Technical Limit (TL) and invisible lost time (ILT) are concepts that have contributed to the success of several oil and gas projects around the world since late 90s, many of them documented and presented in international conferences. The TL represents the optimum time for a given operation, based on statistical analysis or operation team commitment. Defining TL could be challenging when unique activities are programmed or there is a lack of offset data, on these situations the TL estimated may be biased. The objective of this paper is to describe a methodology that allows to define a TL based on specific conditions of the well, to identify not only the ILT from operational performance, but also identify imprecisions on the daily operation reports (DOR), the program and well design.
ILT is the difference between the productive time and TL, this value allows to estimate efficiency. Identified invisible lost time (IILT) is the ILT portion that can be measured with real time data and/or DOR. The other portion is defined as unidentified ILT (UILT). IILT and UILT were estimated to productive and non- productive time (NPT). Geological correlation was used to estimate ILT derived from drilling performance.