Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A complete telemetry system and methods for downhole operations. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A complete telemetry system and methods for downhole operations are described. The telemetry system includes an instrumented near-bit sub located below the Mud Motor and connected to the drill bit as well as a conventional MWD tool located above the mud motor. Parameters such as inclination of the borehole, the natural gamma ray of the formations, the electrical resistivity of the formations, and a range of mechanical drilling performance parameters are measured. Electromagnetic telemetry signals representing these measurements are transmitted uphole to a receiver associated with the conventional MWD tool located above the motor, and transmitted by this tool to the surface via mud pulse signals. The system is particularly useful for accurate control over the drilling of extended reach and horizontally drilled wells.

Abstract: A coal co-gasification method, comprising the following steps: 1, fuel and a first pressurised oxygen-containing gas are injected into a gasifier, and the fuel is ignited so as to increase the temperature inside the gasifier; 2, when the temperature increase reaches a temperature capable of igniting coal-water slurry to be injected, injection of the fuel and the first pressurised oxygen-containing gas is stopped, and the coal-water slurry and a second pressurised oxygen-containing gas are injected into the gasifier so as to perform coal-water slurry gasification; 3, once the coal-water slurry gasification has stabilised, a third pressurised oxygen-containing gas and carbon dioxide carrying powdered coal are injected into the gasifier to perform co-gasification. The method operates stably, and overcomes cumbersome and time-consuming adjustment steps in the prior art.

Abstract: A system for charging a capacitor used to power measurement-while-drilling equipment includes a power bus, which is electrically connected to the capacitor; a first pair of battery terminals; switching circuitry for electrically connecting the power bus to and disconnecting the power bus from the first pair of battery terminals; and a controller, for controlling the switching circuitry, which is configured to charge the capacitor by applying a first pulse width modulated control signal to control the switching circuitry. The first pulse width modulated control signal has a duty cycle selected such that the voltage of the first battery remains above a first minimum operating voltage while the capacitor is being charged.

Abstract: A coal co-gasification method, comprising the following steps: 1, fuel and a first pressurised oxygen-containing gas are injected into a gasifier, and the fuel is ignited so as to increase the temperature inside the gasifier; 2, when the temperature increase reaches a temperature capable of igniting powdered coal to be injected, injection of the fuel is stopped, injection of the first pressurised oxygen-containing gas is continued, and a pressurised carbon dioxide gas carrying the powdered coal to be injected is injected into the gasifier so as to perform powdered coal gasification; 3, once the powdered coal gasification has stabilised, coal-water slurry and an oxygen-containing gas are injected into the gasifier to perform co-gasification. The method operates stably, and overcomes cumbersome and time-consuming adjustment steps in the prior art.

Abstract: The present disclosure is directed at methods, systems, and techniques for managing batteries for use in a downhole drilling application. The system includes a power bus, pairs of battery terminals for connecting to batteries, switching circuitry that connects and disconnects the batteries to the power bus, data collection circuitry that obtains battery parameters obtained during system operation, and a controller that controls the switching circuitry and receives the battery parameters. A control line connects the controller to the switching circuitry and a data line connects the controller to the data collection circuitry, with the control and data lines being distinct such that control and data signals are not multiplexed with each other.

Abstract: Disclosed is a nozzle including a housing, the housing including a first portion and a second portion, the first portion and the second portion being in fluid communication via a front hole, and a side hole being provided on a side wall of the second portion. The nozzle further includes a sealing assembly able to open and close the front hole and the side hole in a sliding manner in the housing, and a spring provided between the housing and the sealing assembly. Furthermore, an underground coal gasification method using the nozzle is disclosed, which includes the steps of adjusting the injection flow rate and injection pressure of a gasification agent and the pressure of a gas output channel port, and controlling the opening and closing of the front hole and the side hole. The nozzle can optionally alternately or simultaneously open the front hole and the side hole without any manual operation.

Abstract: An underground coal gasification furnace comprises an ignition system and a gas injection system. The ignition system is provided with a first vertical drilling well and a first horizontal directional drilling well in communication with the first vertical drilling well. The gas injection system is provided with a second drilling well introduced into a coal seam. At least one second horizontal directional drilling wells of a horizontal section in the coal seam serves as the second drilling well. Also provided is an underground coal gasification method. The method comprises: enabling a flaming fire region of a first horizontal directional drilling well to withdraw in a second horizontal directional drilling well until withdraw to near a coal feeding point. The underground coal gasification furnace eliminates the defects of low cut-through speed and unstable structure in a gasification production stage in the prior art.

Abstract: A system for charging a capacitor used to power measurement-while-drilling equipment includes a power bus, which is electrically connected to the capacitor; a first pair of battery terminals; switching circuitry for electrically connecting the power bus to and disconnecting the power bus from the first pair of battery terminals; and a controller, for controlling the switching circuitry, which is configured to charge the capacitor by applying a first pulse width modulated control signal to control the switching circuitry. The first pulse width modulated control signal has a duty cycle selected such that the voltage of the first battery remains above a first minimum operating voltage while the capacitor is being charged.

Abstract: The present disclosure is directed at methods, systems, and techniques for managing batteries for use in a downhole drilling application. The system includes a power bus, pairs of battery terminals for connecting to batteries, switching circuitry that connects and disconnects the batteries to the power bus, data collection circuitry that obtains battery parameters obtained during system operation, and a controller that controls the switching circuitry and receives the battery parameters. A control line connects the controller to the switching circuitry and a data line connects the controller to the data collection circuitry, with the control and data lines being distinct such that control and data signals are not multiplexed with each other.

Abstract: The present disclosure is directed at methods, systems, and techniques for managing batteries for use in a downhole drilling application. The system includes a power bus, pairs of battery terminals for connecting to batteries, switching circuitry that connects and disconnects the batteries to the power bus, data collection circuitry that obtains battery parameters obtained during system operation, and a controller that controls the switching circuitry and receives the battery parameters. A control line connects the controller to the switching circuitry and a data line connects the controller to the data collection circuitry, with the control and data lines being distinct such that control and data signals are not multiplexed with each other.