The subject matter of this specification can be embodied in, among other things, a method of sensing that includes activating a first emitter to emit at least one incident wave, transmitting the incident wave along a buffer rod having a first axial end abutted to the first emitter and a second axial end opposite the first axial end, reflecting a first echo of the incident wave by a gap defined along a portion of the buffer rod, detecting the first echo, determining a first amplitude of the first echo, reflecting a second echo of the incident wave by the second axial end, detecting the second echo, determining a second amplitude of the second echo, and determining a reflection coefficient based on the first amplitude and the second amplitude.

The subject matter of this specification can be embodied in, among other things, a method of sensing that includes activating a first emitter to emit at least one incident wave, transmitting the incident wave along a buffer rod having a first axial end abutted to the first emitter and a second axial end opposite the first axial end, reflecting a first echo of the incident wave by a gap defined along a portion of the buffer rod, detecting the first echo, determining a first amplitude of the first echo, reflecting a second echo of the incident wave by the second axial end, detecting the second echo, determining a second amplitude of the second echo, and determining a reflection coefficient based on the first amplitude and the second amplitude.

Methods and systems are provided for controlling gas lift in at least one production well, which determine a quadratic function that relates flow rate or value of oil produced from a production well to gas flow rate for gas injected into the production well based on flow rate measurements for gas injected into the production well and corresponding flow rate measurements of oil produced from the production well. The quadratic function is used to determine an optimal flow rate for gas injected into the production well. The optimal flow rate for gas injected into the production well is used to control the flow rate of gas injected into the production well, and an oil flow rate produced from the production well is measured at the optimal gas flow rate for iterative processing to refine the quadratic function and determination of optimal gas flow rate if need be.

Methods and systems are provided for controlling gas lift in at least one production well, which determine a quadratic function that relates flow rate or value of oil produced from a production well to gas flow rate for gas injected into the production well based on flow rate measurements for gas injected into the production well and corresponding flow rate measurements of oil produced from the production well. The quadratic function is used to determine an optimal flow rate for gas injected into the production well. The optimal flow rate for gas injected into the production well is used to control the flow rate of gas injected into the production well, and an oil flow rate produced from the production well is measured at the optimal gas flow rate for iterative processing to refine the quadratic function and determination of optimal gas flow rate if need be.

A measuring system includes a measuring and operation electronic unit (ME) and a transducer device electrically coupled thereto. The transducer device (MW) has at least one tube, through which fluid flows during operation and which is caused to vibrate meanwhile, a vibration exciter, two vibration sensors for generating vibration signals, and two temperature sensors for generating temperature measurement signals (θ1, θ2). The temperature sensors are coupled to a wall of the tube in a thermally conductive manner. The ME is designed to feed electrical power into the at least one vibration exciter to cause mechanical vibrations of the tube by an electrical excitation signal. The ME generates a mass flow sequence representing the instantaneous mass flow rate (m) of the fluid, so that, at least for a reference mass flow rate, the mass flow measurement values are independent of the temperature difference.

A measuring system includes a measuring and operation electronic unit (ME) and a transducer device electrically coupled thereto. The transducer device (MW) has at least one tube, through which fluid flows during operation and which is caused to vibrate meanwhile, a vibration exciter, two vibration sensors for generating vibration signals, and two temperature sensors for generating temperature measurement signals (θ1, θ2). The temperature sensors are coupled to a wall of the tube in a thermally conductive manner. The ME is designed to feed electrical power into the at least one vibration exciter to cause mechanical vibrations of the tube by an electrical excitation signal. The ME generates a mass flow sequence representing the instantaneous mass flow rate (m) of the fluid, so that, at least for a reference mass flow rate, the mass flow measurement values are independent of the temperature difference.

Methods and systems are provided for controlling gas lift in at least one production well, which determine a quadratic function that relates flow rate or value of oil produced from a production well to gas flow rate for gas injected into the production well based on flow rate measurements for gas injected into the production well and corresponding flow rate measurements of oil produced from the production well. The quadratic function is used to determine an optimal flow rate for gas injected into the production well. The optimal flow rate for gas injected into the production well is used to control the flow rate of gas injected into the production well, and an oil flow rate produced from the production well is measured at the optimal gas flow rate for iterative processing to refine the quadratic function and determination of optimal gas flow rate if need be.

Methods and systems are provided for controlling gas lift in at least one production well, which determine a quadratic function that relates flow rate or value of oil produced from a production well to gas flow rate for gas injected into the production well based on flow rate measurements for gas injected into the production well and corresponding flow rate measurements of oil produced from the production well. The quadratic function is used to determine an optimal flow rate for gas injected into the production well. The optimal flow rate for gas injected into the production well is used to control the flow rate of gas injected into the production well, and an oil flow rate produced from the production well is measured at the optimal gas flow rate for iterative processing to refine the quadratic function and determination of optimal gas flow rate if need be.

The subject matter of this specification can be embodied in, among other things, a method of sensing that includes activating a first emitter to emit at least one incident wave, transmitting the incident wave along a buffer rod having a first axial end abutted to the first emitter and a second axial end opposite the first axial end, reflecting a first echo of the incident wave by a gap defined along a portion of the buffer rod, detecting the first echo, determining a first amplitude of the first echo, reflecting a second echo of the incident wave by the second axial end, detecting the second echo, determining a o second amplitude of the second echo, and determining a reflection coefficient based on the first amplitude and the second amplitude.

The subject matter of this specification can be embodied in, among other things, a method of sensing that includes activating a first emitter to emit at least one incident wave, transmitting the incident wave along a buffer rod having a first axial end abutted to the first emitter and a second axial end opposite the first axial end, reflecting a first echo of the incident wave by a gap defined along a portion of the buffer rod, detecting the first echo, determining a first amplitude of the first echo, reflecting a second echo of the incident wave by the second axial end, detecting the second echo, determining a o second amplitude of the second echo, and determining a reflection coefficient based on the first amplitude and the second amplitude.