Calculation method of actual heat consumption of heavy oil reservoir during steam stimulation

Abstract

The present invention provides a method for calculating the actual heat consumption of a heavy oil steam huff-and-puff oil layer, and the method comprises: step 1, testing the bottom hole temperature and calculating the temperature of the heating zone near the bottom hole; step 2, testing the wellhead steam injection temperature and calculating the total thermal enthalpy of the wellhead steam injection; step 3, calculating the heat loss of the wellbore according to the wellbore insulation material; step 4, testing the output fluid temperature, oil production and water production, and calculating the output fluid thermal enthalpy increase; step 5, estimating the heat loss of the top and bottom cap layers; and step 6, calculating the actual heat consumption of the oil layer in this cycle. The method for calculating the actual heat consumption of a heavy oil steam huff-and-puff oil layer provides a fast, simple and effective method for on-site technical personnel to judge the quality of periodic steam injection, the thermal utilization rate of the reservoir, and the evaluation of the effect of periodic development, and provides a basis for reservoir managers to grasp the law of periodic huff-and-puff development in a macroscopic way and carry out macro development decisions.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development, and in particular to a method for calculating actual heat consumption of heavy oil steam huff-and-puff oil layers. Background Art

[0002] As the number of production cycles increases, the effect of steam huff and puff gradually deteriorates. At the end of 2017, there were 1,225 steam huff and puff wells with 6 cycles or more in Shengli East Oilfield, accounting for 34.0% of the total number of wells. After entering the high-cycle huff and puff, the cycle oil production of a single well dropped to less than 1,200 tons, the cycle oil-gas ratio dropped to about 0.6, the cycle water content gradually increased to more than 90%, and the cycle effect gradually deteriorated. The heavy oil reservoir as a whole is in the stage of "high cycle, high water content, low production, low oil-gas ratio, medium-high recovery degree".

[0003] Since the 15th Five-Year Plan, with the in-depth development of steam thermal recovery, although the output has maintained a stable upward trend and the annual output value has exceeded 16 billion yuan, the thermal recovery technology dominated by throughput development has entered the high-cycle development stage, and the steam injection volume has also risen sharply. The current annual steam injection volume exceeds 10 million tons, which is equivalent to an annual consumption of 1.4 million tons of standard coal. While thermal recovery development brings economic benefits, energy consumption is also increasing year by year. A large amount of heat is ineffectively produced, the heat consumption per ton of oil increases sharply, the actual thermal energy utilization rate of the oil layer decreases, and the heating radius increases slowly, resulting in poor development effects and economic benefits. Estimating and evaluating the actual heat consumption during steam throughput is very important for proposing measures to improve the effect of high-cycle throughput development. Therefore, we invented a method for calculating the actual heat consumption of heavy oil steam throughput oil layers to solve the above technical problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for estimating the actual heat consumption of a periodic oil layer during heavy oil steam stimulation based on the law of conservation of energy and production dynamic test data.

[0005] The object of the present invention can be achieved by the following technical measures: a method for calculating the actual heat consumption of an oil layer by heavy oil steam stimulation, the method comprising: step 1, testing the bottom hole temperature and calculating the temperature of a heating zone near the bottom hole; step 2, testing the wellhead steam injection temperature and calculating the total thermal enthalpy of the wellhead steam injection; step 3, calculating the wellbore heat loss according to the wellbore insulation material; step 4, testing the output fluid temperature, oil production and water production, and calculating the output fluid thermal enthalpy increase; step 5, estimating the heat loss of the top and bottom cap layers; and step 6, calculating the actual heat consumption of the oil layer in the cycle.

[0006] The purpose of the present invention can also be achieved by the following technical measures:

[0007] In step 1, based on the test temperature and the original reservoir temperature, the average temperature of the heating zone near the bottom of the well before the current round of steam injection is estimated according to formula (1):

[0008]

[0009] Where, T i Represents the original reservoir temperature, °C

[0010] T b Represents the test well bottom temperature, ℃

[0011] T c Represents the average temperature of the heating zone near the bottom of the well before steam injection, ℃.

