Serpentine, which is a volcanic rock, caused drilling difficulties. Wellbore cavities and pack-off are generally observed problems which causes high torques, pressure build up at SPP and even loss of the well. To minimize well stability problems, modified stresscage system; STIFF DRILL D was improved and achieved in the serpentine section. The serpentine formation is the deepest and longest one in that area as well as in Turkey.

Challenges and Problems:

* Wellbore Stability and Hydrostatic Pressure Control due to Serpentine

* Formation Losses

* Increase in Rheology

* Due to geothermal gradient, the drilling fluid, which was left in the hole, was exposed to high temperature for a long time


STIFF DRILL D is a high performance water-based drilling fluid that adds value to stabilize the serpentine formation with special wellbore strengthening chemicals involved in it. Fluid loss of the system, mud cake quality and encapsulating inhibition were controlled by special polymers and so minimized swelling, dispersing, pack-off potential of the formation. Solid and liquid lubricants were used in this application to minimize the friction between the drill string and casing / formation. Also, special polymers were used to control the rheology to keep the cutting carrying capacity in optimum levels and encapsulate the cuttings to carry to the surface undamaged.

Get Full Version