47 results about "Apparent conductivity" patented technology

A method and a system are provided for allowing determination of a distance from a tool to anomaly ahead of the tool. The apparatus for performing the method includes at least one transmitter and at least one receiver. An embodiment of the method includes transmitting electromagnetic signals from the at least one transmitter through the formation surrounding the wellbore and detecting voltage responses at the at least one receiver induced by the electromagnetic signals. The method includes calculating apparent conductivity or apparent resistivity based on a voltage response. The conductivity or resistivity is monitored over time, and the distance to the anomaly is determined from the apparent conductivity or apparent resistivity values.

A method for providing an image of a formation surrounding a wellbore, includes: obtaining an apparent conductivity curve from main components of resistivity measurements of the formation; performing fitting for cross-components of the resistivity measurements; calculating scaling factors from the cross-component data; scaling apparent conductivity data by the calculated scaling factors; and plotting the scaled conductivity data to provide the image of the anisotropic formation. A system and a computer program product are disclosed.

The invention discloses a time domain aero-electromagnetic data inversion method based on conductivity-depth imaging. First, the apparent conductivity and apparent depth of an underground medium are obtained by use of a conductivity-depth imaging method based on a tale look-up method; then, an inversion initial model is built based on the apparent conductivity and the apparent depth; and finally, inversion is performed by use of a damping characteristic parameter method to complete combination analysis of time domain aero-electromagnetic data. The problem that it is difficult to choose an inversion initial model is solved. As inversion is performed on the basis of the result of approximate imaging, the inversion method has certain constraints of the inversion result, and inversion is of high convergence rate and imaging precision. The invention provides a quick and stable inversion method for time domain aero-electromagnetic data interpretation.

The invention provides a tensor apparent conductivity measurement method. The tensor apparent conductivity measurement method comprises the following steps that 1, an orthogonal electric field E and a curl M of a magnetic field are simultaneously measured on the surface of ground or underground; 2, the tensor apparent conductivity is calculated according to observation data through a formula (please see the formula in the specification), wherein E and M represents observation matrices containing multiple sets of the E and the M. According to the tensor apparent conductivity measurement method, a measured electromagnetic field can adopt a natural electromagnetic field, and also can adopt an electromagnetic field generated through motivation of an artificial field source; the electromagnetic field can be measured at a frequency domain, changes of the tensor apparent conductivity along with the frequency are obtained, and frequency domain sounding is performed; the electromagnetic field also can be measured at a time domain, changes of the tensor apparent conductivity along with time are obtained, and time domain electromagnetic sounding is performed; the calculation formula does not need to make plane wave hypothesis, is also set up on the condition of a non-plane wave field source and is not limited by the field source conditions; the apparent conductivity calculation formula is simple and does not need iteration or parameters such as a field source position and a sending and receiving distance.

A method to determine one or more borehole corrected formation properties using measurements made using a logging tool disposed in a borehole penetrating an earth formation is disclosed. The measurements are used to determine an apparent conductivity tensor for the formation and, for a set of parameters, a parameter value for each parameter in a subset of the set of parameters. A parameter value for each parameter in the set of parameters not in the subset is provided and a borehole-inclusive modeled conductivity tensor is computed. The apparent conductivity tensor and the borehole-inclusive modeled conductivity tensor are iteratively used to optimize the parameter values, and the optimized parameter values are used to compute an optimized conductivity tensor. A borehole corrected conductivity tensor is computed using the optimized conductivity tensor, and the borehole corrected formation properties are determined using the borehole corrected conductivity tensor and/or the optimized parameter values.

The invention discloses a calculating method for the apparent conductivity of multi-layer media. Calculating is conducted through a following formula (please see the specifications for the formula), according to the formula, sigma 1 is the upper surrounding rock conductivity, sigma 3 is the lower surrounding rock conductivity, and sigma 2 is the middle formation conductivity; G<infinity>

is thefull space propagation effect factor; G<2>

is the propagation effect factor of the medium 2; and the G<3>

is the propagation effect factor of the medium 3. The apparent conductivity of four layers of geoelectric cross sections is calculated through an electromagnetic wave propagation theory, and the root-mean-square error is lowered by 12-45% compared with an undisturbed formation.

The invention relates to a phase calibration method of current measuring for induction logging. The phase calibration method includes that vectors of apparent conductivity under the circumstance that distances between an emitting coil and a receiving coil are different are measured for two times respectively, and current measuring phase errors brought in by a current transformer and a nonlinear element in a current measuring circuit are solved, so that errors brought in by a current measuring link are known accurately and eliminated during calculation. By the phase calibration method, scales and measuring accuracy of an array induction logging instrument are improved.

