RU2789613C1 - Integrated equipment for pulse multimethod neutron logging for production and geophysical investigations of cased gas and oil and gas wells - Google Patents

Abstract

FIELD: geophysical studies.

SUBSTANCE: invention relates to the field of geophysical studies of cased gas and oil and gas wells using field geophysical methods (FGM) to control the development of oil and gas fields and provides studies through tubing. The FGM complex, supplemented by the methods for induction resistivity and dielectric moisture logging, makes it possible to determine in detail the composition of the fluid coming from the perforation interval and its distribution along the wellbore or tubing. The complex equipment consists of two downhole modules connected to each other, while in the body of the upper module there are FGM tools, probes for spectrometric gamma ray logging and scanning magnetic-pulse flaw detection, and in the body of the lower module there are large and small probes with detectors of neutron-neutron logging, a pulsed spectrometric neutron gamma ray probe and a neutron source.

EFFECT: invention allows expanding the range of tasks to be solved at all stages of the life of gas and oil and gas wells based on the use of the main types of interaction of neutrons with rock and fluids saturating it in the process of irradiating them with neutron fluxes from a controlled neutron generator operating both in pulsed and stationary modes, with the ability to switch the mode through the program interface for recording measurement data.

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Description

The invention relates to the field of complex geophysical surveys of cased gas and oil and gas wells using field geophysical methods in monitoring the development of oil and gas fields and, in particular, provides surveys through tubing.

Known complex equipment for the study of cased gas and oil and gas wells, containing a set of neutron-neutron logging probes, which use radionuclide (chemical) neutron sources (US Pat. RF No. 2672783, 2680102), and complex equipment of a similar purpose, which uses controlled generators neutrons (RF patent No. 2672782). With the help of this equipment, all types of interaction of neutrons with the rock and fluids saturating it are recorded.

A disadvantage of the known devices is the lack of control over the physical properties of the fluids filling the cased wellbore, as well as the control of the state of the metal lining, including tubing, and the presence of design features in them. The lack of control over behind-the-casing flows and the composition of the inflow from the perforation interval in the presence of the above disadvantages leads to significant errors in determining the nature of reservoir saturation, especially in the case of the use of radionuclide sources.

Known development of FSUE "VNIIA" them. N.L. Dukhova: AINK-43-600 two-probe pulsed neutron logging equipment (A.G. Amursky, Yu.N. Barmakov, E.P. Bogolyubov et al. Improving the information content of pulsed neutron-neutron logging when measuring rock porosity.//NTV " Karotazhnik", No. 302, 2019), which allows to implement two-probe pulsed neutron-neutron logging by thermal neutrons (2INNKt) 200-300 μs after the end of rock irradiation with a fast neutron flux by recording the time spectrum of thermal neutrons and two-probe neutron logging by epithermal neutrons (2INNKnt) by registering the neutron flux during irradiation of the rock with a flux of fast neutrons, followed by compensation for the miscalculation of pulses due to overloads of the measuring channels.

The equipment can operate in a pulsed mode of a neutron generator, which significantly expands the analytical capabilities of the equipment for calculating the geological characteristics of sections in cased gas and oil and gas wells, primarily reservoir porosity and their saturation nature. At the same time, the calculation of the porosity of rocks is carried out according to the 2INNKnt method, the results of which are not affected by the interaction of neutrons with chemical elements with anomalous absorbing neutron properties located in rocks and fluids saturating them, which makes it possible to more reliably identify gas-liquid and water-oil contacts, determine gas saturation coefficients, oil saturation and volumetric values of gas and oil saturation in the wellbore part of the reservoir. When operating an expensive generator in a pulsed mode, the generator resource is limited to 300-500 hours of operation, and when operating in a stationary mode, the resource increases by 2-2.5 times, therefore, based on economic considerations, it is advisable to conduct research in a pulsed generator mode in developed deposits hydrocarbons using advanced analytical capabilities of a complex of pulsed neutron methods. In the interval of the productive stratum or in the promising intervals of accumulation of hydrocarbon fluids, it is advisable to conduct studies with a generator operating in a stationary mode.

