Abstract: Methods and systems may be provided for simulating forming a wide variety of directional wellbores including wellbores with variable tilt rates and/or relatively constant tilt rates. The methods and systems may also be used to simulate forming a wellbore in subterranean formations having a combination of soft, medium and hard formation materials, multiple layers of formation materials and relatively hard stringers disposed throughout one or more layers of formation material.

Abstract: The invention relates to a method for performing a drilling operation at a wellsite having a drilling rig configured to advance a drilling tool into a subsurface. The method steps include obtaining a well trajectory associated with a first volume, obtaining information related to a first subsurface entity associated with a second volume, using a three-dimensional relational comparison to determine that the first volume intersects the second volume to define a first intersection information, updating the well trajectory, based on the first intersection information, to obtain an updated well trajectory, and advancing the drilling tool into the subsurface based on the updated well trajectory.

Abstract: A method and a computer program for economic evaluation of completion methods for drilling a well. An extensive user interface is provided for inputting of reservoir data and parameters relating to a first completion method. A rigorous first skin factor is generated based on the reservoir data and first drilling parameters. An interface is preferably provided for entering cost data related to the first completion technique and a first total cost can be generated. Production data is optionally generated from the first skin factor. The production and cost data can then be combined to generate an economic analysis of the first completion technique. The process can be repeated for alternate completion techniques. Preferably, ranges can be entered for certain reservoir and/or cost variables. Multiple iterations can be performed on the ranges resulting in total cost and production ranges which can be combined to yield ranges of economic data for statistical analysis.

Abstract: An apparatus, method and computer-readable medium for estimating a bulk shale volume of an earth formation. In one aspect, measurements are obtained at a plurality of depths in a wellbore penetrating the earth formation and a first distribution is produced of the obtained measurements. A measurement is obtained at a selected depth in the wellbore and a second distribution is produced using the measurement at the selected depth and the measurements obtained at the plurality of depths. A cumulative distribution is produced cumulative of the first distribution and the second distribution. The bulk shale volume is estimated at the selected depth by comparing the cumulative distribution and the second distribution.

Abstract: Systems and methods for monitoring and/or operating a rig site system are provided. In accordance with one embodiment, a method for monitoring a rig site system may include obtaining sensor data at a rig site and transmitting pre-processed sensor data pertaining to the sensor data from the rig site over a network link to a monitoring site. The method may also include demodulating the pre-processed sensor data at the monitoring site to produce demodulated data. The method may also include analyzing the demodulated data at the monitoring site. The sensor data may comprise at least one of surface sensor data, MWD sensor data, or LWD sensor data, or any combination thereof.

Abstract: A method for conducting density measurements in downhole environments corrects for high standoff, by adding a second correction term to the spine and rib method. This second term is a correction based on an apparent standoff estimated using the photo electric effect of the mud. This correction is term depends on the mud properties, both in terms of apparent standoff and correction and therefore requires property calibration for each well. The calibration can be done using the azimuthal information available with LWD tool when the tool is turning. At each depth in homogeneous formation, there can be a succession of density measurements with various tool standoff when the tool is not centered in the borehole. All this information is used to build up a standoff correction fitting perfectly the mud properties.

Abstract: A method and apparatus for surveying a borehole using a rotating sensor package. A sensor tool preferably including a magnetometer sensor array is disposed in the bottom hole assembly of a drillstring. Conditioning circuitry in the sensor tool processes the sensor readings from the sensor array taken while the drillstring is rotating. In one embodiment, the conditioning circuitry includes processing circuitry adapted to adjust the sensor readings to account for an analytically predicted level of axial current induced in the drillstring as a result of its rotation in the Earth's magnetic field. In another embodiment, a current generator is provided to generate a counter-current intended to cancel the analytically predicted level of axial current induced in the drillstring as a result of rotation in the Earth's magnetic field. In another embodiment, insulating members are disposed above and/or below the sensor tool to prevent conduction of rotation-induced current therein.

Abstract: Method and apparatus for visibly demonstrating a relationship between toolface orientation and quill position by: (1) receiving electronic data on an on-going basis, wherein the electronic data includes quill position data and at least one of gravity-based toolface orientation data and magnetic-based toolface orientation data; and (2) displaying the electronic data on a user-viewable display in a historical format depicting data resulting from a most recent measurement and a plurality of immediately prior measurements.