[0012] In step 2, during the steam injection process, the saturated water enthalpy h is calculated by looking up the table according to the wellhead steam injection temperature. w The enthalpy of dry saturated steam h s Then, according to the wellhead steam dryness x, the enthalpy of wet saturated steam h is calculated according to formula (2). m :

[0013] h m =xh s +(1-x)h w (2)

[0014] In the formula, h s Represents the enthalpy of dry saturated steam, KJ / kg

[0015] h w Represents the enthalpy of saturated water, KJ / kg

[0016] h m Represents the enthalpy of wet saturated steam, KJ / kg.

[0017] In step 2, the enthalpy of steam injected into the wellhead every day is calculated based on the daily wellhead steam volume and the calculated enthalpy of wet saturated steam. Then, the enthalpy of steam injected into the wellhead every day is accumulated according to the number of steam injection days to calculate the total enthalpy of steam injected into the wellhead for this cycle. s :

[0018] Q sd =h m ×q s (3)

[0019]

[0020] In the formula, q s represents the daily amount of steam injected into the wellhead, t;

[0021] Q sd represents the daily wellhead steam injection enthalpy, KJ;

[0022] Q sw Represents the cumulative wellhead injected steam enthalpy in this cycle, KJ;

[0023] n represents the number of days of steam injection in this cycle.

[0024] In step 3, the heat loss per kilometer is determined based on the material of the well insulation string, and the wellbore heat loss ΔQ is estimated:

[0025] Q sr =Q sw -ΔQ (5)

[0026] In the formula, Q sr Represents the cumulative enthalpy of steam injected into the reservoir during this cycle, KJ;

[0027] ΔQ represents the heat loss of the wellbore, KJ.

[0028] In step 4, after the steam injection and well shut-in are completed, the well is opened for production, and the daily oil production, daily water production and liquid production temperature are recorded.

[0029] In step 4, when the oil well starts production, the temperature of the oil layer rises due to the effect of steam injection, the temperature of the produced liquid will inevitably rise, and the heat carried will inevitably increase; according to formulas (6) and (7), the increase in the thermal enthalpy of daily water production and daily oil production is calculated respectively:

[0030] Q wi =c w m w (T wo -T c ) (6)

[0031] Q oi =c o m o (T wo -T c ) (7)

[0032] In the formula, Q wi , Q oi Respectively represent the daily enthalpy increase of water production and oil production, KJ;

[0033] c w 、c o Represent the specific heat capacity of water and oil, KJ / (kg·℃);

[0034] m w 、m o Represent the daily output of water and oil, kg;

[0035] T wo Represents the daily liquid production temperature, ℃.

[0036] In step 4, after the end of this round of production, the daily increase in the enthalpy of the produced liquid is accumulated to calculate the cumulative enthalpy value of the produced liquid in this round:

[0037]

[0038] Where N represents the number of production days in this cycle.

[0039] In step 5, the heating radius of the cycle is estimated according to the Marx-Langenheim formula (9):

[0040]

[0041] Where r is the heating radius, m

[0042] i s is the average steam injection rate of this round, kg / s

[0043] h ma Average saturated steam enthalpy of this round, J / kg

[0044] h represents the oil layer thickness, m

[0045] M R Represents the heat capacity of the oil layer, J / (m3·℃)

[0046] α represents the thermal diffusion coefficient of the top and bottom cover layers, m2 / s;

[0047] λ represents the thermal conductivity of the top and bottom cover rocks, W / (m·℃)

[0048]

[0049] t represents the steam injection time, s

[0050] erfc-cocomplement error function, obtained by looking up the table.

[0051] In step 5, the heat loss of the top and bottom cover layers is estimated according to formula (10):

[0052]

[0053] Where, t m is the stewing time, h.