Known complex spectrometric equipment for nuclear logging (KSPRK-Sh-48), including a probe containing a detector of natural radioactivity (SGK) and gamma radiation detectors of radiation capture (SNGC), and a probe containing thermal neutron detectors (NNKt). These probes have a common neutron source, while the natural radioactivity detectors (NGK) and radiation capture gamma-ray detectors (NGNK) are deployed from the thermal neutron detectors (NNKt) in different directions along the instrument axis relative to the specified source, in addition, the protective casings of these probes connected to the holder of the neutron source (pat. No. 127487, applied on 12/04/2012, published on 04/27/13).

A well-known complex instrument for determining the condition of casing strings, tubing and annular space - OTSK-OSZP, made on the basis of KSPRK-Sh-48, and containing the same type of neutron logging probes based on radionuclide neutron sources, providing the following research methods: three-probe spectrometric neutron wide-range gamma-ray logging (ZSNNK-Sh) and two-probe neutron-neutron logging on thermal neutrons (2NNKt), as well as a set of technical tools for field geophysical research (PLT).

The PLT complex in the equipment is represented by the following methods: thermometry (TM), barometry (BM), natural gamma ray spectrometry (NGK). The OTSK-OSZP equipment additionally includes the method of scanning magnetic-pulse flaw detection (MID-S) (A.V. Kondrashov, A.O. Gabbasova, E.V. Sudnichnikova and others. Multi-method spectrometric equipment for nuclear neutron logging for gas well research. / Problems of resource provision of gas producing regions No. 3 (19), 2014). (Accepted as a prototype for the claimed device).

Structurally, the integrated device OTSK-OSZP consists of two modules that have the ability to work both independently and jointly.

The upper downhole tool module (OTSK) consists of a SGK probe, a scanning magnetic-pulse flaw detection probe (MID-S), a thermometer and a pressure indicator.

The lower downhole tool module (OSZP) consists of two thermal neutron neutron logging probes (2NNKt) located below the sealed radionuclide source of fast neutrons (ZRnI), and three wide-range spectrometric neutron gamma ray logging probes (SNGK-Sh) located above ZRnI. During operation in wells, the device is centered by three centralizers.

The well-known device uses a stationary sealed radionuclide source of fast neutrons (SRnI), which is unable to operate in a pulsed mode, which limits the analytical capabilities of neutron methods for determining the saturation of reservoirs based on the processes of absorption of thermal neutrons and gamma radiation of radiative capture of thermal neutrons elements that are part of the fluids, or the phase state of the hydrocarbon fluid that saturates the pore space of the reservoir. In addition, a high radiation hazard remains when working with SRnI.

The device does not fully implement the PLT complex, in particular, there are no tools for induction resistivity and dielectric moisture metering.

The technical result achieved by the claimed invention is the expansion of the range of tasks to be solved at all stages of the life of gas and oil and gas wells based on the use of almost all the main types of interaction of neutrons with rock and fluids saturating it in the process of irradiating them with neutron fluxes from a controlled neutron generator operating as in a pulsed , and in stationary modes with the possibility of switching the mode through the program interface for recording measurement data related to the processes of neutron moderation, absorption of thermal neutrons, gamma-activity of chemical elements during the moderation of fast neutrons and absorption of thermal neutrons.

The use of an extended logging suite, supplemented by induction resistivity and dielectric moisture metering methods, makes it possible to determine in detail the composition of the fluid coming from the perforation interval and its distribution along the wellbore or tubing.

