Abstract: An assembly for producing oil and/or gas through a well traversing stacked oil and/or gas bearing earth layers comprises a series of expandable packers and integrated perforating gun and sandscreen assemblies mounted on a production tubing such that each integrated perforating gun and sandscreen assembly is located adjacent an oil and/or gas bearing earth layer and at least one expandable packer is located between a pair of adjacent oil and/or gas bearing earth layers, and at least one inflow opening arranged in the wall of the production tubing adjacent to each sandscreen assembly. The integrated perforating gun and sandscreen assemblies are installed in a single run into the well such that uncontrolled fluid and/or sand influx into the well before installation of the sandscreens and expandable packers is avoided.

Abstract: An assembly for producing oil and/or gas through a well traversing stacked oil and/or gas bearing earth layers comprises a series of expandable packers and integrated perforating gun and sandscreen assemblies mounted on a production tubing such that each integrated perforating gun and sandscreen assembly is located adjacent an oil and/or gas bearing earth layer and at least one expandable packer is located between a pair of adjacent oil and/or gas bearing earth layers, and at least one inflow opening arranged in the wall of the production tubing adjacent to each sandscreen assembly. The integrated perforating gun and sandscreen assemblies are installed in a single run into the well such that uncontrolled fluid and/or sand influx into the well before installation of the sandscreens and expandable packers is avoided.

Abstract: A method for controlling alignment of a control loop in an amplifier system includes generating a pilot signal and injecting the pilot signal into the amplifier system. Any uncanceled pilot signal is detected at an output of the control loop. A frequency of the generated pilot signal is detected and is used in adjusting one or more parameters of the control loop. The adjusting is performed at a predetermined direction and with a predetermined step size. A frequency change in the pilot signal in response to the adjusting is detected. The control loop is iteratively aligned by controlling the adjusting based on the detected frequency change, and the step size is determined based on the detected frequency change.

Abstract: A system and method for crest factor reduction of OFDM transmission systems using selective sub-carrier degradation, is disclosed. A modulated communications signal comprising a series of symbols is converted into parallel format in groups of plural symbols in the frequency domain. Crest factor reduction reduces a primary peak of the groups of plural symbols by selective sub-carrier degradation, to generate peak reduction symbols. The groups of plural symbols are converted into time domain symbols, and combined with the peak reduction symbols to provide peak reduced symbols in time domain.

Abstract: A predistortion linearized amplifier system that uses analog polynomial based predistortion is disclosed. An analog polynomial function generator receives polynomial parameter updates from a polynomial parameter generator. The polynomial parameter generator uses a combination of analog and digital signal processing to create the parameter updates. This processing is performed on input signal amplitude, detected using analog circuits, and RF coupled samples of the input signal, and the output signal. By using a combination of analog and digital signal processing means, digital processing can be performed at sub-Nyquist rates, significantly reducing the cost of digital circuits. Also, since the predistortion modulation signal is created with an analog function generator, time correlating delay is minimized reducing circuit costs.

Abstract: An adaptive predistortion linearized amplifier system employing selective sampling is disclosed. Two selective sampling methods of identifying valid measurements using information from the input signal are disclosed. The selective sampling process improves the convergence properties of tuning algorithms based on minimizing the gain error variance. It also reduces the number of data samples processed by the estimator used in the tuning process.

Abstract: A pilot system and method is disclosed that increases the rate of convergence of the second loop alignment control in a feed forward amplifier. Both a pilot generation and detection system and search algorithm controlling the alignment are disclosed. By measuring the frequency of the generated pilot, phase information regarding the second loop cancellation transfer function can be inferred. Changes in the pilot frequency as the search algorithm makes steps in the second loop alignment indicate errors in the direction of the search. Using this pilot frequency measurement along with the existing log-power measurement of the residual pilot power improves the convergence speed because fewer steps will be made to reach the optimal alignment setting.

Abstract: An RF amplifier system employing an analog predistortion module is disclosed. The disclosed analog predistortion module is based on zero crossings of the gain error curves (AM-AM and AM-PM curves minus DC). The hardware structure uses the product of first-order functions avoiding the need for large differential swings in the coefficients to shape the lower part of the gain curves. The higher-order nonlinear functions are preferably derived from a single envelope detector. An equal number of multipliers are preferably used in each path when the order of the magnitude and phase corrections are equal or differ by one, thus reducing delay mismatches between the magnitude and phase correction signals.

Abstract: A feed forward amplifier and method of amplification are disclosed. The amplifier output is used to generate a pilot signal via feedback using uncancelled noise in the amplifier output. An automatic level control circuit maintains the pilot signal at a substantially constant level when the detected uncancelled noise in the amplifier output is above a threshold level. The generated pilot signal strength is allowed to vary when the detected uncancelled noise in the amplifier output is below the threshold and disappears automatically when the amplifier is aligned.

Abstract: A delay mismatched feed forward amplifier system employing a control system and method using floors and penalties is disclosed. The disclosed control system and method allows the second loop phase adjuster setting to be offset in a repeatable and controlled manner. Applying floors and penalties to offset the steady-state phase adjuster setting modifies the conventional pilot cancellation approach. In the conventional case, pilot cancellation has a distinct minimum that corresponds to the desired adjustment setting. In the disclosed approach, the measured pilot cancellation is clipped to a lower bound or floor to produce a set of equal valued minimum control results. The floor is selected to place a desired phase offset to the phase adjuster at the edge of minimum floor. To ensure that the correct phase adjuster offset is selected from the set of equal valued minimum control results, a control direction based penalty is added.

