Method and system for calculating formation water resistivity by using formation water chloride ion concentration

Abstract

The invention relates to the technical field of oil-gas exploration and development, and provides a method and system for calculating formation water resistivity by using formation water chloride ion concentration, and the method comprises the steps: obtaining a regional underground formation water sample; according to the formation water sample, determining the incidence relation between the chloride ion concentration and the sodium ion concentration of different water types and the total mineralization degree of the formation water; respectively determining other core ions of each water type; calculating the concentration of each core ion based on the incidence relation and the ion charge balance principle; according to the conversion relation between the formation water total mineralization degree and the equivalent NaCl mineralization degree, the equivalent sodium ion concentration or the equivalent chloride ion concentration is obtained through the core ion concentration, and then the equivalent NaCl solution total mineralization degree of different water types is obtained through the incidence relation; and calculating the formation temperature value according to the ground temperature gradient and the formation burial depth, and calculating the formation water resistivity according to the relationship among the equivalent NaCl mineralization degree, the formation temperature value and the resistivity. According to the invention, the resistivity of the formation water can be accurately measured.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration and development, and in particular to a method and system for calculating formation water resistivity by using formation water chloride ion concentration. Background Art

[0002] The Neogene and Paleogene sedimentary basins are affected by different original sedimentary environments, later tectonic movements and oil and gas accumulation and migration. The properties of formation water in different strata in the region are complex and changeable in the horizontal and vertical directions. The parameter values ​​such as ion composition, ion concentration and total mineralization in formation water vary greatly and are irregularly distributed in the region, which brings great difficulties to the judgment of formation water properties and reservoir evaluation on site.

[0003] Regional formation water type and chloride ion concentration are important parameters for determining the equivalent NaCl mineralization and resistivity of formation water. At present, there are two main methods for obtaining formation water mineralization parameters in the industry. One is to obtain representative formation water samples by using DST formation testing in exploration wells, water production from development wells, and on-site pump sampling. Due to the limited on-site detection conditions of the platform, only the chloride ion concentration of the water sample can be measured. Therefore, the water sample is usually transported back to the professional laboratory at the base for water analysis to obtain information such as water type, total mineralization, various ion types and concentrations. The parameters measured by this method are accurate and reliable, but it takes a long time and has low timeliness, and cannot meet the requirements of drilling tracking and reservoir evaluation at the operation site. The second is to select a pure sandstone water layer section with a certain thickness and good logging curve quality, and use the Alchei formula to directly calculate the formation water mineralization based on the logging depth resistivity and effective porosity, and convert it into formation water resistivity according to the empirical formula, and finally calculate the formation water saturation. However, since the resistivity and porosity curves of pure water layers are often affected by many factors such as wellbore expansion, mud content, dense minerals such as ash, thin layers and interlayers, measurement errors of different logging instruments, and oil and gas content in the formation, the formation water mineralization obtained by logging back calculation often has large errors, which directly affects the calculation accuracy of formation water saturation, and then affects the reserve evaluation. Summary of the invention

[0004] The object of the present invention is to solve at least one technical problem in the background technology and to provide a method and system for calculating the resistivity of formation water using the chloride ion concentration of formation water.

[0005] To achieve the above object, the present invention provides a method for calculating the resistivity of formation water using the chloride ion concentration of formation water, comprising:

[0006] Obtain regional downhole formation water samples;

[0007] Determine the correlation between chloride ion concentration, sodium ion concentration and total mineralization of formation water of different water types based on underground formation water samples in the area;

[0008] For different water types, the core ions with the largest proportion in each water type, except for chloride ions and sodium ions, are determined;

[0009] For different water types, the concentration of each core ion is calculated based on the above correlation and the principle of ion charge balance;

[0010] According to the conversion chart of total mineralization of formation water and equivalent NaCl mineralization, the core ion concentration can be converted into equivalent sodium ion concentration or equivalent chloride ion concentration after multiplying it by the conversion coefficient, and then the total mineralization of equivalent NaCl solution of different water types can be obtained through the above correlation relationship;

[0011] The formation temperature is calculated based on the geothermal gradient and the burial depth of the formation. The formation water resistivity is calculated based on the relationship between the equivalent NaCl mineralization, the formation temperature and the resistivity.

