Two-dimensional nuclear magnetic resonance logging fluid saturation calculation method and system

Abstract

The invention belongs to the technical field of shale oil exploration and development, and particularly relates to a two-dimensional nuclear magnetic resonance logging fluid saturation calculation method and system. The calculation method comprises the following steps: acquiring attribute data of a reservoir; determining lithology sensitive parameters and shale indexes of the reservoir according to the attribute data; determining a reservoir type according to the attribute data, the lithology sensitive parameters and the shale index; determining a fluid identification model of the reservoir according to the reservoir type and the nuclear magnetic resonance response characteristics; and calculating the fluid saturation of the reservoir by using the fluid identification model. When reservoir fluid identification and fluid saturation quantitative calculation are carried out, multiple reference indexes are referred to at the same time, then the reservoir fluid saturation of the reservoir can be accurately calculated, and the identification accuracy is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of shale oil exploration and development, and in particular relates to a two-dimensional nuclear magnetic resonance logging fluid saturation calculation method and system. Background Art

[0002] The diverse and widely distributed continental lacustrine mixed-accumulation shale oil reservoirs have complex diagenetic minerals, diverse pore types, and the development of both organic and inorganic pores. The fluid occurrence state is complex, which brings challenges to the quantitative evaluation of shale oil content. The reservoir lithology is complex, with both terrigenous clastic minerals and carbonate minerals. The co-development of organic pores and inorganic pores leads to different lithology, total organic carbon content, fluid occurrence state, and fluid properties in strata with little difference in depth. Therefore, it is necessary to classify the source and reservoir types, and then determine the fluid occurrence state of different source and reservoir configuration relationships, and then conduct oil content evaluation.

[0003] At present, there are two major methods for evaluating shale oil fluid saturation at home and abroad: ① T2 cutoff value method: determine the bound fluid saturation and movable fluid saturation through core experiments, centrifugation or displacement, determine the cutoff value, and evaluate the movable fluid saturation; ② Domain analysis method: based on the pore structure of the reservoir and the properties of crude oil, based on experimental data, by segmenting the T1-T2 spectrum, various fluid component information is obtained, and the T2 cutoff value of the movable oil distribution in one-dimensional nuclear magnetic resonance logging and the distribution domain of different components of fluid in two-dimensional T1-T2 nuclear magnetic resonance logging are determined; ③ Blind source separation algorithm based on cluster analysis: a method for quantitative fluid evaluation using cluster analysis and non-negative matrix factorization (NMF), while analyzing all 2DT1-T2 maps in the well to identify the fluid nuclear magnetic resonance characteristics and volume, studying the relationship between fluid characteristics and fluid type, pore system, etc., and dividing and classifying the areas on the two-dimensional spectrum to separate the fluid components. However, these evaluation methods still have certain limitations and do not take into account the impact of siliceous minerals such as dolomite, calcite, quartz, and feldspar in the sand bodies of shale reservoirs on the oil content of the reservoir. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for calculating fluid saturation in two-dimensional nuclear magnetic resonance logging, the calculation method comprising:

[0005] Obtaining reservoir attribute data;

[0006] Determine the lithology sensitivity parameter and shale index of the reservoir according to the attribute data;

[0007] Determine the reservoir type based on the attribute data, lithology sensitivity parameters and shale index;

[0008] Determine a fluid identification model for the reservoir according to the reservoir type and nuclear magnetic resonance response characteristics;

[0009] The fluid saturation of the reservoir is calculated using the fluid identification model.

[0010] Preferably, the attribute data include: total organic carbon content of the reservoir, mineral composition and content of the reservoir, neutron porosity, mud content, total nuclear magnetic resonance porosity of the reservoir, main distribution range of different fluids in one-dimensional T2 and two-dimensional T1-T2 nuclear magnetic resonance spectra, T1 / T2 and weight coefficients of different component fluid signals in the total signal.

[0011] Preferably, the obtaining of reservoir attribute data comprises: measuring the reservoir using a nuclear magnetic resonance logging instrument to collect the nuclear magnetic resonance total porosity of the reservoir.

[0012] Preferably, the step of acquiring reservoir attribute data further comprises:

[0013] Collect shale cores from the reservoir and perform nuclear magnetic resonance tests on the collected shale cores to obtain one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, as well as the main distribution range and T1 / T2 of different component fluids on the nuclear magnetic resonance T1-T2 spectrum;

[0014] Cluster analysis and non-negative matrix decomposition are used to normalize the two-dimensional nuclear magnetic logging data, and the weight coefficients of the signals of different components of fluids in the total signal are calculated, wherein the weight coefficients of the signals of different components of fluids in the total signal are the weight coefficients of the signals of different components of fluids in different states in the long relaxation and short relaxation intervals in the total signal.