Abstract: A power generator for use in a wellbore formed in an earth formation, including an internal combustion engine having a cylinder and a piston defining a combustion chamber in the cylinder, the engine being arranged to induce a reciprocating movement to the piston relative to the cylinder upon combustion of a combustible gas mixture in the combustion chamber, and a linear electricity generator having a stator and a drive shaft. The generator is arranged to generate electricity upon a reciprocating movement of the drive shaft relative to the stator, and the piston is connected to the drive shaft so as to transmit the reciprocating movement of the piston to the drive shaft.

Abstract: A fast search algorithm for loop alignment of a feed forward amplifier is disclosed. The algorithm controls a processor that adjusts, digitally, the gain and phase of the loop alignment based on power measurements at the input and output of cancellation combiners, to find the optimal setting. A “non-collinear descent” algorithm is used to search, iteratively, for the minimum within an error surface. For loop alignment, the error surface is defined by the set of measurement points comprising the alignment settings and the associated cancellation residuals. For the case of first loop alignment, the cancellation residual is measured using the ratio of two power detectors located at the input and after the cancellation (error) combiner. For second loop alignment, cancellation is estimated using the residual pilot power detected at the output of the amplifier. The preferred alignment method uses three successive measurements to estimate the gradient direction with respect to gain and phase shifter settings.

Abstract: A system and method of digitally predistorting a transmitter that has a digital input, up-converter, and a RF amplifier is disclosed. A digital predistorter preferably employs three paths for the digital input signal: a linear path, a memoryless digital predistortion path, and a memory based digital predistortion path. The memoryless path is preferably a look up table (LUT) of gain error corrections indexed to the input magnitude or input power. The linear path is separated to preserve the dynamic range of the system and avoid quantization associated with memoryless LUT correction. The memory based digital predistortion path filters the power envelope, or higher even order modes of the input signal magnitude, employing a hierarchical filter, to produce a gain correction. The input signal is modulated by the gain error corrections produced by the memoryless and memory based paths.

Abstract: A method and apparatus for digital predistortion of power amplifiers are disclosed. Successful digital predistortion parameter settings are correlated with the operating conditions that affect the distortion of an amplifier. These operating conditions may include input power level, carrier frequency, temperature, DC supply voltage, or others. The successful predistortion parameter settings along with the corresponding operating conditions are stored in a list that is indexed using multi-dimensional attribute vectors. The elements of the list are generated automatically.

Abstract: A system and method of correcting memory effects present within power amplifiers using digital predistortion and an improved power amplifier system employing digital predistortion are disclosed. Nonlinearities within a power amplifier having an input derived from a digital signal are compensated by injecting a digital correction signal prior to the power amplifier. A system and method for modeling the distortion created by power amplifier memory effects and generating the desired digital predistortion correction signal are disclosed.

Abstract: A device for sealing off an opening through the wall of a well tubular, which device comprises a tubular spacer having an outer diameter allowing the spacer to be arranged in the well tubular, a first seal collar assembly and a second seal collar assembly arranged opposite ends of the tubular spacer, each seal collar assembly comprising an activator ring and an annular seal collar, the activator rings being interconnected by a cylindrical system of shape memory alloy which system contracts when the temperature of the cylindrical system reaches the transition temperature of the shape memory alloy, and wherein each annular seal collar is arranged so as to be compressed against the inner surface of the well tubular upon contraction of the cylindrical system of shape memory alloy.

Abstract: A power generator for use in a wellbore formed in an earth formation, comprising an internal combustion engine having a cylinder and a piston defining a combustion chamber in the cylinder, the engine being arranged to induce a reciprocating movement to the piston relative to the cylinder upon combustion of a combustible gas mixture in the combustion chamber, and a linear electricity generator having a stator and a drive shaft, the generator being arranged to generate electricity upon a reciprocating movement of the drive shaft relative to the stator, wherein the piston is connected to the drive shaft so as to transmit said reciprocating movement of the piston to the drive shaft.

Abstract: A wellbore system is provided, the wellbore including a main wellbore extending into an earth formation, a branch wellbore extending from a selected location of the main wellbore into the earth formation and a casing arranged in the main wellbore. A branching device is arranged in the casing and connected to a conduit extending through the casing to a wellbore facility at surface, the branching device having a main bore in fluid communication with the wellbore facility via the conduit, and a branch bore providing fluid communication between the main bore and the branch wellbore via a window opening provided in the casing. A seal is provided between said body and the inner surface of the casing so as to prevent fluid communication between the window opening and the interior of the casing.

Abstract: A method for improving the permeability of an earth formation zone surrounding a wellbore formed in the earth formation utilizing hydraulic shockwaves. The selected zone is isolated and fluid is pumped downhole to fracture the earth formation, the fluid extending into the fractures. A shock wave is then created in the fracturing fluid to reduce the presence of illite clays in the formation interstices.

Abstract: Following fracturing operations in a first zone of a well bore traversing an earth formation, a sealing assembly is lowered into the well bore to isolate the first zone from the remainder of the wellbore. The sealing assembly includes a reaction plate that rests on gravel within the borehole, a support strut having one end attached to the reaction plate with an elastomeric sealing member attached to the other end of the strut. The strut provides support for the sealing member and prevents it from being dislodged during subsequent fracturing operations. The sealing assembly is lowered downhole utilizing a mechanical running tool capable of running and retrieving the sealing assembly. A second zone in the well bore may then be subjected to fracturing operations without affecting the fractures in the first zone.