[0012] According to one aspect of the present invention, the determination of the correlation between the chloride ion concentration, the sodium ion concentration and the total mineralization of the formation water of different water types includes:

[0013] Establish the first relationship model between chloride ion concentration and total mineralization of formation water based on different water types;

[0014] Establish a second relationship model between sodium ion concentration and total mineralization of formation water based on different water types;

[0015] The chloride ion concentration of the on-site formation water is measured, and based on the first relationship model, the total mineralization of the on-site formation water is determined, and then based on the second relationship model, the sodium ion concentration of the on-site formation water is determined.

[0016] According to one aspect of the present invention, the water type includes: NaHCO3 type water type, CaCl2 type water type, Na2SO4 type water type and MgCl2 type water type;

[0017] The core ions with the largest proportion in each water type other than chloride ions and sodium ions are determined for different water types, including: the core ions of NaHCO3 type are HCO3-, the core ions of MgCl2 type are Mg 2+ , the core ion of CaCl2 is Ca 2+ , the core ion of Na2SO4 type is SO4 2- .

[0018] According to one aspect of the present invention, based on the correlation relationship and the principle of ion charge balance, the concentration of each core ion is calculated, including:

[0019] According to different water types, the chloride ion concentration of different water types is determined, the total mineralization of formation water is determined by the chloride ion concentration, and then the sodium ion concentration is determined according to the total mineralization of formation water;

[0020] Based on the chloride ion concentration, sodium ion concentration, core ion concentration and the molecular weight of each ion, the charge balance equation of anions and cations was established, and the concentration of the core ion was calculated according to the charge balance equation.

[0021] According to one aspect of the present invention, the formation temperature value is calculated according to the geothermal gradient and the formation burial depth, and the formation water resistivity is calculated according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity, including:

[0022] The formation temperature is calculated according to the formation depth, and the formula is as follows:

[0023] T=0.0332H+30.032,R 2 =0.9776;

[0024] Where: T is the formation temperature; H is the formation depth;

[0025] According to the theoretical relationship between equivalent NaCl mineralization, formation temperature and resistivity, the resistivity of formation water is calculated using the following formula:

[0026] Salinity = (300000 / (R w *(1.8*T+39)-1)) 1.05 ;

[0027]

[0028] Where: R w is the formation water resistivity; Salinity is the equivalent NaCl mineralization.

[0029] Furthermore, to achieve the above object, the present invention also provides a system for calculating formation water resistivity using formation water chloride ion concentration, comprising:

[0030] The formation water sample acquisition module acquires the formation water samples in the regional wells;

[0031] A correlation determination module determines the correlation between chloride ion concentration, sodium ion concentration and total mineralization of formation water of different water types according to the underground formation water samples in the area;

[0032] The core ion determination module determines the core ions with the largest proportion in each water type except chloride ions and sodium ions for different water types;

[0033] The core ion concentration calculation module calculates the concentration of each core ion for different water types based on the correlation relationship and the principle of ion charge balance;

[0034] The equivalent NaCl solution total mineralization calculation module converts the core ion concentration by the conversion coefficient according to the conversion chart of the total mineralization of formation water and the equivalent NaCl mineralization to the equivalent sodium ion concentration or the equivalent chloride ion concentration, and then obtains the total mineralization of the equivalent NaCl solution of different water types through the association relationship;

[0035] The formation water resistivity calculation module calculates the formation temperature value according to the geothermal gradient and the formation burial depth, and calculates the formation water resistivity according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity.

[0036] Furthermore, to achieve the above-mentioned purpose, the present invention also provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described above.

[0037] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described above is implemented.