[0015] Preferably, the state includes: an original-like state and an original-like saturated state.

[0016] Preferably, the calculation formula of the lithology sensitive parameter is:

[0017] Among them, MI is the lithology sensitive parameter, w quarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively.

[0018] Preferably, the calculation formula of the mud index is: SI = Por CNL -Por NMR ;

[0019] Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

[0020] Preferably, determining the reservoir type of a reservoir according to the attribute data, lithology sensitivity parameters and shale index includes:

[0021] If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the total organic carbon content is greater than the fourth threshold value, then the reservoir type of the reservoir is determined to be organic-rich shale;

[0022] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the total organic carbon content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale;

[0023] If the mud index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the total organic carbon content is between the third threshold and the fourth threshold, the reservoir type of the reservoir is determined to be transitional shale.

[0024] Preferably, the fluid saturation of the reservoir is calculated using the fluid identification model, and the calculation formula is as follows:

[0025]

[0026]

[0027]

[0028]

[0029] In the formula, S mo , S io , S cbw , S bitumen They are movable oil saturation, adsorbed oil saturation, bound water saturation, and asphalt saturation; They are movable oil porosity, adsorbed oil porosity, bound water porosity, and asphalt porosity; is the total porosity of NMR logging; the units of saturation and porosity are both %.

[0030] The present invention also proposes a two-dimensional nuclear magnetic resonance logging fluid saturation calculation system, the calculation system comprising: an acquisition module, a determination module, a model building module and a calculation module;

[0031] The acquisition module is used to acquire reservoir attribute data;

[0032] The determination module includes a first determination unit and a second determination unit, the first determination unit is used to determine the lithology sensitivity parameter and the shale index of the reservoir according to the attribute data, and the second determination unit is used to determine the reservoir type of the reservoir according to the attribute data, the lithology sensitivity parameter and the shale index;

[0033] The model building module is used to determine a reservoir fluid identification model according to the reservoir type and nuclear magnetic resonance response characteristics;

[0034] The calculation module is used to calculate the fluid saturation of the reservoir using the fluid identification model.

[0035] Preferably, the acquisition module is used to acquire the attribute data of the reservoir, including: measuring the reservoir with a nuclear magnetic resonance logging instrument to collect the nuclear magnetic resonance total porosity of the reservoir.

[0036] Preferably, the acquisition module is used to acquire reservoir attribute data, and further includes:

[0037] The acquisition module collects shale cores from the reservoir, performs nuclear magnetic resonance testing on the collected shale cores, and obtains one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, as well as the main distribution range and T1 / T2 of different component fluids on the nuclear magnetic resonance T1-T2 spectrum;

[0038] The acquisition module uses cluster analysis and non-negative matrix decomposition to normalize the two-dimensional nuclear magnetic logging data, and calculates the weight coefficients of the fluid signals of different components in the total signal, wherein the weight coefficients of the fluid signals of different components in the total signal are the weight coefficients of the fluid signals of different components of the fluid in different states in the long relaxation and short relaxation intervals in the total signal.

[0039] Preferably, the calculation formula of the lithology sensitive parameter is:

[0040] Among them, MI is the lithology sensitive parameter, w quarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively.

[0041] Preferably, the calculation formula of the mud index is: SI = Por CNL -Por NMR ;

[0042] Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

[0043] Preferably, the second determination unit is used to determine the reservoir type of the reservoir according to the attribute data, lithology sensitivity parameter and shale index, including:

[0044] If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the total organic carbon content is greater than the fourth threshold value, then the reservoir type of the reservoir is determined to be organic-rich shale;

[0045] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the total organic carbon content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale;

[0046] If the mud index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the total organic carbon content is between the third threshold and the fourth threshold, the reservoir type of the reservoir is determined to be transitional shale.

[0047] Preferably, the calculation module is used to calculate the fluid saturation of the reservoir using the fluid identification model, and the calculation formula is as follows:

[0048]

[0049]

[0050]

[0051]

[0052] In the formula, S mo , S io , S cbw , S bitumen They are movable oil saturation, adsorbed oil saturation, bound water saturation, and asphalt saturation; They are movable oil porosity, adsorbed oil porosity, bound water porosity, and asphalt porosity; is the total porosity of NMR logging; the units of saturation and porosity are both %.

[0053] The present invention also provides an electronic device, comprising:

[0054] Processor and memory;

[0055] The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method according to any one of the above items.

[0056] The present invention also provides a computer-readable storage medium.