This problem is solved by the fact that the complex equipment for pulsed multi-method neutron logging (KAIMNK) for field geophysical studies of cased gas and oil and gas wells, consisting of two well modules connected to each other, the bodies of which are equipped with centralizers, while in the body of the upper module there are means for carrying out geophysical surveys (PLT), including temperature and pressure indicators, probes of spectrometric gamma ray logging (SGK) and scanning magnetic pulse flaw detection (MID-S), and large (BZ) and small (MZ) probes are placed in the body of the lower module with detectors of neutron-neutron logging, a pulsed spectrometric neutron gamma-ray logging probe (INGK-S) and a neutron source, in contrast to the known one, in the equipment, a controlled neutron generator is used as a neutron source, operating both in pulsed and in stationary modes with the ability to switch modes through installed a program interface for recording measurement data in a ground-based computer, while the INGK-S probe (SONGK in stationary mode) is located between the BZ and MZ probes of pulsed neutron-neutron logging (neutron-neutron logging in stationary mode), all probes INGK-S / SNGK, BZ and MZ are installed on one side of the neutron source, and the tools for field geophysical research (PLT) include indicators of induction resistivity (IR) and dielectric moisture metering (DM).

The centralizers of the two-module tool are made with a mechanism for forced opening of the centering levers in the well, controlled from the surface via a logging cable.

A chemical neutron source can be used as a neutron source.

In addition, the insert, which is installed in the housing of the neutron-neutron logging module and contains a tube with a neutron source, is made removable, with the possibility of its replacement.

The attached figure shows a schematic diagram of the design of the complex apparatus for pulsed multi-method neutron logging (KAIMNK).

In the attached figure, the neutron-neutron logging probes are designated as MZ INNK and BZ INNK probes operating in the pulse mode of the neutron generator (MZ NNK and BZ NNK in stationary mode), and the spectrometric neutron gamma-ray logging probe is designated as INGK-S (spectrometric neutron probe). gamma-ray logging of SNGK in stationary mode). This version of the designation was adopted in view of the fact that the main and most informative measurement takes place when the neutron generator is operating in a pulsed mode.

KAIMNK is a two-module design and includes a lower module of pulsed-stationary neutron logging (MISNK), enclosed in a housing 1, in which are located: a neutron source, in particular, a controlled neutron generator 2, operating both in pulsed and stationary modes with the ability to switch modes through the interface of the program for recording measurement data installed in the ground computer 3, two neutron neutron logging probes, including a small pulsed neutron logging probe MZ INNK (small neutron logging probe MZ NNK in stationary mode) 4 and a large probe neutron logging BZ INNK (large neutron logging probe BZ NNK in stationary mode) 5, and spectrometric pulsed neutron gamma ray logging probe INGK-S (spectrometric neutron gamma logging probe in stationary mode - SNGK) 6, located between MZ 4 and BZ 5.

A chemical neutron source can be used as a neutron source.

The insert 7 installed in the body 1 of the device, containing the tube with the neutron source 2, is made removable, with the possibility of its replacement.

In the building 8 of the upper module KAIMNK there are: a spectrometric gamma ray logging probe (SGK) 9, tools for field geophysical research (PLT): detectors (indicators) for thermometry (TP) - thermometer 10, barometry (BR) - pressure gauge 11, induction resistivity (IR) - resistivity meter 12, dielectric moisture meter (VM) - moisture meter 13, as well as the probe of scanning magnetic-pulse flaw detection (MID-S) 14. Cases 1 and 8 of the modules are interconnected by a threaded connection through a centralizer 15 and equipped with an upper centralizer 16 and the lower centralizer 17, and are also connected by a logging cable 18 to the computer 3 of the logging station (not shown in the figure). Centralizers 15,16,17 of the tool are made with a mechanism for forced opening of the centering levers in the well, controlled from the surface via a wireline 18. The drive for the forced opening of the centering levers can be made of an electromechanical or electrohydraulic type with a well-known operating principle.

In the process of studying cased gas and oil and gas wells during the rise of KAIMNK, using the pulsed mode of operation of the neutron generator 2, the main complex of pulsed neutron-neutron logging (PNL) is implemented, which includes the following methods:

2INNKt - two-probe pulsed neutron-neutron logging on thermal neutrons,

2INNKnt - two-probe pulsed neutron-neutron logging on epithermal neutrons,

INGK - integrated impulse neutron gamma ray logging,

INGK-S - spectrometric pulsed neutron gamma-ray logging.