[0038] According to the scheme of the present invention, the present invention only needs to obtain reliable chloride concentration and water type of water samples that can effectively reflect the original formation. Taking formation water samples for determination at the platform operation site is the most effective, rapid and direct method for determining formation water parameters. Since it is easy to operate, reliable, efficient, low-cost and takes a short time, the chloride ion concentration of the water sample can be quickly obtained, which provides a reliable basis for quickly determining the equivalent NaCl mineralization and resistivity of formation water on site, and also provides data guarantee for on-site rapid logging interpretation. On this basis, further combined with regional rock electrical parameters and conventional logging curves, the formation water saturation can be effectively calculated, providing key and reliable reservoir parameters for oil field exploration, reserve evaluation and later development. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart schematically showing a method for calculating formation water resistivity using formation water chloride ion concentration according to one embodiment of the present invention;

[0040] Figure 2 A diagram schematically showing the field rapid evaluation results of formation water resistivity and water saturation according to Example 1 of the present invention;

[0041] Figure 3 A diagram schematically showing the relationship between the total mineralization and chloride ion concentration of formation water samples based on different water types according to Example 1 of the present invention;

[0042] Figure 4 A diagram schematically showing the relationship between the total mineralization and sodium ion concentration of formation water samples of different water types according to Example 1 of the present invention;

[0043] Figure 5 Schematically represents a diagram of converting the total mineralization of formation water under different water conditions into an equivalent NaCl mineralization according to Example 1 of the present invention. DETAILED DESCRIPTION

[0044] The present invention will now be discussed with reference to exemplary embodiments. It should be understood that the embodiments discussed are only to enable those skilled in the art to better understand and thus implement the present invention, rather than implying any limitation on the scope of the present invention.

[0045] As used herein, the term “including” and variations thereof are to be interpreted as open-ended terms meaning “including, but not limited to.” The term “based on” is to be interpreted as “based, at least in part, on.” The terms “one embodiment” and “an embodiment” are to be interpreted as “at least one embodiment.”

[0046] Figure 1 The flowchart schematically shows a method for calculating the resistivity of formation water using the chloride ion concentration of formation water according to one embodiment of the present invention. Figure 1 As shown, in this embodiment, the method for calculating the resistivity of formation water using the chloride ion concentration of formation water includes:

[0047] Obtain regional downhole formation water samples;

[0048] Based on the regional underground formation water samples, determine the correlation between the chloride ion concentration, sodium ion concentration and the total mineralization of the formation water of different water types;

[0049] For different water types, the core ions with the largest proportion in each water type, except for chloride ions and sodium ions, are determined;

[0050] For different water types, the concentration of each core ion is calculated based on the principles of correlation and ion charge balance;

[0051] According to the conversion chart of total mineralization of formation water and equivalent NaCl mineralization, the core ion concentration can be converted into equivalent sodium ion concentration or equivalent chloride ion concentration after multiplying it by the conversion coefficient, and then the total mineralization of equivalent NaCl solution of different water types can be obtained through the above correlation relationship;

[0052] The formation temperature is calculated based on the geothermal gradient and the burial depth of the formation. The formation water resistivity is calculated based on the relationship between the equivalent NaCl mineralization, the formation temperature and the resistivity.

[0053] Further, according to an embodiment of the present invention, the correlation between the chloride ion concentration, the sodium ion concentration and the total mineralization of the formation water of different water types is determined, including:

[0054] Establish the first relationship model between chloride ion concentration and total mineralization of formation water based on different water types;

[0055] Establish a second relationship model between sodium ion concentration and total mineralization of formation water based on different water types;

[0056] The chloride ion concentration of the on-site formation water is measured, and the total mineralization of the on-site formation water is determined based on the first relationship model, and then the sodium ion concentration of the on-site formation water is determined based on the second relationship model.

[0057] Further, according to one embodiment of the present invention, the water type includes: NaHCO3 type water type, CaCl2 type water type, Na2SO4 type water type and MgCl2 type water type;

[0058] For different water types, the core ions with the largest proportion in each water type other than chloride ions and sodium ions are determined separately, including: the core ion of NaHCO3 type is HCO3-, the core ion of MgCl2 type is Mg 2+ , the core ion of CaCl2 is Ca 2+ , the core ion of Na2SO4 type is SO4 2- .

