Geophysical probe and a set of probes

 

(57) Abstract:

Usage: for downhole or surface works when searching tanks filled with hydrocarbons, to search for other minerals, geological mapping, etc., the inventive in geophysical probe and the set of probes, each of which contains at least one stimulating and two measuring elements, the distance between the measuring elements and exciting and the nearest measuring element are members of a number of

Lr= Lr-1+ Lr-2,

where r = 3, 4...; L1= G, L2= 2G (where G is the base number). When selecting distances can be used in adjacent members of the series. 2 S. and 2 C.p. f-crystals, 2 Il.

The invention relates to Geophysics, in particular to electrical exploration, and can be used for downhole or surface works when searching tanks filled with hydrocarbons, to search for other minerals, geological mapping, geothermal, geotechnical, hydrogeological studies, etc.

When conducting seismic and GPR, gravity survey, magnetic or p source or exciter field; the meter of this field and the second meter this particular field.

In particular, Schlumberger proposed a probe containing two current and two potential electrodes located on one straight line (U.S. patent 1719786, G 01 V 3/02, 1929). The potential electrodes M and N are near the current electrode A and the second current electrode B is removed from the binomial system of electrodes A, M, n

Also known downhole acoustic device containing accommodated in the housing the transmitter and three receivers (U.S. patent 4992994, G 01 V 1/40, 1991).

In the EPO 0184898, G 01 V 5/12, 1985 describes a probe for gamma-ray logging tool containing placed on the same line source and two receivers gamma-quanta.

The closest to the invention can be considered as a combined geophysical probe, in which the mentioned characteristic points are points of placement of the magnetometer, the source and receiver of acoustic signal, respectively (U.S. patent 4962490, G 01 V 1/40, 1990).

In practice, this and the above-mentioned probes are used in combination with other probes or equipment of the same design, but different size, which allows a comprehensive study of the geological object, to identify all the features of its s or sets of probes, low. Not in all cases, the results of the survey using a known probe or set of probes able to interpret unambiguously.

This is because when solving specific geological problems improving the accuracy and precision of the result is determined by the comparability and aggregation of information. At the same time, the depth, resolution, and accuracy of the device depends on the distance between their elements, angles, and ratios between them, and whether these parameters are fundamental structural characteristics of geological objects and used electric fields. The specified ratio and compliance are not considered in the described device, which does not allow sufficiently to eliminate these disadvantages and to create on the basis of the known devices standardized and unified measurement system, a set of electrical probes. This requires undue complication of the algorithm, information processing, increasing its volume due to the implementation of additional measurements.

Thus, the technical result expected from use of the invention is to simplify algorithm, the use of the device will allow you to create on its basis a uniform kits for the study of geological objects at different levels of the hierarchy.

This result is achieved in that in the known geophysical probe containing at least one stimulating and two measuring elements, the distance between the measuring elements and exciting and its nearest measuring element are members of a number of

Lr= Lr-1+ Lr-2, (1)

where r = 3, 4...; L1= G; L2= 2G (where G is the base number).

In addition, the choice of distances using the adjacent members of the series.

This result is achieved by the fact that in the known set of geophysical probes, each of which contains at least one stimulating and two measuring elements, the distance between the measuring elements and exciting and its nearest measuring element are members of a number of

Lr= Lr-1+ Lr-2, (1)

where r = 3,4...; L1= G; L2= 2G (where G is the base number).

In addition, the choice of distances using the adjacent member of the straight.

In Fig. 1 schematically shows a probe for em; Fig. 2 - acoustic probe.

The device shown in Fig. 1, contains the electrodes 1, located at points A, B, M, N, and called in the future in accordance with these points, key 2, source 3 DC and a voltage meter 4.

The ratio of the distances MN/AM is equal to the ratio Lm/Ln, m<n. For example, when G = 1 m, MN and AM can be 1 and 2 m, 3 and 5 m, 5 and 13 m, and so on

Conducted comparative tests of known and proposed probes for lateral logging sensing. In the known probes of size MN and AM was 0,1/0,4; 0,1/1,0; 0,5/2,0; 0,5/4,0; 1,0/8,0, and offer accordingly 0,14/0,28; 0,28/0,42; 0,42/0,70,..., 4,76/7,70.

In working with probes and comparative tests have identified the following benefits of the proposed probes:

the set of probes is formalized, standardized;

the coefficients of the probes vary linearly and the same lengths of the probes (equal to AO, where O is the midpoint of the segment MN) differ significantly, which allows to increase sensitivity by 30 - 40%;

- the same depth of research was achieved with the smaller sizes of the probe and accordingly, when magnemite 7, 8.

The device operates as follows.

The acoustic signal from the transducer 6 affects the well wall, and the reflected signals are received by the receivers 7, 8. The analog signal output from the receiver is fed to a corresponding digital processing unit (not shown).

The number of receivers in the device depends on the processing algorithm and the methods of measurement and can be more than two. But in any case, the distance L1selected from a number (1). For example, in this example, the value of L1and L2, L1and L3or L2and L3when G = 1 can take any of the following pairs of values: 1, 2; 2, 3; 3, 5; 5, 8; 5, 13; 13, 21; 8, 21 and so on, If the number of receivers is more than two, it is advisable, but not necessarily counting distances lead from one point, for example, the location of the emitter 2.

The choice of the basis of the number is based on the results of measurement of parameters of layers with known properties of the conditions for obtaining maximum sensitivity of the device.

The kit may include multiple sets of devices, with each set of distances is selected taking into account its Foundation G, and G1selected from a range with a basis of G1.

You umacze any receivers, in particular, the same type or of different types (directional and omnidirectional).

The tests showed that the choice of distance in accordance with equation (1) provides the alignment of the probe with the studied geological structure and processing unit. The result provides the highest sensitivity and noise immunity of the devices increases the reproducibility and reliability of the results. In addition, unifies devices with different base, it is possible to interpret the research results.

1. Geophysical probe containing at least one stimulating and two measuring elements, characterized in that the distance between the measuring elements and exciting and blizhayshim to him measuring element are members of a number of

Lr= Lr-1+ Lr-2,

where r = 3,4...; L1= G; L2= 2G (where G is the base number).

2. The probe p. 1, wherein selecting distances use the adjacent members of the series.

3. Set of geophysical probes, each of which contains at least one stimulating and two izmeritelnaya measuring element are members of a number of

Lr= Lr-1+ Lr-2,

where r = 3,4...; L1= G; L2= 2G (where G is the base number).

4. Kit p. 3, characterized in that the choice of distances using the adjacent members of the series.

 

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