Abstract: A method to design well trajectories includes determining dogleg severity as a function of inclination, and a corresponding rate of penetration performance of the tool by a hybrid model including physical modelling and machine learning correction. The method includes solving for optimal steering parameters to predict a dogleg severity as close as possible to a desired dogleg severity at a given inclination of the trajectory, which is repeated for dogleg severity and inclination combinations of interest. The rate of penetration for feasible points is also determined and a rate of penetration (or time-to-target) map can be produced. Potential trajectories are then evaluated relative to the map to estimate drilling time-to-target, and an optimal trajectory can be selected that has a lowest time-to-target while also being feasible for the tool and optionally avoiding risks or downhole obstacles.

Abstract: By combining analyte concentration monitoring electrodes and infusion functions into a single subcutaneous element, the described sensing cannulae having a rectangular cross-section avoids the need for two separate devices for insulin delivery and glucose concentration determination. The substantially flat, thus planar, surface of the sensing cannula provides a substrate for deposition of one or more sensing electrodes, preferably through a lithographic-type process. The inner lumen of the sensing cannula serves as a conduit for drug delivery and is formed in a manner that is compatible with lithographic-type electrode formation. The rectangular cross-section of the sensing cannula also allows face and side ports establishing fluid communication between the inner lumen and tissue that preferably reduces the incidence of occlusion of the inner lumen of the sensing cannula.