[0054] In step 6, according to the law of conservation of energy, the heat loss of wellhead steam enthalpy = heat loss of injected reservoir steam = heat loss of top and bottom cap layers + actual heat consumption of oil layer + heat brought out by produced fluid, thus calculating the actual heat consumption of oil layer in this cycle, that is:

[0055] Q=Q sr -Q d -Ql =Q sw -ΔQ-Q d -Q l (11)

[0056] Where, Q is the actual heat consumption of the oil layer, KJ;

[0057] Q sr Represents the cumulative enthalpy of steam injected into the reservoir during this cycle, KJ;

[0058] Q d is the heat loss of the top and bottom cover layers, KJ;

[0059] Q l is the accumulated enthalpy of the produced fluid in this round, KJ;

[0060] Q sw Represents the cumulative wellhead injected steam enthalpy in this cycle, KJ;

[0061] ΔQ represents the heat loss of the wellbore, KJ.

[0062] In step 6, the actual heat consumption of the oil layer in each cycle during the heavy oil steam stimulation process is calculated, and the heat consumption per ton of oil in each round and the change law of the cycle are further calculated based on the oil production in the cycle.

[0063] The present invention provides a new method for calculating the actual heat consumption of the heavy oil steam huff-and-puff oil layer. First, the bottom hole temperature is tested, the temperature of the heating zone near the bottom hole is estimated, then the wellhead steam injection temperature is counted, the wellhead steam enthalpy value is calculated, and the actual steam enthalpy value injected into the oil reservoir at the bottom hole is calculated according to the material of the steam injection pipeline, etc.; then, the production data including daily oil production, daily water production, and liquid production temperature are tested and measured to calculate the increase in the enthalpy of the produced liquid; and according to the Marx-Langenheim formula for heavy oil steam injection development, the heating radius and the heat loss of the top and bottom cap layers are estimated; finally, according to the law of conservation of energy, the steam enthalpy injected into the oil reservoir = the heat loss of the top and bottom cap layers + the actual heat consumption of the oil layer + the heat brought out by the produced liquid, so as to calculate the actual heat consumption of the oil layer in this cycle. Traditional methods and technologies do not involve the actual heat consumption of the steam huff-and-puff oil layer. Even if they are similar, they all rely purely on the seepage theory and the material balance equation to carry out theoretical calculations. Some parameters of the theoretical calculation are difficult to obtain or are quite different from those in the mine, resulting in a relatively large difference between the theoretical calculation results and the mine practice. This invention is not a simple calculation, but mainly based on the mine test data, including the bottom hole test temperature, wellhead steam injection temperature, steam injection volume, output liquid temperature, liquid volume, etc. to estimate the actual heat consumption of the oil layer during steam huff and puff. By combining theory with practice on the steam huff and puff development test data and the law of conservation of energy, an engineering calculation method for quickly judging the efficiency of steam heat utilization in a cycle round is proposed. This method fully considers the influence of the change in oil layer temperature before steam injection on the next cycle round steam injection, and also fully considers the influence of formation heat carried by the output liquid on the heat utilization of the oil layer. It is a comprehensive, practical and effective method for quickly calculating the actual heat consumption of the oil layer during periodic steam huff and puff. This method is more practical and down-to-earth, and the prediction effect is closer to the mine practice and more in line with the law of heavy oil steam huff and puff development. The present invention provides a fast, simple and effective method for field technicians to judge the quality of periodic steam injection, the thermal utilization rate of the reservoir, and the effect of periodic development, and provides a basis for reservoir managers to grasp the law of periodic huff and puff development in a macroscopic way and make macro development decisions. The present invention is a method for calculating the actual heat consumption of heavy oil steam huff-and-puff oil layers, which fully considers technical and economic factors and mainly relies on field testing and production data. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a flow chart of a specific embodiment of a method for calculating actual heat consumption of heavy oil steam huff-and-puff oil layer according to the present invention;

[0065] Figure 2 A curve diagram showing the actual heat consumption of the oil layer calculated in each production cycle of Well Ping 142 according to a specific embodiment of the present invention as a function of the cycle;

[0066] Figure 3 This is a curve diagram showing the heat consumption per ton of oil calculated in each production cycle of Well Ping 142 according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0067] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings.