The invention discloses a deconvolution specific resistance treatment method of a cased well. On the basis of the secondary field difference measured by two adjacent depth points, the relation betweenthe secondary field difference and the apparent conductivity difference and stratum conductivity sequence is derived, a stratum conductivity curve is reduced through the deconvolution method, and a stratum specific resistance curve is reduced in a reciprocal manner. The solving problem of the stratum conductivity curve is solved through difference deconvolution; and under the condition that longitudinal geometrical factor spacing is selected correctly, the stratum conductivity can be completely reduced, and the stratum resolution ratio is increased.

The invention provides a method of calculating stratum true conductivity by using well axis electric field distribution, which is simple and effective. The electric field distribution is generated by a transmitting coil after gradual moving of devices, and apparent conductivity distribution is acquired by a plurality of receiving coils, and requirements under conventional technical conditions are satisfied. The method comprises steps that step 1, electric field intensity distribution is measured along a well axis in a wellbore; every time a well logging device moves to a field point, the corresponding electric field distribution is measured; step 2, the measured electric field intensity distribution is converted into an apparent conductivity function; step 3, the apparent conductivity function is used for wellbore correction; step 4, a correct function value is selected from apparent conductivity function values after the wellbore correction, and the stratum true conductivity is acquired. By adopting the brand new induced electric field well logging method principle, the stratum true conductivity is calculated, and therefore the method is simple, calculation efficiency is high, and accuracy is good.

The invention provides a resistivity processing method based on the geometrical factor of a cased well. A reception waveform difference is obtained by conducting subtraction on waveforms measured at adjacent depths at the same source distance, a secondary field difference of measured formations (areas) at two adjacent depth points is obtained, an apparent conductivity difference is further obtained, and deconvolution is conducted on the apparent conductivity difference and a vertical differential geometrical factor difference; the shape of the geometrical factor difference of the cased well isput forward for the first time, the appropriate geometrical factor difference is found from the waveform difference, reception waveforms at four different source distances (0.275 m, 0.43 m, 0.6 m and0.77 m) are utilized to complete restoration of a formation conductivity curve, and the obtained formation conductivity curve is compared and verified with a real formation conductivity curve; and byobtaining reciprocals of the formation conductivities obtained after the first step, the second step, the third step, the fourth step and the fifth step are executed, the formation resistivity curveis obtained, and then distribution of remaining oil can be evaluated.

The invention provides a method for detecting an underground obstacle by utilizing apparent conductivity and a relative dielectric constant, which comprises the following steps of: measuring the apparent conductivity, delineating a horizontal position, reflecting the relative dielectric constant, determining the burying depth and determining the position of the obstacle, and directly measuring the distribution condition of the apparent conductivity in a work area by utilizing a ground conductivity meter. According to the method, the detection means is simple and rapid, and the apparent conductivity profile can be directly obtained to delineate the horizontal direction distribution condition of underground obstacles. Then, according to the horizontal position, a geological radar survey line is established for detailed exploration, and finally, the three-dimensional distribution condition of the underground obstacles is comprehensively determined in combination with a geological radar profile result. According to the invention, the working efficiency is improved, accurate three-dimensional positioning of underground obstacles is realized, and reliable guarantee is provided for later safety construction.

The invention provides a coal seam internal water-rich property calculation method and device and electronic equipment, and relates to the technical field of coal seam water-rich property, and the method comprises the steps: obtaining a normalized induction voltage value through adoption of a ground transient electromagnetic method; calculating apparent conductivity according to the normalized induction voltage value; acquiring electromagnetic wave field intensity by using a wireless electromagnetic wave perspective method; calculating an attenuation coefficient according to the electromagnetic wave field intensity; calculating and obtaining a coal seam dielectric constant according to the apparent conductivity and the attenuation coefficient; determining the coal seam internal water-richproperty according to the coal seam dielectric constant. The coal seam internal water-rich property calculation method and device and electronic equipment can effectively improve the detection precision of the water-rich property of the coal seam.

