Abstract: A method and apparatus for imaging subsurface fractures using an ST plane for quick looks and quality checks at the wellsite. Incident angles of impinging acoustic waves with respect to receivers are estimated from actual and apparent slowness, and the position of the fracture is estimated from the travel time and incident angle. The fracture can be imaged by plotting values from the ST plane onto the position of the fracture.

Abstract: A system and method of creating a filter for use with locally dense seismic data is disclosed. The method includes obtaining survey geometry characteristics from a locally dense seismic survey. A filter is designed which uses spatial derivatives of the wavefield of order between (1) and the maximum order of spatial derivatives of the wavefield that can be estimated within a group. The filter can be designed so as to separate up/down going components, p/s components, or both up/down and p/s components. Partial derivatives in space and time of the wavefield can be calculated, using, for example, a taylor series expansion as an approximation. The seismic data is filtered by combining estimated near surface material properties, the seismic data, and the calculated partial derivatives.

Abstract: A method and apparatus is disclosed for estimating brine water conductivity in a multiphase mixture of brine water and other substances by combining measured mixture permittivity and conductivity with a known or derived relationship between brine water conductivity and brine water permittivity. The mixture permittivity and conductivity are measured using an open-ended coaxial probe or other probes at microwave frequencies. A number of applications for the brine water conductivity estimate are disclosed including making salinity corrections of a dual energy flow meter.

Abstract: Seismic detection apparatus comprising seismic detection means capable of detecting a plurality of seismic components over a defined tetrahedral volume is provided. The seismic detection means comprises four three-component geophones. Seismic data acquired by the geophones is processed to separate P-wave components from S-wave components. The geophones are spaced apart by distances smaller than the wavelength of the detected seismic components. The apparatus may be used on surface or in a marine environment or transition zone. A method of processing seismic data is also provided comprising acquiring seismic data relating to a wavefield over a selected volume of acquisition, and measuring the curl and divergence of the wavefield from the seismic data, to thereby identify seismic components within the seismic data. Additionally, an apparatus and method for hydrocarbon exploration is disclosed for using three or more seismic receivers placed in a plane and spaced closely to each other.

Abstract: A method and apparatus is disclosed for determining the flow rates of fluid phases in a pipe containing multiple fluid phases. A Venturi is provided to measure total volumetric flow rate measurement and a holdup measurement is taken approximately 3-10 pipe diameters downstream of the Venturi. The holdup measurement is made at a downstream location where a substantial amount of mixing occurs and the differences between the velocities of the fluid phases can effectively be ignored. The flow rates of the phases can thus be determined directly from the holdup measurements.

Abstract: A method and system for cable-based communication between the drilling rig and the bottom hole assembly is disclosed. A cable is provided along the outside of an upper portion of the drillstring. The cable is connected to a cross-over sub assembly below which is attached a second cable that extends down towards the bottom hole assembly. During drilling the cable rotates with the drillstring, and the unused cable is stored in a reel mounted on the top drive unit. New pipe stands are connected and the cable is clamped to the outside of the drillstring. The method and system are particularly well suited for use in deep-water drilling environments.

Abstract: A method of generating seismic waves in a rock mass surrounding a well comprises the steps of: (a) providing a packer and a fluid withdrawal line within the well, wherein the packer is located below the weathering zone and defines the upper limit of a working volume within the well, and the fluid withdrawal line is adapted to withdraw fluid from the working volume; and (b) providing and detonating an air-fuel mixture in the working volume to generate seismic waves, combustion products of the detonation being withdrawn from the working volume via the fluid withdrawal line.

Abstract: An improved de-ghosting method and system that utilizes multi-component marine seismic data recorded in a fluid medium. The method makes use of two types of data: pressure data that represents the pressure in the fluid medium, such as sea water, at a number of locations; and vertical particle motion data that represents the vertical particle motion of the acoustic energy propagating in the fluid medium at a number of locations within the same spatial area as the pressure data. The vertical particle motion data can be in various forms, for example, velocity, pressure gradient, displacement, or acceleration. A spatial filter is designed so as to be effective at separating up and down propagating acoustic energy over substantially the entire range of non-horizontal incidence angles in the fluid medium.

Abstract: A method and system is disclosed for interactively displaying estimated stability of rock surrounding a wellbore. The display shows a three-dimensional representation of the orientation of a portion of the wellbore and the associated estimation of stability of the rock surrounding the wellbore. The user can alter the orientation of the portion of the wellbore, after which in real time the stability estimation is recalculated and redisplayed. The method and system can be used for planning or modifying a well plan, either before or during the drilling process. The method and system can also be used for diagnosis of stability problems. The method and system can also be used for displaying and analyzing the estimated stability of perforations surrounding a wellbore and for planning and arranging such perforations.

Abstract: A method of processing seismic data, said seismic data having been obtained by: performing a plurality of sweeps, wherein each sweep comprises generating seismic signals in the earth using a plurality of vibrators by applying a pilot sweep wave-form to each vibrator, each pilot sweep being a waveform of changing frequency; measuring the force applied to the earth by each vibrator to determine a measured force waveform; and measuring the seismic signals at one or more locations remote from the vibrators; said method comprising: filtering the measured force waveform to remove harmonics of the pilot sweep and thus determining a filtered force waveform; generating an inversion operator from the filtered force waveform for each vibrator; and applying said inversion operator to the measured seismic signals to determine the contribution of each vibrator to the seismic signals.

Abstract: A method and system for real time updating of an earth model. The efficiency with which an oil or gas well is constructed can be enhanced by updating the relevant earth model using real-time measurements of the effective density of the drilling fluid and other parameters. The method includes generating an earth model used for predicting potential problems in drilling of a borehole having a predetermined trajectory. Evaluations of the state of the borehole and local geological features are obtained which are based on the earth model. Real time data is used to create a diagnosis of the state of the borehole and local geological features. The evaluations are compared with a diagnosis to identify inconsistencies. A component of the earth model is identified that is both related to the identified inconsistency and has a high degree of uncertainty. The selected component of the earth model is then updated prior to completing construction of the borehole using the received data.

Abstract: There is provided an apparatus for measuring flow rates of multi-phase flows in metal pipes, the apparatus comprising a transceiver generating a pulsed Doppler signal in the range 100 KHz to 10 microHz and an impedance device adapted to be coupled to a pipe so as to reduce or prevent reflections occurring from a pipe wall in response to the pulsed signal. The apparatus includes signal processor for analysing reflected signals received by the transceiver and for calculating the energy contained in a received signal. The pulsed signal is a shear wave which assists analysis of the reflected signals. The impedance device comprises a sound absorbing block made from plastics material with tungsten particles embedded therein. Different embodiments using various arrangements of transceivers are described, and also a related method of using the apparatus.

Abstract: The invention relates to an apparatus for separation of a first fluid from a mixture of at least the first fluid and a second fluid and a method for doing the same. The apparatus is preferably located downhole, but also can operate on the surface. According to the invention, the apparatus comprises:—a production pipe for flowing the mixture;—at least one settling chamber surrounding the production pipe;—at least one aperture allowing the mixture flowing into the production pipe to flow into the settling chamber; and—an exit pipe, connected to the settling chamber, allowing the first fluid to flow out of the settling chamber.

Abstract: A wavefield separation method and apparatus for 3D VSP data, which handles arbitrary 3D source and receiver geometries, and common shot 3C data oriented to North, East and Vertical geographical coordinates and makes use of anisotropic medium properties at the downhole receivers. When given a range of propagation angles, slowness and polarization vectors are computed for each plane wave and a linear system is solved at each frequency to yield the scalar plane-wave amplitudes. A novel regularization scheme is used that obviates the need for eigen analysis of the steering matrix. Sums within subsets of these scalar plane waves are constructed to provide up and down qP (P), qS (Sv) and Sh wavefields. Vector residuals can be computed for parameter testing, quality control and imaging purposes.

Abstract: A sleeve for an acoustic logging tool has a structure with a window section having fewer bars than a conventional sleeve separated by a slotted region with thin circumferential slots which are stress-relieved at the ends (“dumb-bell” shaped). Steel receiver mounts are provided for hydrophone pressure sensors and this, together with the axially oriented hydrophones makes the tool less susceptible to interfering vibration.

Abstract: A potentiometric sensor for wellbore applications having a permanent aqueous contact between measuring and reference electrode, whereby contact is ensured by discharging the internal solution from the reference electrode directly onto a measuring (ion-sensitive) membrane and protecting the reference junction of the reference electrode with water wet porous material, such as sintered glass. It is advantageously applied to oil-water mixtures under high pressure and/or temperature.

Abstract: The invention concerns a method of sampling the formation fluids in an earth formation surrounding a borehole, the region of the formation immediately surrounding the borehole being at least partially invaded by borehole fluids, and an apparatus for carrying out such a method. According to the invention, a borehole tool is adapted to be lowered into the borehole and is provided with a sampling probe device and means for urging the sampling probe device into contact with the borehole wall, the sampling probe device comprising an inner probe and an outer probe surrounding the inner probe for withdrawing respective fluid samples from the formation, wherein the ratio between the respective flow areas of the inner and outer probes is selected so as to tend to reduce the time taken to obtain via the inner probe a sample of the formation fluids having a given level of contamination by borehole fluids.

Abstract: A method and apparatus for the separation of the water from the oil/gas in the well itself, down-hole, in which gravity is allowed to work on the mixture in a non-vertical section of the well, and then, using separated flow paths, the gravity-separated components pumped to the surface or into a subterranean discharge zone. Detectors are used to control the pumping so as to keep the unsettled/unseparated mixture away from the flow paths. Preferably the discharge zone is chosen to have a formation pressure which is lower than the pressure of the producing zone.

Abstract: A method and system is described for estimating stress characteristics from seismic data. The method includes receiving seismic data acquired over a region, receiving properties of rock at a location within the region, and estimating one or more stress characteristics for a sub-region by combining the seismic data and the rock properties using a relationship between the stress characteristics in the sub-region and elastic stiffness and/or sonic velocity in the sub-region. The relationship is based on a non-linear elasticity theory.

Abstract: A method of monitoring the density of a subterranean fluid comprises the steps of: using a subterranean radiation detector to obtain measurements over a plurality of time intervals of the amount of natural background radiation traversing said fluid, and calculating the relative density of said fluid at each of said time intervals from said measurements.