Classification evaluation method for green and recyclable utilization of sedimentary basin type geothermal resources

Abstract

The invention discloses a classification evaluation method for green and recyclable utilization of sedimentary basin type geothermal resources. The classification evaluation method comprises the following steps that S1, the geothermal gradient and the heat storage temperature are determined; s2, determining heat storage thickness and permeability; s3, classifying based on the geothermal field scale of the heat storage single well; s4, classification is carried out based on heat storage and heat compensation parameters; and S5, carrying out comprehensive classification evaluation on the quality of the geothermal resources. The method is suitable for the technical field of classification evaluation on the availability of the geothermal resources. The geothermal resource sustainable utilization classification evaluation is carried out by comprehensively utilizing the single well geothermal field heat power and the geothermal heat flow heat compensation parameters, classification is more comprehensive and reasonable, and the geothermal resources can be evaluated from the perspective of green and sustainable cyclic utilization.

Description

Technical Field

[0001] The present invention belongs to the technical field of classification and evaluation of the availability of geothermal resources, and specifically relates to a classification and evaluation method for the green and recyclable utilization of sedimentary basin-type geothermal resources. Background Art

[0002] The classification and evaluation of the availability of geothermal resources mainly evaluates the potential for the sustainable development and utilization of geothermal resources, and is of great significance for selecting favorable areas for the development of geothermal resources on the premise of green and recyclable development and utilization.

[0003] At present, the classification of the availability of geothermal resources is mainly carried out from a single perspective such as the chemical components of geothermal fluids, temperature, well depth of geothermal wells, extractable amount of geothermal fluids and their production capacity. Among them, the content of the chemical components of geothermal fluids can determine whether it can be developed as a mineral spring and its utilization direction and method, the temperature of geothermal fluids can be used to determine the utilization range of geothermal resources, and the extractable amount of geothermal fluids and their production capacity are used to evaluate the scale of their exploitable utilization. In addition, in the patent "Method for Classifying Geothermal Resources in Sedimentary Basins" by Song Mingshui, Zhao Minghai, etc. of China Petroleum and Chemical Corporation, a method for classifying geothermal resources by using the geothermal heat replenishment parameter that can reflect the heating efficiency of the heat reservoir for low-temperature recharged tail water is proposed.

[0004] For the rift-type sedimentary basins in eastern China dominated by buried geothermal resources, the salinity of geothermal fluids is generally high, with strong scaling and corrosiveness, and the possibility of being developed and utilized as mineral springs is small. And the temperature of geothermal fluids is mainly between 40°C and 90°C, which can mainly be used for heating. Therefore, the utilization range of geothermal energy determined by the chemical components and temperature of geothermal fluids has no meaning for the classification and evaluation of the availability of geothermal resources; simply using the well depth, extractable amount of geothermal fluids and their production capacity does not consider the temperature conditions of the heat reservoir, and cannot comprehensively evaluate the feasibility of geothermal development and utilization, especially geothermal heating.

[0005] And for buried geothermal resources in sedimentary basins, carrying out geothermal tail water recharge to maintain formation pressure is an important measure for the development and utilization of this type of geothermal resources. However, simply classifying from the geothermal heat replenishment parameter that reflects the heating ability of the heat reservoir rock's heat conduction efficiency for recharged low-temperature fluids cannot evaluate the amount of geothermal resources contained in the geothermal field itself and its potential for recyclable utilization.

[0006] Yang Yonghong of the Exploration and Development Research Institute of Sinopec Shengli Oilfield Company and Duan Zhongfeng of the School of Geosciences and Technology, China University of Petroleum (East China) proposed a method for classifying and evaluating the quality of geothermal resources by combining the single-well heat production power with the heat recharge type and fluid quality in the non-patent document "A Method for Evaluating the Quality of Geothermal Resources with 'Three-Element Coupling'". However, the division of the single-well heat production power limit involves artificial economic factors such as heating costs, and its universality is poor. Moreover, the fluid quality varies greatly in different depressions, making it difficult to evaluate with a unified standard. Therefore, it can only be used as a reference parameter. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions:

[0009] A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, comprising the following steps:

[0010] S1 Determine the geothermal gradient and reservoir temperature;

[0011] S2 Determine the reservoir thickness and permeability;

[0012] S3 Classify based on the scale of the geothermal field of a single well in the reservoir;

[0013] S4 Classify based on the heat recharge parameter of the reservoir;

[0014] S5 Comprehensive classification and evaluation of the quality of geothermal resources.

[0015] Preferably, in the step S1, it specifically includes:

[0016] According to the formation temperature test data obtained during the oil well testing process in the oil and gas exploration, use the formation temperature calculation formula to calculate and clarify the geothermal gradient and the distribution characteristics of the reservoir temperature within the geothermal utilization area.

