JAKARTA – Behind the veil of difficulty there is always a way. When tenacity is intertwined with wisdom, being able to explore problems, solutions become a necessity. That experience was wisely captured by the young engineers of PT Pertamina EP Cepu (PT Pertamina EP Cepu). In the midst of the decline in world oil prices since mid-2014, which has an impact on cost efficient and cost-effective policies in all lines of the company, both operations and investment. Responding to the conditions triggered by the implementation of the policy, various innovations were born which were successfully created by Pertamina’s young engineers. These innovations are part of the solution to various operational problems. The impact is immediately visible in the significant savings in operating costs.
For example, what was done by PT Pertamina EP Cepu engineers in the face of total loss of drilling mud (total loss circulation) during development drilling operations at Banyu Urip Field, Bojonegoro (East Java). Total loss circulation is the loss of all drilling mud that enters the formation during drilling operations. The factor causing loss circulation is because the drilling route passes through a very porous rock formation. Or, there is a large enough open gap in the borehole, so that all the volume of running mud is absorbed into the formation. These cracks are caused by cavernour, fracture, or hydrostatic pressure due to the weight of the drilling mud being greater than the formation pressure.
According to Firman Auliya, PT Pertamina EP Cepu’s Petrophysical Specialist, the problem was initially resolved by plugging the loss zone using loss circulation material (LCM), to no avail. The next step is to pump DOB2C (Diesel Oil Bentonite), with various combinations of compositions, but still cannot close the pores of the loss zone. This is because the formation encountered is carbonate rock with a very heterogeneous grain shape. If this problem is not handled properly, it has the potential to cause various losses such as delays in drilling operations, the use of drill bits becomes wasteful, and more fatally it can cause blowouts. Such conditions, of course, must be prevented. Because, it will have a significant effect on increasing overall drilling operating costs. Or, it is even more severe and dangerous when there is a wild outburst. “We have avoided this because it is not in accordance with the cost effective and efficient principles promoted by the company,” said Firman.
For this reason, Firman and PT Pertamina EP Cepu engineers who are members of the PC Prove Amada Reborn work team are looking for alternative methods as solutions to overcome the problem of total loss circulation in the Banyu Urip Field. After evaluating the history of preventing loss circulation of drilling wells in Banyu Urip, especially exploration wells, the choice fell on the Pressurized Mud Cap Drilling (PMCD) method. This method is a way to overcome total mud loss because it cannot be treated with various chemicals.
According to Firman, the PMCD method uses a closed system, where drilling mud is pumped into the wellbore through two sides, namely from a series of drilling pipes, and from the annulus. By continuing to pump drilling mud according to the drilling program, the formation conditions are not damaged, so that the reservoir quality is maintained. “In the realization of eight wells that implemented the PMCD method, the company was able to reduce drilling costs by up to $26.2 million and save project time for five months,” said Firman.