[0068] like Figure 1 As shown, Figure 1 The present invention is a flow chart of a method for calculating the actual heat consumption of a heavy oil layer during steam stimulation.

[0069] Step 101, before steam injection, test the bottom hole temperature and estimate the average temperature of the heating zone near the bottom hole before steam injection; before steam injection of heavy oil, first test the bottom hole temperature. According to the test temperature and the original temperature of the reservoir, according to formula (1), estimate the average temperature of the heating zone near the bottom hole before this round of steam injection.

[0070]

[0071] Where, T i Represents the original reservoir temperature, °C

[0072] T b Represents the test well bottom temperature, ℃

[0073] T c Represents the average temperature of the heating zone near the bottom of the well before steam injection, ℃.

[0074] Step 102, during steam injection, the daily steam injection volume, the wellhead steam injection temperature and the wellhead dryness are measured, and the wellhead steam enthalpy is calculated; during the steam injection process, the saturated water enthalpy h is calculated by looking up the table according to the wellhead steam injection temperature. w The enthalpy of dry saturated steam h s According to formula (2), calculate the enthalpy of wet saturated steam h m .

[0075] h m =xh s +(1-x)h w (2)

[0076] In the formula, h s Represents the enthalpy of dry saturated steam, KJ / kg

[0077] h w Represents the enthalpy of saturated water, KJ / kg

[0078] h m Represents the enthalpy of wet saturated steam, KJ / kg.

[0079] According to the daily steam injection volume and the calculated wet saturated steam enthalpy, the daily injected steam enthalpy value is calculated, and then accumulated according to the number of steam injection days to calculate the total injected steam enthalpy Q for this cycle.s .

[0080] Q sd =h m ×q s (3)

[0081]

[0082] In the formula, q s represents the daily amount of steam injected into the wellhead, t

[0083] Q sd represents the daily wellhead steam injection enthalpy, KJ;

[0084] Q sw Represents the cumulative wellhead injected steam enthalpy in this cycle, KJ;

[0085] n represents the number of days of steam injection in this cycle.

[0086] Step 103, calculate the actual steam enthalpy value injected into the reservoir at the bottom of the well according to the heat loss per kilometer of the wellbore; and estimate the wellbore heat loss ΔQ according to the material of the well insulation pipe string.

[0087] Q sr =Q sw -ΔQ (5)

[0088] In the formula, Q sr Represents the cumulative enthalpy of steam injected into the reservoir during this cycle, KJ;

[0089] ΔQ represents the heat loss of the wellbore, KJ.

[0090] Step 104, after the well is opened for production, the daily production data, including daily oil production and daily water production, are recorded, and the increase in thermal enthalpy of the produced liquid is calculated based on the average temperature near the bottom of the well before steam injection; after the steam injection and well shut-in are completed, the well is opened for production, and the daily oil production, daily water production and produced liquid temperature are recorded.

[0091] When the oil well starts to produce, the temperature of the oil layer rises due to the effect of steam injection, the temperature of the produced liquid will inevitably rise, and the heat carried will inevitably increase. Therefore, the increase in the thermal enthalpy of daily water production and daily oil production can be calculated respectively according to formulas (6) and (7).

[0092] Q wi =c w m w (T wo -T c ) (6)

[0093] Q oi =c o m o (T wo -Tc ) (7)

[0094] In the formula, Q wi , Q oi Respectively represent the daily enthalpy increase of water production and oil production, KJ;

[0095] c w 、c o Represent the specific heat capacity of water and oil, KJ / (kg·℃);

[0096] m w 、m o Represent the daily output of water and oil, kg;

[0097] T wo Represents the daily liquid temperature, ℃

[0098] After the end of this round of production, the daily increase in the thermal enthalpy of the produced liquid is accumulated to calculate the cumulative thermal enthalpy value of the produced liquid in this round.

[0099]

[0100] Where N represents the number of production days in this cycle.

