Abstract: Systems, devices and methods for evaluating a volume of interest of an earth formation. The method may include modeling the volume as being in one of two states using a plurality of measurements corresponding to a plurality of measurement types, and may include assigning a relative credence indicator value to each measurement in dependence upon the corresponding measurement value and using the relative credence indicator value for each of the plurality of measurements to estimate the state of the volume by estimating the state of the volume using a state indicator value derived from the relative credence indicator values. The first state of the two states may correspond with presence of a condition associated with the formation, and the second state of the two states may correspond with absence of the condition. The condition may comprise presence of a fluid in the formation having a selected fluid type.

Abstract: Systems, devices and methods for evaluating a volume of interest of an earth formation. The method may include modeling the volume as being in one of two states using a plurality of measurements corresponding to a plurality of measurement types, and may include assigning a relative credence indicator value to each measurement in dependence upon the corresponding measurement value and using the relative credence indicator value for each of the plurality of measurements to estimate the state of the volume by estimating the state of the volume using a state indicator value derived from the relative credence indicator values. The first state of the two states may correspond with presence of a condition associated with the formation, and the second state of the two states may correspond with absence of the condition. The condition may comprise presence of a fluid in the formation having a selected fluid type.

Abstract: An apparatus for controlling fluid flow that includes a chamber having a first valve and a second valve; a sensor that senses a pressure parameter associated with the chamber; and a controller programmed to operate the first valve and the second valve in response to the sensed pressure parameter may be used to control for flow and to obtain data relating to a formation and/or formation fluid.

Abstract: Disclosed is a method for transmitting data from a tool disposed in a borehole penetrating the earth to a receiver. The method includes disposing the tool in a borehole and receiving a series of measurements using a processor disposed at the tool. A telemetry system transmits a latest received measurement that meets acceptance criteria to the receiver after completion of transmission of a previously transmitted measurement.

Abstract: Measurements of fluorescence spectra of fluid samples recovered downhole are processed to give the fluid composition. The processing may include a principal component analysis followed by a clustering method or a neutral network. Alternatively the processing may include a partial least squares regression. The latter can give the analysis of a mixture of three or more fluids.

Abstract: An apparatus for controlling fluid flow that includes a chamber having a first valve and a second valve; a sensor that senses a pressure parameter associated with the chamber; and a controller programmed to operate the first valve and the second valve in response to the sensed pressure parameter may be used to control for flow and to obtain data relating to a formation and/or formation fluid.

Abstract: A method includes calculating a correction factor that uses a tool component volume change model to estimate a system volume change resulting from a change in the tool component. An apparatus includes a carrier conveyable into a well borehole, a formation test tool coupled to the carrier, the formation test tool including a tool component. A measurement device to estimate a change in the tool component during operation, and a compensator uses an estimated system volume change resulting at least in part from the change in the tool component during a downhole operation, the compensator compensating for the system volume change and wherein the estimated system volume change is estimated at least in part using a volume change model.

Abstract: A method for conducting a formation test includes providing a volume change model for a tool component, and providing a control program that uses the volume change model to estimate a system volume change resulting from a change in the tool component during a downhole operation. An apparatus for conducting a formation test includes a carrier, a formation test tool, a measurement device that estimates a change in a tool component during operation, and a processor that uses a volume change model to estimate a system volume change resulting at least in part from the change in the tool component during a downhole operation.

Abstract: Measurements of fluorescence spectra of fluid samples recovered downhole are processed to give the fluid composition. The processing may include a principal component analysis followed by a clustering method or a neutral network. Alternatively the processing may include a partial least squares regression. The latter can give the analysis of a mixture of three or more fluids.

Abstract: A method includes calculating a correction factor that uses a tool component volume change model to estimate a system volume change resulting from a change in the tool component. An apparatus includes a carrier conveyable into a well borehole, a formation test tool coupled to the carrier, the formation test tool including a tool component. A measurement device to estimate a change in the tool component during operation, and a compensator uses an estimated system volume change resulting at least in part from the change in the tool component during a downhole operation, the compensator compensating for the system volume change and wherein the estimated system volume change is estimated at least in part using a volume change model.

