Abstract: In an MRI apparatus, a static magnetic field is generated by a pair of magnets facing each other within a spacing. An axis direction of a subject inserted within the spacing is orthogonal to that of the static magnetic field. Gradient magnetic fields with X, Y and Z direction are generated by two pairs of plane coils, two pairs of plane coils, and a pair of plane coils, respectively, arranged between a pair of magnets. The plane coils for generated the gradient magnetic field in X direction is the same form as the plane coils for generating the gradient magnetic field in Z direction. By such an arrangement, gradient magnetic fields generated within the spacing have enough magnitude and linearity to obtain magnetic resonance signals. It is also enough spacing to insert a subject.

Abstract: The apparatus of the present invention relates to a down hole tool capable of extraction of valid samples and making pressure measurements useful in calculating formation permeability. The tool incorporates the features of a staddle packing to allow formation fluid specimens to be taken at large flow rates without depressing the pressure below the formation fluid bubble point. When used in combination with a pressure probe the tool is used to obtain meaningful permeability readings in a larger radius area than previously permitted with known dsigns. Additionally, the apparatus of the present invention allows flow control during the creation of the pressure pulse which enhances extraction of valid samples and the permeability determination.

Abstract: A formation testing apparatus is shown for testing subsurface earth formations penetrated by a borehole. A tester body has two longitudinally spaced sealing pads which are used to isolate a portion of the well bore from well bore fluids. A pair of sample collectors are carried by the body and communicate thru openings provided in the sealing pads for receiving samples of connate fluids produced from the surrounding formations. A pair of control fluid passages containing a control fluid of known density are pressure communicative with the connate fluid contained in each sample passageway. A pressure sensor is provided for sensing the pressure of the known density fluid in the control fluid passages and for comparing the pressures to determine a fluid pressure-depth gradient from which the nature of the connate fluid in the earth formations adjacent the formation testing device can be predicted.

Abstract: A magnetic resonance imaging system includes a magnetic resonance exciting unit having an imaging mode which is executed such that a slicing gradient field and a high-frequency field are applied to an object placed in a uniform static field to excite a slice of the object, a read gradient field which is repeatedly switched is applied to the object, and a phase-encoding gradient field is applied to the object, thereby generating a series of echo signals, a data acquiring unit for sampling and acquiring the echo signals generated by the exciting unit, and an image forming unit for performing image reconstruction using sampling data obtained in the imaging mode of the exciting unit. The exciting unit also has an echo position detection mode which is executed such that the fields except for phase-encoded gradient field are applied to the object to excite the slice of the object in the same manner as in the imaging mode, and to generate a series of phase-nonencoded magnetic resonance echo signals.

Abstract: The magnetic resonance (MR) imaging system, in which magnetic resonance is caused on the spin of a specific nucleus using a gradient field and a excitation pulse, and, through observation of an MR signal, an image representing the density distribution of that nucleus in a target region of a body is attained, provides at least one of a density distribution image of protons in water of the body and that of protons in the body's fat. First image data comprising complex image data representing the distribution of the spin in a water phantom and second image data comprising complex image data representing the spin distribution in the body are obtained. The first and second image data are acquired in the excitation sequence in which the phase of the MR signal for the water protons is opposite to that of the fat protons. By comparing the first and second image data, it is discriminated which one of the densities of water and fat protons in the second image data is dominant.

Abstract: The high frequency magnetic field generating portions are arranged at spatially different positions, respectively, and high frequency currents having phase difference corresponding to a spatial deviation between the high frequency magnetic field generating portions are supplied to the high frequency magnetic field generating portions, resultant high frequency magnetic fields being combined to produce a single rotating magnetic field.

Abstract: An antenna for nuclear magnetic resonance imaging devices has two electromagnetic circuits connected to each other so as to produce mutual opposition of their electromotive force when they are placed in a uniform electromagnetic induction field. It is considered that a localized transmitter does not produce a uniform field. This antenna therefore makes it possible to detect this field if it comes close to this latter. On the other hand, this antenna does not present any reactive field to a transmitter in which it may be considered that the field opposite to said antenna is uniform.