[0017] Preferably, in the step S1, the geothermal gradient is the growth rate of the formation temperature that is not affected by the atmospheric temperature with the increase of depth, expressed as the number of degrees increased per 100-meter vertical depth, and is obtained by using the wellbore temperature measurement data.

[0018] Preferably, in the step S1, the geothermal gradient calculation formula is as follows:

[0019] G = 100×(t - t 0 ) / (h - h 1 ) (Equation 1);

[0020] In the formula: G - geothermal gradient, °C / 100m; t - oil well testing temperature measurement, °C; t 0- Temperature of the constant temperature layer, take 14.75 °C; h - Temperature measurement depth, m; h 1 - Depth of the constant temperature layer, take 17.45 m.

[0021] Preferably, in the step S1, the reservoir temperature is the average temperature of the geothermal fluid calculated using the geothermal gradient and the reservoir burial depth.

[0022] Preferably, in the step S1, the calculation formula for the reservoir temperature is as follows:

[0023] t = t 0 + (h - h 0 ) × G / 100 (Equation 2);

[0024] In the formula: t - Reservoir temperature, °C; t 0 - Temperature of the constant temperature layer, take 14.75 °C; h - Reservoir burial depth, m; h 0 - Depth of the constant temperature layer, take 17.45 m; G - Geothermal gradient, °C / 100 m.

[0025] Preferably, in the step S2, it specifically includes: collecting and determining the thickness and permeability coefficient of the reservoir sandstone of the geothermal resource through the geological logging, well logging, and testing data obtained during the oil and gas exploration process.

[0026] Preferably, in the step S2, the thickness of the reservoir sandstone of the geothermal resource is obtained by statistically analyzing the spontaneous potential curve data of the logging data or well logging data, and the porosity and permeability coefficient are obtained from the conventional analysis data of the core of the coring well or the interpreted data of the well logging porosity and permeability treatment.

[0027] Preferably, in the step S3, it specifically includes:

[0028] Calculating the influence radius and water production of a single well based on the thickness and permeability coefficient of the reservoir sandstone, taking the influence radius of a single well as the evaluation boundary of the geothermal field, and calculating and determining the thermal power scale provided by the geothermal field delineated by a single well based on the water production of a single well and the reservoir temperature, and dividing the scale of the geothermal field into the first-level classification according to the national standard.

[0029] Preferably, in the step S3, calculating the influence radius and water production of a single well based on the thickness and permeability coefficient of the reservoir sandstone, taking the influence radius of a single well as the evaluation boundary of the geothermal field, and calculating and determining the thermal power scale provided by the geothermal field delineated by a single well based on the water production of a single well and the reservoir temperature.

[0030] Preferably, in the step S3, the calculation formula for the influence radius of a single well is as follows:

[0031]

[0032] Where: R - influence radius of a single well, m; Sw - drawdown, m; K - permeability coefficient, m / d.

[0033] Preferably, in step S3, the formula for calculating the water yield within the influence radius of a single well is as follows:

[0034] Q = 2.68×(K×M×Sw) / lg(R / r) (Equation 4);

[0035] Where: Q - daily water production of a single well, m 3 / d; K - permeability coefficient of the heat reservoir, m / d; M - thickness of the heat reservoir, m; Sw - drawdown, m; r - well diameter, m; R - influence radius, m.

[0036] Preferably, in step S3, the formula for calculating the thermal power that the geothermal field can provide is as follows:

[0037] Qr = Q×Cw×ρw×(t y -t p ) (Equation 5);

[0038] Where: Qr ─ thermal power production of a single well, MW; Q ─ daily water production of a single well, m 3 / d; Cw ─ specific heat of hot water, with a value of 4186.8 J / kg·°C; ρw ─ density of hot water, with a value of 986 kg / m 3 ; t y ─ temperature of geothermal fluid, °C; t p ─ temperature of the abandoned water, 25.0 °C.

[0039] Preferably, in step S3, according to the thermal power resource scale of the geothermal field within the influence radius of a single well calculated in step 2 and the geothermal field scale classification standard, the heat reservoir is classified into three levels of large, medium, and small according to the thermal power of a single well geothermal field being greater than 50 MW, 10 - 50 MW, and less than 10 MW.

[0040] Preferably, in step S4, it specifically includes:

[0041] Comprehensively utilize the thermal conductivities and geothermal gradients of different lithologies. Based on the thermal conductivity and geothermal gradient parameters of a single well, calculate and determine the heat compensation parameters that affect the temperature recovery of low-temperature geothermal fluids according to the formula. Through the variation characteristics of the correlation between the heat compensation parameters and the distance from the bedrock, determine the division nodes of the heat compensation parameters, and conduct a first-level classification according to the distribution law of the heat compensation parameters of the main heat reservoir.