Abstract: Systems and methods in which data compression techniques are utilized to fill a predetermined channel capacity are shown. According to one configuration, event data points within test data are selected for communication via the data communication channel and a data decimator is utilized to identify other data points within the test data to fill or substantially fill the predetermined channel capacity. The foregoing data decimator may employ one or more variables for selecting data for communication, wherein one or more of the variables are preferably adjusted in decimator iterations to select an optimum or otherwise desirable subset of data for communication. Data decimators may additionally or alternatively implement a suitable “growth” function to select the particular data for communication and/or the amount of data communicated.

Abstract: The present invention provides a computer-implemented software tool that is adapted to listen continuously to data streams from a drilling operation and to process the data to generate a situation description for a current drilling situation in a form useful for automated continuous matching with a set of past cases stored in a knowledge database. The invention implements a case-based reasoning (CBR) approach to match the current drilling situation as defined by the situation description with one or more stored past cases having a degree of similarity above a predetermined threshold level. Matching cases are displayed to the drilling engineer as symbols on a case “radar”, allowing the drilling engineer to retrieve and view the details of a past case and take appropriate action based on drilling advice provided within the past case.

Abstract: Method, system, and apparatus for evaluating drilling accuracy performance in drilling a wellbore that can include: (1) monitoring an actual toolface orientation of a tool, e.g., a downhole steerable motor, by monitoring a drilling operation parameter indicative of a difference between the actual toolface orientation and a toolface advisory; (2) recording the difference between the actual toolface orientation and the toolface advisory; and (3) scoring the difference between the actual toolface orientation and the toolface advisory.

Abstract: A multi-station gravity and magnetic survey is carried out in a borehole. The data from the survey are processed to estimate the inclination and azimuth of the borehole. The drill collar relative permeability is estimated, and the estimated drill collar permeability is then used to remove the effects of induced magnetization of the drill collar on the magnetic measurements.

Abstract: Measurements are made continuously with a seismic while drilling (SWD) system and the measured data are stored in a working memory of a downhole processor along with quality control (QC) measurements. The QC data are analyzed and based on the analysis, portions of the data in working memory are recorded in permanent memory for retrieval. Alternatively, QC measurements are made substantially continuously predictions are made when data quality for SWD measurements are likely to be good. Recording of SWD data are then started based on the prediction.

Abstract: A method of identifying one or more rock properties and/or one or more abnormalities occurring within a subterranean formation. The method includes obtaining a plurality of drilling parameters, which include at least the rate of penetration, the weight on bit, and the bit revolutions per minute, and then normalizing these plurality of drilling parameters by calculating a depth of cut and an intrinsic drilling impedance. Typically, the intrinsic drilling impedance is specific to the type of bit used to drill the wellbore and includes using a plurality of drill bit constants. From this intrinsic drilling impedance, the porosity and/or the rock strength may be determined which is then compared to the actual values to identify the specific type of the one or more abnormalities occurring. Additionally, the intrinsic drilling impedance may be compared to other logging parameters to also identify the specific type of the one or more abnormalities occurring.

Abstract: A multicomponent induction logging tool is used on a MWD bottomhole assembly. Multifrequency focusing that accounts for the finite, nonzero, conductivity of the mandrel is applied. Using separation of modes, the principal components and relative dip angles in an earth formation are determined. The results are used for reservoir navigation in an earth formation.

Abstract: A method for selecting an optimal trajectory of a wellbore while drilling the wellbore and a computer program having instructions for the same are disclosed. The method and program may include obtaining data, such as real-time date, related to the wellbore and obtaining data related to drilling limitations. The method and program also obtains data related to production considerations or drilling considerations. A target is selected and the optimal trajectory is selected from possible trajectories to the target. Ideally, the optimal trajectory conforms with the drilling limitations and satisfies one or more of the production considerations or drilling considerations.

Abstract: A method for drilling a well, the method including: identifying another well proximate to the well being drilled; collecting spatial information for at least a portion of the another well and the well being drilled; estimating a trajectory for at least a portion of the well being drilled and the another well; estimating an uncertainty in spatial information for each trajectory; estimating a probability of a collision with the another well during the drilling of the well by integrating a probability density function using the uncertainties and the trajectories; and performing the drilling in a manner that limits the probability of collision. A system and another method are provided.

Abstract: A method and apparatus for providing a downhole measurement-while-drilling (MWD) tool with diagnostic capability by including one or more printed circuit boards to the tool with firmware processors that internally record significant system diagnostic events that can be time correlated with known tool operational problems. The concept includes firmware protocol to enable transfer all of the recorded data to an external software analysis program after the MWD tool is removed from a drilling run.