[0059] Further, according to an embodiment of the present invention, based on the principle of association relationship and ion charge balance, the concentration of each core ion is calculated, including:

[0060] According to different water types, the chloride ion concentration of different water types is determined, the total mineralization of formation water is determined by the chloride ion concentration, and then the sodium ion concentration is determined according to the total mineralization of formation water;

[0061] Based on the chloride ion concentration, sodium ion concentration, core ion concentration and the molecular weight of each ion, the charge balance equation of anions and cations was established, and the concentration of the core ion was calculated according to the charge balance equation.

[0062] Further, according to an embodiment of the present invention, the formation temperature value is calculated according to the geothermal gradient and the formation burial depth, and the formation water resistivity is calculated according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity, including:

[0063] The formation temperature is calculated according to the formation depth, and the formula is as follows:

[0064] T=0.0332H+30.032,R 2 =0.9776;

[0065] Where: T is the formation temperature; H is the formation depth;

[0066] According to the theoretical relationship between equivalent NaCl mineralization, formation temperature and resistivity, the resistivity of formation water is calculated using the following formula:

[0067] Salinity = (300000 / (R w *(1.8*T+39)-1)) 1.05 ;

[0068]

[0069] Where: R w is the formation water resistivity; Salinity is the equivalent NaCl mineralization.

[0070] According to the above scheme of the present invention, the present invention only needs to obtain reliable chloride concentration and water type of water samples that can effectively reflect the original formation. Taking formation water samples for determination at the platform operation site is the most effective, rapid and direct method for determining formation water parameters. Because it is easy to operate, reliable, efficient, low-cost and takes a short time, the chloride ion concentration of the water sample can be quickly obtained, which provides a reliable basis for the on-site rapid determination of the equivalent NaCl mineralization and resistivity of formation water and also provides data guarantee for on-site rapid logging interpretation. On this basis, further combined with regional rock electrical parameters and conventional logging curves, the formation water saturation can be effectively calculated, providing key and reliable reservoir parameters for oilfield exploration, reserve evaluation and later development.

[0071] Furthermore, to achieve the above object, the present invention also provides a system for calculating formation water resistivity using formation water chloride ion concentration, comprising:

[0072] The formation water sample acquisition module acquires the formation water samples in the regional wells;

[0073] A correlation determination module determines the correlation between chloride ion concentration, sodium ion concentration and total mineralization of formation water of different water types according to the underground formation water samples in the area;

[0074] The core ion determination module determines the core ions with the largest proportion in each water type except chloride ions and sodium ions for different water types;

[0075] The core ion concentration calculation module calculates the concentration of each core ion for different water types based on the correlation relationship and the principle of ion charge balance;

[0076] The equivalent NaCl solution total mineralization calculation module converts the core ion concentration by the conversion coefficient according to the conversion chart of the total mineralization of formation water and the equivalent NaCl mineralization to the equivalent sodium ion concentration or the equivalent chloride ion concentration, and then obtains the total mineralization of the equivalent NaCl solution of different water types through the association relationship;

[0077] The formation water resistivity calculation module calculates the formation temperature value according to the geothermal gradient and the formation burial depth, and calculates the formation water resistivity according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity.

[0078] Further, according to an embodiment of the present invention, the correlation between the chloride ion concentration, the sodium ion concentration and the total mineralization of the formation water of different water types is determined, including:

[0079] Establish the first relationship model between chloride ion concentration and total mineralization of formation water based on different water types;

[0080] Establish a second relationship model between sodium ion concentration and total mineralization of formation water based on different water types;

[0081] The chloride ion concentration of the on-site formation water is measured, and the total mineralization of the on-site formation water is determined based on the first relationship model, and then the sodium ion concentration of the on-site formation water is determined based on the second relationship model.

[0082] Further, according to one embodiment of the present invention, the water type includes: NaHCO3 type water type, CaCl2 type water type, Na2SO4 type water type and MgCl2 type water type;

[0083] For different water types, the core ions with the largest proportion in each water type other than chloride ions and sodium ions are determined separately, including: the core ion of NaHCO3 type is HCO3-, the core ion of MgCl2 type is Mg 2+ , the core ion of CaCl2 type is Ca 2+ , the core ion of Na2SO4 type is SO4 2- .