[0042] Preferably, in step S4, according to the geothermal resource type classification method, the determination of the heat compensation parameters of the heat reservoir in different tectonic zones is obtained by weighted calculation of the borehole geothermal gradient and rock thermal conductivity of the heat reservoir in different tectonic zones.

[0043] Preferably, the calculation formula is as follows:

[0044] q = -100 kr G (Equation 6);

[0045] In the formula, q: heat compensation parameter, mW / m2; kr: rock thermal conductivity, W / (m·K); dt / dz: geothermal gradient, ℃ / hm, and the negative sign indicates that the vertical coordinate is positive towards the surface; t: temperature, ℃; z: depth, m.

[0046] Preferably, in step S4, it is divided by the inflection point of the correlation curve between the heat compensation parameter and the change in the heat storage burial depth. According to greater than 70 mw / m 2 , 50 mw / m 2 , -70 mw / m 2 , less than 50 mw / m 2 , the heat storage in different tectonic belts is divided into three types: high-speed, medium-speed, and low-speed heat compensation types, and the first-level classification of the temperature recovery ability of the low-temperature reinjection water in the heat storage is carried out.

[0047] Preferably, in step S5, it specifically includes: comprehensively coupling the first-level and second-level classification criteria for comprehensive classification evaluation of the availability of geothermal resources.

[0048] Preferably, in step S5, it specifically includes: on the basis of the first-level classification of the geothermal field thermal power resource scale and the first-level classification of the temperature recovery ability of the low-temperature reinjection water in the heat storage, a second-level classification is carried out. The sedimentary basin-type geothermal resources are divided into three major categories and nine sub-categories, and the classification evaluation of the sustainable utilization of geothermal resources is completed according to good, medium, and poor.

[0049] Preferably, in step S5, the good evaluations include large-scale single-well geothermal fields with rapid heat compensation, medium-scale single-well geothermal fields with rapid heat compensation, and large-scale single-well geothermal fields with medium-speed heat compensation. The medium evaluations include small-scale single-well geothermal fields with rapid heat compensation, medium-scale single-well geothermal fields with medium-speed heat compensation, and large-scale single-well geothermal fields with low-speed heat compensation. The poor evaluations include small-scale single-well geothermal fields with medium-speed heat compensation, medium-scale single-well geothermal fields with low-speed heat compensation, and small-scale single-well geothermal fields with low-speed heat compensation.

[0050] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0051] In the present invention, through the division of the geothermal power of the single-well geothermal field combined with the heat conduction efficiency, that is, the temperature recovery ability level of the heat storage for low-temperature reinjection water, the comprehensive utilization of the geothermal power of the single-well geothermal field and the heat compensation parameter of the terrestrial heat flow is used for the classification evaluation of the sustainable utilization of geothermal resources. It overcomes the problems of single evaluation angle, low accuracy, and lack of consideration of the green recyclable conditions of geothermal resources in the previous classification evaluation of the quality of sedimentary basin buried geothermal resources. The classification is more comprehensive and reasonable, and it is more conducive to evaluating geothermal resources from the perspective of green sustainable recycling.

[0052] In the present invention, the difficulties that the current qualitative classification and evaluation can only be carried out according to a single factor such as temperature, fluid components, single-well productivity, heat compensation parameters, etc., and the quantitative evaluation of the temperature recovery ability of the reinjected fluid cannot be carried out are solved, which has practical significance for improving the application effect of the classification evaluation of the buried geothermal resources in sedimentary basins.

[0053] In the present invention, the green and sustainable utilization classification evaluation of the buried geothermal resources in sedimentary basins can be realized, which provides a prerequisite for the subsequent selection of areas for the development and utilization of geothermal resources. Description of the Drawings

[0054] Figure 1 is the flow chart of the present invention;

[0055] Figure 2 is the diagram of the division of geothermal resource quality types in the comparative example of the present invention;

[0056] Figure 3 is the diagram of the thermal power distribution and thermal power classification results of the geothermal reservoir single-well geothermal field in the embodiment of the present invention;

[0057] Figure 4 is the diagram of the classification result of the temperature recovery ability level of the low-temperature fluid in the geothermal reservoir according to the heat compensation parameter in the embodiment of the present invention. Detailed Embodiments

[0058] The following further describes the detailed embodiments of a classification evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources in the present invention in conjunction with the attached Figures 1-4 , etc. The classification evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources in the present invention is not limited to the description of the following embodiments.