[0101] Step 105, estimating the heating radius of the cycle and the heat loss value of the top and bottom cover layers within the heating range according to the Marx-Langenheim formula;

[0102] According to the Marx-Langenheim formula (9), the heating radius of this cycle is estimated.

[0103]

[0104] Where r is the heating radius, m

[0105] i s is the average steam injection rate of this round, kg / s

[0106] h ma Average saturated steam enthalpy of this round, J / kg

[0107] h represents the oil layer thickness, m

[0108] M R Represents the heat capacity of the oil layer, J / (m3·℃)

[0109] α represents the thermal diffusion coefficient of the top and bottom cover layers, m2 / s;

[0110] λ represents the thermal conductivity of the top and bottom cover rocks, W / (m·℃)

[0111]

[0112] t represents the steam injection time, s

[0113] erfc-cocomplement error function, which can be obtained by looking up the table.

[0114] According to formula (10), the heat loss of the top and bottom cover layers is estimated as:

[0115]

[0116] Where, t m is the stewing time, h.

[0117] Step 106, according to the law of energy conservation, the enthalpy of the injected reservoir steam = the heat loss of the top and bottom cap layers + the actual heat consumption of the oil layer + the heat brought out by the produced fluid, so as to calculate the actual heat consumption of the oil layer in this cycle. That is:

[0118] Q=Q sr -Q d -Q l =Q sw -ΔQ-Q d -Q l (11)

[0119] Where, Q is the actual heat consumption of the oil layer, KJ

[0120] The actual heat consumption of the oil layer in each cycle during the heavy oil steam injection process can be calculated, and the heat consumption per ton of oil in each round and the change law of the cycle can be further calculated based on the oil production in the cycle.

[0121] In a specific embodiment of the present invention, the following steps are included:

[0122] In step 1, the bottom hole temperature is first tested before steam injection of heavy oil. In one embodiment, the steam injection round of Ping 142 Well is the third cycle. Before this round of steam injection, a test instrument is used to test the bottom hole temperature of Ping 142 Well at a temperature of T. b =55℃. According to the original oil layer temperature T i = 28℃, calculate the average temperature of the bottom heating area according to the formula T c =41.5° C. The process proceeds to step 102 .

[0123] In step 2, calculate the total injected steam enthalpy Q for this cycle. sw In one embodiment, the injected steam enthalpy at the wellhead of Well 142 can be calculated respectively by calculation, thereby calculating the cumulative injected steam enthalpy. Table 1 shows the daily steam injection parameters of Well 142 during the steam injection process, including injection temperature, injection time, injection dryness, injection speed, calculated injection enthalpy value and total injection enthalpy value Q sw=5111146551KJ.

[0124] Table 1 Calculation process of the daily wellhead steam injection enthalpy in the third cycle of Ping 142 well

[0125]

[0126]

[0127] In step 3, the heat loss of the wellbore is ΔQ. The material of the pipeline of the well 142 has a heat loss of 8% per kilometer and a well depth of 420m. The heat loss of the wellbore can be calculated as ΔQ=5111146551×8%=4702254827KJ, and the process enters step 104.

[0128] In step 4, calculate the increase in the enthalpy of the produced liquid. When Well Ping 142 starts production, the temperature of the oil layer rises due to the effect of steam injection, and the temperature of the produced liquid must rise, and the heat carried must increase. First, according to the daily production data, the enthalpy increase of the water production and the oil production is calculated according to the formula, and then the enthalpy increase of the produced liquid is calculated by adding them. After the end of this round of production of Well Ping 142, a total of 62 days of production, the enthalpy increase of each day is calculated in turn, and then accumulated and added to obtain the cumulative enthalpy value of the produced liquid in this round is Q l =367679235KJ. Table 2 shows the calculation process of the enthalpy increase of the liquid production of Well 142 in the embodiment.

[0129] Table 2 Calculation process of the enthalpy increase of daily liquid production in Ping 142 Well after steam injection and production

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137] In step 5, the heating radius of this cycle is calculated. According to the Marx-Langenheim formula, the heating radius of this cycle is estimated.

