Method and device for calculating formation water quantity in fracturing flow-back fluid and evaluating fracturing effect

Abstract

The invention relates to the technical field of oil testing operation, in particular to a method and device for calculating formation water quantity in fracturing flow-back fluid and evaluating fracturing effect, and the method comprises the following steps: obtaining total mineralization degree of formation water of a well to be fractured and total mineralization degree of fracturing fluid during fracturing construction, and in the flow-back process after fracturing, obtaining the total mineralization degree of the formation water of the well to be fractured and the total mineralization degree of the fracturing fluid; and collecting the total mineralization degree and the return volume of the flow-back fluid in each time period, obtaining the formation water content in each time period according to the formation water amount and the content calculation model, and evaluating the fracturing effect according to the proportional relation between the formation water content and the flow-back fluid amount on that day. According to the method, the formation water quantity and the formation water content in the mixed liquid in each time period are quantitatively calculated, and the fracturing effect in the time period is evaluated on the basis of the formation water content in the mixed liquid in each time period, so that accurate guidance is provided for optimization of a drainage and mining system, and meanwhile, a design scheme of a well to be fractured is guided.

Description

Technical Field

[0001] The present invention relates to the technical field of well testing operations, and is a method and device for calculating the formation water volume in fracturing flowback fluid and evaluating the fracturing effect. Background Art

[0002] With the continuous deepening of oil and gas exploration and development, complex lithologies and unconventional oil and gas reservoirs have gradually become the key targets. Due to the poor permeability of such reservoirs, there is generally no natural productivity after perforation, and productivity is mainly obtained through fracturing transformation. After fracturing transformation, it is extremely important to comprehensively analyze the production data to timely and accurately determine whether the formation produces water. At present, based on data such as daily liquid production, fracturing fluid flowback rate, and liquid chloride ion content, only qualitative judgment can be made on whether the formation produces water, and the formation water volume and content cannot be accurately and quantitatively calculated. Summary of the Invention

[0003] The present invention provides a method and device for calculating the formation water volume in fracturing flowback fluid and evaluating the fracturing effect, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problem of unable to quantitatively calculate formation water in existing fracturing operations.

[0004] One of the technical solutions of the present invention is achieved by the following measures: A method for calculating the formation water volume in fracturing flowback fluid and evaluating the fracturing effect includes:

[0005] Obtain the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during fracturing construction 压裂液 ;

[0006] During the flowback process after fracturing, collect the total salinity S of the flowback fluid and the flowback volume Q 返排液 in each time period 返排液 ;

[0007] Input the total salinity S of the formation water before fracturing 地层水 , the total salinity S of the fracturing fluid during fracturing construction 压裂液 , the total salinity S of the flowback fluid in each time period 返排液 and the flowback volume Q 返排液 into the formation water volume calculation model to obtain the formation water volume Q in each time period 地层水 ;

[0008] Based on the formation water volume Q in each time period 地层水 , determine the formation water content n on the day of flowback after fracturing, and evaluate the fracturing effect through the formation water content n on the day under the premise of considering the fracturing fluid flowback rate.

[0009] The following is a further optimization and / or improvement of the above-mentioned technical solution of the invention:

[0010] The above formation water volume calculation model is as follows:

[0011]

[0012] Or / and, the calculation formula for the formation water content n% on the current day is as follows:

[0013]

[0014] The above-mentioned total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during the fracturing operation 压裂液 , including:

[0015] Judge whether it is possible to obtain the formation water test data of the same layer in the area or adjacent wells;

[0016] In response to yes, then according to the formation water test data of the same layer in the area or adjacent wells, determine the total salinity S of the formation water of the well to be fractured 地层水 ;

[0017] In response to no, after perforating the well to be fractured, obtain the formation water sample, and test to obtain the total salinity S of the formation water of the well to be fractured 地层水 ;

[0018] During the fracturing operation, take samples of the fracturing fluid for testing to obtain the total salinity S of the fracturing fluid 压裂液 .

[0019] During the backflow process after fracturing, collect the total salinity S of the backflow fluid and the backflow volume Q in each time period by sampling and testing 返排液 and the backflow volume Q 返排液 .