[0084] Further, according to an embodiment of the present invention, based on the principle of association relationship and ion charge balance, the concentration of each core ion is calculated, including:

[0085] According to different water types, the chloride ion concentration of different water types is determined, the total mineralization of formation water is determined by the chloride ion concentration, and then the sodium ion concentration is determined according to the total mineralization of formation water;

[0086] Based on the chloride ion concentration, sodium ion concentration, core ion concentration and the molecular weight of each ion, the charge balance equation of anions and cations was established, and the concentration of the core ion was calculated according to the charge balance equation.

[0087] Further, according to an embodiment of the present invention, the formation temperature value is calculated according to the geothermal gradient and the formation burial depth, and the formation water resistivity is calculated according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity, including:

[0088] The formation temperature is calculated according to the formation depth, and the formula is as follows:

[0089] T=0.0332H+30.032,R 2 =0.9776;

[0090] Where: T is the formation temperature; H is the formation depth;

[0091] According to the theoretical relationship between equivalent NaCl mineralization, formation temperature and resistivity, the resistivity of formation water is calculated using the following formula:

[0092] Salinity = (300000 / (R w *(1.8*T+39)-1)) 1.05 ;

[0093]

[0094] Where: R w is the formation water resistivity; Salinity is the equivalent NaCl mineralization.

[0095] According to the above scheme of the present invention, the present invention only needs to obtain reliable chloride concentration and water type of water samples that can effectively reflect the original formation. Taking formation water samples for determination at the platform operation site is the most effective, rapid and direct method for determining formation water parameters. Because it is easy to operate, reliable, efficient, low-cost and takes a short time, the chloride ion concentration of the water sample can be quickly obtained, which provides a reliable basis for the on-site rapid determination of the equivalent NaCl mineralization and resistivity of formation water and also provides data guarantee for on-site rapid logging interpretation. On this basis, further combined with regional rock electrical parameters and conventional logging curves, the formation water saturation can be effectively calculated, providing key and reliable reservoir parameters for oilfield exploration, reserve evaluation and later development.

[0096] Furthermore, to achieve the above-mentioned purpose, the present invention also provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described above is implemented.

[0097] Furthermore, to achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described above is implemented.

[0098] Based on the above solution of the present invention, the following Figure 1 The technical solution of the present invention is described in detail by way of specific embodiments.

[0099] Example 1

[0100] Taking the formation water analysis and reservoir evaluation of the first section of X-1 well in a certain basin as an example, the method of calculating the formation water resistivity using the chloride ion concentration of the formation water includes the following steps:

[0101] Step 1, acquisition of regional underground formation water samples: obtain regional undisturbed formation water samples by means of DST formation testing of exploration wells, water production from development wells and on-site pump sampling. In this process, water samples that are greatly affected by drilling fluids need to be eliminated to select relatively pure and representative undisturbed formation water samples as samples;

[0102] Step 2: Based on the water analysis sample data of the basin area, a relationship model between the chloride ion concentration, sodium ion concentration and the total mineralization of the formation water based on different water types is established. That is, after clarifying the regional water type and chloride ion concentration, the total mineralization of the formation water and the sodium ion concentration can be determined.

[0103] The relationship between the chloride ion concentration X and the total mineralization Y of different water samples in the basin is as follows:

[0104] NaHCO3 type: Y = 2.0477X, R 2 =0.9086;

[0105] CaCl2 type: Y = 1.6762X, R 2 =0.9967;

[0106] Na2SO4 type: Y = 1.9351X, R 2 =0.9046;

[0107] MgCl2 type: Y = 1.7969X, R 2 =0.94;

[0108] The relationship between the sodium ion concentration Z and the total mineralization Y of different water types in the basin is as follows:

[0109] NaHCO3 type: Z = 0.3638Y, R 2 =0.9929;