Abstract: Apparatus, methods for forming the apparatus, and methods for operating the apparatus provide a value for a formation property or a borehole property from measurements obtained in a well. The value may be generated from determining a weighted average of the value for the formation property or the borehole property using both values corresponding to different azimuths and weights corresponding to different azimuths.

Abstract: Efficiency of a hydraulically driven system is evaluated by monitoring the change in ratio of output torque to input hydraulic pressure. The hydraulic pressure data is received from a hydraulic sensor. The torque data is received from a load cell receiving a force transmitted to it by a back-up wrench. Filters are applied to the data to obtain peak levels of torque and hydraulic pressure. A ratio is generated for each process associated with a rod or other elongated member based on peak torque and hydraulic pressure levels achieved during the process. The ratio is stored and compared to historical ratios to determine if the ratio has changed more than a predetermined amount over time. A similar evaluation can be achieved by comparing speed generated on the elongated member by the hydraulically driven system to the current level controlling the flow of hydraulic fluid to the hydraulically driven system.

Abstract: Methods and systems may be provided for simulating forming a wide variety of directional wellbores including wellbores with variable tilt rates and/or relatively constant tilt rates. The methods and systems may also be used to simulate forming a wellbore in subterranean formations having a combination of soft, medium and hard formation materials, multiple layers of formation materials and relatively hard stringers disposed throughout one or more layers of formation material. Values of bit steerability and controllability calculated from such simulations may be used to design and/or select drilling equipment for use in forming a directional wellbore.

Abstract: A steering tool configured for making azimuthal and non-azimuthal formation evaluation measurements is disclosed. In one embodiment a rotary steerable tool includes at least one formation evaluation sensor deployed in the steering tool housing. The steering tool may include, for example, first and second circumferentially opposed formation evaluation sensors or first, second, and third formation evaluation sensors, each of which is radially offset and circumferentially aligned with a corresponding one of the steering tool blades. The invention further includes methods for geosteering in which a rotation rate of the steering tool housing in the borehole (and therefore the rotation rate of the formation evaluation sensors) is controlled. Steering decisions may be made utilizing the formation evaluation measurements and/or derived borehole images.

Abstract: Aspects of this invention include methods for surveying a subterranean borehole. In one exemplary aspect, a change in borehole azimuth between first and second longitudinally spaced gravity measurement sensors may be determined directly from gravity measurements made by the sensors and a measured angular position between the sensors. The gravity measurement sensors are typically disposed to rotate freely with respect to one another about a longitudinal axis of the borehole. Gravity MWD measurements in accordance with the present invention may be advantageously made without imposing any relative rotational constraints on first and second gravity sensor sets. The present invention also advantageously provides for downhole processing of the change in azimuth between the first and second gravity sensor sets. As such, Gravity MWD measurements in accordance with this invention may be advantageously utilized in closed-loop steering control methods.

Abstract: A drill bit for drilling a subterranean formation includes a plurality of cutting elements and a shank extending from a bit body. A set of accelerometers disposed in the drill bit include a radial accelerometer and a tangential accelerometer. An annular chamber is formed within the shank. A data evaluation module is disposed in the annular chamber and includes a processor, a memory, and a communication port. The data evaluation module is configured for performing a bit acceleration analysis. The analysis includes sampling acceleration information from the radial accelerometer and the tangential accelerometer over an analysis period and storing the acceleration information in the memory to generate an acceleration history. The acceleration history is analyzed to determine a cutting effectiveness of the cutting elements responsive to changes in the acceleration history. The cutting effectiveness is reported through the communication port.

Abstract: A system to monitor drilling rig activity and to provide and manage drilling rig information, program product, and associated methods are provided. The system can include a communication network, a drilling rig information management server, a database accessible to the processor of the server, and drilling rig information management program product stored in the memory of the drilling rig information management server and including instructions that when executed by the processor of the drilling rig information management server cause the server to perform the operations of retrieving drilling rig location data from the database responsive to user selection of a geospatial location attribute, accessing digital mapping data to display a digital map associated with the user selected geospatial location attribute, and providing data to display indicia of a drilling rig location for at least one drilling rig overlaid upon and spatially oriented to at least portions of the digital map.

