This invention provides a measurement-while-drilling (MWD) downhole assembly for use in drilling boreholes which utilizes directional formation evaluation devices on a rotating assembly in conjunction with toolface orientation sensors. The data from the toolface orientation sensors are analyzed by a processor and toolface angle measurements are determined at defined intervals. Formation evaluation sensors operate substantially independently of the toolface orientation sensors and measurements of the formation evaluation sensors are analyzed in combination with the determined toolface angle to obtain formation parameters.
CROSS REFERENCES TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/399,741 filed on Jul. 30, 2002 and U.S. Provisional Patent Application Ser. No. 60/408,308 filed on Sep. 5, 2002.
A nuclear sensor on a bottomhole assembly (BHA) makes measurements of a property of an earth formation during continued rotation of the BHA. Magnetometers that are susceptible to bias error are deployed on the BHA to make measurements of the magnetic toolface angle. A processor separates the sensor measurements into azimuthal sectors while compensating for inherent time delays in the electronics, non-uniform rotation, and bias.
Caliper measurements made during rotation of a bottomhole assembly are processed to estimate the location of the BHA, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool.
A logging-while-drilling density sensor includes a gamma ray source and at least two NaI detectors spaced apart from the source for determining measurements indicative of the formation density. A magnetometer on the drill collar measures the relative azimuth of the NaI detectors. Measurements made by the detectors are partitioned into bins defined by azimuth. A compensated bulk density is determined for selected ones of said azimuthal sectors that meet a threshold test related to a minimum difference of measurements or a minimum correction. The method of the invention may also be used with neutron porosity logging devices.
A flow sensor is incorporated into a junk basket to sense a flow stoppage due to a plugged screen or plugged cuttings ports in a mill. The sensor triggers a signal to the surface to warn personnel that a problem exists before the equipment is damaged. The sensor signal to the surface can take a variety of forms including mud pulses, a detectable pressure buildup at the surface, electromagnetic energy, electrical signal on hard wire or radio signals in a wifi system to name a few options. Surface personnel can interrupt the signal to take corrective action that generally involves pulling out of the hole or reverse circulating to try to clear the screen or mill cuttings inlets. Other variables can be measured such as the volume or weight or rate of change of either and a signal can be sent to the surface corresponding to one of those variables to allow them to be detected at the surface in near real time.
Disclosed are methods, systems, and/or processor program products that include generating a population of genotypes, the genotypes based on at least one stimulus to a system, measuring at least one response of the system upon providing the population of genotypes to at least one model of the system, and, based on the measured at least one response of the system, performing at least one of: (a) applying at least one genetic operator to at least some of the population of genotypes, and iteratively returning to generating a population of genotypes, and (b) associating a condition of the system with at least one of the population of genotypes.