[0059] Embodiment 1:

[0060] A classification evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, as Figure 1 shown, includes the following steps:

[0061] S1 Determine the geothermal gradient and reservoir temperature;

[0062] S2 Determine the reservoir thickness and permeability;

[0063] S3 Classify based on the scale of the geothermal reservoir single-well geothermal field;

[0064] S4 Classify based on the heat compensation parameter of the reservoir;

[0065] S5 Comprehensive classification evaluation of geothermal resource quality.

[0066] Embodiment 2:

[0067] A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, as Figure 1 shown. The other steps are similar to those in Embodiment 1. Further, in step S1, it specifically includes:

[0068] According to the formation temperature test data obtained during the oil well testing process in the oil and gas exploration process, use the formation temperature calculation formula to calculate and clarify the geothermal gradient and the distribution characteristics of the heat reservoir temperature within the geothermal utilization area.

[0069] Further, in step S2, it specifically includes: Through the geological logging, logging, and testing data obtained during the oil and gas exploration process, collect and determine the thickness and permeability coefficient of the heat reservoir sandstone of the geothermal resources.

[0070] Further, in step S3, it specifically includes:

[0071] Calculate the influence radius and water production of a single well according to the thickness and permeability coefficient of the heat reservoir sandstone. Take the influence radius of a single well as the evaluation boundary of the geothermal field, and combine the water production of a single well and the heat reservoir temperature to calculate and determine the thermal power scale provided by the geothermal field delineated by a single well. Make a classification of the geothermal field scale at the first level according to the national standard.

[0072] Further, in step S4, it specifically includes:

[0073] Comprehensively utilize the thermal conductivities and geothermal gradients of different lithologies. Based on the thermal conductivity and geothermal gradient parameters of a single well, calculate and determine the thermal compensation parameters that affect the temperature recovery of low-temperature geothermal fluids according to the formula. Determine the division nodes of the thermal compensation parameters through the variation characteristics of the correlation relationship between the thermal compensation parameters and the distance from the bedrock. Make a classification at the first level according to the distribution law of the thermal compensation parameters of the main heat reservoirs.

[0074] Further, in step S5, it specifically includes: Comprehensively couple the classification criteria at the first and second levels to conduct a comprehensive classification and evaluation of the availability of geothermal resources.

[0075] Embodiment 3:

[0076] A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, as Figure 1 shown. The other steps are similar to those in Embodiment 2. Further, in step S1, the geothermal gradient is the growth rate of the formation temperature that is not affected by the atmospheric temperature with the increase in depth, expressed as the number of degrees increased per 100-meter vertical depth, and is obtained using the wellbore temperature measurement data.

[0077] Further, in step S1, the geothermal gradient calculation formula is as follows:

[0078] G = 100×(t - t 0 ) / (h - h 1 ) (Equation 1);

[0079] Where: G - geothermal gradient, °C / 100m; t - measured temperature during oil testing, °C; t 0 - temperature of the constant temperature layer, taking 14.75 °C; h - measured depth, m; h 1 - depth of the constant temperature layer, taking 17.45 m.

[0080] Furthermore, in step S1, the reservoir temperature is the average temperature of the geothermal fluid calculated using the geothermal gradient and the reservoir burial depth.

[0081] Furthermore, in step S1, the formula for calculating the reservoir temperature is as follows:

[0082] t = t 0 +(h - h 0 ) × G / 100 (Equation 2);

[0083] Where: t - reservoir temperature, °C; t 0 - temperature of the constant temperature layer, taking 14.75 °C; h - reservoir burial depth, m; h 0 - depth of the constant temperature layer, taking 17.45 m; G - geothermal gradient, °C / 100m.

[0084] Furthermore, in step S2, the sandstone thickness of the geothermal resource reservoir is obtained by statistically analyzing the well logging data or the spontaneous potential curve data of the logging data, and the porosity and permeability coefficient are obtained from the conventional analysis data of the core of the core well or the interpreted data of the logging porosity and permeability treatment.

[0085] Furthermore, in step S3, based on the sandstone thickness and permeability coefficient of the reservoir, the influence radius of single-well production and the water production volume are calculated. Taking the influence radius of single-well production as the evaluation boundary of the geothermal field, combined with the single-well water production volume and the reservoir temperature, the thermal power scale provided by the geothermal field delineated by single-well production is calculated and determined.

[0086] Furthermore, in step S4, according to the geothermal resource type classification method, the determination of the heat recharge parameters of the reservoirs in different tectonic zones is obtained by weighted calculation of the wellbore geothermal gradient and the rock thermal conductivity of the reservoirs in different tectonic zones.