Abstract: A system and method for producing fluid from a completed well is provided wherein the method in one aspect includes determining a first setting of at least one first device under use for producing the fluid from the well; selecting a first set of input parameters that includes at least one parameter relating to health of at least one second device and a plurality of parameters selected from a group consisting of information relating to flow rate, pressure, temperature, presence of a selected chemical, water content, sand content, and chemical injection rate; and using the selected first set of parameters as an input to a computer model, determining a second setting for the at least one first device that will provide at least one of an increased life of at least one second device and enhanced flow rate for the fluid from the completed well.

Abstract: A method and apparatus for testing a blowout preventer (BOP) wherein a pressurization unit applies fluid to an isolated portion of the throughbore of the BOP. A signal that is representative of the actual pressure in the isolated portion of the throughbore over successive time points and a pre-determined non-deterministic finite state automaton are used to predict the pressure in the isolated portion of the throughbore as a function of time relative to a pre-determined acceptable leak rate and the time at which stability is achieved. In one embodiment stability is achieved when successive predicted pressures are within a predetermined difference over a predetermined interval of time. Visual indications are provided to depict the progress of testing.

Abstract: Systems and methods for controlling a drill string are provided. A method comprises receiving one or more first signals from a first sensor package mounted in a first portion of the drill string at a first position within a wellbore. The first signals may be indicative of an orientation of the first portion of the drill string. The method also includes receiving one or more second signals from a second sensor package mounted in a second portion of the drill string at a second position within the wellbore. In certain embodiments, the second signals indicative of an orientation of the second portion of the drill string. The drill string may be adapted to bend between the first portion and the second portion and certain embodiments include calculating a first amount of bend between the first portion and the second portion in response to the first signals and the second signals.

Abstract: Downhole drilling vibration analysis uses acceleration data measured in three orthogonal axes downhole while drilling to determine whether drilling assembly's efficiency has fallen to a point where the assembly needs to be pulled. In real or near real time, a downhole tool calculates impulse in at least one direction using the measured acceleration data over an acquisition period and determines whether the calculated impulse exceeds a predetermined acceleration threshold for the acquisition period. If the impulse exceeds the threshold, the tool pulses the impulse data to the surface where the calculated impulse is correlated to efficiency of the assembly as the drillstring is used to drill in real time. Based on the correlation, operators can determine whether to pull the assembly if excessive impulse occurs continuously over a predetermined penetration depth.

Abstract: A novel method is presented to automatically design a multi-well development plan given a set of previously interpreted subsurface targets. This method identifies the optimal plan by minimizing the total cost as a function of existing and required new platforms, the number of wells, and the drilling cost of each of the wells. The cost of each well is a function of the well path and the overall complexity of the well.

Abstract: In one embodiment, a system can include a centralized storage module, for example a database, that stores data relating to petroleum, natural gas and other related products taken from several different sources and entities. The entity storing and maintaining this data can be an entity independent from the operators, producers and/or other working interests. This system can use automated techniques to reconcile distributions to all entities associated with a well due to the removal of a mineral, for example, petroleum, natural gas and/or other related products, from that well, on a periodic basis. These automated techniques include, for example, reconciling all agreements associated with the well, reconciling the amount of mineral removed at the well, reconciling the spot market price associated with the well at the time of removal, automating approval by the removing entity, automating payment and the like.

Abstract: A method and apparatus for displaying depth of positional data with tubing analysis data obtained by instruments analyzing tubing sections being withdrawn from a well includes an apparatus for communicably linking an encoder or other positional or depth sensors to the tubing analysis data processor. In addition, sensors capable of detected collars holding pieces of tubing section together can transmit signals to the analysis data processor that a collar has been detected and insert collar location information into the analysis data. Furthermore, information based on the length of the individual pieces of tubing or the data from the encoder or other positional sensor can be analyzed or associated with the analysis data and displayed with the analysis data by overlaying a depth component on a display of the analysis data.

Abstract: An apparatus for detecting a position of a component in an earth formation is disclosed. The apparatus includes: a transmitter configured to emit a first magnetic field into the earth formation and induce an electric current in the component, the transmitter having a first magnetic dipole extending in a first direction; and a receiver for detecting a second magnetic field generated by the component in response to the first magnetic field, the receiver having a second magnetic dipole extending in a second direction orthogonal to the first direction. A method and computer program product for detecting a position of a component in an earth formation is also disclosed.

Abstract: An apparatus and method for providing images of a downhole tool during drilling of a wellbore are provided. A sensor on a rotating tool occupies a number of azimuthal sectors of the wellbore which are determined by a processor. The processor determines a time during which the sensor is in each of the azimuthal sectors during each revolution of the tool and provides a depth-correlated image of the sector residence times for the tool.