[0138] Steam injection rate i s According to the steam data of this round, the average value is 13.8t / h; the saturated steam enthalpy h maThe average value is 2234.6 J / kg; the oil layer thickness h is 6 m; the average steam injection temperature T in this round s is 306℃; the oil layer volume heat capacity M R 2277KJ / (m 3 ·℃); the thermal diffusion coefficient of the top and bottom cover layers is 0.0045m 2 / h; the thermal conductivity of the top and bottom cover rocks is λ2.56W / (m·℃); dimensionless time The steam injection time t is 163.5h, and the dimensionless time t is calculated. D The value obtained by looking up the table of erfc complement error function is 0.05635.

[0139] After calculation, it can be obtained that the heating radius r = 20.0m.

[0140] Estimate the heat loss of the top and bottom cap layers. m According to the formula, the heat loss of the top and bottom cover layers in this round can be calculated as Q d =38170454KJ.

[0141] In step 6, the actual heat consumption of the oil layer and the change law of heat consumption per ton of oil in a cycle are calculated. According to the law of conservation of energy, the heat loss of wellhead steam enthalpy wellbore = the heat loss of injected oil reservoir steam enthalpy = the heat loss of top and bottom cap layers + the actual heat consumption of the oil layer + the heat carried out by the produced fluid.

[0142] Q=Q sr -Q d -Q l =Q sw -ΔQ-Q d -Q l

[0143] =3731532908-298522633-38170454-367679235

[0144] =429640518KJ

[0145] The oil production in this cycle is 1652.8t, and the heat consumption per ton of oil in this cycle can be calculated as

[0146] According to the above steps, the actual heat consumption of the oil layer and the heat consumption per ton of oil in each cycle of Well Ping 142 can be calculated, and its changing rules can be seen from it, such as Figure 2 and Figure 3 shown.

Claims

1. Calculation method of actual heat consumption of heavy oil steam huff and puff reservoir, It is characterized in that The calculation method of the actual heat consumption of the heavy oil steam stimulation oil layer includes: Step 1, testing the bottom hole temperature and calculating the average temperature of the heating zone near the bottom hole; Step 2: Test the wellhead steam injection temperature and calculate the total enthalpy of wellhead steam injection; calculate the enthalpy of steam injected into the wellhead every day according to the daily amount of steam injected into the wellhead and the calculated enthalpy of wet saturated steam, and then add them up according to the number of steam injection days to calculate the total enthalpy of steam injected into the wellhead in this round: Step 3, calculating the heat loss of the wellbore according to the wellbore insulation material; Step 4, testing the temperature of the produced fluid, the oil production and the water production, and calculating the increase in thermal enthalpy of the produced fluid; Step 5, estimating the heat loss of the top and bottom cover layers; Step 6, calculating the actual heat consumption of the oil layer; In step 2, the total enthalpy of injected wellhead steam in this round is: Q sd =h m ×q s (3) In the formula, q s represents the daily amount of steam injected into the wellhead, t; h m Represents the enthalpy of wet saturated steam, KJ; Q sd Represents the enthalpy of steam injected into the wellhead per day, KJ; Q sw represents the cumulative wellhead injected steam enthalpy, KJ; n represents the number of days of steam injection; In step 3, the heat loss per kilometer is determined based on the material of the well insulation string, and the wellbore heat loss ΔQ is estimated: Q sr =Q sw -ΔQ (5) In the formula, Q sr represents the cumulative enthalpy of steam injected into the reservoir, KJ; ΔQ represents the heat loss of the wellbore, KJ; In step 4, when the oil well starts production, the temperature of the oil layer rises due to the effect of steam injection, the temperature of the produced liquid will inevitably rise, and the heat carried will inevitably increase; according to formulas (6) and (7), the increase in the thermal enthalpy of daily water production and daily oil production is calculated respectively: Q wi =c w m w (T wo -T c ) (6) Q oi =c o m o (T wo -T c ) (7) In the formula, Q wi , Q oi Respectively represent the daily enthalpy increase of water production and oil production, KJ; c w 、c o Represent the specific heat capacity of water and oil, KJ / (kg·℃); m w 、m o Represent the daily output of water and oil, kg; T wo Represents the daily liquid production temperature, °C; T c represents the average temperature of the heating zone near the bottom of the well before steam injection, °C; In step 6, according to the law of conservation of energy, the heat loss of wellbore steam enthalpy = heat loss of injected reservoir steam = heat loss of top and bottom cap layers + actual heat consumption of oil layer + heat brought out by produced fluid, thus calculating the actual heat consumption of oil layer, that is: Q=Q sr -Q d -Q l =Q sw -ΔQ-Q d -Q l (11) Where, Q is the actual heat consumption of the oil layer, KJ; Q sr represents the cumulative enthalpy of steam injected into the reservoir, KJ; Q d is the heat loss of the top and bottom cover layers, KJ; Q l is the accumulated enthalpy of the produced fluid in this round, KJ; Q sw represents the cumulative wellhead injected steam enthalpy, KJ; ΔQ represents the heat loss of the wellbore, KJ.