[0057] The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is enabled to execute any one of the above-mentioned two-dimensional nuclear magnetic resonance logging fluid saturation calculation methods.

[0058] The present invention has the following beneficial effects:

[0059] The present invention obtains the total organic carbon content, rock mineral composition and content, neutron porosity, nuclear magnetic resonance porosity, and nuclear magnetic resonance response characteristics (main peak value, spectrum morphology, relaxation time) of the reservoir; determines the lithology sensitive parameters of the reservoir according to the rock mineral composition and content of the reservoir, and determines the mud index of the reservoir according to the neutron porosity and nuclear magnetic resonance total porosity of the reservoir; determines the nuclear magnetic resonance response characteristics (main peak value, spectrum morphology, relaxation time) of the shale core obtained by a laboratory core analyzer, and determines the shale core in the nuclear magnetic resonance second The distribution interval and T1 / T2 on the two-dimensional T1-T2 spectrum, the fluid component type and the weight coefficient of the fluid signal of different components in the total signal; the reservoir type is determined according to the total organic carbon content, lithology sensitivity parameters and mud index of the reservoir; according to the reservoir type and the distribution interval and T1 / T2 of the shale core on the two-dimensional nuclear magnetic resonance T1-T2 spectrum, the fluid component type and the weight coefficient of the fluid signal of different components in the total signal, combined with cluster analysis and non-negative matrix decomposition, a reservoir shale oil two-dimensional nuclear magnetic resonance fluid identification model is established to quantitatively calculate the reservoir fluid saturation. Because this embodiment refers to multiple reference indicators at the same time when performing reservoir fluid identification and fluid saturation quantitative calculation, the reservoir fluid saturation of the reservoir can be accurately calculated, and the identification accuracy is high.

[0060] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 A diagram showing a method for calculating fluid saturation in two-dimensional nuclear magnetic resonance logging according to an embodiment of the present invention;

[0063] Figure 2 An analysis diagram showing the lithology sensitivity parameters and shale index of the reservoir in the embodiment of the present invention;

[0064] Figure 3 An analysis diagram showing the mud index and total organic carbon content of the reservoir in an embodiment of the present invention;

[0065] Figure 4 The organic-rich shale fluid identification chart in the embodiment of the present invention is shown;

[0066] Figure 5 The transitional shale fluid identification diagram in the embodiment of the present invention is shown;

[0067] Figure 6 The organic-poor shale fluid identification chart in the embodiment of the present invention is shown;

[0068] Figure 7 A schematic diagram of a process in an embodiment of the present invention is shown;

[0069] Figure 8 An application example diagram is shown in the embodiment of the present invention;

[0070] Fig. 9 An analysis diagram showing the movable oil saturation and average daily oil production calculated in an embodiment of the present invention;

[0071] Fig.10 A diagram showing a two-dimensional nuclear magnetic resonance well logging fluid saturation calculation system according to an embodiment of the present invention is shown;

[0072] Fig.11 A diagram showing an electronic computing device in an embodiment of the present invention. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] Different depths are located in different strata, different strata have different reservoirs, and different reservoirs have different total organic carbon contents, that is, the main lithology and fluid occurrence states of different reservoirs are different. It is necessary to identify the reservoir type, and then determine the fluid occurrence state and oil content of different reservoirs, so as to facilitate oil extraction. Reservoir fluid occurrence state characterization and oil content evaluation are one of the main contents of shale oil reservoir interpretation and evaluation.

[0075] like Figure 1 As shown, a two-dimensional nuclear magnetic resonance logging fluid saturation calculation method, the calculation method comprises the following steps:

[0076] S101. Obtaining reservoir attribute data;

[0077] The attribute data include: total organic carbon content of the reservoir, mineral composition and content of the reservoir, neutron porosity, mud content, total nuclear magnetic resonance porosity of the reservoir, main distribution range of different fluids in one-dimensional T2 and two-dimensional T1-T2 nuclear magnetic resonance spectra, T1 / T2 and weight coefficients of different component fluid signals in the total signal.

[0078] The method of obtaining the reservoir attribute data includes: measuring the reservoir using a nuclear magnetic resonance logging instrument to collect the nuclear magnetic resonance total porosity of the reservoir.

[0079] The obtaining of reservoir attribute data also includes:

[0080] Collect shale cores from the reservoir and perform nuclear magnetic resonance tests on the collected shale cores to obtain one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, as well as the main distribution range and T1 / T2 of different component fluids on the nuclear magnetic resonance T1-T2 spectrum;

[0081] Cluster analysis and non-negative matrix decomposition are used to normalize the two-dimensional nuclear magnetic logging data, and the weight coefficients of the signals of different components of fluids in the total signal are calculated, wherein the weight coefficients of the signals of different components of fluids in the total signal are the weight coefficients of the signals of different components of fluids in different states in the long relaxation and short relaxation intervals in the total signal.

