This research presents detailed notes on the penetrating geological formations of the wellbore. Logs can be presented in two forms of good geological logs, means visual inspection of surface-carrying samples, and geophysical logs, means physical measurements by instruments that are lowered into holes. Logs that are created during drilling are called real-time logs. LWD tool is produced from real-time data transmitted to the surface computer from downhole. Three common services are Natural Gamma Ray, Resistivity, and Porosity and Bulk Density. The output of an LWD service is a log. A log is a graphical representation of the properties of the formation. Some factors that affect data quality are Depth Calculation, Sensor Malfunction and LWD Tools Measurements Fault. During drilling, borehole path monitoring is the important thing to be maintained because the quality of LWD data is critical for the success of any LWD job. Therefore, the field engineer has to understand the factors that affect data quality. Quality Control Process is the key to ensure that the tools are working properly.