Abstract: In one aspect, a removable module or sub is provided for use in drilling a wellbore, which sub in one embodiment may include a body having a pin end and a box end configured for coupling between two members of a drill string, the body having a bore therethrough for flow of a fluid, and a sensor disposed in a pressure-sealed chamber in one of the pin end and the box end and configured to provide measurements relating to a downhole condition.

Abstract: A method and computer program product of either preventing or minimizing pore pressure increase near the wellbore wall within argillaceous formations through which a borehole has been drilled. By interpreting relevant drilling experience data, the type, extent and time-dependency of wellbore instability mechanisms are determined. The impact of drilling mud designs on the time-dependent wellbore instability and hole enlargement is determined by back-analyzing observed drilling events. At least one field-based criterion relationship between net mud weight reduction percentage ratio and hole enlargement is determined. A maximum allowable percentage ratio(s) of net mud weight reduction and either breakout mud weight or mud weight used for the adopted maximum hole enlargement that the wellbore may experience during drilling is determined. Drilling mud salinity value and salt type to satisfy maximum allowable percentage ratio(s) is then determined.

Abstract: Using an electromagnetic logging tool, desired antenna responses are synthesized from a combination of measured antenna responses, as well as antenna arrays particularly suited to provide the measurements. Those arrays may include cross dipole and double cross dipole antennas. Direct and derivative responses are used to synthesize the desired response, and the synthesized desired response is used to determine formation properties.

Abstract: An orientation vector, referred to hereinafter as the “geosteering vector,” is directed to the more conductive formation area within the DOI of the tool and away from the more resistive formation areas. Accordingly, drilling in a direction opposite the geosteering vector leads to more resistive formation. Also, the disclosed geosteering vectors obtained from the real and imaginary components will not align with each other for non-planar formations and therefore the misalignment of the geosteering obtained from real and imaginary components is indicative of a non-planar formation. A superposition method is disclosed which can be used to calculate electromagnetic (EM) couplings in a non-planar geometry formation (as well as in a planar geometry formation) in real time, without requiring two or three dimensional modeling calculations.

Abstract: A method, apparatus and computer-readable medium for evaluating an earth formation includes making measurements with a logging tool having a first depth of investigation in a borehole in the earth formation. A first dip of the formation is estimated using multi-component measurements. The estimated dip is compared with a second dip measurement in the borehole. The results of the comparison are stored on a tangible medium.

Abstract: The present invention is directed to methods for an off-site supervisor or well owner to evaluate the rig load data provided by a well service rig at a well site by evaluating charts of sensor data obtained from sensors on or associated with the well service rig. A rig load data chart can be reviewed and activities completed by the rig identified based on the data curves on the rig load data chart. In addition the hook load carried by the service rig can be determined by evaluating the rig load data charts of sensor data. Furthermore, well bore and tubing conditions in the well can be analyzed based on the rig load data in the rig load data charts while tubing and rods are being pulled from the well or well bore.

Abstract: Various systems and methods determine a distance, magnitude, and azimuthal angle describing the location of an anomaly within a geologic formation. For example, a method involves identifying an electrical characteristic (e.g., resistivity or conductivity) at each of several sensors in a measurement-while-drilling (MWD) tool. Based on the electrical characteristic, information identifying a formation property of the anomaly is generated. The information includes at least one magnitude and at least one distance. Information information identifying an azimuthal angle is also generated based upon the electrical characteristic. The azimuthal angle relates a position of the anomalous formation to a position of a first sensor in the MWD tool.

Abstract: An apparatus, method and computer-readable medium for obtaining a resistivity image of an earth formation. The apparatus includes a downhole assembly configured to be conveyed in a borehole penetrating the earth formation; a plurality of sensor electrodes on the downhole assembly, at least one of the electrodes having a different area than another of the electrodes; and at least one processor configured to: (i) process measurements using each of the sensor electrodes; (ii) process a subset of the measurements substantially unaffected by the different capacitances to produce an image of the borehole wall; and (iii) record the image on a suitable medium.