[0110] CaCl2 type: Z = 0.3626Y, R 2 =0.9841;

[0111] Na2SO4 type: Z = 0.3493Y, R 2 =0.945;

[0112] MgCl2 type: Z = 0.3443Y, R 2 =0.8318;

[0113] Step 3, measuring the chloride ion concentration and obtaining the mineralization of the on-site formation water sample: Due to the limitation of the on-site laboratory analysis conditions of the platform, only the chloride ion concentration of the formation water sample can be measured, and the concentration of other ions and the total mineralization cannot be measured; using the regional sample model in step 2, the total mineralization and sodium ion concentration of the on-site formation water sample can be calculated;

[0114] Step 4: For the four different water types, determine the representative ions with the largest proportion other than chloride ions and sodium ions, i.e., core ions. Among them: the core ion of NaHCO3 type is HCO3 - MgCl2-type core ion is Mg 2+ , the core ion of CaCl2 type is Ca 2+ , the core ion of Na2SO4 type is SO4 2- .

[0115] Step 5, based on the principle of charge balance between anions and cations, the total charge of anions and cations is theoretically equal, so an equation can be established to determine the concentration of core ions. Both theory and practice show that for a certain water type, the sum of the concentrations of chloride ions, sodium ions and core ions is close to the total mineralization. Figure 2 As shown, taking the first section of the X-1 well in the basin as an example, this layer group is a marine sedimentary stratum, and the confirmed water type is CaCl2 water type. According to the above, in order to facilitate analysis and evaluation, the ion composition of the formation water of this layer group can be simplified to only contain 3 ion components: chloride ion, sodium ion and calcium ion. Assuming that the chloride concentration is D, the sodium ion concentration is E, and the core ion calcium ion concentration is F, combined with the molecular weight of different ions, the charge balance equation of anions and cations can be established, and then:

[0116]

[0117] A pure water sample was obtained from the upper part of the first section of Well X-1. The chloride concentration of the water sample was 19940ppm. Figure 3 and Figure 4From the regional conversion chart, it can be obtained that the total mineralization of formation water is 33423ppm, and the sodium ion concentration is 12119ppm. According to the above charge balance equation, the total charge of anions is 561.7, the total charge of sodium ions in cations is 526.9, and the remaining 34.8 cationic charges are all distributed to calcium ions. Theoretically, 17 calcium ions need to be supplemented. From this, it can be calculated that the concentration of calcium ions is 696.6ppm, that is to say, the total concentration of anions and cations other than chloride ions, sodium ions and calcium ions in the water sample is only about 667.5ppm, which accounts for less than 2% of the total mineralization, which is a low proportion.

[0118] Step 6: Since the formation water mineralization used in calculating formation water saturation by logging is equivalent to NaCl mineralization, it is necessary to convert the total mineralization measured by the above water analysis data into equivalent NaCl water mineralization. Figure 5 ( Figure 5 It is a classic diagram known in the art for converting the total mineralization of formation water under different water type conditions into equivalent NaCl mineralization. According to the total mineralization value of the water sample, the conversion coefficient between the core ion concentration of different water types and the chloride ion or sodium ion concentration can be determined, thereby obtaining the total equivalent NaCl mineralization value of the water sample. The conversion relationship between the total mineralization of formation water under different water type conditions and the equivalent NaCl mineralization is obtained by multiplying the core ion concentration by the conversion coefficient to convert to Na + or Cl - Concentration, and finally get the total mineralization of equivalent NaCl solution. In X-1 well, when the total mineralization of formation water is 33423ppm, the calcium ion concentration needs to be multiplied by 0.82 to convert it into sodium ion concentration, thus obtaining the equivalent concentration of calcium ions converted to sodium ions of 572ppm, and finally the total equivalent NaCl mineralization of the water sample is 32631ppm.

