Abstract: A pulse width modulated downhole flow control. A downhole flow control system includes a flow control device with a flow restrictor which variably restricts flow through the flow control device. An actuator varies a vibratory motion of the restrictor to thereby variably control an average flow rate of fluid through the flow control device. A method of controlling flow in a well includes the steps of: installing a flow control device in the well, the flow control device including a flow restrictor which variably restricts flow through the flow control device; and displacing the restrictor to thereby pulse a flow rate of fluid through the flow control device.

Abstract: Casing valves for selective well stimulation and control. A well system includes at least one valve interconnected in a casing string operable via at least one line external to the casing string to selectively control fluid flow between an exterior and interior of the casing string, and the casing string, valve and line being cemented in a wellbore. A method of selectively stimulating a subterranean formation includes: positioning a casing string in a wellbore, the casing string including spaced apart valves operable via a line to selectively control fluid flow between an interior and exterior of the casing string; and for each of multiple intervals of the formation in sequence, stimulating the interval by opening a corresponding one of the valves, closing the remainder of the valves, and flowing a stimulation fluid from the casing string into the interval.

Abstract: Positional control of downhole actuators. A method for positional control of an actuator includes the steps of: applying pressure to both an input line and an output line connected to the actuator; and then releasing a predetermined volume of fluid from the output line, thereby displacing a piston of the actuator a corresponding predetermined distance. A system for positional control of an actuator includes the actuator included in a well tool positioned in a well; the input line connected to the actuator and extending to a remote location; the output line connected to the actuator and extending to the remote location; and a fluid volume measurement device connected to the output line at the remote location, the fluid volume measurement device being operative to meter the predetermined volume of fluid from the output line.

Abstract: A direct proportional control system for remotely controlling actuation of a tool. A well control system includes an actuator for a downhole well tool, the actuator including an actuator member which displaces to operate the well tool. A control system member is positioned at a remote location. A displacement of the control system member is proportional to a displacement of the actuator member.

Abstract: A downhole electrical power generator. A downhole electrical power generating system includes a flow restricting device which variably restricts flow through an opening, the restricting device vibrating in response to flow through the opening and the restricting device thereby alternately increasing and decreasing flow through the opening; and an electricity generating device which generates electricity in response to vibration of the restricting device.

Abstract: A multi-line back pressure control system for providing two way hydraulic line movement while maintaining back pressure control. Check valves are integrated in hydraulic fluid control lines extending downhole into a wellbore. Each check valve is pilot operated with pressure from another hydraulic line to selectively open the lines for two way fluid communication. Removal of the pilot pressure closes the check valves to provide passive back pressure control against catastrophic wellbore events. Pilot pressure operation between multiple pressurized lines can be provided with valves such as three-way, three-position piloted valves.

Abstract: A downhole well tool is provided which includes a shifting sleeve for opening a flow communication port. The well tool includes first and second primary seal elements positioned upstream and downstream, respectively, of the port as well as upstream and downstream of the threaded connections between the well tool and sections of tubing forming the well flow conduit. A fluid diffuser element may be included to abate flow damage across the primary seal elements during the shifting of the sleeve. A method of selectively transmitting fluid incorporating said well tool also is disclosed.