[0020] Based on the formation water volume Q in each time period 地层水 , determine the formation water content n on the day of backflow after fracturing. On the premise of considering the fracturing fluid backflow rate, evaluate the fracturing effect through the formation water content n on the current day, including:

[0021] Based on the formation water volume Q in each time period 地层水 , determine the formation water content n on the current day;

[0022] Through the formation water content n on the current day, evaluate the fracturing effect based on the evaluation conditions, where the evaluation conditions include:

[0023] If the fracturing fluid backflow rate ≤ 30% and the formation water content n on the current day ≥ 50%, it indicates that the reservoir permeability is good, there are many natural or fracturing cracks, and the subsequent production reduction nozzle system should be reduced;

[0024] If 30% < fracturing fluid backflow rate ≤ 60% and the formation water content n on the current day ≥ 50%, the reservoir permeability is medium, and continue to maintain the current backflow production reduction system;

[0025] If the fracturing fluid flowback rate > 60% and the formation water content n ≤ 50% on the same day, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fracture is generated by fracturing, the fracturing fluid is mainly distributed in the fracture, the choke size system is enlarged, the production pressure difference is increased, and the flowback is accelerated;

[0026] If the formation water content n ≥ 80% on the same day and the production is stable, the formation fluid property is clearly understood at this time, and the well testing can be ended to shorten the well testing cycle.

[0027] The second technical solution of the present invention is achieved by the following measures: A device for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect, including:

[0028] A first data acquisition unit that acquires the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during the fracturing construction 压裂液 ;

[0029] A second data acquisition unit that, during the flowback process after fracturing, collects the total salinity S of the flowback fluid and the flowback volume Q 返排液 in each time period 返排液 ;

[0030] A formation water content analysis unit that inputs the total salinity S of the formation water before fracturing 地层水 , the total salinity S of the fracturing fluid during the fracturing construction 压裂液 , the total salinity S of the flowback fluid in each time period 返排液 and the flowback volume Q 返排液 into the formation water volume calculation model to obtain the formation water volume Q 地层水 in each time period;

[0031] A fracturing effect evaluation unit that, based on the formation water volume Q 地层水 in each time period, determines the formation water content n on the day of flowback after fracturing, and evaluates the fracturing effect through the formation water content n on the premise of considering the fracturing fluid flowback rate.

[0032] The following is a further optimization or / and improvement of the above-mentioned invention technical solution:

[0033] The above-mentioned fracturing effect evaluation unit includes:

[0034] An acquisition module that determines the formation water content n on the same day based on the formation water volume Q 地层水 in each time period;

[0035] An evaluation module that evaluates the fracturing effect through the formation water content n based on the evaluation conditions, where the evaluation conditions include:

[0036] If the fracturing fluid flowback rate ≤ 30% and the formation water content n ≥ 50% on the same day, it indicates good reservoir permeability, many natural or fracturing fractures, and the subsequent production rate should be reduced.

[0037] If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n ≥ 50% on the same day, the reservoir permeability is medium, and the current production rate should be maintained for flowback.

[0038] If the fracturing fluid flowback rate > 60% and the formation water content n ≤ 50% on the same day, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fracturing fracture is generated, the fracturing fluid is mainly distributed in the fracture, the production nozzle system should be enlarged, the production pressure difference should be increased, and the flowback should be accelerated.

[0039] If the formation water content n ≥ 80% on the same day and the production is stable, the formation fluid property is clearly understood at this time, the well testing can be ended, and the well testing cycle can be shortened.

[0040] The present invention is based on the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during fracturing construction 压裂液 , the total salinity S of the flowback fluid in each time period 返排液 and the flowback volume Q 返排液 , quantitatively calculates the formation water volume and formation water content in the mixed liquid in each time period, and evaluates the fracturing effect in this time period based on the formation water content in the mixed liquid in each time period, which has an important role in clearly recognizing the formation fluid property in time, preventing bottom water encroachment and water flooding, and has important significance for accurately evaluating the fracturing effect of oil and gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Appendix Figure 1 is a schematic flow chart of the method of the present invention.

[0042] Appendix Figure 2 is a schematic structural diagram of the device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention is not limited by the following embodiments, and the specific implementation manner can be determined according to the technical solution of the present invention and the actual situation.

