The paper is the case study of catching basement in specific Basin of CuuLong which is considered as major production field of Vietnam. The case study is conducted on experience of Mud-logging service and Well Site Geologist (WSG) service of PVDLogging, which is subsidiary of PVD Company.
Production of the basin is mainly found in fractures of Granite basement. Those fractures could cause the major loss of drilling fluid when hitting the top of basement (TOB). The accuracy in identification of this top while drilling is one of the key successes of drilling operations.
Methodology is combination of drilling parameters behavior accordingly to the bit type when approaching the top of granite with or without confirmation of lag data and mud-logging data, such as formation gas, lithology and variation in mud pit volumes. The appropriate application of this method is able to catch the TOB in this field earlier than using Logging While Drilling (LWD) data which usually come later due to the nature design of Bottom Hole Assembly (BHA).