[0119] Step 7: Calculate the formation temperature T based on the geothermal gradient and the formation depth. This area is a normal temperature and pressure system. Existing research results show that the geothermal gradient is 3.3℃ / 100m. Therefore, the formula for calculating the formation temperature based on the formation depth in this area is as follows:

[0120] T=0.0332H+30.032,R 2 =0.9776;

[0121] Where: T is the formation temperature, in °C; H is the formation depth, in m;

[0122] According to the theoretical relationship between equivalent NaCl mineralization, formation temperature and resistivity, the formation water resistivity can be accurately calculated. The formula is as follows:

[0123] Salinity = (300000 / (R w*(1.8*T+39)-1)) 1.05 ;

[0124]

[0125] Where: R w is the formation water resistivity, in Ω.m; Salinity is the equivalent NaCl mineralization.

[0126] The formation temperature of the target layer of Well X-1 is about 73°C. According to the above formula, the formation water resistivity R can be calculated. w It is 0.094Ω.m.

[0127] Furthermore, in this embodiment, the method further includes: step 8, calculating the formation water saturation according to important reservoir parameters such as formation water resistivity, well logging curves and regional rock electrical parameters using the Indonesian saturation model that has been proven to be applicable to the entire regional shale sandstone formation, and the expression thereof is as follows:

[0128]

[0129] Where: Vsh is the mud content, in decimal; Rsh is the resistivity of mudstone, in decimal; a and m are the regional rock electrical parameters, in decimal; φ is the effective porosity, in decimal; Rt is the deep resistivity, in Ω.m; Sw is the water saturation, in decimal.

[0130] In order to verify the effectiveness of the method used in the present invention, the water samples collected on site were transported back to land and measured in a professional water analysis laboratory. The concentrations of various ions were obtained, and the total mineralization of the water samples was 33584ppm, and the equivalent NaCl mineralization was 32987ppm, which was consistent with the rapid evaluation results of the on-site water samples. At the same time, closed coring operations were carried out in this well section, and the water saturation and oil saturation of the cores were measured. Statistics show that the sum of the two is above 90%, indicating that during the coring, core transportation and measurement process, there is very little fluid loss in the core. Therefore, the measured water saturation value of the core can better represent the true water saturation of the formation. Figure 2 It can be seen that the water saturation of the oil layer section obtained by the on-site rapid evaluation is generally consistent with the water saturation of the closed coring experiment.

[0131] According to the embodiment scheme of the present invention, the method obtains representative original formation water samples by means of regional exploration well DST formation testing, development well production and on-site pump sampling, and obtains chloride ion concentration by on-site measurement. According to the relationship model between chloride ion concentration, sodium ion concentration and total formation water salinity of samples of different water types in the region, the total formation water salinity and sodium ion concentration can be effectively determined. Then, according to the principle of ion charge balance, the core ion concentration of different water types can be determined by establishing a balance equation. According to the classic conversion chart of total formation water salinity and equivalent NaCl salinity existing in the art, the core ion concentration is converted into equivalent sodium ion or chloride ion concentration, and finally the total salinity of equivalent NaCl solution of different water types is obtained. According to the theoretical relationship between equivalent NaCl salinity and temperature and resistivity, the formation water resistivity can be accurately calculated. After obtaining the formation water resistivity, the Indonesian saturation model can be used to calculate the formation water saturation.

[0132] Those skilled in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0133] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method implementation methods, and will not be repeated here.

[0134] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0135] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0136] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0137] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the energy-saving signal sending / receiving method of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0138] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0139] It should be understood that the size of the serial numbers of each step in the content of the invention and the implementation methods of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation methods of the present invention.

Claims

1. A method for calculating formation water resistivity using formation water chloride ion concentration, characterized in that: include: Obtain regional downhole formation water samples; Determine the correlation between chloride ion concentration, sodium ion concentration and total mineralization of formation water of different water types based on underground formation water samples in the area; For different water types, the core ions with the largest proportion in each water type, except for chloride ions and sodium ions, are determined; For different water types, the concentration of each core ion is calculated based on the above correlation and the principle of ion charge balance; According to the conversion chart of total mineralization of formation water and equivalent NaCl mineralization, the core ion concentration can be converted into equivalent sodium ion concentration or equivalent chloride ion concentration after multiplying it by the conversion coefficient, and then the total mineralization of equivalent NaCl solution of different water types can be obtained through the above correlation relationship; The formation temperature is calculated based on the geothermal gradient and the burial depth of the formation. The formation water resistivity is calculated based on the relationship between the equivalent NaCl mineralization, the formation temperature and the resistivity.