[0082] The states include: an original-like state and an original-like saturated state.

[0083] S102. Determine the lithology sensitivity parameter and shale index of the reservoir according to the attribute data;

[0084] The calculation formula of the lithology sensitivity parameter is:

[0085] Among them, MI is the lithology sensitive parameter, w quarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively.

[0086] The calculation formula of the mud index is: SI = Por CNL -Por NMR ;

[0087] Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

[0088] S103. Determine the reservoir type according to the attribute data, lithology sensitivity parameters and shale index;

[0089] If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the TOC (total organic carbon) content is greater than the fourth threshold value, it is determined that the reservoir type of the reservoir is organic-rich shale;

[0090] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the TOC content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale;

[0091] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the TOC content is between the third threshold and the fourth threshold, then the reservoir type of the reservoir is determined to be transitional shale;

[0092] In this embodiment, the first threshold is 7, the second threshold is 1.65, the third threshold is 0.5%, and the fourth threshold is 1.0%.

[0093] S104. Determine a fluid identification model for the reservoir according to the reservoir type and nuclear magnetic resonance response characteristics;

[0094] The nuclear magnetic resonance response characteristics include main peak value, spectrum morphology and relaxation time.

[0095] S105. Calculate the fluid saturation of the reservoir using the fluid identification model.

[0096] In this embodiment, specifically, after the development is completed, each reservoir can be analyzed to identify the reservoir type and corresponding nuclear magnetic resonance characterization plate of each reservoir. When the reservoir type and fluid occurrence state of each reservoir are identified, the method provided in this embodiment can be executed for each reservoir.

[0097] For each reservoir, we first need to obtain the total organic carbon content, lithology sensitivity parameters and mud index of the reservoir, the main distribution range of different fluids in the one-dimensional T2 and two-dimensional T1-T2 nuclear magnetic spectra, T1 / T2, and the weight coefficient of different component fluid signals in the total signal;

[0098] Specifically, the formation element logging method can be used to obtain the total organic carbon content, rock mineral composition and content of the reservoir, and the sum of the quartz and feldspar content of the reservoir is divided by the sum of the dolomite and calcite content of the reservoir, and the obtained ratio is the lithology sensitive parameter of the reservoir. The formation element logging method is a method in the prior art.

[0099] like Figure 7As shown, the nuclear magnetic resonance logging method can be used to obtain the nuclear magnetic resonance total porosity of the reservoir, and the neutron logging method can be used to obtain the neutron porosity, and the difference obtained by subtracting the nuclear magnetic resonance total porosity from the neutron porosity is the shale index of the reservoir. The nuclear magnetic resonance logging method and the neutron logging method are methods in the prior art.

[0100] The core collected from the reservoir can be tested using a laboratory nuclear magnetic resonance core analyzer to obtain the nuclear magnetic resonance response characteristics (main peak value, spectrum morphology, relaxation time) under different states (original sample, original sample saturation), and then obtain the main distribution range of different fluids on the one-dimensional T2 and two-dimensional T1-T2 nuclear magnetic spectra, T1 / T2, and the weight coefficient of different component fluid signals in the total signal. The nuclear magnetic resonance core analyzer is a device in the prior art.

[0101] The above data can then be analyzed as follows:

[0102] For the well section with the reservoir type of organic-poor shale, the performance is that the lithology sensitive parameter MI is greater than or equal to 1.65, the mud index SI is less than 7, the TOC content is less than 0.5%, and the NMR fluid signal is mainly distributed in the medium and short transverse relaxation components, with the main peak at about 1ms; the main lithology is silty shale, with a strong fluid signal at a long T2 relaxation time, and the overall relaxation time of the T2 spectrum is relatively long, about 1000ms;

[0103] For the well section with transitional shale as the reservoir type, the lithology sensitive parameter MI is less than 1.65, the shale index SI is less than 7, the TOC content is between 0.5% and 1.0%, and the NMR fluid signal is distributed in the transverse relaxation time spectrum, mainly in the long relaxation component, with the main peak at about 10ms, mostly single peak or double peak, and the main lithology is dolomitic shale;

[0104] For the well section with organic-rich shale as the reservoir type, the mud index SI is greater than or equal to 7, the TOC content is greater than 1.0%, and the NMR fluid signal is mainly distributed in the short transverse relaxation component, with the main peak at around 0.2ms. This feature is consistent with the typical NMR response characteristics of muddy shale. The overall relaxation time of the T2 spectrum is short, not exceeding 200ms, and the overlap degree of fluid signals of different components is high.