Abstract: An apparatus for measuring the quantity and flow rate of liquids in a flowing fluid stream containing liquids and gases such as found in oil well production, with an optional controller for oil well pumps to control the pumping period or speed based on pump displacement. Total number of tank fill events provide a precise measurement of total volume. Volumes are accumulated on a time base to determine flow rate and on the basis of strokes to determine pump displacement. Liquid measurement is accomplished without restriction to the flowing stream, even in the event of a valve failure. The filling of each tank with oil of low or high viscosity can be measured by level, hydrostatic pressure, or weight sensors. Measurement of total produced volumes are accumulated with the accuracy and repeatability needed when correlating producing wells with injection wells, and when diagnosing well problems.

Abstract: A method and apparatus for determining the physical integrity of geological shales and for simulating the environment experienced by geological strata comprising forming a test specimen of the stratum to be measured; immersing the specimen in a drilling fluid, or a mixture of drilling fluids, for a predetermined length of time; spinning the test specimen while immersed up to a predetermined speed while adjusting the temperature of the fluid; and then physically measuring the specimen for disintegration, liquid absorption, and hardness. The apparatus for simulating the environment experienced by geological strata includes means for immersing the specimen in the drilling fluid which comprises a nail having the specimen attached to the shank adjacent the head to hold the specimen inverted below the surface of the drilling fluid.

Abstract: A fluid flow velocity measuring device is shown. In the preferred and illustrated embodiment, an elongate body receives a removable spinner cartridge assembly. The assembly is formed of an elongate sleeve surrounding a rotating shaft supported by bearing assemblies at opposite ends of the shaft. The shaft supports a spinner. Particular sizes of spinners are calibrated to a particular flow velocity ranges and density of material. The insert is held in position by a compressed spring behind the insert so that fluid flow is directed from an inlet port in the tool adjacent a petal basket, along an axial passage in the tool, and through the spinner and out through an outlet port.

Abstract: Downhole torque and rate of penetration are utilized to develop indications of formations that are porous, argillaceous or tight. This information is useful as an aid in selecting drilling practices and drilling bits. The method separates bit effects from lithology effects when drilling with roller cone or PDC bits by utilizing surface and subsurface wellsite sensors to determine averaged values of real time penetration rate and downhole torque. Changes in bit torque are used to broadly classify the lithology into three categories: porous, argillaceous and tight formations while trends in bit torque and rate of penetration in shale are used to separate wear of the bit from changes in formation strength.

Abstract: An incomplete set of three dimensional magnetic resonance data is collected and stored in acquired data memory (40). The incomplete data set is complete with respect to first and second directions and incomplete with respect to a third direction. However, the acquired data set has data along the third direction between .+-.n central values and half the remaining values. One dimensional inverse Fourier transforms (64, 66) are performed with respect to the first and second directions to create an intermediate data set (68). A phase correction array or plurality of phase correction vectors p(r) are generated from the intermediate data and stored in a phase correction memory (82). A symmetric data set (100) is created as the complex conjugate of the intermediate data set. The intermediate and symmetric data sets are one dimensionally inverse Fourier transformed (96, 104) with respect to the third direction one vector at a time to produce vectors of first and second complex image arrays (f.sub.A, f.sub.

Abstract: A test head for NMR spectrometers comprises an rf coil mounted on a carrier pipe and a shielding which extends over at least one section of two parallel conductors extending in the axial direction of the carrier pipe. In order to improve the effect of shielding, the shielding is connected, in an electrically conductive manner, to a turn section of the rf coil which contains a cold point. The shielding is thereby maintained at a fixed neutral potential, relative to the rf voltage supplied, with the result that no fields impairing the measuring accuracy and resolution of the spectrometer can any longer exist in the shielded area. The shielding may be connected directly to one turn section of the coil, for example by soldering.