2. The method for calculating formation water resistivity using formation water chloride ion concentration according to claim 1, characterized in that: The determination of the correlation between the chloride ion concentration, the sodium ion concentration and the total mineralization of the formation water of different water types includes: Establish the first relationship model between chloride ion concentration and total mineralization of formation water based on different water types; Establish a second relationship model between sodium ion concentration and total mineralization of formation water based on different water types; The chloride ion concentration of the on-site formation water is measured, and based on the first relationship model, the total mineralization of the on-site formation water is determined, and then based on the second relationship model, the sodium ion concentration of the on-site formation water is determined.

3. The method for calculating formation water resistivity using formation water chloride ion concentration according to claim 1, characterized in that: The water types include: NaHCO3 type water type, CaCl2 type water type, Na2SO4 type water type and MgCl2 type water type; The core ions with the largest proportion in each water type other than chloride ions and sodium ions are determined for different water types, including: the core ions of NaHCO3 type are HCO3-, the core ions of MgCl2 type are Mg 2+ , the core ion of CaCl2 type is Ca 2+ , the core ion of Na2SO4 type is SO4 2- .

4. The method for calculating formation water resistivity using formation water chloride ion concentration according to claim 1, characterized in that: Based on the correlation and the principle of ion charge balance, the concentration of each core ion is calculated, including: According to different water types, the chloride ion concentration of different water types is determined, the total mineralization of formation water is determined by the chloride ion concentration, and then the sodium ion concentration is determined according to the total mineralization of formation water; Based on the chloride ion concentration, sodium ion concentration, core ion concentration and the molecular weight of each ion, the charge balance equation of anions and cations was established, and the concentration of the core ion was calculated according to the charge balance equation.

5. The method for calculating formation water resistivity using formation water chloride ion concentration according to claim 1, characterized in that: The formation temperature value is calculated according to the geothermal gradient and the formation depth, and the formation water resistivity is calculated according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity, including: The formation temperature is calculated according to the formation depth, and the formula is as follows: T=0.0332H+30.032,R 2 =0.9776; Where: T is the formation temperature; H is the formation depth; According to the theoretical relationship between equivalent NaCl mineralization, formation temperature and resistivity, the resistivity of formation water is calculated using the following formula: Salinity=(300000 / (R w *(1.8*T+39)-1)) 1.05 ; Where: R w is the formation water resistivity; Salinity is the equivalent NaCl mineralization.

6. A system for calculating formation water resistivity using formation water chloride ion concentration, characterized in that: include: The formation water sample acquisition module acquires the formation water samples in the regional wells; A correlation determination module determines the correlation between the chloride ion concentration, the sodium ion concentration and the total mineralization of the formation water of different water types according to the underground formation water samples in the area; The core ion determination module determines the core ions with the largest proportion in each water type except chloride ions and sodium ions. The core ion concentration calculation module calculates the concentration of each core ion for different water types based on the correlation relationship and the principle of ion charge balance; The equivalent NaCl solution total mineralization calculation module converts the core ion concentration by the conversion coefficient according to the conversion chart of the total mineralization of formation water and the equivalent NaCl mineralization to the equivalent sodium ion concentration or the equivalent chloride ion concentration, and then obtains the total mineralization of the equivalent NaCl solution of different water types through the association relationship; The formation water resistivity calculation module calculates the formation temperature value according to the geothermal gradient and the formation burial depth, and calculates the formation water resistivity according to the relationship between the equivalent NaCl mineralization, the formation temperature value and the resistivity.

7. An electronic device, characterized in that The invention comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein when the computer program is executed by the processor, the method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described in any one of claims 1 to 5 is implemented.

8. 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 method for calculating the resistivity of formation water using the chloride ion concentration of formation water as described in any one of claims 1 to 5 is implemented.

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