A Concept Platform for Highly Efficient, Highly Accurate Wireline Special Operations
Authors: Garcia German D. , Dumont Hadrien , Mishra Vinay , Chen Li , Hayden Ron , Babin Christopher , Cig Koksal 
Published: November 2018

A concept platform integrating the precise movement of a linear or azimuthal actuator, such as in instrumented wireline intervention tools (IWIT), with fast pressure measurement and/or rock sampling instruments is presented. This device accurately moves the measurement probe or sampling assembly either in the longitudinal or azimuthal direction in the wellbore to significantly improve operational efficiency and data quality.

Precise movement control enables acquiring data at exact intervals to eliminate errors induced by cable stretching, overpull, or variable cable creep. Specific lithofacies can be targeted from a borehole image log. Simulation with current IWIT capabilities shows significantly reduced uncertainty over common wireline protocols. The operational procedure includes correlation using standard wireline gamma ray methods. The platform is anchored at the top of the zone of interest and a distributed survey made with the linear actuator for every probe displacement. Removing cable movement significantly reduces an important source of error in distributed pressure measurement. A similar approach is proposed for the coring tool with the added benefit of being able to rotate the tool's bit at different azimuths to collect rock samples.

This concept platform would enable reducing the time spent on pressure surveys if similar accuracy to current standard practices is acceptable. Because the only remaining source of error is gauge accuracy, results show that fewer stations are necessary to replicate standard wireline results. Where accuracy is important, as with distributed pressure measurements to quantify reserves using gradient intersection to define fluid contacts or determine compositional gradients, the proposed approach is shown to significantly reduce error using the same number of stations. We use data sets from previous work to show the impact of the error reduction in the position of the fluid contact.

IWITs currently used in cased hole employ active anchoring to perform intervention tasks, including linear actuators capable of delivering up to 80,000 lbf of stroking force. In the proposed concept platform, this pulling force could be instrumental where there is high risk of differential sticking. By anchoring the upper part of the platform in overlying impermeable intervals, the probe could be lowered into the permeable interval to conduct the pressure survey or fluid or rock sampling operation without exposing the full length of the platform to the pressure differential forces for significant risk mitigation.

The proposed architecture for the concept platform innovatively combines several operational concepts used today as separate entities in wireline operations. Their integration, however, generates important efficiency gains, reduces the risk in stationary measurements and operations, improves accuracy, and enables the implementation of unprecedent distributed pressure measurements and coring practices with azimuthal rotational capabilities using wireline.