[0105] like Figure 2 As shown, Figure 2 The following is an analysis diagram of the reservoir lithology sensitivity parameters and mud index in the embodiment of the present invention. The horizontal axis is the lithology sensitivity parameters and the vertical axis is the mud index. The points in the lower left corner area represent transitional shales, the points in the lower right corner area represent organic-poor shales, and the points in the upper area represent organic-rich shales. Figure 2Two line segments are used to separate organic-rich shale, transitional shale and organic-poor shale. It can be seen that the reservoir lithology sensitivity parameters and mud index can be used to clearly distinguish the reservoir lithology.

[0106] like Figure 3 As shown, Figure 3 The analysis diagram of the mud index and total organic carbon content of the reservoir in the embodiment of the present invention can be obtained by drawing a cross-plot using the TOC content and lithology sensitivity parameters of the reservoir. Figure 3 The horizontal axis is TOC content, and the vertical axis is lithology sensitive parameters. Figure 3 As shown, the points in the lower left corner area represent organic-poor shale, the points in the upper right corner area represent organic-rich shale, and the points in the middle area represent transitional shale. It can be seen that the reservoir types can be clearly distinguished by using the lithology-sensitive parameters and TOC content of the reservoir.

[0107] like Figure 4 As shown, Figure 4 This is an identification chart of organic-rich shale fluid in the embodiment of the present invention. The nuclear magnetic resonance experiment analysis of shale cores under different conditions can be used to obtain Figure 4 .from Figure 4 It can be seen that the corresponding NMR response characteristics are that the movable oil has a T1 / T2 of about 5 to 30, and a T2 signal of 30 to 100ms; the bound oil has a T1 / T2 of about 2 to 50, and a T2 fluid signal of 0.3 to 30ms; the capillary bound water has a T1 / T2 of about 2, and a T2 fluid signal of 0.3 to 3ms. The clay bound water has a T1 / T2 of about 1, and a T2 fluid signal of 0.03ms to 0.3ms. The asphalt has a T1 / T2 of about 3 to 100, and a T2 fluid signal of 0.03 to 0.3ms. The main fluid types are asphalt, clay bound water, and bound oil.

[0108] like Figure 5 As shown, Figure 5 The transitional shale fluid identification chart in the embodiment of the present invention can be obtained by analyzing the shale core under different reservoir conditions using nuclear magnetic resonance experiments. Figure 5 . The corresponding NMR response characteristics are that the T1 / T2 of movable oil is about 5-30, and the T2 signal is 30-200ms; the T1 / T2 of bound oil is about 2-50, and the T2 fluid signal is 0.3-30ms; the T1 / T2 of capillary bound water is about 2, and the T2 fluid signal is 0.5-5ms. The T1 / T2 of clay bound water is about 1, and the T2 fluid signal is 0.1ms-0.3ms. The T1 / T2 of asphalt is about 3-100, and the T2 fluid signal is 0.1-0.3ms. The main fluid types are asphalt, clay bound water, capillary bound water, bound oil and movable oil.

[0109] like Figure 6 As shown, Figure 6 This is an identification chart of organic-poor shale fluid in the embodiment of the present invention. The nuclear magnetic resonance experiment analysis of shale cores under different reservoir conditions can be used to obtain Figure 6 . The corresponding NMR response characteristics are that the T1 / T2 of movable oil is about 5-30, and the T2 signal is 30-300ms; the T1 / T2 of bound oil is about 2-50, and the T2 fluid signal is 0.3-30ms; the T1 / T2 of capillary bound water is about 2, and the T2 fluid signal is 0.5-5ms. The T1 / T2 of clay bound water is about 1, and the T2 fluid signal is 0.05ms-0.3ms. The T1 / T2 of asphalt is about 3-100, and the T2 fluid signal is 0.05-0.3ms; the main fluid types are clay bound water, capillary bound water, bound oil and movable oil.

[0110] Through the above experimental analysis, the total organic carbon content, lithology sensitive parameters and mud index of the reservoir can be used as reference indicators for identifying the reservoir type, and the distribution range and T1 / T2 of different fluid components obtained from the nuclear magnetic resonance core experiment on the two-dimensional T1-T2 spectrum can be used as reference indicators for characterizing the fluid occurrence state.

