Formation Evaluation from Logging While Drilling Prospective the Effects of Drilling Dynamics and Environment, Case Study from Abu Dhabi

Wireline (WL) measurement emerged a long time before the logging while drilling (LWD) technology which created generations of petrophysicists with different school of thoughts. With the dramatic increase in the adoption rate of the advanced LWD technologies, highlighting the logging environment effects and revisiting our understanding of the formation responses logged under different borehole conditions are more critical than ever. Hundreds of LWD datasets from various environments have been reviewed to identify its effects on data quality and responses from bottom-hole-assembly (BHA) design, driving mechanism, tool eccentricity, well angle, mud properties, differential invasion, borehole condition, formation fluid properties, and drilling fluids interactions. Some of these effects co-occur on many occasions, complicating the log response. Examples and demonstrations of our understanding and interpretation of these phenomena are discussed in the study. Looking to the reservoir in the relatively fresh state, a few minutes after drilling with an understanding of the logging environment provides a unique opportunity to obtain precise formation evaluation and insight into reservoir behavior when combined with different time laps acquisitions. This work is a continuation and addition to (Parmanand et al., 2018) which was extended to include more environmental factors in different oil fields and reservoirs with more advanced LWD technologies. This work summarizes the long cumulative experience of interpreting LWD measurements, shares the main observations related to LWD responses and serves as a ready reference to identify measurement artifacts from actual formation responses. It is helpful as a reference guidebook for log analysts, geologists, geo-steering engineers, and others.