[0087] Furthermore, in step S5, it specifically includes: on the basis of the first-level classification of the geothermal field thermal power resource scale and the first-level classification of the heat storage low-temperature recharge water temperature recovery ability, a secondary classification is carried out, and the sedimentary basin type geothermal resources are divided into three categories and nine sub-categories, and the sustainable utilization classification evaluation of the geothermal resources is completed according to good, medium, and poor.

[0088] Example 4:

[0089] A classification and evaluation method for the green recyclable utilization of sedimentary basin type geothermal resources, such as Figure 1As shown, other steps are similar to those in Embodiment 3. Further, in step S3, the calculation formula for the influence radius of a single well is as follows:

[0090] q = -100 kr G (Equation 6);

[0091] In the formula, q: heat compensation parameter, mW / m2; kr: rock thermal conductivity, W / (m·K); dt / dz: geothermal gradient, ℃ / hm, the negative sign indicates that the vertical coordinate is positive towards the surface; t: temperature, ℃; z: depth, m.

[0092] Further, in step S3, the calculation formula for the influence radius of a single well is as follows:

[0093]

[0094] In the formula: R - influence radius of a single well, m; Sw - drawdown, m; K - permeability coefficient, m / d.

[0095] Further, in step S3, the calculation formula for the water yield within the influence radius of a single well is as follows:

[0096] Q = 2.68×(K×M×Sw) / lg(R / r) (Equation 4);

[0097] In the formula: Q - daily water production of a single well, m 3 / d; K - permeability coefficient of the heat reservoir, m / d; M - thickness of the heat reservoir, m; Sw - drawdown, m; r - well diameter, m; R - influence radius, m.

[0098] Further, in step S3, the calculation formula for the thermal power that the geothermal field can provide is as follows:

[0099] Qr = Q×Cw×ρw×(t y -t p ) (Equation 5);

[0100] In the formula: Qr ─ thermal power production of a single well, MW; Q ─ daily water production of a single well, m 3 / d; Cw ─ specific heat of hot water, with a value of 4186.8 J / kg·℃; ρw ─ density of hot water, with a value of 986 kg / m 3 ; t y ─ temperature of geothermal fluid, ℃; t p ─ temperature of the abandoned water, 25.0℃.

[0101] Further, in step S4, it is divided with the inflection point of the correlation curve between the heat compensation parameter and the change in the buried depth of the heat reservoir as the boundary. According to being greater than 70 mw / m 2 , 50 mw / m 2 -70 mw / m 2 , less than 50 mw / m 2, different-structured heat reservoirs are divided into three types: high-speed, medium-speed, and low-speed heat replenishment types, and a first-level classification of the temperature recovery ability of the low-temperature reinjected water in the heat reservoir is carried out.

[0102] Further, in step S5, good evaluations include large-scale rapid heat replenishment, medium-scale rapid heat replenishment, and large-scale single-well geothermal fields with medium-speed heat replenishment. Medium evaluations include small-scale rapid heat replenishment, medium-scale medium-speed heat replenishment, and large-scale single-well geothermal fields with low-speed heat replenishment. Poor evaluations include small-scale medium-speed heat replenishment, medium-scale low-speed heat replenishment, and small-scale single-well geothermal fields with low-speed heat replenishment.

[0103] Example 5:

[0104] A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, as Figure 1 shown. Other steps are similar to those in Example 4. Further, in step S3, according to the thermal power resource scale of the geothermal field within the influence radius of the single well calculated in step 2 and the geothermal field scale classification standard, the heat reservoir is classified at the first level according to the thermal power greater than 50 MW, 10 - 50 MW, and less than 10 MW for the single-well geothermal field thermal power resource scale, and is divided into three types: large, medium, and small.

[0105] Example 6:

[0106] A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, as Figure 1 shown. In step 101, the geothermal gradient refers to the growth rate of the formation temperature that is not affected by the atmospheric temperature with the increase in depth, expressed as the number of degrees increased per 100-meter vertical depth, and is obtained using the wellbore temperature measurement data. The calculation formula is as follows:

[0107] G = 100×(t - t 0 ) / (h - h 1 );

[0108] In the formula: G - geothermal gradient (℃ / 100m); t - oil test temperature measurement (℃); t 0 - constant temperature layer temperature, taking 14.75℃; h - temperature measurement depth (m); h 1 - constant temperature layer depth, taking 17.45m.

[0109] The heat reservoir temperature refers to the average temperature of the geothermal fluid calculated using the geothermal gradient and the heat reservoir burial depth. The calculation formula is as follows:

[0110] t = t 0 +(h - h 0 )×G / 100;

[0111] In the formula: t - heat reservoir temperature (℃); t 0- Temperature of the constant temperature layer (taking 14.75 °C); h - Depth of the heat reservoir (m); h 0 - Depth of the constant temperature layer (taking 17.45 m); G - Geothermal gradient (°C / 100 m).