[0044] The present invention will be further described below in conjunction with the embodiments and the drawings:

[0045] Embodiment 1: As shown in Appendix Figure 1 , the embodiment of the present invention discloses a method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect, including:

[0046] Step S210, obtaining the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during fracturing construction 压裂液 ;

[0047] This step specifically includes:

[0048] (1) Determine whether it is possible to obtain the formation water test data of the same horizon in the area or adjacent wells;

[0049] (2) In response to yes, determine the total salinity S of the formation water of the well to be fractured according to the formation water test data of the same horizon in the area or adjacent wells 地层水 ;

[0050] (3) In response to no, after perforating the well to be fractured, obtain a formation water sample and test to obtain the total salinity S of the formation water of the well to be fractured 地层水 ;

[0051] (4) During the fracturing operation, take a sample of the fracturing fluid for testing to obtain the total salinity S of the fracturing fluid 压裂液 .

[0052] Step S220, during the flowback process after fracturing, collect the total salinity S of the flowback fluid and the flowback volume Q within each time period 返排液 and the flowback volume Q 返排液 ;

[0053] In this step, the time period is set according to the actual situation and can be set to 24 hours. Specifically, during the flowback process after fracturing, measure the flowback volume Q within a time period every 24 hours 返排液 , and take a sample of the flowback fluid for testing to obtain the total salinity S of the flowback fluid within a time period 返排液 .

[0054] Step S230, input the total salinity S of the formation water before fracturing 地层水 , the total salinity S of the fracturing fluid during the fracturing operation 压裂液 , the total salinity S of the flowback fluid within each time period 返排液 and the flowback volume Q 返排液 into the formation water volume calculation model to obtain the formation water volume Q within each time period 地层水 .

[0055] The formation water volume calculation model in this step is as follows:

[0056]

[0057] Its construction process is as follows:

[0058] (1) Determine the relationship among the total salinity S of the formation water of the well to be fractured 地层水 , the total salinity S of the fracturing fluid during the fracturing operation 压裂液 , the total salinity S of the flowback fluid 返排液 and the flowback volume Q 返排液 , specifically as follows:

[0059] Q 地层水 ×S 地层水 +(Q 返排液 -Q 地层水 )×S 压裂液 =Q 返排液 ×S 返排液

[0060] (2) The above formula is transformed to obtain the formation water volume calculation model in this embodiment.

[0061] Step S240: Based on the formation water volume Q 地层水 in each time period, determine the formation water content n on the day of post-fracture flowback. On the premise of considering the fracturing fluid flowback rate, evaluate the fracturing effect through the formation water content n on that day.

[0062] This step specifically includes:

[0063] (1) Based on the formation water volume Q 地层水 in each time period, determine the formation water content n on that day;

[0064]

[0065] (2) Through the formation water content n on that day, evaluate the fracturing effect based on the evaluation conditions, where the evaluation conditions include:

[0066] If the fracturing fluid flowback rate ≤ 30% and the formation water content n on that day ≥ 50%, it indicates that the reservoir permeability is good, there are many natural or induced fractures, and the subsequent production choke size should be reduced to prevent bottom water coning and water flooding of the formation;

[0067] If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n on that day ≥ 50%, the reservoir permeability is medium, and the current flowback production system should be maintained;

[0068] If the fracturing fluid flowback rate > 60% and the formation water content n on that day ≤ 50%, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fractures are generated by fracturing, the fracturing fluid is mainly distributed in the fractures, and the fracturing fluid in the fractures is preferentially flowbacked during flowback. The production choke size should be enlarged, the production pressure difference should be increased, the flowback should be accelerated, and the fluid in the matrix pores should be promoted to flow out;

[0069] If the formation water content n on that day ≥ 80% and the production is stable, the formation fluid property is clearly understood at this time, and the well testing can be ended to shorten the well testing period.

[0070] The present invention is based on the total salinity S 地层水 of the formation water of the well to be fractured and the total salinity S 压裂液 of the fracturing fluid during fracturing construction, the total salinity S 返排液 of the flowback fluid in each time period, and the flowback volume Q 返排液, quantitatively calculate the formation water volume and content in the mixed liquid within each time period, and evaluate the fracturing effect during this time period based on the formation water content in the mixed liquid within each time period. This is of great significance for promptly understanding the formation fluid properties, preventing bottom water encroachment and water flooding, and accurately evaluating the fracturing effect of oil and gas wells.

