SPE 173645: Combined Distributed Temperature and Acoustic Sensing with Production Logging for Improved Horizontal Well Evaluations


Distributed fiber optic (DFO) sensing makes it possible to monitor data, gathered over time, along the entire length of a wellbore. Distributed Temperature Sensing (DTS) using a permanently installed fiber optic cable has been a downhole permanent monitoring application for nearly 20 years. Fiber optic deployed intervention systems have been used with slick line and coiled tubing since 2008 and 2009 respectively which allows for real time downhole data monitoring during interventions, previously unavailable with these conveyance methods. Recently, another advancement in the intervention domain has been achieved with the development of a .36”  iameter, electric wireline cable which includes fiber optics for both DTS and Distributed Acoustic Sensing (DAS), combined with production logging (PLT) measurements run in a “dip-in” mode. Temperatures and acoustics are recorded along the optical sensor cable, as a continuous profile while the PLT data is acquired in the traditional fashion. A primary industry benefit from this technology is in horizontal well applications where more robust measurements and analysis of production logging data is needed to quantify production profiles in multi-phase environments. Typically, DTS systems can locate the temperature to a spatial resolution of 1 m with accuracy to within ±1°C at a resolution of 0.01°C, and DAS systems can detect acoustic events to a spatial resolution of ½ m across a wide frequency range with variable energy levels. Critically, both are monitored across the entire wellbore in the time domain, thereby achieving an improved understanding of flowing, shut-in, and cross wellbore fluid dynamics. DAS, when appropriately filtered, will identify fluid entries and flow regimes beyond the resolution of spinner arrays. This paper will discuss a new DTS/DAS, electric line cable that has been developed, field trialed and combined with measurements from production logging surveys. The conductor in this cable is capable of handling tractor power for conveyance into horizontal wells. A detailed case history will be presented.

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