[0112] In step 102, the sandstone thickness of the geothermal resource heat reservoir is obtained by statistically analyzing the spontaneous potential curve data of logging data or well logging data, and the porosity and permeability coefficient are obtained from the conventional analysis data of core samples in the coring well or the interpreted data of well logging porosity and permeability processing.

[0113] In step 103, based on the sandstone thickness and permeability coefficient of the heat reservoir, the influence radius and water output of single-well exploitation are calculated. Taking the influence radius of single-well exploitation as the evaluation boundary of the geothermal field, combined with the single-well water output and heat reservoir temperature, the thermal power scale provided by the geothermal field delineated by single-well exploitation is calculated. The calculation formula for the influence radius of a single well is as follows:

[0114]

[0115] In the formula: R - Influence radius of a single well (m); Sw - Drawdown (m); K - Permeability coefficient (m / d);

[0116] The calculation formula for the water output within the influence radius of a single well is as follows:

[0117] Q = 2.68 × (K × M × Sw) / lg(R / r);

[0118] In the formula: Q - Daily water output of a single well (m 3 / s); K - Permeability coefficient of the heat reservoir (m / d); M - Sandstone thickness of the heat reservoir (m); Sw - Drawdown (m); r - Well diameter (m); R - Influence radius (m);

[0119] The calculation formula for the thermal power provided by the geothermal field is as follows:

[0120] Qr = Q × Cw × ρw × (Ty - Tp)

[0121] In the formula: Qr ─ Thermal power output of a single well (MW); Q ─ Daily water output of a single well (m3 / s); Cw ─ Specific heat of hot water (taking 4186.8 J / kg·°C); ρw ─ Density of hot water (taking 986 kg / m3); Ty ─ Temperature of geothermal fluid (°C); Tp ─ Abandoned water temperature (25.0 °C);

[0122] In step 103, according to the thermal power resource scale of the geothermal field within the influence radius of the single well calculated in step 102 and the geothermal field scale classification standard (GB / T11615 - 2010), the heat reservoir is classified into three levels according to the thermal power > 50 MW, 10 - 50 MW, < 10 MW for the single-well geothermal field thermal power resource scale classification, and it is divided into large, medium, and small types (such as Figure 3as shown

[0123] In step 104, according to the geothermal resource type classification method in the patent document "Classification Method of Geothermal Resource Types in Sedimentary Basin Type", the determination of the heat rechargeability parameters of the heat reservoirs in different tectonic zones is obtained by weighted calculation of the wellbore geothermal gradient and rock thermal conductivity of the heat reservoirs in different tectonic zones. The calculation formula for the heat rechargeability parameters is as follows:

[0124] q = -100kr dt / dz

[0125] In the formula, q: heat rechargeability parameter, mW / m 2 ; kr: rock thermal conductivity, W / (m·K); dt / dz: geothermal gradient, ℃ / hm, the negative sign indicates that the vertical coordinate is positive towards the surface; t: temperature (℃); z: depth (m).

[0126] According to the patent document "Classification Method of Geothermal Resource Types in Sedimentary Basin Type", it is divided by the inflection point of the correlation curve between the heat rechargeability parameter and the change of heat reservoir burial depth. According to >70mw / m 2 , 50mw / m 2 -70 mw / m 2 , <50mw / m 2 , the heat reservoirs in different tectonic zones are divided into three types: high-speed, medium-speed, and low-speed heat recharge types, and the first-level classification of the temperature recovery ability of low-temperature reinjection water in the heat reservoir is carried out (as Figure 4 shown).

[0127] In step 105, on the basis of the first-level classification of the geothermal field heat power resource scale and the first-level classification of the temperature recovery ability of low-temperature reinjection water in the heat reservoir, the second-level classification is carried out. The sedimentary basin type geothermal resources are divided into three major categories and nine sub-categories, and the classification evaluation of the availability of geothermal resources is completed according to good (large-scale rapid heat recharge, medium-scale rapid heat recharge, large-scale single-well geothermal field with medium-speed heat recharge), medium (small-scale rapid heat recharge, medium-scale medium-speed heat recharge, large-scale single-well geothermal field with low-speed heat recharge), and poor (small-scale medium-speed heat recharge, medium-scale low-speed heat recharge, small-scale single-well geothermal field with low-speed heat recharge) (as shown in Table 1).