In the stationary mode of operation of the neutron generator 2, a complex of multi-method multi-probe neutron logging (MMNC) is implemented, which includes the following methods:

2NNKt - two-probe stationary neutron-neutron logging on thermal neutrons,

NGK - stationary neutron gamma-ray logging,

SNGK - spectrometric stationary neutron gamma-ray logging. The upper module 7 of the PLT complex equipment provides the implementation of the following methods:

SGK - spectrometric gamma ray logging,

TP - thermometry,

BR - barometry,

IR - induction resistivity,

VM - dielectric moisture measurement,

MID-S - scanning magnetic-pulse flaw detection.

The implementation of the neutron methods INNK or MMNK is based on irradiating the well and rocks with neutrons from a controlled neutron generator 2, for example, ING-08, and measuring the density of neutron fluxes distributed in space and time, coming from the side of the well, by probe detectors 4 and 5, and the flux gamma radiation of inelastic scattering (GINR) and radiative capture (GIRZ) with registration of its spectral distribution by the energy of gamma rays by the detector of the spectrometric pulsed neutron gamma ray logging probe (INGK-S) 6.

In the pulse mode of operation of the generator 2, additionally, based on the results of processing the temporal spectral neutron flux during irradiation of the rock with a flux of fast neutrons on large and small probes 4 and 5, the intensities of epithermal neutron fluxes BZ INNKnt and MZ INNKnt (2INNKnt) are determined with compensation for the miscalculation of pulses due to an overabundance of data on the measuring channel.

At time delays of more than 200-300 μs, the intensities of thermal neutron fluxes are determined, and the thermal neutron lifetime or damping decrement is determined from the decay of neutron flux intensities with time.

Produce simultaneous registration of the distribution of neutron gamma radiation (INGK) and the energy distribution of gamma radiation of radiative capture of thermal neutrons (INGK-S).

According to the results of processing the readings of INGK, the intensity of the flux of GIRS and GINR and the lifetime of thermal neutrons are determined, and when processing the readings of INGK-S, the content of radiation-active chemical elements is determined by the spectral distribution of GIRS (H, Na, Al, Si, S, Cl, K, Ca, Fe, Mg, Ti), which serve as the basis for the lithological subdivision of the section and the C / O ratio according to the GINR spectral distribution, which serves as the basis for estimating the oil saturation factor.

When the neutron generator 2 is operating in the stationary mode, the probes 4, 5, and 6 provide the implementation of the 2NNKt, NGK, and SNGK methods.

PLT complex provides the implementation of the following methods: SGK - spectrometric gamma ray logging, TP - thermometry, BR - barometry, IR - induction resistivity logging, VM - dielectric moisture logging and MID-S - scanning magnetic pulse flaw detection.

Based on the results of the SGC, the measurement results are linked to the geological section of the well and the content of clay material in the rocks is assessed with an assessment of the lithology of clays for the subsequent introduction of corrections from the effect of clay content on the results of the interpretation of neutron methods, as well as an assessment of the zones of radio-geochemical anomalies (RGCA), which make it possible to predict flooding of productive deposits containing mobile hydrocarbons.

According to the BR data, the energy of the reservoir reservoir opened by the perforation is determined and the possibility of the accumulation of dissolved gas in the oil and gas deposit is predicted when the reservoir pressure drops below the saturation pressure of oil with gas, and thus the phase composition of hydrocarbons is assessed. It should be noted that the interpretation of neutron methods without taking into account the phase state of hydrocarbons in the reservoir is not very informative.

According to the MFA-S, the condition of the metal lining of the well and the features of its design, including the tubing, are assessed. The metal lining of the well and the features of the structural elements are manifested through the iron content, which has a significant impact on the readings of neutron methods, especially when measured in the stationary mode of the neutron generator, and are characterized by an underestimation of the calculated parameters of saturation of the reservoir with hydrocarbon fluids with an increase in the iron content in the structural elements of the well.

According to the IR data, the composition of the fluid along the wellbore or tubing is estimated, which must be taken into account when interpreting neutron methods when measuring in the stationary mode of the neutron generator.