Abstract: A method of measuring a dry gas flow from hydrocarbon wells. The hydrocarbon wells produce a stream which contains liquids and natural gas. The method comprises providing an differential flow measurement device (orifice) located at a well site containing the hydrocarbon wells. The method further includes testing the stream for gas composition and physical characteristics. Additionally, the method comprises measuring a static temperature (T) of the stream, measuring a static pressure (Ps), and measuring a pressure differential (dP) in the differential flow measurement device (orifice). The method includes computing the liquid-gas ratio (LGR) of the stream, computing the wet gas flow rate (Qw) of the stream, computing a first dry gas flow rate (Qd1) and a second dry gas flow rate and utilizing a iterative process to correct and obtain the dry gas flow rate. The data may be transmitted to another location.

Abstract: A method for constructing elastoplastic property correlations in multicomponent particulate systems. The method includes obtaining parameters from geophysical data of a sediment-hydrate system, where the parameters include shyd and pc, and where shyd is a hydrate saturation and pc is a confining pressure. The method further includes determining a Young's modulus (E) of the sediment-hydrate system using the parameters and a correlation, where the correlation is E p c = 90.58 + 78.90 ? 0.5831 + 800.4 ? s hyd 1.371 ? 1.022 , and where ?=pc/c and c is a scaling variable with dimensions of pressure. The method further includes adjusting a field operation based on the Young's modulus of the sediment-hydrate system.

Abstract: A drilling system provides indications of the lithology of the formation being drilled by dynamically measuring at least one parameter of interest that is affected by the lithology of the formation being drilled. Suitably positioned sensors make dynamic measurements of parameters such as downhole weight on bit, bit torque, bit revolutions, rate of penetration and bit axial acceleration. One or more processors use the sensor measurements in conjunction with predetermined lithological models to determine whether the measurements indicate a change in formation lithology. Suitable models can be on derived expressions such as rock drillability, drilling response, dynamic drilling response, normalized or dimensionless torque; and formation shear strength. The lithological indications provided by the processor can be used to adjust drilling parameters, steer the BHA, monitor BHA health, and provide depth locations for bed boundaries and formation interfaces.

Abstract: A method for identifying drilling induced fractures while drilling a wellbore into a formation is disclosed. The method includes: obtaining multi-component induction data collected by a drill string including a multi-component induction tool; processing the data to estimate values for principal components; and identifying drilling induced fractures from the principal components. An instrument and a computer program product are disclosed.

Abstract: A core orientation device (10) for a core drill (12). The device (10) comprises an arrangement (14) for providing signals (16) associated with a physical orientation (18) of the core orientation device (10). Processing means (22) are provided for processing the signals (16) so as to provide processed data (23) from which a measure (24) of the physical orientation (18) of the core orientation device (10) can be established. The measure (24) is associated with the physical orientation (18) of the device (10) at a particular moment in time. A memory (26) is coupled to the processing means 22 for storing the processed data 23. To this end there is provided an interface means (27) comprising first means (28) for storing the processed data (23) in the memory (26) and second means (30) for accessing the memory (26) to provide the measure (24) of the physical orientation (18) of core orientation device (10) when required.

Abstract: A tunnel boring machine (90) having a rotating cutter head (93) that rotatably supports a plurality of cutter assemblies (10). A plurality of instrument packages (50) are attached to the rotating cutter head, each instrument package having a distal end in contact with an associated cutter assembly. The instrument packages include a plurality of sensors including an accelerometer (32), magnetometer (33) and temperature sensor (34), for monitoring the associated cutter assembly. The sensors are mounted in a distal end of the instrument packages that is biased to remain in contact with the cutter assembly. The instrument packages include a wireless transmitter, and they are interconnected in a mesh or peer to peer network. A power supply (176) such as a battery pack is provided for each instrument package. The data from the sensors may be used to control operation of the tunnel boring machine and/or to monitor the condition of the cutter assemblies.

Abstract: Method of processing seismic data corresponding to acquisitions carried out in a medium exhibiting azimuthal anisotropy, characterized in that for two sets of data corresponding, for one and the same seismic variable and for one and the same ground zone, to at least two different source/azimuth receiver pair sectors, an average between the data which correspond to the azimuth considered and data which correspond, for the same variable and the same ground zone, to a perpendicular azimuth sector is determined for each of the azimuths considered, and in that an estimate of the part common to the two sets thus obtained of averaged data is determined.

Abstract: Methods and apparatus facilitating measurement of anisotropy are disclosed. According to some aspects, anisotropy can be determined while drilling. Monopole/quadrupole interactions, as well as monitoring dipole excitations and other methods, may be used to find the principal shear directions of a formation while drilling or during wireline or other operations.