[0128] Table 1

[0129]

[0130] Comparative example:

[0131] Figure 2It is a diagram for classifying the quality types of geothermal resources according to the factor of temperature in the comparative example. According to the Specifications for Geothermal Resource Geological Exploration (GB / T 11615-2010) (shown in Table 2) and the temperature distribution characteristics, the geothermal resources in the Dongying Formation, Dongying Depression can be divided into three types: low-temperature warm-hot water geothermal resources (40-60 °C), low-temperature hot water geothermal resources (60-90 °C), and medium-temperature geothermal resources (90-150 °C). Although it can well characterize the main uses of geothermal resources, it is difficult to determine the quality for the sustainable utilization of geothermal resources.

[0132] Table 2

[0133]

[0134] In summary, this application overcomes the problems of the previous single-angle and low-precision classification and evaluation of the quality of buried geothermal resources in sedimentary basins and does not consider the green and recyclable conditions of geothermal resources. The classification is more comprehensive and reasonable, and it is more conducive to evaluating geothermal resources from the perspective of green and sustainable recycling; it solves the difficulty that the current qualitative quality classification and evaluation can only be carried out according to temperature, fluid components, single-well production capacity, etc., and it is impossible to carry out quantitative evaluation of recyclability for the temperature recovery of reinjected fluids, and improves the accuracy of the classification and evaluation of the available quality of buried geothermal resources in sedimentary basins.

[0135] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources, characterized in that, it includes the following steps: S1 Determine the geothermal gradient and reservoir temperature; S2 Determine the reservoir thickness and permeability; S3 Classify based on the scale of the geothermal field of a single well in the reservoir; S4 Classify based on the heat recharge parameter of the reservoir; S5 Comprehensive classification and evaluation of geothermal resource quality.

2. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 1, characterized in that, in the step S1, it specifically includes: According to the formation temperature test data obtained during the oil well testing process in the oil and gas exploration, use the formation temperature calculation formula to calculate and clarify the geothermal gradient and the distribution characteristics of the reservoir temperature within the geothermal utilization area.

3. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 2, characterized in that, in the step S1, the geothermal gradient is the growth rate of the formation temperature that is not affected by the atmospheric temperature of the earth with the increase of depth, expressed in degrees increased per 100-meter vertical depth, and obtained by using the wellbore temperature measurement data.

4. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 3, characterized in that, in the step S1, the geothermal gradient calculation formula is as follows: G = 100×(t - t 0 ) / (h - h 1 ) (Equation 1); Where: G - geothermal gradient, °C / 100m; t - measured temperature during oil testing, °C; t 0 - temperature of the constant temperature layer, taken as 14.75 °C; h - depth of temperature measurement, m; h 1 - depth of the constant temperature layer, taken as 17.45 m.

5. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 2, characterized in that, in the step S1, the reservoir temperature is the average temperature of the geothermal fluid calculated by using the geothermal gradient and the reservoir burial depth.

6. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 5, characterized in that, in the step S1, the reservoir temperature calculation formula is as follows: t = t 0 +(h - h 0 ) × G / 100 (Equation 2); Where: t - heat reservoir temperature, °C; t 0 - constant temperature layer temperature, taken as 14.75 °C; h - heat reservoir burial depth, m; h 0 - constant temperature layer depth, taken as 17.45 m; G - geothermal gradient, °C / 100 m.

7. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 1, characterized in that, in the step S2, it specifically includes: Through the geological logging, logging, and test data obtained during the oil and gas exploration process, collect and determine the sandstone thickness and permeability coefficient of the geothermal resource reservoir.

8. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 7, characterized in that, in the step S2, the sandstone thickness of the geothermal resource reservoir is obtained by statistical analysis of the spontaneous potential curve data of logging data or logging data, and the porosity and permeability coefficient are obtained by the conventional analysis data of the core of the core well or the interpreted data of the logging porosity and permeability processing.

9. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 1, characterized in that, in the step S3, it specifically includes: According to the sandstone thickness and permeability coefficient of the reservoir, calculate the influence radius and water production of a single well during exploitation. Taking the influence radius of a single well during exploitation as the evaluation boundary of the geothermal field, combined with the water production of a single well and the reservoir temperature, calculate and determine the thermal power scale provided by the geothermal field delineated by a single well during exploitation, and conduct the classification of the first-level scale of the geothermal field according to national standards.

10. The classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources according to claim 9, characterized in that, In step S3, the influence radius and water yield of a single well are calculated based on the thickness and permeability coefficient of the heat storage sandstone. Taking the influence radius of a single well as the evaluation boundary of the geothermal field, the thermal power scale provided by the geothermal field delineated by a single well is calculated in combination with the water yield of a single well and the heat storage temperature.

11. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 10, characterized in that, in step S3, the calculation formula for the influence radius of a single well is as follows: In the formula: R - influence radius of a single well, m; Sw - drawdown, m; K - permeability coefficient, m / d.

12. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 10, characterized in that, in step S3, the calculation formula for the water yield within the influence radius of a single well is as follows: Q = 2.68×(K×M×Sw) / lg(R / r) (Formula 4); Where: Q - daily water production of a single well, m 3 / d; K - permeability coefficient of the heat reservoir, m / d; M - thickness of the heat reservoir, m; Sw - drawdown, m; r - well diameter, m; R - radius of influence, m.

13. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 10, characterized in that, in step S3, the calculation formula for the thermal power that the geothermal field can provide is as follows: Qr = Q × Cw × ρw × (t y - t p ) (Equation 5); Where: Qr─Thermal production power of a single well, MW; Q─Daily water production of a single well, m 3 / d; Cw─Specific heat of hot water, with a value of 4186.8 J / kg·°C; ρw─Density of hot water, with a value of 986 kg / m 3 ; t y ─ Geothermal fluid temperature, °C; t p ─ Temperature of the rejected water, 25.0 °C.

14. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 10, characterized in that, in step S3, according to the thermal power resource scale of the geothermal field within the influence radius of a single well calculated in step 2 and the geothermal field scale classification standard, the heat storage is classified into three levels according to the thermal power greater than 50MW, 10 - 50MW, and less than 10MW for the thermal power resource scale of a single well geothermal field, and it is divided into large, medium, and small types.

15. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 1, characterized in that, in step S4, it specifically includes: Comprehensively using the thermal conductivities and geothermal gradients of different lithologies, based on the thermal conductivity and geothermal gradient parameters of a single well, the heat replenishment parameters affecting the temperature recovery of low-temperature geothermal fluids are calculated and determined according to the formula. Through the correlation relationship change characteristics of the heat replenishment parameters with the distance from the bedrock, the heat replenishment parameter division nodes are determined, and the first-level classification is carried out according to the distribution law of the heat replenishment parameters of the main heat storage.

16. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 15, characterized in that, in step S4, according to the geothermal resource type classification method, the determination of the heat replenishment parameters of the heat storage in different tectonic zones is obtained by weighted calculation of the wellbore geothermal gradient and rock thermal conductivity of the heat storage in different tectonic zones.

17. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 16, characterized in that, the calculation formula is as follows: q = -100 kr G (Formula 6); In the formula, q: heat replenishment parameter, mW / m2; kr: rock thermal conductivity, W / (m·K); dt / dz: geothermal gradient, ℃ / hm, the negative sign indicates that the vertical coordinate is positive towards the surface; t: temperature, ℃; z: depth, m.

18. A classification and evaluation method for the green recyclable utilization of sedimentary basin-type geothermal resources as described in claim 15, It is characterized in that In the step S4, it is divided by taking the inflection point of the correlation curve between the heat compensation parameter and the change of the heat storage burial depth as the boundary. According to greater than 70 mw / m 2 , 50 mw / m 2 , -70 mw / m 2 , less than 50 mw / m 2 , the heat storage in different structural belts is divided into three types: high-speed, medium-speed, and low-speed heat compensation types, and the first-level classification of the temperature recovery ability of the low-temperature recharged water in the heat storage is carried out.

19. A classification and evaluation method for green recyclable utilization of sedimentary basin-type geothermal resources according to claim 1, It is characterized in that In the step S5, it specifically includes: comprehensively coupling the first-level and second-level classification criteria for comprehensive classification and evaluation of the availability of geothermal resources.

20. A classification and evaluation method for green recyclable utilization of sedimentary basin-type geothermal resources according to claim 19, It is characterized in that In the step S5, it specifically includes: based on the first-level classification of the geothermal field thermal power resource scale and the first-level classification of the heat reservoir low-temperature reinjection water temperature recovery ability, a second-level classification is carried out, and the sedimentary basin-type geothermal resources are divided into three major categories and nine sub-categories, and the classification and evaluation of the sustainable utilization of geothermal resources are completed according to good, medium, and poor.

21. A classification and evaluation method for green recyclable utilization of sedimentary basin-type geothermal resources according to claim 20, It is characterized in that In the step S5, the good evaluations include large-scale single-well geothermal fields with rapid heat replenishment, medium-scale single-well geothermal fields with rapid heat replenishment, and large-scale single-well geothermal fields with medium-speed heat replenishment; the medium evaluations include small-scale single-well geothermal fields with rapid heat replenishment, medium-scale single-well geothermal fields with medium-speed heat replenishment, and large-scale single-well geothermal fields with low-speed heat replenishment; the poor evaluations include small-scale single-well geothermal fields with medium-speed heat replenishment, medium-scale single-well geothermal fields with low-speed heat replenishment, and small-scale single-well geothermal fields with low-speed heat replenishment.

Images