ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

A Study on the Mud Losses in the Ultra Deepwater Operations in Black Sea
Ayşenur Mazlum
Turkish Petroleum Corporation, Drilling Department, Ankara
In ultra deep offshore operations, one of the major problems during both well planning and
drilling is that pore pressure and fracture pressure gradients are very close. As these gradients
come closer, possibility of having losses while drilling increases. One of the important problems
of Black Sea offshore operations was losses in which TPAO has one partnership and two
operatorships. The mud weights that was considered as sufficient with respect to the expected
pressure values exceeded the fracture pressure gradients, which led to revision on previous
hydraulic programs. In order to stop those losses, as common in the industry, loss prevention
chemicals were used. Moreover, the casing depths were changed after the real time pressure
measurements. At first, losses were tired to be cured by monitoring the drilling parameters such
as equivalent circulating density (ECD) and penetration rate (ROP) , which are fairly less easy and
reduced in cost. Using synthetic or oil based mud in Black Sea should also be considered after
experiencing the water based mud. In this study, mud losses; which is one of the major problems
in Black Sea ultra deep water operations, will be presented by analyzing the drilling parameters,
mud and formation properties.
Keywords: Mud Losses, Black Sea, Loss Prevention, TPAO
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