[0071] Example 2: For an exploration well DX1 in a new exploration area, the method disclosed in the present invention is used to calculate the formation water volume in the flowback fluid and evaluate the fracturing effect, as follows:

[0072] First step: For an exploration well DX1 in a new exploration area, there is no adjacent well water test data. After perforating this well, there is no natural productivity. The chloride ion in the water sample is tested daily during pumping. After the chloride ion stabilizes, a bottom water sample is taken to obtain the total salinity S of the water sample of this layer 地层水 which is 6320 mg / L.

[0073] Second step: During the fracturing of Well DX1, the fracturing fluid is sampled and tested to obtain the total salinity S of the fracturing fluid 压裂液 which is 18628 mg / L.

[0074] Third step: After fracturing, the well is opened for flowback. One water sample is taken every 24 hours, and the corresponding total salinity S of the flowback fluid and the flowback volume Q are obtained through testing and measurement 返排液 and the specific data obtained are as follows: 返排液 Q

[0075] Q 返排液1 、S 返排液1 are 50 m 3 、18132 mg / L;

[0076] Q 返排液2 、S 返排液2 are 46 m 3 、17593 mg / L; .....

[0078] Fourth step: Based on the formation water volume calculation model, the formation water volume Q in the flowback fluid within the time period and the formation water content n on the same day are obtained, as follows: 地层水 and the specific data are as follows:

[0079] Q 地层水1 = 50×(18132 - 18628) / (6320 - 18628)= 2.0 m 3 ; n = 2 / 50×100% = 4%;

[0080] Q 地层水2 = 46×(17593 - 18628) / (6320 - 18628)= 3.9 m 3 ; n = 3.9 / 46×100% = 8.5%; .....

[0082] Step 5: Analyze the proportional relationship between the formation water content and the fluid production volume on the day, and evaluate the fracturing effect based on the evaluation conditions. The calculation results and analysis data of the formation water in the fracturing fluid production of Well DX1 are shown in the following table.

[0083] Table 1 Calculation Results and Analysis Data of Formation Water in Fracturing Fluid Production of Well DX1

[0084] Flowback days <![CDATA[Q 地层水 m 3 > Daily formation water content n% Fracturing fluid flowback rate % 1 2.0 4.0 8.0 2 3.9 8.5 15.0 3 20.2 44.4 19.2 4 21.1 46.7 23.1 5 20.0 50.0 26.5 6 15.3 43.7 29.8 7 12.5 37.9 33.2 8 11.8 39.3 36.2 9 10.7 38.2 39.1 10 10.5 37.5 42.0

[0085] According to the variation characteristics of the formation water production volume during the fluid production process after fracturing, guide the production and injection plan and evaluate the fracturing effect: A total of 600 m 3 of fracturing fluid was used in this well. After fracturing, a 3-mm choke was used for blowout and fluid production. When the fluid production reached the 5th day, the fluid production rate of the fracturing fluid was 26.5%, but the proportion of formation water production reached 50%, indicating good reservoir permeability or well-developed fractures. To prevent the too-fast water influx rate, the choke size was timely adjusted to 2 mm, and the content of formation water in the fluid production decreased significantly.

[0086] Example 3, as shown in the appendix Figure 2 discloses a method for calculating the formation water volume in the fracturing fluid production and evaluating the fracturing effect, including:

[0087] The first data acquisition unit acquires the total salinity S 地层水 of the formation water of the well to be fractured and the total salinity S 压裂液 of the fracturing fluid during the fracturing operation;

[0088] The second data acquisition unit acquires the total salinity S 返排液 of the fluid production and the fluid production volume Q 返排液 in each time period during the fluid production process after fracturing;

[0089] The formation water content analysis unit inputs the total salinity S 地层水 of the formation water before fracturing, the total salinity S 压裂液 of the fracturing fluid during the fracturing operation, the total salinity S 返排液 of the fluid production and the fluid production volume Q 返排液 in each time period into the formation water volume calculation model to obtain the formation water volume Q 地层水 in each time period;

[0090] The fracturing effect evaluation unit determines the formation water content n on the day of fluid production after fracturing based on the formation water volume Q 地层水 in each time period, and evaluates the fracturing effect through the formation water content n on the day under the premise of considering the fluid production rate of the fracturing fluid.