2. The method for calculating the actual heat consumption of the heavy oil steam huff-and-puff oil layer according to claim 1, It is characterized in that In step 1, based on the test temperature and the original reservoir temperature, the average temperature of the heating zone near the bottom of the well before the current round of steam injection is calculated according to formula (1): Where, T i represents the original reservoir temperature, °C; T b Represents the test well bottom temperature, °C.

3. The method for calculating the actual heat consumption of the heavy oil steam huff-and-puff oil layer according to claim 1, It is characterized in that In step 2, during the steam injection process, the saturated water enthalpy h is calculated by looking up the table according to the wellhead steam injection temperature. w The enthalpy of dry saturated steam h s Then, according to the wellhead steam dryness x, the enthalpy of wet saturated steam h is calculated according to formula (2). m : h m =xh s +(1-x)h w (2) In the formula, h s Represents the enthalpy of dry saturated steam, KJ / kg; h w Represents the enthalpy of saturated water, KJ / kg.

4. The method for calculating the actual heat consumption of heavy oil steam huff-and-puff oil layer according to claim 1, It is characterized in that In step 4, after the steam injection and well shut-in are completed, the well is opened for production, and the daily oil production, daily water production and liquid production temperature are recorded.

5. The method for calculating the actual heat consumption of heavy oil steam huff-and-puff oil layer according to claim 1, It is characterized in that In step 4, after the end of this round of production, the daily increase in the enthalpy of the produced liquid is accumulated to calculate the cumulative enthalpy value of the produced liquid in this round: Where N represents the number of production days.

6. The method for calculating the actual heat consumption of heavy oil steam huff-and-puff oil layer according to claim 1, It is characterized in that In step 5, the heating radius is estimated according to the Marx-Langenheim formula (9): Where r is the heating radius, m; i s is the average steam injection rate of this round, kg / s; h ma Average saturated steam enthalpy of this round, J / kg; h represents the oil layer thickness, m; M R represents the volume heat capacity of the oil layer, J / (m³·℃); α represents the thermal diffusion coefficient of the top and bottom cover layers, m² / s; λ represents the thermal conductivity of the top and bottom cover rocks, W / (m·℃); T s represents boiler outlet temperature, °C; t represents the steam injection time, s; erfc-cocomplement error function, obtained by looking up the table.

7. The method for calculating the actual heat consumption of the heavy oil steam huff-and-puff oil layer according to claim 6, It is characterized in that In step 5, the heat loss of the top and bottom cover layers is estimated according to formula (10): Where, t m is the stewing time, h.

8. The method for calculating the actual heat consumption of heavy oil steam huff-and-puff oil layer according to claim 7, It is characterized in that In step 6, the actual heat consumption of the oil layer in each round during the heavy oil steam stimulation process is calculated, and the heat consumption per ton of oil in each round and the change law of the cycle are further calculated based on the cycle oil production.

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