[0111] Based on reservoir classification, Figure 4-Figure 6 The characteristics of different components of fluids are determined, and the saturation of different components of fluids is calculated using two-dimensional nuclear magnetic logging data:

[0112]

[0113]

[0114]

[0115]

[0116] In the formula, S mo , S io , S cbw , S bitumen They are movable oil saturation, adsorbed oil saturation, bound water saturation, and asphalt saturation; They are movable oil porosity, adsorbed oil porosity, bound water porosity, and asphalt porosity; is the total porosity of NMR logging; the units of saturation and porosity are both %; the units of saturation and porosity are both %.

[0117] like Figure 8 As shown, Figure 8This is an application example diagram of a reservoir in a two-dimensional nuclear magnetic resonance logging fluid saturation calculation method provided in an embodiment of the present application. The four tracks on the left are depth, natural gamma, wellbore, natural potential, resistivity and three-porosity curves; tracks 5 and 6 are lithology sensitive parameters and total organic carbon content; tracks 7, 8, 9 and 10 are the fluid saturations of different components of shale oil calculated by the fluid saturation calculation model established in this paper; track 11 is the average daily oil production of different perforation sections.

[0118] like Fig. 9 As shown, Fig. 9 : is an analysis chart of the movable oil saturation and the average daily oil production calculated in the embodiment of the present invention, in which the horizontal axis is the average daily oil production and the vertical axis is the movable oil saturation. Fig. 9 As shown, the higher the movable oil saturation, the higher the average daily oil production, and the two are positively correlated. Fig. 9 The practicality and accuracy of the present invention in calculating fluid saturation are illustrated.

[0119] like Fig.10 As shown, the present invention also proposes a two-dimensional nuclear magnetic resonance logging fluid saturation calculation system, the calculation system comprising: an acquisition module 1, a determination module 2, a model building module 3 and a calculation module 4;

[0120] The acquisition module 1 is used to acquire reservoir attribute data;

[0121] It includes: using nuclear magnetic resonance logging instruments to measure the reservoir and collect the nuclear magnetic total porosity of the reservoir;

[0122] It also includes: an acquisition module acquires shale cores of the reservoir, performs nuclear magnetic resonance testing on the acquired shale cores, acquires one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, and main distribution ranges and T1 / T2 of fluids with different components on the nuclear magnetic resonance T1-T2 spectra;

[0123] The acquisition module uses cluster analysis and non-negative matrix decomposition to normalize the two-dimensional nuclear magnetic logging data, and calculates the weight coefficients of the signals of different components of fluids in the total signal, wherein the weight coefficients of the signals of different components of fluids in the total signal are the weight coefficients of the signals of different components of fluids in different states in the long relaxation and short relaxation intervals in the total signal.

[0124] The determination module 2 includes a first determination unit and a second determination unit;

[0125] The first determination unit is used to determine the lithology sensitivity parameter and the shale index of the reservoir according to the attribute data;

[0126] The calculation formula of the lithology sensitivity parameter is: Among them, MI is the lithology sensitive parameter, wquarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively;

[0127] The calculation formula of the mud index is: SI = Por CNL -Por NMR ;

[0128] Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

[0129] The second determination unit is used to determine the reservoir type of the reservoir according to the attribute data, lithology sensitivity parameters and shale index;

[0130] include:

[0131] If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the TOC content is greater than the fourth threshold value, it is determined that the reservoir type of the reservoir is organic-rich shale;

[0132] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the TOC content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale;

[0133] If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the TOC content is between the third threshold and the fourth threshold, then the reservoir type of the reservoir is determined to be transitional shale;

[0134] In this embodiment, the first threshold is 7, the second threshold is 1.65, the third threshold is 0.5%, and the fourth threshold is 1.0%.

[0135] In this embodiment, if it is determined that the mud index SI of the reservoir is greater than or equal to 7 and the TOC content is greater than 1.0%, then the reservoir type of the reservoir is determined to be organic-rich shale, and its corresponding nuclear magnetic resonance impact characteristics are that the T1 / T2 of movable oil is about 5 to 30, and the T2 signal is 30 to 100ms; the T1 / T2 of bound oil is about 2 to 50, and the T2 fluid signal is 0.3 to 30ms; the T1 / T2 of capillary bound water is about 2, and the T2 fluid signal is 0.3 to 3ms. The T1 / T2 of clay bound water is about 1, and the T2 fluid signal is 0.03ms to 0.3ms. The T1 / T2 of asphalt is about 3 to 100, and the T2 fluid signal is 0.03 to 0.3ms;

[0136] If it is determined that the reservoir's mud index SI is less than 7, the lithology sensitivity parameter MI is greater than or equal to 1.65, and the TOC content is less than 0.5%, then the reservoir type of the reservoir is determined to be organic-poor shale, and its corresponding nuclear magnetic resonance impact characteristics are that the movable oil's T1 / T2 is about 5 to 30, and the T2 signal is 30 to 300ms; the bound oil's T1 / T2 is about 2 to 50, and the T2 fluid signal is 0.3 to 30ms; the capillary bound water's T1 / T2 is about 2, and the T2 fluid signal is 0.5 to 5ms. The clay bound water's T1 / T2 is about 1, and the T2 fluid signal is 0.05ms to 0.3ms. The asphalt's T1 / T2 is about 3 to 100, and the T2 fluid signal is 0.05 to 0.3ms.