Abstract: A method is proposed for the elimination of the effect of coherent interference signals which give rise to image artefacts in off-center imaging which usually requires roll correction in order to obtain a correct image. To this end, the image is shifted independently with respect to the artefact signal over an arbitrary distance which depends on the isocentric shift. The method is advantageous for off-center imaging where usually surface coils are used. A band of interference signals in the phase encoding direction can thus be shifted to the edge of the image.

Abstract: A method is provided for generating an improved torque-drag model for at least the collar portion of the drill string in a directional oil or gas well. The technique of the present invention determine the stiffness of incremental portions of the drill string, and uses this information, the borehole clearance, and the borehole trajectory to determine the contact locations between the drill string and the sidewalls of the well. The contact force at these determined locations can be calculated, taking into consideration all significant kinematic, external, and internal forces acting on that incremental portion of the drill string. More acurate torque-drag analysis provided by the improved model of the present invention assists in well planning, prediction, and control, assists in avoiding drilling problems, and reduces total costs for the well.

Abstract: An in-situ linear flow proppant conductivity test cell is provided which allows a downhole fracturing operation to be accurately simulated under laboratory conditions. The test apparatus includes a housing, having pistons therein, a plurality of heating elements, and a packer with a plurality of ports therethrough. Core samples are inserted into the test apparatus and a proppant bed, such as a sand slurry, is introduced into the test cell between the core samples. An external press then provides pressure to the pistons simulating the overburden experienced downhole, while the heating elements simulate downhole temperatures. Pressure, differential pressure, flow rate temperature and fluid loss characteristics can then be measured through the plurality of ports within the packer.

Abstract: Certain wellbore fluid stimulation treatments may be monitored by a system including instrumented manifolds which may be connected between a base fluid source and a blending unit and between the blending unit and fluid injection pumps, respectively for measuring flow rates of the base fluid, the fluid additives and the fluid composition formed by the base fluid and the fluid additives. Instruments are also provided for measuring fluid temperature, pH, viscosity and flow behavior indexes (n', K') and fluid density. Quality control and determination of pressure losses in the wellbore together with modeling of stimulation treatments may be carried out by the continuous monitoring of parameters with the base fluid manifold and the mixed composition manifold.

Abstract: Radio frequency pulses (40, 50, 60) having tip angles in the range of 5.degree. to 15.degree. are applied concurrently with slice select gradient pulses (42, 52, 62) to tip a component of the magnetization into a transverse plane. Phase encode gradients (44, 54, 64) phase encode magnetic resonance echoes (48, 58, 68) which are collected in the presence of read gradients (46, 56, 66). The magnitude of components of the slice select , read, and phase encode gradients along three system axes (grad1, grad2, grad3) are different in conjunction with each echo such that each echo represents a view of data along a different slice through a region of interest. The tip angle (.alpha.) and duration (t) between RF pulses are selected such that the magnetization of dipoles within the most recently selected slice regrows along the magnetic field axis until it is indistinguishable over integrated noise from the magnetization corresponding to other dipoles in the image region.

Abstract: A magnetic resonance imaging apparatus utilizes a gradient coil system with different arc angles for different arc conductors of the essentially saddle-shaped coil elements of the magnet. As result, the arc conductors can be oriented nearer to the radial symmetry plane so that not only the spatial field homogeneity in an active zone is maintained or improved, but also the efficiency of the gradient magnet system is substantially increased and the power stored in the coil is reduced, thus enabling faster switching.

Abstract: The invention relates to a procedure for measuring the rate of penetration V.sub.F of a drill bit fixed to the lower end of a drill string lowered into a well. During an initial period, the well is drilled keeping, on average, the value of weight F of the drill string measured at the surface relatively constant, and the instantaneous values of the drill string rate of penetration V.sub.S and the weight F are measured at the surface at different successive moments. The value of the drill string average rate of penetration V.sub.SM at the surface is determined from the values of V.sub.S measured and the successive values of dF/dt of the first derivative with respect to time. The coefficient of apparent rigidity of the drill string during the initial period is then determined from the values of V.sub.SM, V.sub.S and dF/dt. Finally, the rate V.sub.F is calculated.