Based on the results of the VM, the content of hydrocarbon fluids in the liquid filling the wellbore or tubing is estimated, which must be taken into account when interpreting neutron methods when measuring in the stationary mode of the neutron generator, especially if there is free gas in the liquid.

According to the TP data, behind-the-casing flows of formation fluids are controlled, which, in combination with neutron methods, makes it possible to increase the reliability of the interpretation of the latter.

Optimal geological and technical conditions for the effective use of the INP complex to determine reservoir porosity (Kp), geological parameters of reservoir saturation with hydrocarbon fluids - oil and gas saturation coefficients (Kn, Kg) and their volumetric values (Kp * Kn, Kp * Kg), as well as lithological subdivision of the section are:

- for the complex 2INNKnt+INGK-S - reservoirs with any porosity and low salinity of formation waters (Cpl) and flushing fluid (Spzh), including when filling the wellbore with gas in gas, oil and gas and oil wells;

- for the complex 2INNKt + INGK-S - reservoirs with any porosity, but with high Cpl and Cf values, including when gas filling the wellbore in gas, oil and gas and oil wells;

- for the 2INNKt complex - reservoirs with medium and high porosity with a consistent mineral composition of rocks in gas and oil and gas wells with high Cpl and Spzh values.

To solve the geological problems of determining the porosity of the reservoir and assessing its saturation in the MMNK complex, the optimal geological and technical conditions for use are reservoirs with medium and high porosity and with any values of Cpl and Cv, including gas filling of the wellbore with low wellbore trickiness in gas, oil and gas and oil wells.

The PLT complex is recorded simultaneously with the INNK or MMNK complexes to improve the reliability of the geological interpretation of neutron method complexes and solve geological and technical and geological and field problems associated with the operation of gas and oil and gas wells.

During the operation of the KAIMNK equipment, physical field sensors of the geophysical methods used are used to convert physical fields into electrical signals of probe detectors 4, 5, 6, which, after amplification and digitization, are transmitted via logging cable 18 to the recorder and then to computer 3 of the logging station.

During the study, the KAIMNK modules are reliably centered inside the well by the forced opening levers of the centralizers 15, 16, 17, which can significantly reduce the influence of the uncertainty of the position of the tool inside the string or tubing, which is a difficult to take into account interference when recording the data of ongoing complex measurements. In addition, during the descent of the KAIMNK inside the string, the levers of the centralizers are in the folded state, which greatly facilitates the passage of the tool, especially in the tubing.

Claims (4)

1. Complex equipment for pulsed multi-method neutron logging for field logging of cased gas and oil and gas wells, consisting of two well modules connected to each other, the bodies of which are equipped with centralizers, while in the body of the upper module there are tools for conducting field logging - PLT, including indicators of thermometry (TP), barometry (BR), probes of spectrometric gamma ray logging (SGK) and scanning magnetic pulse flaw detection (MID-S), and in the case of the lower module there are large (BZ) and small (MZ) probes with detectors neutrons, a probe of pulsed spectrometric neutron gamma-ray logging (INGK-S) and a tube with a neutron source, characterized in that the equipment uses a controlled neutron generator as a neutron source, operating both in pulsed and in stationary modes, with the ability to switch modes through the prog interface installed in the ground computer frames for recording measurement data, while the INGK-S probe is placed between the BZ and MZ probes, all the INGK-S, BZ and MZ probes are installed on one side of the neutron source, and the PLT tools include induction resistivity (IR) indicators and dielectric moisture measurement (VM). 2. Complex equipment for pulsed multi-method neutron logging for field logging of cased gas and oil and gas wells according to claim 1, characterized in that the centralizers are made with a mechanism for forced opening of the centering levers in the well, controlled from the surface via a logging cable. 3. Complex equipment for pulsed multi-method neutron logging for field geophysical studies of cased gas and oil and gas wells according to claim 1, characterized in that a chemical neutron source is used as a neutron source. 4. Complex equipment for pulsed multi-method neutron logging for field geophysical studies of cased gas and oil and gas wells according to claim 1, characterized in that the tube with a neutron source is placed in an insert installed in the instrument housing, which is removable, with the possibility of its replacement.

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