초록 ▼

A system and method is provided for pressure testing a tubing string. A valve is utilized within the tubing string to enable selective application of pressure in the tubing above the valve. However, between pressure tests, the valve may be opened to allow fluid flow into the tubing. Thus, the tubing

A system and method is provided for pressure testing a tubing string. A valve is utilized within the tubing string to enable selective application of pressure in the tubing above the valve. However, between pressure tests, the valve may be opened to allow fluid flow into the tubing. Thus, the tubing string may readily be moved, for example, downhole into a wellbore with periodic application of pressure to test the tubing.

대표청구항 ▼

A system and method is provided for pressure testing a tubing string. A valve is utilized within the tubing string to enable selective application of pressure in the tubing above the valve. However, between pressure tests, the valve may be opened to allow fluid flow into the tubing. Thus, the tubing

A system and method is provided for pressure testing a tubing string. A valve is utilized within the tubing string to enable selective application of pressure in the tubing above the valve. However, between pressure tests, the valve may be opened to allow fluid flow into the tubing. Thus, the tubing string may readily be moved, for example, downhole into a wellbore with periodic application of pressure to test the tubing. und clockwise, while the fourth coil portion is wound counterclockwise, as viewed from the top of the impedance device. Therefore, the laminated impedance device yields a high inductance in the low-permeability coil unit, and can be mounted in any direction and orientation. an oscillator that outputs an asynchronous sample clock and the 1/2 symbol frequency component, wherein the base band signal to be input into said in-phase component square calculation unit and said orthogonal component square calculation unit is a signal that has been sampled based on the asynchronous sample clock, said squared-preamble in-phase correlation calculating unit calculates the correlation value using the 1/2 symbol frequency component output from said oscillator, and said squared-preamble orthogonal correlation calculating unit calculates the correlation value using the 1/2 symbol frequency component output from said oscillator. 5. A timing regenerating device according to claim 1, wherein said timing phase difference calculating unit calculates a timing phase difference from a square root of the in-phase component and the vector angle of a square root of the orthogonal component of the combined correlation signal. 6. A timing regenerating device according to claim 1, further comprising: a clip detecting unit configured to receive digitally sampled in-phase and quadrature components of the base band signal having a preamble symbol, and either converts both the in-phase and orthogonal components of the base band signal into "0" when at least one value of the in-phase and orthogonal components of the base band signal is outside a predetermined range or outputs the received, digitally sampled in-phase and quadrature components of the base band signal without alteration when all values of the in-phase and orthogonal components of the base band signal are within the predetermined range, wherein the base band signal to be input into said in-phase component square calculation unit and into said orthogonal component square calculation unit is the base band signal output of said clip detecting unit. 7. A timing regenerating device comprising: an in-phase component square calculation unit that receives a base band signal having a preamble symbol, calculates square of an in-phase component of the base band signal and outputs the squared in-phase component; an in-phase multiplier that multiplies a sign bit (±1) of the in-phase component of the base band signal to the squared in-phase component and outputs the result as signed squared in-phase component; an orthogonal component square calculation unit that receives the base band signal, calculates square of an orthogonal component of the base band signal and outputs the squared orthogonal component; an orthogonal multiplier that multiplies a sign bit (±1) of the orthogonal component of the base band signal to the squared orthogonal component and outputs the result as a signed squared orthogonal component; a squared-preamble in-phase correlation calculating unit that calculates a correlation value between the signed squared in-phase component and a 1/2 symbol frequency component, and outputs the correlation value as an in-phase correlation signal; a squared-preamble orthogonal correlation calculating unit that calculates a correlation value between the signed squared orthogonal component and the 1/2 symbol frequency component, and outputs the correlation value as an orthogonal correlation signal; a vector combination selecting unit that compares the magnitudes of the in-phase and orthogonal correlation signals, matches the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is smaller to the direction of a vector obtained from the in-phase or orthogonal correlation signals whichever is larger, combines these signals, and outputs a correlation signal after the combination as a combined correlation signal; and a preamble detecting/timing phase difference calculating unit that calculates a vector angle and a vector length of the combined correlation signal, decides that the preamble symbol has been detected when the vector length is larger than a predetermined threshold value, calculates a timing phase differe