[0137] If it is determined that the reservoir's mud index SI is less than 7, the lithology sensitivity parameter MI is less than 1.65, and the TOC content is between 0.5% and 1.0%, then the reservoir type of the reservoir is determined to be transitional shale, and its corresponding nuclear magnetic resonance impact characteristics are that the movable oil's T1 / T2 is about 5 to 30, and the T2 signal is 30 to 200ms; the bound oil's T1 / T2 is about 2 to 50, and the T2 fluid signal is 0.3 to 30ms; the capillary bound water's T1 / T2 is about 2, and the T2 fluid signal is 0.5 to 5ms. The clay bound water's T1 / T2 is about 1, and the T2 fluid signal is 0.1ms to 0.3ms. The asphalt's T1 / T2 is about 3 to 100, and the T2 fluid signal is 0.1 to 0.3ms.

[0138] The model building module 3 is used to determine the reservoir fluid identification model of the reservoir according to the reservoir type and nuclear magnetic resonance response characteristics; the nuclear magnetic resonance response characteristics include main peak value, spectrum morphology and relaxation time.

[0139] The calculation module 4 is used to calculate the fluid saturation of the reservoir using the fluid identification model.

[0140] like Fig.11 As shown, corresponding to the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method provided above, the present invention also provides an electronic device. Since the embodiment of the device is similar to the above method embodiment, the description is relatively simple. For relevant parts, please refer to the description of the above method embodiment part. The device described below is only schematic. The device may include: a processor 10, a memory 20 and a communication bus (i.e., the above device bus) and a search engine, wherein the processor 10 and the memory 20 complete mutual communication through the communication bus and communicate with the outside through the communication interface. The processor 10 can call the logic instructions in the memory 20 to execute the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method.

[0141] In addition, the logic instructions in the above-mentioned memory 20 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a storage chip, a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes.

[0142] On the other hand, an embodiment of the present invention further provides a processor-readable storage medium, on which a computer program 30 is stored. When the computer program 30 is executed by the processor 10, it is implemented to execute the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method provided in the above embodiments.

[0143] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor 10, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0144] Those skilled in the art should understand that although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating fluid saturation in two-dimensional nuclear magnetic resonance logging, characterized in that: The calculation method includes: Obtaining reservoir attribute data; Determine the lithology sensitivity parameter and shale index of the reservoir according to the attribute data; Determine the reservoir type based on the attribute data, lithology sensitivity parameters and shale index; Determine a fluid identification model for the reservoir according to the reservoir type and nuclear magnetic resonance response characteristics; The fluid saturation of the reservoir is calculated using the fluid identification model.

2. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation method according to claim 1, characterized in that: The attribute data include: total organic carbon content of the reservoir, mineral composition and content of the reservoir, neutron porosity, mud content, total nuclear magnetic resonance porosity of the reservoir, main distribution range of different fluids in one-dimensional T2 and two-dimensional T1-T2 nuclear magnetic resonance spectra, T1 / T2 and weight coefficients of different component fluid signals in the total signal.

3. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation method according to claim 2, characterized in that: The method of obtaining the reservoir attribute data includes: measuring the reservoir using a nuclear magnetic resonance logging instrument to collect the nuclear magnetic resonance total porosity of the reservoir.

4. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 2, characterized in that: The obtaining of reservoir attribute data also includes: Collect shale cores from the reservoir and perform nuclear magnetic resonance tests on the collected shale cores to obtain one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, as well as the main distribution range and T1 / T2 of different component fluids on the nuclear magnetic resonance T1-T2 spectrum; Cluster analysis and non-negative matrix decomposition are used to normalize the two-dimensional nuclear magnetic logging data, and the weight coefficients of the signals of different components of fluids in the total signal are calculated, wherein the weight coefficients of the signals of different components of fluids in the total signal are the weight coefficients of the signals of different components of fluids in different states in the long relaxation and short relaxation intervals in the total signal.

5. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 4, characterized in that: The states include: an original-like state and an original-like saturated state.

6. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 1, characterized in that: The calculation formula of the lithology sensitivity parameter is: Among them, MI is the lithology sensitive parameter, w quarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively.

7. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 2, characterized in that: The calculation formula of the mud index is: SI = Por CNL -Por NMR ; Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

8. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 2, characterized in that: The reservoir types determined based on the attribute data, lithology sensitivity parameters and shale index include: If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the total organic carbon content is greater than the fourth threshold value, then the reservoir type of the reservoir is determined to be organic-rich shale; If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the total organic carbon content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale; If the mud index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the total organic carbon content is between the third threshold and the fourth threshold, the reservoir type of the reservoir is determined to be transitional shale.

9. The method for calculating fluid saturation by two-dimensional nuclear magnetic resonance logging according to claim 2, characterized in that: The fluid saturation of the reservoir is calculated using the fluid identification model, and the calculation formula is as follows: In the formula, S mo , S io , S cbw , S bitumen They are movable oil saturation, adsorbed oil saturation, bound water saturation, and asphalt saturation; They are movable oil porosity, adsorbed oil porosity, bound water porosity, and asphalt porosity; is the total porosity of NMR logging; the units of saturation and porosity are both %.

10. A two-dimensional nuclear magnetic resonance logging fluid saturation calculation system, characterized in that: The computing system includes: an acquisition module, a determination module, a model building module and a computing module; The acquisition module is used to acquire reservoir attribute data; The determination module includes a first determination unit and a second determination unit, the first determination unit is used to determine the lithology sensitivity parameter and the shale index of the reservoir according to the attribute data, and the second determination unit is used to determine the reservoir type of the reservoir according to the attribute data, the lithology sensitivity parameter and the shale index; The model building module is used to determine a reservoir fluid identification model according to the reservoir type and nuclear magnetic resonance response characteristics; The calculation module is used to calculate the fluid saturation of the reservoir using the fluid identification model.

11. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The acquisition module is used to acquire the attribute data of the reservoir, including: measuring the reservoir with a nuclear magnetic resonance logging instrument to collect the nuclear magnetic resonance total porosity of the reservoir.

12. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The acquisition module is used to acquire the attribute data of the reservoir, and also includes: The acquisition module collects shale cores from the reservoir, performs nuclear magnetic resonance testing on the collected shale cores, and obtains one-dimensional T2 spectra and two-dimensional T1-T2 spectra of fluids in different states, as well as the main distribution range and T1 / T2 of different component fluids on the nuclear magnetic resonance T1-T2 spectrum; The acquisition module uses cluster analysis and non-negative matrix decomposition to normalize the two-dimensional nuclear magnetic logging data, and calculates the weight coefficients of the fluid signals of different components in the total signal, wherein the weight coefficients of the fluid signals of different components in the total signal are the weight coefficients of the fluid signals of different components of the fluid in different states in the long relaxation and short relaxation intervals in the total signal.

13. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The calculation formula of the lithology sensitivity parameter is: Among them, MI is the lithology sensitive parameter, w quarz 、w fledspar 、w calcite and w dolomite are the percentages of quartz, feldspar, calcite and dolomite in the reservoir, respectively.

14. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The calculation formula of the mud index is: SI = Por CNL -Por NMR ; Among them, SI is the mud index, Por CNL is the neutron porosity, Por NMR is the total NMR porosity.

15. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The second determination unit is used to determine the reservoir type of the reservoir according to the attribute data, the lithology sensitivity parameter and the shale index, including: If the shale index SI of the reservoir is greater than or equal to the first threshold value, and the total organic carbon content is greater than the fourth threshold value, then the reservoir type of the reservoir is determined to be organic-rich shale; If the shale index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is greater than or equal to the second threshold, and the total organic carbon content is less than the third threshold, then the reservoir type of the reservoir is determined to be organic-poor shale; If the mud index SI of the reservoir is less than the first threshold, the lithology sensitivity parameter MI is less than the second threshold, and the total organic carbon content is between the third threshold and the fourth threshold, the reservoir type of the reservoir is determined to be transitional shale.

16. The two-dimensional nuclear magnetic resonance logging fluid saturation calculation system according to claim 10, characterized in that: The calculation module is used to calculate the fluid saturation of the reservoir using the fluid identification model. The calculation formula is as follows: In the formula, S mo , S io , S cbw , S bitumen They are movable oil saturation, adsorbed oil saturation, bound water saturation, and asphalt saturation; They are movable oil porosity, adsorbed oil porosity, bound water porosity, and asphalt porosity; is the total porosity of NMR logging; the units of saturation and porosity are both %.

17. An electronic device, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method according to any one of claims 1 to 9.

18. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is enabled to execute the two-dimensional nuclear magnetic resonance logging fluid saturation calculation method according to any one of claims 1 to 9.

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