[0091] Among them, the fracturing effect evaluation unit includes:

[0092] An acquisition module that determines the formation water content n of the current day based on the formation water volume Q within each time period 地层水 , and determines the formation water content n of the current day;

[0093] An evaluation module that evaluates the fracturing effect based on the formation water content n of the current day according to evaluation conditions, where the evaluation conditions include:

[0094] If the fracturing fluid flowback rate ≤ 30% and the formation water content n of the current day ≥ 50%, it indicates good reservoir permeability, many natural or fracturing cracks, and the subsequent production choke size regime should be reduced;

[0095] If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n of the current day ≥ 50%, the reservoir permeability is medium, and the current production and flowback regime should be maintained;

[0096] If the fracturing fluid flowback rate is greater than 60% and the formation water content n of the current day ≤ 50%, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fractures are generated by fracturing, the fracturing fluid is mainly distributed in the fractures, the production choke size regime should be enlarged, the production pressure difference should be increased, and the flowback should be accelerated;

[0097] If the formation water content n of the current day ≥ 80% and the production is stable, the formation fluid properties are clearly understood at this time, and the well testing can be ended to shorten the well testing period.

[0098] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and the best implementation effect. Non-essential technical features can be added or subtracted according to actual needs to meet the requirements of different situations.

Claims

1. A method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect, characterized in that, it includes: Obtain the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during the fracturing operation 压裂液 ; During the flowback process after fracturing, collect the total salinity S of the flowback fluid within each time period 返排液 and the flowback volume Q 返排液 ; The total salinity S of formation water before fracturing 地层水 , the total salinity S of fracturing fluid during fracturing construction 压裂液 , the total salinity S of the flowback fluid within each time period 返排液 and the flowback volume Q 返排液 are input into the formation water volume calculation model to obtain the formation water volume Q within each time period 地层水 ; Based on the formation water volume Q within each time period 地层水 , determine the formation water content n on the day of post-fracture flowback. On the premise of considering the flowback rate of the fracturing fluid, evaluate the fracturing effect through the formation water content n on that day.

2. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 1, characterized in that, the formation water volume calculation model is as follows: Or / and, the calculation formula for the formation water content n% on the current day is as follows:

3. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 1 or 2, characterized in that, Obtaining the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during the fracturing operation 压裂液 , including: judge whether it is possible to obtain the formation water test data of the same layer in the area or adjacent wells; In response thereto, based on the formation water test data of the same horizon in the area or adjacent wells, determine the total salinity S of the formation water of the well to be fractured 地层水 ; If the response is negative, after perforating the well to be fractured, a formation water sample is obtained, and the total salinity S of the formation water of the well to be fractured is obtained through chemical analysis. 地层水 ; During the fracturing operation, the fracturing fluid is sampled and analyzed to obtain the total salinity S of the fracturing fluid 压裂液 .

4. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 1 or 2, characterized in that, During the flowback process after fracturing, the total salinity S of the flowback fluid in each time period is collected by sampling and testing 返排液 and the flowback volume Q 返排液 .

5. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 3, characterized in that, During the flowback process after fracturing, the total salinity S of the flowback fluid in each time period is collected by sampling and testing 返排液 and the flowback volume Q 返排液 .

6. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 1 or 2 or 5, characterized in that, Based on the formation water volume Q within each time period 地层水 , determine the formation water content n on the day of post-fracture flowback. On the premise of considering the flowback rate of the fracturing fluid, evaluate the fracturing effect through the formation water content n on the day, including: Based on the formation water volume Q within each time period 地层水 , determine the formation water content n on the current day; evaluate the fracturing effect based on the evaluation conditions through the formation water content n on the current day, where the evaluation conditions include: If the fracturing fluid flowback rate ≤ 30% and the formation water content n on the current day ≥ 50%, it indicates that the reservoir permeability is good, there are many natural or fracturing cracks, and the subsequent production choke size system should be reduced; If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n on the current day ≥ 50%, the reservoir permeability is medium, and continue to return using the current production drainage system; If the fracturing fluid flowback rate > 60% and the formation water content n on the current day ≤ 50%, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fracturing cracks are generated, the fracturing fluid is mainly distributed in the cracks, enlarge the oil nozzle system, increase the production pressure difference, and accelerate the flowback; If the formation water content n on the current day ≥ 80% and the production is stable, at this time the formation fluid property is clearly understood, the well testing can be ended, and the well testing period can be shortened.

7. The method for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 3 or 4, characterized in that, Based on the formation water volume Q within each time period 地层水 , determine the formation water content n for the current day. On the premise of considering the flowback rate of the fracturing fluid, evaluate the fracturing effect through the formation water content n for the current day, including: Based on the formation water volume Q within each time period 地层水 , determine the formation water content n on the current day; evaluate the fracturing effect based on the evaluation conditions through the formation water content n on the current day, where the evaluation conditions include: If the fracturing fluid flowback rate ≤ 30% and the formation water content n on the current day ≥ 50%, it indicates that the reservoir permeability is good, there are many natural or fracturing cracks, and the subsequent production choke size system should be reduced; If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n on the current day ≥ 50%, the reservoir permeability is medium, and continue to return using the current production drainage system; If the fracturing fluid flowback rate > 60% and the formation water content n on the current day ≤ 50%, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fracturing cracks are generated, the fracturing fluid is mainly distributed in the cracks, enlarge the oil nozzle system, increase the production pressure difference, and accelerate the flowback; If the formation water content n on the current day ≥ 80% and the production is stable, at this time the formation fluid property is clearly understood, the well testing can be ended, and the well testing period can be shortened.

8. A device for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect by applying the method according to any one of claims 1 to 7, characterized in that, it includes: The first data acquisition unit acquires the total salinity S of the formation water of the well to be fractured 地层水 and the total salinity S of the fracturing fluid during the fracturing operation 压裂液 ; The second data acquisition unit collects the total salinity S of the flowback fluid and the flowback volume Q in each time period during the flowback process after fracturing. 返排液 and the flowback volume Q 返排液 ; The formation water content analysis unit inputs the total salinity S of the formation water before fracturing 地层水 , the total salinity S of the fracturing fluid during the fracturing operation 压裂液 , the total salinity S of the flowback fluid in each time period 返排液 and the flowback volume Q 返排液 into the formation water volume calculation model to obtain the formation water volume Q in each time period 地层水 ; Fracturing effect evaluation unit, based on the formation water volume Q within each time period 地层水 , determine the formation water content n on the day of post-fracture flowback. On the premise of considering the fracturing fluid flowback rate, evaluate the fracturing effect through the formation water content n on that day.

9. The device for calculating the formation water volume in the fracturing flowback fluid and evaluating the fracturing effect according to claim 8, characterized in that, the fracturing effect evaluation unit includes: An acquisition module, based on the formation water volume Q within each time period 地层水 , determines the formation water content n on the current day; Evaluation module, based on the formation water content n on the same day, evaluates the fracturing effect according to the evaluation conditions, where the evaluation conditions include: If the fracturing fluid flowback rate ≤ 30% and the formation water content n on the same day ≥ 50%, it indicates that the reservoir has good permeability, many natural or fracturing cracks, and the subsequent production rate of the oil nozzle system should be reduced; If 30% < fracturing fluid flowback rate ≤ 60% and the formation water content n on the same day ≥ 50%, the reservoir permeability is medium, and the current flowback system should be maintained for flowback; If the fracturing fluid flowback rate > 60% and the formation water content n on the same day ≤ 50%, the reservoir matrix permeability is poor, the fracturing fluid filtration loss is small, the main fractures are generated by fracturing, the fracturing fluid is mainly distributed in the fractures, the oil nozzle system should be enlarged, the production pressure difference should be increased, and the flowback should be accelerated; If the formation water content n on the same day ≥ 80% and the production is stable, the formation fluid properties are clearly understood at this time, the well testing can be ended, and the well testing cycle can be shortened.

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