Abstract: A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation and drawing down a test volume at an increasing draw rate during a first draw period and decreasing the draw rate during a second draw period to create a smooth draw down cycle. The draw down can be step-wise or continuous. The formation parameter is determined using formation rate analyis and characteristics determined during the draw down cycle.

Abstract: A method for conducting a formation test includes providing a volume change model for a tool component, and providing a control program that uses the volume change model to estimate a system volume change resulting from a change in the tool component during a downhole operation. An apparatus for conducting a formation test includes a carrier, a formation test tool, a measurement device that estimates a change in a tool component during operation, and a processor that uses a volume change model to estimate a system volume change resulting at least in part from the change in the tool component during a downhole operation.

Abstract: A method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool. A fluid sample pressure is determined at two different times during the drawdown. The fluid sample pressures are analyzed using a higher-order pressure derivative with respect to time technique to determine the formation pressure during the drawdown. Another method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool. A fluid sample pressure is determined at two different times during the drawdown. The fluid sample pressures are analyzed using at least two analysis techniques to each determine an estimate of the formation pressure during the drawdown.

Abstract: A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation, determining a first formation characteristic during a first test portion, initiating a second test portion, the second test portion having test parameters determined at least in part by the determinations made during the first test portion, determining a second formation characteristic during the second test portion, and determining the formation parameter from one of the first formation characteristic and the second formation characteristic. The apparatus includes a draw down unit and a control system for closed loop control of the draw down unit. A microprocessor in the control system processes signals from a sensor in the draw down unit to determine formation characteristics and to determine test parameters for subsequent test portions.

Abstract: A method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool. A fluid sample pressure is determined at two different times during the drawdown. The fluid sample pressures are analyzed using a higher-order pressure derivative with respect to time technique to determine the formation pressure during the drawdown. Another method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool. A fluid sample pressure is determined at two different times during the drawdown. The fluid sample pressures are analyzed using at least two analysis techniques to each determine an estimate of the formation pressure during the drawdown.

Abstract: Methods for estimating formation pressure from data taken during the drawdown cycle are presented. In one aspect, a method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool having a sample volume and a fluid sampling device. At least one time dependent parameter of interest related to the fluid is determined during the drawdown. The at least one time dependent parameter is analyzed using a plurality of calculation techniques to determine the formation pressure. The techniques include (i) a first pressure derivative technique; (ii) a second pressure derivative technique; (iii) a formation rate analysis technique; (iv) a dp/dt-ratio technique; and (v) a stepwise drawdown technique.

Abstract: A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation and drawing down a test volume at an increasing draw rate during a first draw period and decreasing the draw rate during a second draw period to create a smooth draw down cycle. The draw down can be step-wise or continuous. The formation parameter is determined using formation rate analyis and characteristics determined during the draw down cycle.

Abstract: Methods for estimating formation pressure from data taken during the drawdown cycle are presented. In one aspect, a method of determining a formation pressure during drawdown of a formation comprises sampling fluid from a formation using a downhole tool having a sample volume and a fluid sampling device. At least one time dependent parameter of interest related to the fluid is determined during the drawdown. The at least one time dependent parameter is analyzed using a plurality of calculation techniques to determine the formation pressure. The techniques include (i) a first pressure derivative technique; (ii) a second pressure derivative technique; (iii) a formation rate analysis technique; (iv) a dp/dt-ratio technique; and (v) a stepwise drawdown technique.

Abstract: A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation, determining a first formation characteristic during a first test portion, initiating a second test portion, the second test portion having test parameters determined at least in part by the determinations made during the first test portion, determining a second formation characteristic during the second test portion, and determining the formation parameter from one of the first formation characteristic and the second formation characteristic. The apparatus includes a draw down unit and a control system for closed loop control of the draw down unit. A microprocessor in the control system processes signals from a sensor in the draw down unit to determine formation characteristics and to determine test parameters for subsequent test portions.

Abstract: A method of performing a formation rate analysis from pressure and formation flow rate data. Pressure and flow rate data are measured as fluid is withdrawn from a formation. Variable system volume is accounted for. The pressure and flow rate data are correlated using a multiple linear regression technique. Time derivative terms related to pressure and flow rate are smoothed using a summation technique, thereby providing better correlations than using the time derivatives directly. Formation parameters comprising formation permeability, formation pressure, and fluid compressibility may be determined from the correlation.