This paper describes the investigation of a single-well enhanced geothermal system comprised of a downhole thermosiphon and a novel completion design using a downhole heat exchanger. The thermosiphon is a device that takes advantage of the gravity head difference between liquid flowing down the annulus and vapor flowing up the tubing. Without a connection to a large reservoir volume, a downhole...

Executive summary This thesis proposes and evaluates a concept for downhole depth estimation by matching subsurface measurements from two sensors in a bottom hole assembly. The application of a downhole depth estimate in automated subsurface navigation has also been demonstrated. One of the key hurdles in achieving real time subsurface navigation lies in communication bottom neck between surfac...

The heat transfer characteristics of a downhole heat exchanger (DHE) were studied experimentally in a laboratory scale. The permeable aquifer was simulated by using a rectangular tank filled with glass beads of diameter ranging from 3 to 5 mm. The downhole heat exchanger was modeled by a Ushaped copper tube. We have simulated various configurations of DHE by changing the geometrical parameters ...

This paper treats stabilization of multiphase flow in a gas lifted oil well. Two different controllers are investigated, PI control using the estimated downhole pressure in the well, and nonlinear model based control of the total mass in the system. Both control structures rely on the use of a state estimator, and are able to stabilize the well flow with or without a downhole pressure measureme...

In this paper we develop and demonstrate a method to estimate the reservoir pressure, a mass productivity index, and a thermal power productivity index for vertical water-fed geothermal wells, from its production characteristic (also called output) curves. In addition, the method allows to estimate the radius of influence of the well, provided that a value of the reservoir transmisivity is avai...

This paper introduces a method for selecting the best sensor layout when using wired pipe for drilling operations. The introduction of wired pipe in drilling operations increases the data rate significantly compared to standard telemetry systems. Various sensors systems are available, measuring parameters such as drillstring vibration, drillstring torque, downhole fluid temperature and downhole...

intelligent wells provide the ability for monitoring and control of downhole environment of the wells. downhole monitoring is achieved through sensors while control is realized with downhole valves. recovery from intelligent wells can be improved by proper selection of candidate wells/fields and optimizing the number, location and performance of the installed interval control valves. design cri...

This paper proposes the use of a hybrid approach to perform the trajectory control in the oil drilling industry using Rotary Steerable Systems (RSS). Two levels of automation are proposed, the attitude control (Level 1) regulating inclination and azimuth downhole and the outer loop (Level 2), that monitors the performance of the inner loop and controls the directional drilling commands issued t...