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, nAlso 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 onConducted 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.
FIELD: geophysical prospecting by electric means by the method of induced polarization.
SUBSTANCE: the device has an exciting field forming unit and a signal measurement unit. The exciting field forming unit has a ship generator, switch forming bipolar DC square pulses, generating plant and a ballast device. The signal measurement unit has a receiving multi-electrode line, resistivimeter, multi-channel measuring device, ship echo sounder, Global Position System receiving indicator and a signal processor. According to the claimed method, the research of the geological medium along the observation outline is carried out by excitation of periodic alternating current pulses and determination of geoelectric medium parameters, geoelectric sections are constructed, a conclusion is made on the presence of a deposit of hydrocarbons according to the exposed anomalies of conduction and the parameters of induced polarization.
EFFECT: enhanced reliability of the research results.
8 cl, 5 dwg
FIELD: physics; geophysics.
SUBSTANCE: current pulse is excited in the medium under investigation, and parameters of its induced polarisation are defined. Geoelectric section is generated to make a conclusion about the presence of hydrocarbon fields on the basis of abnormal manifestations of induced polarisation parameters. At that, electromagnetic and seismic waves are excited simultaneously or with a time shift. To excite the said waves unipolar rectangular impulses of direct current are generated, their absolute and relative duration depending on parameters of medium under investigation. In the beginning of timing pulse electric field is measured simultaneously at measuring probe groups of two detector lines towed at different depth. Besides, detector line depth and hydroacoustic pressure of seismic source are measured. Also a device is offered, which includes pulse generator, capacitor charging unit, power generator, bank of capacitors, switchboard, seismic emitter, transmitter/receiver line, receiver line, multi-channel gauge, echo-sounder, GPS satellite navigation receiver, signal processor.
EFFECT: higher reliability of research results.
18 cl, 6 dwg
FIELD: geoelectrical prospecting.
SUBSTANCE: invention relates to geoelectrical prospecting by the electrical resistance method. The method uses two fixed supplying grounding circuits, the first of them being located in practical infinity, the other one along with two fixed reception grounding circuits being arranged nearby the observation profile, two additional movable grounding circuits located at equal distance from the second supplying grounding circuit. In measurements, in every position of the movable grounding circuits, the latter are connected in turns to a power source or an instrument. On connecting them to the power source, a voltage drop between the fixed reception grounding circuits is measured. On connecting them to instrument and measuring the voltage drop between them, the fixed supplying grounding circuits are connected to electric power source. The aforesaid operations are effected for all preset positions of the movable grounding circuits. Proceeding the measurement results, sections of apparent electrical resistance and voltage drop are plotted to estimate the availability of geoelectrical irregularities in the section.
EFFECT: higher efficiency of revealing geoelectrical irregularities and lower ambiguity in experimental data interpretation.
SUBSTANCE: current is cutoff to soil through two point sources. The first source is placed close by vertical interface, and the second is taken to infinity. Position of one equipotential line of electric field is detected. Measuring electrodes is mounted by tangent to equipotential line symmetrically to tangency point of ray lined from auxiliary point presenting mirror reflection of point source relative to interface with specified equipotential. Besides, measuring electrodes can be placed by line, perpendicular to interface symmetrically to power supply provided close by interface. Near to interface there is compensatory point source with current value fixed by parity where I0, Ik are currents from the first and compensatory sources, ΔΨ1MN is differential of the space function that determinates position of measuring electrodes relative to the first source, ΔΨ2MN is differential of space function that determinates position of measuring electrodes relative to compensatory source. Measuring electrodes voltage indicates time variations of resistivity.
EFFECT: simplified positioning of electrical survey unit and improved measurement accuracy.
SUBSTANCE: at the profile points the current is supplied through a pair of feeding electrodes to the earth. Current value and potential difference between pair of receiving electrodes is measured. Feeding electrodes are moved with pitch equal to 1 m symmetrically relative to the centre to limit distance between feeding electrodes, which is determined by the specified investigation depth. As per measurement results the apparent specific resistance is calculated. As per data of apparent specific resistance the graph of its behaviour is built depending on half-spacings of feeding electrodes. Specific resistances of frozen beds are calculated as per apparent specific resistance graph. Percentage of clay in unit volume of rock is calculated as per data of specific resistances of frozen beds by the following formula: where ρclay - specific clay resistance, which in permafrost zone section is characterised as constant value which on average is equal to 100 ohm m, ρfb -specific resistance of frozen bed. Lithologic composition of sand-clay complex of frozen rocks is determined as per clay content.
EFFECT: reducing the cost of operations and improving informativity owing to determining lithologic composition of frozen rocks without any drilling data and using common data on geologic structure of investigation region.
