Bibliographic Details
| Title: |
Data acquisition method with a three dimensional small bin electromagnetic consecutive array |
| Document Number: |
20110037473 |
| Publication Date: |
February 17, 2011 |
| Appl. No: |
12/924268 |
| Application Filed: |
September 22, 2010 |
| Abstract: |
Disclosed herein is a three dimensional small bin electromagnetic consecutive array data acquisition method used in oil exploration comprising the steps of recording data using small bin lattices on execution of arrangement electrodes, each acquisition station (Ex, Ey) records the natural electromagnetic field time series data with the same acquisition parameter simultaneously; interference is removed first, for recorded data processing to get interference-free data; for border points and center point, the recording point serves as center point, and the same component from adjacent two points to total points area added together to obtain the average value of electric field data at time domain for each observation point; for corner points, the average values of the same electric field component from adjacent two points to total survey points toward bin direction is calculated; the electric field components acquired in maximum space serve as the new electric field values respectively; new time series data acquired in which the noise and the static shift effect have been suppressed, and apparent resistivity and phase curves of each point are acquired after processing with conventional method. |
| Inventors: |
He, Zhanxiang (Zhuozhou, CN); Sun, Weibin (Zhuozhou, CN); Wang, Yongtao (Zhuozhou, CN); Tao, Deqiang (Zhuozhou, CN); Hu, Zuzhi (Zhuozhou, CN); Luo, Weifeng (Zhuozhou, CN); Zhang, Yue (Zhuozhou, CN) |
| Claim: |
1. A three-dimensional small bin electromagnetic consecutive array data acquisition method comprising the following steps: (1) applying small bin lattice data acquisition on execution of arrangement electrodes in a working area, arranging a two-component electric field acquisition station (Ex, Ey) at the center of a small bin, in said small bin lattice acquisition, an “L” electrode-arrangement mode of a conventional method is used for corner points, a “T” electrode-arrangement mode of a conventional method is used for border points, and a “+” electrode-arrangement mode of a conventional method is used for a center point; arranging a two-component orthogonal horizontal magnetic field (Hx, Hy) magnetic bar or a three-component orthogonal magnetic fields (Hx, Hy, Hz) magnetic bar at the center point of the smallest bin, wherein the directions of Hx and Hy are parallel to those of the electric field components; (2) acquiring data, wherein each acquisition station records natural electromagnetic field time series data with the same acquisition parameters simultaneously, and a sampling rate being set upon frequency; (3) interference is first removed during data processing to obtain interference-free data; (4) for the border points and center point, the recording point serves as the center point, adding the same component from the adjacent two points to total points respectively to obtain the average value of time domain electric field data of all survey points; for the corner points, calculate the average values of the same electric field component from the adjacent two points to the total survey points toward a bin direction; us the electric field components acquired in the maximum space as new electric field values; (5) after the observation field values are processed with the above steps, new time series data are acquired in which noise and static shift effect have been suppressed, and apparent resistivity and phase curves of each point can be acquired after processing with a conventional method. |
| Claim: |
2. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (1), in said small bin lattice acquisition, each small bin is chosen from the group consisting of a unit of 2×2, 3×3, 4×4 or 5×5 points, wherein a unit bin of 3×3 points is divided into four smaller bins, and a unit bin of 4×4 points is divided into nine smaller bins. |
| Claim: |
3. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (1), the corner points and border points of the small bin and the center point of the connection line between each two adjacent survey points are grounded points of receiving electrodes (M, N), also common electrodes of the adjacent survey points, and no electrode is used for the center point. |
| Claim: |
4. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (1), each two adjacent survey points of the small bin are connected by the same common electrode, and the inner potential difference of the entire small bin is closed and the sum of the potential differences recorded by the acquisition station at any time is equal to zero. |
| Claim: |
5. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (1), the distance between the survey points and the magnetic field acquisition station in the smallest bin is 0.5 L or 0.707 L, where L is the side length of the smallest bin. |
| Claim: |
6. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (2), the high frequency range of the sampling rate uses a high sampling rate to obtain a shorter acquisition time period, the medium frequency range uses a medium sampling rate, and the low frequency range uses a low sampling rate to obtain a longer acquisition time period. |
| Claim: |
7. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, further comprising, in step (3), the interference removal processing comprises the following steps: 1) assigning a data error in each closed loop to the respective survey points; 2) first adjust the small loop inside of each of the smallest bin; 3) identify interference data, and obtain interference-free data by using the closed loop principle for potential fields; wherein, if the whole closed loop at some time is has interference and the closing error is greater than a specified minimum tolerance value, the data at this time is deleted, and the outmost loop of the small bin is then adjusted, thus acquiring interference-free data. |
| Claim: |
8. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1 wherein in step (3), said data without interference means the closing error of any loop is smaller than the specified minimum tolerance value. |
| Claim: |
9. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, wherein, in step (4), said adjacent two points to total points comprises two points to all the electric field record points on both sides of a straight survey line, and the adjacent two points to total survey points toward a bin direction for corner points comprises two points to all the electric field record points on one side of the straight survey line. |
| Claim: |
10. The three-dimensional small bin electromagnetic consecutive array data acquisition method according to claim 1, wherein, in step (5), said conventional method comprises steps: 1) calculating a power spectrum and impedance tensor to obtain the apparent resistivity and phase curves and other calculated results of each point, wherein the magnetic field components of the respective survey points of the smallest bin share the same magnetic field as that of the center point; 2) conduct a power spectrum analysis and impedance tensor estimate on the time series data for each survey point with different lengths of electrode distance to obtain a sequence of topology apparent resistivity curves of the same record point; 3) drawing frequency-apparent resistivity curves with different electrode distances of the same survey point on a log-log logarithmic coordinate, and 4) comparing the variation rules of the curves to analyze whether said curves are affected by the static shift: the apparent resistivity curve acquired by the electric field with the largest electrode distance is the representative of the minimum static shift effect, wherein if all curves are coincident with the apparent resistivity curve with the largest electrode distance, there is no static shift, and if curves of a relatively smaller electrode distance are offset relative to the curve of the largest electrode distance, there is static shift; in general, the larger the offset, the greater the static shift effect. |
| Current U.S. Class: |
324/350 |
| Current International Class: |
01 |
| Accession Number: |
edspap.20110037473 |
| Database: |
USPTO Patent Applications |
