Abstract: A high vertical resolution antenna design is provided for use in an NMR measurement apparatus. Multiple coils are situated along the length of a magnet. A primary coil is energized to cause an oscillating magnetic field in a portion of earth formation surrounding a borehole. A secondary coil having smaller dimensions than the primary coil is operated to receive spin echoes from a depth of investigation associated with the secondary coil. A distance sufficient to minimize electrical coupling separates the coils. The separation distance can be reduced by selecting a secondary coil with orthogonal polarization to the primary coil. Alternatively, a cross coil configuration can be implemented where the orthogonal secondary coil at least partially overlaps the primary coil, thereby reducing the overall length necessary for the polarizing magnet.

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 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an air-fuel mixture in the working volume to generate seismic waves, combustion products of the detonation being withdrawn from the working volume via the fluid withdrawal line.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: The invention is directed toward a subsurface gravity measurement device and a method for calibrating the same that includes a tilt meter and a gravity sensor. The method includes associating tilt information produced by the gravity sensor as a function of a relationship between tilt information produced by the tilt meter and a correction parameter. The tilt meter produces tilt data, and the gravity meter produces gravity data, corresponding to the tilt data. The tilt data and gravity data is fitted to a polynomial equation that has a plurality of initial coefficients associated therewith. The initial coefficients includes information concerning the correction parameter. The correction parameter is derived as a function of the initial coefficients.

Abstract: A method of analysing scale at a location in a hydrocarbon well flow system comprises the steps of: using an in situ gamma-ray detector to obtain a gamma-ray spectrum from said scale, and spectroscopically analysing said spectrum to determine the abundances of radioactive isotopes in said scale.

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: Methods for optimization of oil well production with deference to reservoir and financial uncertainty include the application of portfolio management theory to associate levels of risk with Net Present Values (NPV) of the amount of oil expected to be extracted from the reservoir. Using the methods of the invention, production parameters such as pumping rates can be chosen to maximize NPV without exceeding a given level of risk, or, for a given level of risk, the minimum guaranteed NPV can be predicted to a 90% probability. An iterative process of generating efficient frontiers for objective functions such as NPV is provided.

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: Apparatus and methods for sensing one or more physical parameters at a remote location while minimizing or eliminating contact between reservoir fluids and the like at the remote location and the sensor used to sense the physical parameters. In one example arrangement, the apparatus includes a tubing containing a communication cable and a sensor in communication with the cable, the sensor being located within the tubing proximate the remote location. The apparatus is configured to impose a barrier of a fluid between the sensor and the environment at the remote location. A fluid barrier reservoir containing the barrier fluid is also provided in some example arrangements.

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: A method for determining downhole reservoir wettability includes acquiring a first set of NMR measurements of formation fluids in earth formations at a selected axial depth; inverting the first set of the NMR measurements to produce a first distribution of a spin relaxation parameter for a fluid component in the formation fluids; acquiring a second set of NMR measurements of a formation fluid sample removed by a formation fluid testing tool at the selected axial depth, the formation fluid sample being kept at a substantially same pressure and temperature as those of the formation fluids in the earth formations at the selected axial depth; inverting the second set of NMR measurements to produce a second distribution of the spin relaxation parameter for the fluid component in the formation fluid sample; determining the reservoir wettability from a comparison of the first and second distributions of the spin relaxation parameter.

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: The present invention discloses a method and apparatus to detect bubbles in a fluid sample to determine if gases are present, wherein an ultrasonic source is used and its properties monitored. Fluctuations in the ultrasonic source's electrical properties indicate the presence of bubbles/gas. Alternatively, the ultrasonic source may be used to cavitate the sample and induce the nucleation of bubbles. In such a system/method, bubbles may be detected by either (1) monitoring the ultrasonic source properties, (2) monitoring the compressibility of the sample, (3) monitoring the sample properties, including harmonics and subharmonics. The method and apparatus disclosed herein may be used in a borehole such as with a sampling means (including either a flowing sample or a stationary sample) or in a surface lab.

Abstract: The present invention provides an apparatus and method for achieving proper space-out of well components. One aspect of the invention utilizes a dummy production string with a sliding measurement device to measure the proper space-out distance.

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 method is disclosed for reducing noise in a measured telemetry signal. The method includes tracking a characteristic of at least one harmonic of a noise component in the measured telemetry signal band. The at least one harmonic has a frequency outside a telemetry signal band. The characteristic of the noise component is determined for at least one other harmonic thereof. The at least one other harmonic has a frequency inside the telemetry signal band. A noise reference is generated from the characteristic of the in band harmonic, and the noise reference is combined with the measured telemetry signal to generate a noise-canceled telemetry signal.

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: A core sample retaining sleeve is provided for preventing loss of a cut core sample from the distal end of a coring bit, particularly during retraction of the coring bit to within the coring tool. Preferably, the core sample retaining sleeve is disposed concentrically within the coring bit to fit around the received core sample. The core sample retaining sleeve has one or more retaining fingers formed on the distal end of the coring bit. The retaining fingers are selectively closeable, preferably by urging the one or more retaining fingers against one or more guide members. A guide member is preferably provided as a stationary ridge on the inner, distal surface of the coring bit. The core sample is contained and protected within the closed retaining sleeve.