1 tbl, 2 dwg
SUBSTANCE: potentially dangerous area is selected on territory to be analysed. At least three measuring modules are arranged on said area. Every said module consists of radiating electrode, main electrode pair with its one electrode making zero electrode, and at least one additional electrode pair. Said electrode pairs of measuring electrode are arranged at 180°/n to each other where n stands for number of electrode pair. All electrodes are located on one equipotentional line of radiating electrode. Electrodes of one pair are arranged on one line with radiating electrode. Directional diagrams of electrode pairs are plotted. Potential difference is measured between zero electrode and main electrode pair, and other electrodes of appropriate measuring module. Abnormal potential difference and direction diagram are used to determine direction for each measuring module to zone of rocks irregularities. Zone location is defined at intersection of said directions.
EFFECT: higher accuracy and validity.
SUBSTANCE: at an observation line, two three-electrode electrical soundings are performed using an apparatus comprising four earthing contacts lying on one line symmetrically about the observation point. The fifth earthing contact relates to virtual "infinity" and is connected to one terminal of an electric current source. Central earthing contacts are connected to a voltage measuring device. When taking measurements, outermost power earthing contacts are successively connected to the other terminal of the electric current source. Potential drop Δ UAMN and ΔUA'MN between receiving earthing contacts is measured. The operations are repeated for all given positions of power earthing contacts. Potential drop for vertical electrical sounding and potential drop for unipolar sounding is calculated from the measured potential drop at each observation point for given differences. The distribution of apparent electrical resistance in sections for two three-electrode and vertical sounding and distribution in section of potential drop for unipolar sounding is determined from the measured and calculated potential drops. The results determine the presence and location in the section of geological irregularities.
EFFECT: high efficiency of detecting geological irregularities in the geological environment.
1 tbl, 1 dwg
FIELD: oil and gas industry.
SUBSTANCE: complex instrument includes loaded drilling pipe that consists of the first and the second part separated by isolated gap, and distant-measuring cartridge containing distant measuring scheme that includes power source generating voltage drop at isolated gap, and axle current at drilling column that is returned through geologic bed, it also includes isolated measuring electrode connected to the first part and scheme for specific resistance measuring connected in the course of operation to measuring electrode and distant-measuring scheme.
EFFECT: integration of possibilities to measure specific resistance into electro-magnetic distant-measuring instrument and obtaining the data of specific resistance as well as distant measuring.
58 cl, 11 dwg
SUBSTANCE: disclosed is a system for monitoring local surface earthquake precursors on a secure territory, having two supply earth terminals connected to a probe current pulse generator, and a system of receiving earth terminals connected to a receiver which is connected to a signal processing unit. The system of receiving earth terminals is formed by N buried electrodes, N-1 of which are arranged uniformly on a circle of diameter D=0.5-0.6 km, and one central electrode placed at the centre of said circle. Radial conductors are connected each of the N-1 electrodes of the system of receiving earth terminals. Electrodes of the supply earth terminals are spaced apart by a distance L=(15-20)D. The system of receiving earth terminals is directed in the plan randomly relative electrodes of the supply earth terminals and lies from the latter at a distance X=(1.5-1.6)L. The probe current pulse generator generates current pulse bursts with frequency of 0.02-0.2 Hz, burst duration of 10-30 s and current in the pulse of 1-10 KA at least twice a day at the same time of the day.
EFFECT: high reliability of information on the hypocentre of an imminent surface earthquake and its parameters, particularly the event time and amplitude estimate.
5 cl, 3 dwg
FIELD: measurement equipment.
SUBSTANCE: device comprises a dielectric body of streamlined shape with installed metering electrodes, a metering unit comprising amplifiers, to inputs of which electrodes are connected, a summator, inputs of which are connected with outputs of amplifiers, and also an additional electrode, at the same time metering electrodes are made in the form of wires with insulated side surface, assembled into a cord or bundle with a polished end, the minimum distance between which and the additional electrode exceeds the size of the turbulence zone, the number of amplifiers is equal to the number of metering electrodes, every of which is connected to the input of the appropriate amplifier, and the additional electrode is connected with the common bus of the metering unit. The additional electrode is made in the form of a hollow metal cylinder installed on the dielectric body, the surface area of which is ten times and more exceeds the total area of the end surface of metering electrodes, at the same time the cord of wires, in the form of which metering electrodes are arranged, is installed inside the second electrode so that its end protrudes beyond the edge of the additional electrode.
EFFECT: increased resolving capacity and increased accuracy of measurement of small-scale fluctuations of flow speed.
2 cl, 2 dwg