The invention discloses a method for joint inversion of a stratigraphic dip on the basis of array induction and anisotropy. Firstly, on the basis of array induction electrical resistivity logging data, computational formulas of apparent conductivity and horizontal conductivity of a double-coil system in an inclined heterogeneous stratum are derived; a relation formula of apparent conductivity andhorizontal conductivity of an ideal potentiometric electrode system in an infinitely thick transverse anisotropic stratum is introduced; an anisotropic parameter calculation model of an target stratumsection is built; and apparent conductivity and horizontal conductivity of the target stratum section are obtained through processing with array induction electrical resistivity logging, a functionalrelational expression is built through the apparent conductivity, the horizontal conductivity and anisotropy, and the method for joint inversion of the stratigraphic dip through array induction and anisotropy is formed. The method is applied in a new well, the stratigraphic dip of the target stratum section is obtained, the stratigraphic dip and electric imaging logging are processed to obtain the stratigraphic dip, data dependency is good, so that the tight sandstone stratigraphic dip is calculated accurately through array induction electrical resistivity logging data, precision is high, andreliable data are provided for looking for a tight gas reservoir trap in the future.

The invention belongs to the field of processing methods for time domain airborne electromagnetic data and discloses a fixed wing airborne electromagnetic data conductivity depth imaging method with system auxiliary parameters. The fixed wing airborne electromagnetic data conductivity depth imaging method comprises the following steps: establishing all time channel data tables at multiple fixed flight heights, fixed swing angles, fixed yaw angles and fixed pitch angles; sequentially extracting data and date tables corresponding to time channels; determining the positions of measured data in the tables, and determining apparent conductivity and all auxiliary parameter values according to a linear interpolation algorithm; if the measured data meet a set threshold, outputting the conductivityand auxiliary parameters; judging whether conductivity query of all time channels is finished or not; and obtaining imaging depth according to a skin effect formula. The algorithm is high in imagingspeed and efficiency, meets the requirements of aviation transient electromagnetic processing on mass data, and lays an important science and technology base for rapid exploration capability of mineral resources in China.

The invention discloses a method and device for detecting the thickness and conductivity of a metal coating on the surface of a metal conductor. The method comprises the following steps: generating astandard curve of normalized apparent conductivity according to the characteristics of different coating thicknesses, conductivities and substrate conductivities; acquiring an experimental curve of the equivalent conductivity according to a relationship between the equivalent conductivity of a specific coated conductor to be measured and the penetration depth of an electromagnetic wave under different excitation source frequencies; and determining parameters of a to-be-measured flat plate, and calculating the conductivity of a metal coating and the conductivity of a thickness substrate metal conductor according to the standard curve and the experimental curve. According to the method, the thickness, the conductivity and the substrate conductivity of the micron-order metal coating can be detected at the same time in a high-precision, rapid and nondestructive manner without prior experimental data, and the method is simple and easy to implement.

The invention discloses a logging system and method for measuring true resistivity of a stratum based on an electric field. The logging system comprises a downhole measurement mechanism and an acquisition data analysis mechanism, the acquisition data analysis mechanism comprises a ground mobile data acquisition mechanism and a data processing module, a wellbore is placed in a logging well excavated to a measurement stratum, the downhole measurement mechanism descends to the measurement formation in the wellbore, the ground mobile data acquisition mechanism is connected to the downhole measurement mechanism through a cable, and a wellhead is equipped with a cable hoisting device, and the downhole measurement mechanism is composed of a measurement coil and an electric field measurement maincontrol system. The method is based on the detection and data processing technology under the condition of the full-space multi-frequency emission and multi-point reception measurement stratum electric field, by obtaining massive electric field data, distribution of electric field intensity measured along a well axis is quickly achieved, the electric field intensity distribution is converted intoan apparent conductivity function, and by adaptively processing the apparent conductivity function, rapid measurement of different radial true stratum resistivity under the high signal-to-noise ratiocondition is achieved.

The invention discloses a diode junction capacitance calculation method. The method comprises the following steps: A1, measuring an apparent capacitance value, an apparent conductivity value, an S11 parameter real part, an S11 parameter imaginary part and voltage-current of a diode; A2, calculating a real part and an imaginary part of diode impedance by using the real part and the imaginary part of the parameter S11; A3, according to the impedance relation between the two equivalent circuits of the diode, obtaining calculation formulas of junction capacitance and series resistance; A4, setting an initial junction conductance value Ginit; A5, substituting the initial junction conductance value into the junction capacitance calculation formula to obtain a current junction capacitance value; A6, substituting the current junction capacitance value and the initial junction conductance value into the series resistance calculation formula to obtain a current series resistance value, obtaining a voltage applied to the junction conductance or the junction capacitor according to a voltage-current relationship, and obtaining a current junction conductance calculation value G' according to a conductance formula; and A7, judging whether the difference value between the Ginit and the G' is smaller than a preset threshold value or not; if so, taking the current junction capacitance value as the final value of the junction capacitance; and if not, making Ginit to be equal to G', and executing the step A5 again.