| Author | Ekkarat Rattanaphra |
| Note | An internship report submitted in partial fulfillment of the requirements for the degree of Master of Engineering (Professional) in Offshore Technology and Management, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | The objective of this rig visited is to observe and familiarize with drilling operations and procedures for each specific drilling activities operated by PTTEP and their services companies in the Sirikit field. Two wells with two strings design were visited from 8-22 June 2011. However, there are many problems encounter during the drilling operations. The most critical one is seem to be lost circulation issue.
Lost circulation might be occurred due to several reasons. In the Sirikit field operation, the heavy inhibitive oil based mud was used to maintain the wellbore instability both mechanical and chemical in the Main seal and reservoir sections. As a result, this heavy mud weight contributed a large pressure drop across the low pressure formation below the Main seal which probably caused the lost circulation. The CaCo3 and EZ squeeze, Lost Circulation Material (LCM), were normally used to cure the losses depending on the lost severity. If the losses still persist, the cement slurry was the other option to stop the losses of drilling fluid into the formation.
Consequently, lost circulation problem directly affected and changed whole drilling activities in term of safety aspect and cost increasing. Whenever lost circulation occurred, the probability of well kick was increasing if the mud capability could not handle the lost severity. Moreover, the rig time to cure the loss was also added which directly increased the well cost and effect the master well planning. Well schematic might also be changed depending on the lost circulation situation.
It has clearly seen that lost circulation is the critical drilling problem in the Sirikit field operation that challenges the drilling engineer to figure out the solution to prevent or avoid losses of drilling fluid into the formation. In my point of view, I personally purpose three following solutions to prevent and cure the lost circulation issues:
1. Lost Circulation Material (LCM) -- Cure the losses
2. Balanced Pressure Drilling (MPD/UBD) -- Prevention the losses
3. Well schematics Re-design -- Prevention the losses
This internship report aims to review and study the lost circulation remedy both technical and economic feasibility in order to prevent and minimize losses of drilling fluid into the formation by comparing advantages for each methodology. |
| Year | 2011 |
| Type | Research Report |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Offshore Technology and Management (OTM) |
| Chairperson(s) | Chiu, Gregory L.F. |
| Examination Committee(s) | Sarunphong Articharte;Jirawat Chewaroungroaj |
| Scholarship Donor(s) | PTT Exploration and Production Public Co.,Ltd |