Abstract: A method and apparatus is provided for collecting reservoir data. The method includes providing one or more electromagnetic sources for generating an electromagnetic field in a reservoir and providing one or more electromagnetic sensors equipped with capacitive electrodes. The electromagnetic source is located separately from the electromagnetic sensor. The electromagnetic sensor may either be located within a well or at the surface, is capable of measuring the electromagnetic field in three dimensions, and may be isolated from the well fluids. The data collected by the electromagnetic sensors can be used to create a model of the oil reservoir, including the water saturation.

Abstract: The present disclosure relates to determining the attenuation of an electromagnetic signal passing through a conductive material. An antenna is provided and placed in relatively close proximity to the conductive material. An alternating current is passed through the antenna and the impedance of the antenna is measured. The attenuation is determined using the measured impedance. A single frequency measurement may be made, or multiple measurements using different frequencies may be made. Grouped parameters based on properties of the material and the frequency of the current are used to relate the coil impedance to the attenuation. A current frequency for which the ratio of the antenna's resistive part of the impedance to the angular frequency of the current is substantially insensitive to at least one of the parameters is preferred.

Abstract: A method of determining anisotropy in a borehole is disclosed. An array of measurements along the borehole is obtained and a first depth in the borehole is selected. An arbitrary plane oriented with respect to the borehole at the first depth is designated and an anisotropy for the first depth with respect to the arbitrary plane is determined. The arbitrary plane is repositioned at the first depth and an anisotropy for different positions of the arbitrary plane at the first depth is determined. A minimum anisotropy coefficient with respect to the arbitrary plane at the first depth is identified based on anisotropy for different positions of the arbitrary plane. An anisotropy tensor for the first depth is then identified.

Abstract: An adaptive array wireless communication apparatus able to suitably select antenna elements, small in amount of processing, fast in convergence speed, and suitable for transmission/reception, and a method of the same, which controls the directionalities of array antenna elements based on array weights, controls an antenna element selecting unit 23 so that the antenna elements are intermittently determined, and adjusts a period of determination of the antenna elements based on information of the antenna elements determined at a controlling unit 26.

Abstract: A system for use in a wellbore includes plural modules for positioning in the wellbore and including respective interfaces, where the plural modules are configured to perform predefined downhole tasks in the wellbore. The plural modules are associated with respective local power sources. A telemetry subsystem enables communication between at least two of the plural modules, where the communication between the at least two of the plural modules allows one of the two modules to affect an operation of another of the two modules.

Abstract: A method is disclosed for locating a receiver in a borehole having a conductive liner by inducing an electromagnetic field from a transmitter in a first borehole, detecting at a first location by at least one receiver located in a second borehole having a conductive liner, a first electromagnetic field induced by the transmitter, detecting at a second location by the at least one receiver, a second electromagnetic field induced by the transmitter and calculating a set of geometry coordinates for the first location based on the first electromagnetic field and the second electromagnetic field.

Abstract: A method is disclosed for locating a receiver in a borehole having a conductive liner by inducing an electromagnetic field from a transmitter in a first borehole, detecting at a first location by at least one receiver located in a second borehole having a conductive liner, a first electromagnetic field induced by the transmitter, detecting at a second location by the at least one receiver, a second electromagnetic field induced by the transmitter and calculating a set of geometry coordinates for the first location based on the first electromagnetic field and the second electromagnetic field.

Abstract: The invention relates to apparatus with capacitive electrodes for electrical prospecting in a borehole, the apparatus comprising at least two injection electrodes (16, 18), at least two measurement electrodes (28, 34), and a current generator (22) for applying an electrical current between the two injection electrodes. The current generator (22) delivers alternating current at a frequency of 5 kHz to 100 kHz and at a voltage of less than 1000 volts. At least one of the measurement or injection electrodes (16, 28) is placed in a borehole (12, 14) and presents an outer surface that is cylindrical and electrically conductive. The apparatus further comprises means (24) for measuring the current flowing through said injection electrodes, means (36, 36b) for measuring the potential difference between the measurement electrodes, and means for processing the measured current and potential difference to deduce therefrom the characteristics of the subsoil in which the borehole is situated.

Abstract: The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

Abstract: A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

Abstract: This invention relates to the measurement of the longitudinal components of low frequency A.C. magnetic fields from within cased boreholes which are used to measure the geophysical properties of geological formations. The applied A.C. magnetic fields are generated by passing low frequency A.C. current through insulated wires or by conducting low frequency A.C. current through geological formations. The currents generating the applied A.C. magnetic fields are in the frequency range between 0.001 Hz and 20 Hz. The measured longitudinal components of the resulting total A.C. magnetic fields are responsive to various geophysical parameters which include the resistivities of the portions of the geological formations subject to said applied A.C. magnetic fields.

Abstract: Multiple arrays of electric or magnetic transmitters and receivers are used in a borehole geophysical procedure to obtain a multiplicity of redundant data suitable for processing into a resistivity or induced polarization model of a subsurface region of the earth.

Abstract: The present invention relates to an economical, high resolution non-destructive method to remotely image rock mass and subsoil features. More specifically, the invention relates to a method measuring the properties of subsoil structure by first creating at least two boreholes in the area to be examined. At least one electromagnetic radiation transmitter is placed in one borehole and at least one receiver is placed in a second at least one other borehole. The transmitter produces a continuous constant signal of about 100 Hz or greater, which traverses the plane between the transmitter and receiver. After measuring simultaneously both the amplitude and phase of the received electromagnetic signal, the signal information is processed using a linear approximation algorithm. Upon comparison of the processed data, with standard data for nearby geological formations, it is possible to accurately determine both the dielectric constant and the conductivity of the subsoil in the plane.

Abstract: A method of determining the oil and brine saturation distribution in an oil field by taking electrical current and potential measurements among a plurality of open-hole wells geometrically distributed throughout the oil field. Poisson's equation is utilized to develop fluid saturation distributions from the electrical current and potential measurement. Both signal generating equipment and chemical means are used to develop current flow among the several open-hole wells.

Abstract: In an in situ uranium leaching process, a method of detecting presence or absence of leach solution escaping from a desired leaching zone involves monitoring the electrical impedance of a zone just outside the desired zone to detect high ionic concentration indicative of leach solution. Electrical impedance is measured by locating monitor wells just outside the leaching zone and positioning pairs of current and voltage probes within the monitor wells and closest injection wells. Low frequency, constant current is generated by each pair of current probes between corresponding injection and monitor wells to develop a zone impedance-dependent voltage drop that is measured by each set of voltage probes and correlated to presence or absence of escaping leach solution. In an alternative embodiment, electrical impedances are measured between a single, central recovery well and a series of distributed, monitor wells to reduce the total number of probes required.