Patent ID: 7519474
Filing Date: 2009-04-14
Classification: G01V

Abstract:
1. A method for measuring resistivity of electromagnetic waves of the earth, comprising: (1) establishing a linear coordinate system for observation and presetting initial parameters for capturing data, wherein, said linear coordinate system is based on an equation between a propagation frequency (F) and a stratum depth (H), said equation being F=a+bK′/H, wherein, F is the propagation frequency and its unit is Hz, H is the strata depth and its unit is meter, a is a surface-layer coefficient having a small and neglectable value, b is a coefficient in regional stratum resistivity varied with the stratum depth, having a value of 0.1, K′ is a measured depth that is defined during the propagation of the electromagnetic wave in the strata, wherein, said initial parameters include a measurement starting depth (H (2) determining a depth coefficient (B) via the steps of: (a) selecting a known drilling well in a region to be measured or a region adjacent to said region to be measured; (b) performing exploration and measurement around said known drilling well to obtain a curve of electromagnetic wave resistivity; (c) comparing said curve obtained in step (b) with a curve of the electromagnetic wave resistivity of the known drilling well to determine said depth coefficient (B), wherein said comparing further comprises: i. selecting a segment from said curve obtained in (b) and comparing with a corresponding segment of said curve of the electromagnetic wave resistivity of the known drilling well; ii. determining a sampling interval S′ using an equation of S′=(Hp (3) calibrating a surface-layer depth coefficient (Ha) through the steps of: (a) comparing said curve obtained in step (2)(b) with said curve of the electromagnetic wave resistivity of the known drilling well in respective segments to obtain a value of system error of depths at each characteristic point, said value of system error being Ha=Hd−Hc, wherein, Ha is a surface-layer depth coefficient, Hd is a depth of the characteristic point of electrical well logging of the known drilling well, and Hc is a depth of said characteristic point of the electromagnetic wave resistivity curve; and (b) using said surface-layer depth coefficient Ha to calibrate a surface-layer depth for a measured depth using the curve of the electromagnetic wave resistivity, wherein the calibrated measurement starting depth is: (4) determining other parameters through the steps of: (a) determining a measurement starting depth or a measurement ending depth for data capturing purposes based on pre-specified needs; (b) selecting a number of sampling intervals depending on different conditions including: i. for comparing different regional strata and tracking electrical interfaces of different, 5 meter, 10 meter or 20 meter being selected as said sampling intervals; and ii. for tracking and detecting ore bed such as oil bed, coal bed and metal ore bed or a crack band, 0.2 meter, 0.5 meter or 1 meter being selected as said sampling intervals; wherein, a number of sampling points can be determined depending on different conditions including: i. taking 8 points when the finishing depth is less than or equal to 1000 meter; ii. taking 16 points when the finishing depth is less than or equal to 2000 meter; iii. taking 32 points when the finishing depth is less than or equal to 4000 meter; and iv. taking 64 points when the finishing depth is less than or equal to 8000 meter; wherein, the corresponding sampling periods being 128, 64, 32 and 16 respectively; (c) determining a channel gain by selecting the first channel (CH (5) determining whether data captured through the steps (1) to (4) meets a quality standard required of original data, and responsive to the determination that the standard is met, recording said data in a data capturing, controlling and processing system, wherein said system is configured to: