A test method for flow conductivity of segmented sand-laying method based on standard API flow chamber

Abstract

The present invention discloses a flow conductivity testing method based on a segmented sand-paving method of a standard API flow diversion chamber, comprising: dividing a sand-paved area of ​​an inner chamber of the API flow diversion chamber into an actual pressure measuring area and an invalid pressure measuring area; determining the filling size and sand-paving concentration / thickness of the actual pressure measuring area and the invalid pressure measuring area; calculating the filling amount of the actual pressure measuring area and the invalid pressure measuring area, the filling amount being determined according to the filling size and sand-paving concentration / thickness of the actual pressure measuring area and the invalid pressure measuring area; performing a sand-paving operation on the actual pressure measuring area and the invalid pressure measuring area according to the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the actual pressure measuring area is filled with a proppant, and the invalid pressure measuring area is filled with a filler, and the filler and the proppant are of the same type and specification; placing the API flow diversion chamber after sand-paving on a stage of a hydraulic press, connecting pipelines, evacuating and saturating a displacement liquid, pressurizing to a preset closing pressure, and then conducting a flow conductivity test, and recording the displacement liquid flow rate and pressure difference at different closing pressure points.

Description

Technical Field

[0001] The present application relates to the field of petroleum and natural gas engineering technology, and in particular to a method for testing the flow conductivity of a segmented sand-laying method based on a standard API flow chamber. Background Art

[0002] Hydraulic fracturing technology is one of the core technologies for the effective development of unconventional oil and gas reservoirs. Whether the proppant can play an effective supporting role in the fracture is the key to the success of hydraulic fracturing transformation. In the reservoir fracturing transformation operation, in order to take into account the requirements of high fracture conductivity and construction difficulty, it is necessary to carry out segmented sanding operations. Indoor proppant filling layer conductivity test is of great reference significance for guiding on-site segmented sanding operations.

[0003] The common equipment for testing the conductivity of indoor proppant filling layers is the standard API diversion equipment. The structural design of its diversion chamber is mainly based on the needs of testing the conductivity of a single type of proppant filling layer. Its test methods and procedures are not suitable for testing the conductivity under the segmented sand laying method. Summary of the invention

[0004] The present application provides a method for testing the flow conductivity of a segmented sand-laying method based on a standard API flow diversion chamber, so as to solve the problem that the structural design of the flow diversion chamber is mainly based on the need for testing the flow conductivity of a single type of proppant filling layer, and its testing method is not suitable for testing the flow conductivity under the segmented sand-laying method.

[0005] The technical solutions adopted in this application are as follows:

[0006] The present invention discloses a flow conduction capacity testing method based on a segmented sand-laying method of a standard API flow conduction chamber, wherein the sand-laying area of ​​the inner chamber of the API flow conduction chamber is divided into an actual pressure measurement area and an invalid pressure measurement area;

[0007] Determine the filling size and sand concentration / thickness of the actual pressure measuring area and the invalid pressure measuring area;

[0008] Calculating the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the filling amount is determined according to the filling size and the concentration / thickness of the sand in the actual pressure measuring area and the invalid pressure measuring area;

[0009] Performing sand laying operation on the actual pressure measuring area and the invalid pressure measuring area according to the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the actual pressure measuring area is filled with proppant, and the invalid pressure measuring area is filled with filler, and the filler and the proppant are of the same type and specification;

[0010] Place the API diversion chamber with sand on the loading table of the hydraulic press, connect the pipeline, evacuate and saturate the displacement liquid, pressurize it to the preset closing pressure point, and then conduct the diversion capacity test, and record the displacement liquid flow and pressure difference at different preset closing pressure points.

[0011] In an achievable implementation, the sanding operation of the actual pressure measuring area and the invalid pressure measuring area is divided into small difference ratio sanding and large difference ratio sanding, wherein the small difference ratio sanding is that the volumes of the large, medium and small components to be tested are not more than four times in sequence;

[0012] If the sand spreading ratio is small, use a single API diversion chamber to carry out the diversion capacity test under the segmented sand spreading method.

[0013] In an achievable implementation, the sanding operation on the actual pressure measuring area and the invalid pressure measuring area includes large-difference sanding, wherein the large-difference sanding is that the volumes of the three components, large, medium, and small, to be tested are more than four times in sequence;

[0014] If the sand is laid with a large differential ratio, two or three API diversion chambers are used to connect in series;

[0015] Two or three API diversion chambers are placed in the same horizontal plane or stacked up and down.

[0016] In an achievable implementation, the division rule between the actual pressure measuring area and the invalid pressure measuring area includes:

[0017] If the sand is laid with a small difference ratio: the actual pressure measuring area includes the rectangular area between the high-pressure pressure measuring hole of the API diversion chamber close to the API diversion chamber inlet interface and the low-pressure pressure measuring hole close to the API diversion chamber outlet interface; the invalid pressure measuring area is the area of ​​the sand-paved area inside the API diversion chamber except the actual pressure measuring area in the rectangular area.

[0018] In an achievable implementation, the division rule of the actual pressure measuring area and the invalid pressure measuring area further includes:

[0019] If the sand is laid with a large difference ratio: the actual pressure measuring area includes the area between the high-pressure pressure measuring hole of the first API diversion chamber close to the API diversion chamber inlet interface and the low-pressure pressure measuring hole of the terminal API diversion chamber outlet interface; the invalid pressure measuring area is the area in the cavity of two or three API diversion chambers connected in series except the actual pressure measuring area.

[0020] In a feasible embodiment, the filler is selected based on the proppant, and the filler is a material having properties close to those of the proppant, specifically, being of the same type and specification as the proppant.

[0021] In an achievable implementation, the actual amount of the proppant in the pressure measuring area and the filler in the invalid pressure measuring area are calculated according to the sand spreading concentration or the sand spreading thickness, and include:

[0022] If calculated according to the sand concentration, the actual weight of proppant a in the pressure measurement area is calculated as follows:

[0023] M a =0.1·A e ·C a ·x a

[0024] The calculation formula for the amount of filler weighed in the single-side invalid pressure measuring area is:

[0025] M f =0.1·A f ·C f

[0026] If calculated based on the thickness of the sand, the actual weight of the proppant a in the pressure measurement area is calculated as follows:

[0027] M a =A e ·w·ρ a ·x a

[0028] The calculation method for the amount of filler weighed in the single-sided invalid pressure measuring area is:

[0029] M f =A f ·w·ρ f

[0030] Where M a —The weight of the proppant in the actual pressure measurement area, g;

[0031] M f —The mass of the filling material in the single-side invalid pressure measurement area, g;

[0032] A e —Area of ​​actual pressure measurement area, cm 2 ;

[0033] A f —Area of ​​the unilateral invalid pressure measurement area, cm 2 ;

[0034] C a —Proppant sand concentration, kg / m 2 ;

[0035] C f —Sand concentration of the filling material in the single-side invalid pressure measurement area, kg / m 2 ;

[0036] x a —The percentage of a certain proppant a in all proppant, %;

[0037] w—sand paving thickness, cm;

[0038] ρ f —Density of the filling material on one side, g / cm 3 ;

[0039] ρ a —Density of a proppant a, g / cm 3 .

[0040] In a feasible implementation, if the sand is laid with a large differential ratio, the actual pressure measuring area includes the area from the first to the last API diversion chamber except the rectangular area, and the area can be equivalent to a semicircle. By using the pressure drop equivalent principle, the semicircular area is equivalent to a rectangular actual pressure measuring area with the same width and different length as the actual pressure measuring area of ​​the adjacent rectangular area. The length calculation formula of the equivalent rectangular area is:

[0041]

[0042] Where, L is the length of the equivalent rectangular area, cm; W is 1 / 2 of the width of the internal cavity of the API flow chamber, cm.

[0043] In a feasible implementation, if the actual pressure measuring area includes the semicircular area at the end of the API diversion chamber, the length of the rectangular actual pressure measuring area equivalent to the semicircular area is added to the length of the rectangular actual pressure measuring area to calculate the total length of the rectangular area actual pressure measuring area. The specific calculation formula of the flow conductivity under the segmented sand laying method includes:

[0044] If the sand is laid with a small difference ratio: the actual pressure measurement area includes the rectangular area in the API diversion chamber, and the flow diversion capacity calculation formula is:

[0045]

[0046] In case of large differential sand laying: When two API diversion chambers are used, the calculation formula for diversion capacity is:

[0047]

[0048] When the number of API diversion chambers used is three, the calculation formula for diversion capacity is:

[0049]

[0050] In the formula, kW f —Flow conductivity of proppant filling layer under segmented sand spreading method, μm 2 cm;

[0051] Q—displacing fluid flow rate, mL / min;

[0052] Δp—pressure difference between high-pressure pressure measuring hole and low-pressure pressure measuring hole, kPa;

[0053] μ—Viscosity of the test liquid, mPa·s.

[0054] The beneficial effects of adopting the technical solution of this application are as follows:

[0055] The segmented sand spreading conductivity testing method based on the standard API diversion chamber of the present invention can meet the test accuracy requirements under different segmented sand spreading ratios by detailed division of the sand spreading area; the method first proposes a test idea of ​​increasing the lateral sand spreading distance by connecting multiple API diversion chambers in series, which is particularly suitable for the conductivity evaluation test needs in the segmented sand spreading chamber when the volume ratios of each proppant component differ greatly during segmented sand spreading, and can greatly improve the test accuracy, so as to better provide effective guidance for on-site fracturing construction design. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0057] Figure 1 It is a schematic diagram of the internal structure of a standard API flow guide chamber provided in an embodiment of the present invention;

[0058] Figure 2 1 is a schematic diagram of the appearance of a standard API diversion chamber provided in an embodiment of the present invention (front view);

[0059] Figure 3 It is a schematic diagram of the division of the actual pressure measuring area and the invalid pressure measuring area inside the standard API diversion chamber under the condition of small difference ratio provided by the embodiment of the present invention;

[0060] Figure 4 Schematic diagram of the effect of segmented sand paving in Example 1 of the present invention;

[0061] Figure 5 Schematic diagram of the placement and loading method of the guide chamber in Example 1 in the embodiment of the present invention;

[0062] Figure 6 It is a schematic diagram of the division of the actual internal pressure measuring area and the invalid pressure measuring area when two standard API diversion chambers are connected in series under the condition of large differential ratio provided by an embodiment of the present invention;

[0063] Figure 7 It is a schematic diagram of the division of the actual internal pressure measuring area and the invalid pressure measuring area when three standard API diversion chambers are connected in series under the large differential ratio provided by the embodiment of the present invention;

[0064] Figure 8 yes Figure 6A schematic diagram of a standard API diversion chamber placement method on a press provided in;

[0065] Fig. 9 yes Figure 7 A schematic diagram of a standard API diversion chamber placement method on a press provided in;

[0066] Fig.10 It is a schematic diagram of a semicircular area of ​​a fluid flowing through an actual pressure measuring area provided in an example of the present invention;

[0067] Fig.11 Schematic diagram of a semicircular actual pressure measuring area being equivalent to a rectangular actual pressure measuring area in an embodiment of the present invention;

[0068] Fig.12 It is a schematic diagram of a coordinate system constructed by deriving a formula for equivalence of a semicircular actual pressure measurement area to a rectangular actual pressure measurement area in an embodiment of the present invention;

[0069] Fig.13 It is a schematic diagram of equivalent results of actual pressure measurement area in a single diversion chamber in the embodiment of the present invention when two standard API diversion chambers are connected in series;

[0070] Fig.14 This is a standard API flow chamber internal cavity dimension diagram in an embodiment of the present invention;

[0071] Illustration Description:

[0072] Among them, 1-first standard API diversion chamber; 2-second standard API diversion chamber; 3-third standard API diversion chamber; 4-force device (hydraulic cylinder); 5-lower plate surface of press (carrier); 6-upper plate surface of press; 7-displacing fluid inlet; 8-displacing fluid outlet; 9-turntable; 10-hydraulic cylinder pipeline inlet;

[0073] 12-standard API diversion chamber high pressure measuring hole; 13-standard API diversion chamber pore pressure measuring hole; 14-standard API diversion chamber low pressure measuring hole; 15-standard API diversion chamber inlet end interface; 16-standard API diversion chamber upper piston; 17-standard API diversion chamber lower piston; 18-diversion chamber fastening screw hole; 19-standard API diversion chamber outlet end interface;

[0074] 22- High-pressure pressure measuring hole of the second standard API diversion chamber; 23- Pore pressure measuring hole of the second standard API diversion chamber; 24- Low-pressure pressure measuring hole of the second standard API diversion chamber; 32- High-pressure pressure measuring hole of the third standard API diversion chamber; 33- Pore pressure measuring hole of the third standard API diversion chamber; 34- Low-pressure pressure measuring hole of the third standard API diversion chamber; 39- Outlet interface of the third standard API diversion chamber;

[0075] 100-actual pressure measurement area; 101-invalid pressure measurement area; 111-70 / 100 mesh quartz sand proppant; 112-40 / 70 mesh quartz sand proppant; 113-20 / 40 mesh quartz sand proppant. DETAILED DESCRIPTION

[0076] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0077] The present invention combines the internal structural characteristics of the standard API diversion chamber and proposes a test procedure and method for the diversion capacity of the segmented sand-laying chamber based on the standard API diversion chamber, which can effectively solve the above problems. The details are as follows:

[0078] See also Figures 1 to 14 .in, Figures 1 to 14 The accompanying drawings are marked as follows: 1-first standard API flow diversion chamber; 2-second standard API flow diversion chamber; 3-third standard API flow diversion chamber; 4-force-applying device (hydraulic cylinder); 5-lower plate of press (carrier); 6-upper plate of press; 7-displacing fluid inlet; 8-displacing fluid outlet; 9-turntable; 10-hydraulic cylinder pipeline inlet; 12-standard API flow diversion chamber high pressure measuring hole; 13-standard API flow diversion chamber pore pressure measuring hole; 14-standard API flow diversion chamber low pressure measuring hole; 15-standard API flow diversion chamber inlet end interface; 16-standard API flow diversion chamber upper piston; 17-standard API flow diversion chamber lower piston; 18-flow diversion chamber fastening screw hole; 1 9-standard API diversion chamber outlet interface; 22-second standard API diversion chamber high pressure pressure measuring hole; 23-second standard API diversion chamber pore pressure measuring hole; 24-second standard API diversion chamber low pressure pressure measuring hole; 32-third standard API diversion chamber high pressure pressure measuring hole; 33-third standard API diversion chamber pore pressure measuring hole; 34-third standard API diversion chamber low pressure pressure measuring hole; 39-third standard API diversion chamber outlet interface; 100-actual pressure measuring area; 101-invalid pressure measuring area; 111-70 / 100 mesh quartz sand proppant; 112-40 / 70 mesh quartz sand proppant; 113-20 / 40 mesh quartz sand proppant.

[0079] The present application provides a method for testing the flow conductivity of segmented sand based on a standard API flow chamber. The method is based on an existing API flow conductivity testing device, and mainly includes a hydraulic press, an API flow chamber, a differential pressure sensor, an experimental fluid displacement system, a balance, a back pressure regulator, a temperature control system, etc. Among them, the internal cavity of the API flow chamber is a streamlined design (such as Figure 1 As shown), one side of the shell includes three equally spaced pressure measuring holes 12, 13, and 14 (the specific structure is as shown in Figure 2 As shown). According to the designed segmented sand spreading ratio, the segmented sand spreading method is designed in two cases: small difference ratio sand spreading (case 1) and large difference ratio sand spreading (case 2). Among them, the small difference ratio sand spreading is when the proportions of the components to be tested are relatively small (the components here refer to the different types (sizes) of proppants that need to be tested for segmented sand spreading conductivity, with the attached Figure 4 For example, each component includes proppants of three particle sizes: large, medium and small (20 / 40 mesh quartz sand proppant 113, 40 / 70 mesh quartz sand proppant 112, 70 / 100 mesh quartz sand proppant 111); the proportion means that the total number of all proppant types in the segmented sand spreading is small, and the small difference in the proportions of each component means that the difference in the amount of sand spread of each component in the actual pressure measuring area is small, and the sand spreading operation is not difficult); the large difference ratio sand spreading is when the proportions of the components to be tested are greatly different. If the sand spreading is small, a single API diversion chamber is used to carry out the diversion capacity test under the segmented sand spreading method; if the sand spreading is large, two or three API diversion chambers are used to be connected in series; the two or three API diversion chambers can be placed on the same height horizontal plane or stacked up and down.

[0080] The actual pressure measuring area is the area where the differential pressure gauge can actually test the pressure difference, and the differential pressure sensor is used to test the pressure difference.

[0081] Scenario 1: When the ratio of proppants of different types or specifications to be tested is relatively small (the specification includes but is not limited to volume ratio, and can also be mass ratio, etc.), the proppant is laid in a single API diversion chamber where the standard API diversion chamber lower piston 17 has been installed and fixed. According to the positions of the three pressure measuring holes of the API diversion chamber (standard API diversion chamber high pressure measuring hole, standard API diversion chamber pore pressure measuring hole, standard API diversion chamber low pressure measuring hole), the sand-laying area in the API diversion chamber cavity is divided into an actual pressure measuring area and an invalid pressure measuring area. Among them, if Figure 3As shown, the scope of the actual pressure measuring area includes the rectangular area between the high pressure measuring hole position near the inlet end of the API diversion chamber and the low pressure measuring hole position near the outlet end, the standard API diversion chamber high pressure measuring hole 12 to the standard API diversion chamber low pressure measuring hole 14, and the scope of the invalid pressure measuring area is the part of the internal cavity except the rectangular actual pressure measuring area. In the rectangular actual pressure measuring area in the cavity of a single API diversion chamber, the proppant is laid inside the API diversion chamber according to the calculated filling amount and laying order. The invalid pressure measuring area is filled with filler according to the preset segmented filling rules, and then the API diversion chamber is placed on the hydraulic press stage. According to the direction of the displacement fluid flowing through the API diversion chamber, three pressure measuring holes (standard API diversion chamber high pressure measuring hole, standard API diversion chamber pore pressure measuring hole, standard API diversion chamber low pressure measuring hole) are respectively connected to the high pressure inlet end of the differential pressure gauge, the pressure sensor and the low pressure inlet end of the same differential pressure gauge. Then a certain confining pressure is applied to test the diversion capacity.

[0082] Scenario 2: If Figure 6 and Figure 7 As shown, when the ratios of proppants of different types or specifications to be tested differ greatly, proppants are laid in multiple API guide chambers with standard API guide chamber lower pistons 17 installed, and multiple API guide chambers are connected in series. (Note: Considering the difficulty of experimental operation, it is recommended that the number of API guide chambers used should not exceed 3)

[0083] The actual pressure measurement area and the invalid pressure measurement area in situation 2 are divided as follows: according to the order in which the displacement fluid flows through the standard API diversion chamber, the first standard API diversion chamber through which the displacement fluid flows is the first standard API diversion chamber, the diversion chamber adjacent to the first standard API diversion chamber is the second standard diversion chamber, and so on, until the standard API diversion chamber through which the fluid flows last. Figure 6 Shown and Figure 7 As shown, the range of the actual pressure measuring area is: the portion from the central axis of the high-pressure pressure measuring hole of the first standard API diversion chamber to the central axis of the low-pressure pressure measuring hole of the last standard API diversion chamber and the inner side wall of the API diversion chamber cavity. It should be noted that if the number of diversion chambers used exceeds two, the internal chambers of all diversion chambers between the first standard API diversion chamber and the last API diversion chamber are the areas included in the actual pressure measuring area, and the range of the invalid pressure measuring area is: the area inside the cavities of the first standard API diversion chamber and the last standard API diversion chamber except the actual pressure measuring area.

[0084] In order to prevent sand blockage at the inlet and outlet of the API diversion chamber and to improve the success rate of the segmented sand paving (sand paving is performed in the actual pressure measurement area according to the sand paving ratio to be tested, and in order to prevent the proppant in the actual pressure measurement area from dispersing to the invalid pressure measurement area after being pressurized, some suitable fillers are also needed on both sides of the area to fill) diversion test, a filter screen with a certain mesh size is placed at the inlet and outlet of the API diversion chamber or filled with proppant with large particle size. The actual pressure measurement area is paved according to the calculated proppant filling amount, and the invalid pressure measurement area is filled with filler according to the preset segmented filling rules. The API diversion chamber is placed on the hydraulic press stage. Multiple API diversion chambers can be placed at the same height level, or multiple API diversion chambers can be placed in an up-and-down stacking manner. The specific placement method is mainly determined by the area and size of the hydraulic press stage. The pipeline connection method under this sand laying ratio is: according to the direction of the displacement fluid flowing through the API diversion chamber, the displacement fluid flows through the pressure measuring hole of the first API diversion chamber and is connected to the high-pressure inlet end of the differential pressure gauge, the fluid flows through the third pressure measuring hole of the last API diversion chamber and is connected to the low-pressure inlet end of the differential pressure gauge, and the remaining pressure measuring holes are closed.

[0085] The filler filling rule for the invalid pressure measurement area recommended for use in the segmented sand-laying flow conductivity test procedure and method for the API flow chamber proposed in the present invention is:

[0086] The selection of filling materials for the invalid pressure measurement area must take into account both operational feasibility and pressure bearing performance. The performance difference of the filling materials selected in the connection area between the actual pressure measurement area and the invalid pressure measurement area should be minimized as much as possible to prevent a large pressure drop at the junction of the two areas to affect the accuracy of the differential pressure test. The filler should preferably be a proppant from the same series as the actual pressure measurement area.

[0087] The present invention proposes a method for testing the flow conductivity of a segmented sand-laying method based on a standard API flow chamber, comprising:

[0088] The sand-paved area inside the API diversion chamber is divided into an actual pressure measurement area and an invalid pressure measurement area;

[0089] Determine the filling size and sand concentration / thickness of the actual pressure measuring area and the invalid pressure measuring area;

[0090] Calculating the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the filling amount is determined according to the filling size and the concentration / thickness of the sand in the actual pressure measuring area and the invalid pressure measuring area;

[0091] Performing sand laying operation on the actual pressure measuring area and the invalid pressure measuring area according to the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the actual pressure measuring area is filled with proppant, and the invalid pressure measuring area is filled with filler, and the filler and the proppant are of the same type and specification;

[0092] Place the API diversion chamber with sand on the loading table of the hydraulic press, connect the pipeline, evacuate and saturate the displacement liquid (if the vacuum operation is not performed, direct displacement will inevitably cause the residual gas in the pipeline to be unable to be completely discharged. In order to avoid the residual gas in the pipeline causing the liquid in the pipeline to be discontinuous and the liquid cannot completely fill the pressure measuring pipeline, resulting in abnormal fluctuations in the differential pressure gauge, etc., the usual practice is to use a vacuum pump to evacuate the entire system to a certain vacuum degree before the test officially begins after the installation is completed and before the test officially begins, and then suck the test liquid (displacement liquid) into the test pipeline to ensure that all pipelines are completely saturated with liquid, thereby reducing the measurement error of the differential pressure gauge (pressure gauge) caused by excessive fluctuations in the differential pressure gauge due to residual gas), pressurize to the preset closing pressure point, and then carry out the diversion capacity test, and record the displacement liquid flow and pressure difference at different preset closing pressure points.

[0093] The method for calculating the amount of each proppant component in the actual pressure measuring area and the filler in the invalid pressure measuring area of ​​the segmented sand-laying flow conductivity test procedure for the API flow chamber proposed in the present invention is:

[0094] (1) If calculated by the sand concentration method, the mass of a certain proppant a in the actual pressure measurement area needs to be weighed as follows:

[0095] M a =0.1·A e ·C a ·x a (1)

[0096] Where M a —The weight of a proppant in the actual pressure measurement area, g;

[0097] A e —Area of ​​actual pressure measurement area, cm 2 ;

[0098] C a —Proppant sand concentration, kg / m 2 ;

[0099] x a —The percentage of a certain proppant a in all proppant, %.

[0100] The calculation method for weighing the mass of the filler in the single-sided invalid pressure measuring area is:

[0101] M f =0.1·A f ·C f (2)

[0102] Where M f —The mass of the filling material in the single-side invalid pressure measurement area, g;

[0103] Af —Area of ​​the unilateral invalid pressure measurement area, cm 2 ;

[0104] C f —Sand concentration of the filling material in the single-side invalid pressure measurement area, kg / m 2 ;

[0105] (2) If calculated by the sand-laying thickness method, the mass of a certain proppant a in the actual pressure measurement area needs to be weighed as follows:

[0106] M a =A e ·w·ρ a ·x a (3)

[0107] Where M a —The weight of a proppant in the actual pressure measurement area, g;

[0108] A e —Total area of ​​actual pressure measurement area, cm 2 ;

[0109] w—sand paving thickness, cm;

[0110] ρ a —Density of a proppant a, g / cm 3 ;

[0111] x a —The percentage of a certain proppant a in all proppant, %.

[0112] The calculation method for weighing the mass of the filling material in the single-sided invalid pressure measuring area is:

[0113] M f =A f ·w·ρ f (4)

[0114] Where M f —The mass of the filling material in the single-side invalid pressure measurement area, g;

[0115] A f —Area of ​​the unilateral invalid pressure measurement area, cm 2 ;

[0116] w—sand paving thickness, cm;

[0117] ρ f —Density of the filling material on one side, g / cm 3 ;

[0118] The specific calculation method of the flow conductivity of the segmented sand-laying flow conductivity test procedure applicable to the API flow chamber proposed in the present invention is:

[0119] For situation one:

[0120] When testing the conductivity of small-ratio segmented sand, a single API diversion chamber is used. In this case, the actual pressure measurement area is a rectangular area. Based on the standard API diversion chamber size data, the proppant filling layer conductivity calculation formula is shown in formula (5):

[0121]

[0122] In the formula, kW f —Flow conductivity of proppant filling layer under segmented sand spreading method, μm 2 cm;

[0123] Q—displacing fluid flow rate, mL / min;

[0124] Δp—pressure difference between high-pressure pressure measuring hole and low-pressure pressure measuring hole, kPa;

[0125] μ—Viscosity of the test liquid, mPa·s.

[0126] For situation 2:

[0127] When testing the conductivity of large differential segmented sand paving, multiple API diversion chambers need to be connected in series. In this case, the actual pressure measurement area includes not only the rectangular area, but also the semicircular area at the end of the API diversion chamber cavity (such as Figure 3 , Figure 6 , Figure 7 For the semicircular area, Fig.10 As shown in FIG. 1 , the flow of the displacement fluid in this area is a gradual flow, that is, the flow cross section is a rectangular cross section with a constant height and a gradual length. In order to simplify the calculation procedure of the flow conductivity of the segmented sand proppant filling layer under the second situation, the present invention uses the idea of ​​pressure drop equivalence to convert the semicircular pressure measurement area into a rectangular area with the same width as the actual rectangular pressure measurement area (such as Fig.11 The specific derivation process is as follows:

[0128] Taking the center of the semicircular area as the origin, the straight line where the center axis of the API diversion chamber cavity is located is the L axis, and the straight line passing through the origin and perpendicular to the L axis is the W axis, such as Fig.12 shown.

[0129] According to the established rectangular coordinate system, the radius of the semicircular area is recorded as R, and each point on the semicircular contour line satisfies the equation:

[0130] L 2 +W 2 =R 2 (0≤L≤R) (6)

[0131] Assuming that the fluid flows along the positive direction of the L axis, the flow velocity at any flow section A is:

[0132]

[0133] According to the principle of mass conservation, the flow rate at any flow section should be equal. From Q = v·A, we get:

[0134]

[0135] The cross-sectional area A can be converted into the thickness of the proppant filling layer W. f The product of the length of the bottom side of the current section 2W is expressed as:

[0136] A=2WW f (9)

[0137] Substituting formula (9) into formula (8), we can obtain

[0138]

[0139] Combining equation (6) and equation (10), we can get:

[0140]

[0141] Separating the variables and integrating gives,

[0142]

[0143] In formula (12), p1 and p2 are the pressures at the two end surfaces of the semicircular area, MPa.

[0144] After integration, the pressure difference generated by the fluid flowing through the semicircular area is:

[0145]

[0146] If the same fluid (same μ) flows at the same flow rate Q through a rectangular filling layer with the same thickness w and the same filling state (same k), the integration of the separated variables in equation (10) yields:

[0147]

[0148] In formula (14), p′1 and p′2 are the pressures at the two end surfaces of the equivalent rectangular region, MPa.

[0149] After integration, the pressure difference generated by the fluid flowing through the rectangular area is:

[0150]

[0151] By the pressure drop equivalent, that is, Δp 半圆 =Δp 矩形, combining equation (13) and equation (15), we can get:

[0152]

[0153] According to formula (16), according to the principle of pressure drop equivalence, the semicircular area at the end of the API flow chamber cavity can be equivalent to the width of the rectangular pressure measurement area (i.e., both are 2W), and the length The rectangular area.

[0154] So far, the flow of fluid in the actual pressure measurement area of ​​the proppant filling layer in a single API diversion chamber in case 2 is based on the idea of ​​pressure drop equivalence, such as Fig.13 As shown, a length of L 矩 The flow in the rectangular area and the semicircular area with a radius of R is equivalent to the flow in the rectangular area with a width of 2W and a length of L. 矩 +L's entire rectangular flow area.

[0155] If two standard API diversion chambers are used, the length L2 of the equivalent rectangular actual pressure measurement area is given by formula (17):

[0156]

[0157] If two standard API diversion chambers are used, the length L3 of the equivalent rectangular actual pressure measurement area is given by formula (18):

[0158]

[0159] like Fig.14 As shown, according to the size of the API diversion chamber, the diversion chamber proppant filling width is 2W = 3.81 cm; according to the equivalent length calculated based on different numbers of standard API diversion chambers, it can be obtained that

[0160] The calculation formula for the proppant filling layer conductivity in the segmented sand spreading method achieved by two standard API diversion chambers in series in case 2 is shown in formula (19):

[0161]

[0162] The calculation formula for the proppant filling layer conductivity under the staged sand laying method realized by three standard API diversion chambers in series in case 2 is shown in formula (20):

[0163]

[0164] Embodiment 1

[0165] When the ratio of proppants of different types or specifications to be tested is relatively small (including but not limited to volume ratio, mass ratio, etc.), the proppants are laid in a single API flow chamber 1 where the lower piston has been installed and fixed.

[0166] like Figure 3 As shown, according to the positions of the three pressure measuring holes in the API diversion chamber 1, the sand-paved area in the cavity of the API diversion chamber 1 is divided into an actual pressure measuring area 101 and an invalid pressure measuring area 100. Among them, the range of the actual pressure measuring area 101 is Figure 3 The area covered by the middle shaded filling is the rectangular area between the high pressure measuring hole 12 near the inlet end of the standard API diversion chamber and the low pressure measuring hole 14 near the outlet end; the range of the invalid pressure measuring area 100 is Figure 3 The part of the inner cavity of the middle guide chamber other than the shadow filling.

[0167] In the rectangular actual pressure measuring area 101 in the cavity of a single API diversion chamber, the proppant is laid inside the API diversion chamber according to a preset ratio and laying order. The invalid pressure measuring area 100 is filled with a suitable material according to a certain filling rule.

[0168] The connection method of the pressure measuring pipeline is: according to the direction of the displacement fluid flowing through the API diversion chamber, the pressure measuring hole 12 is connected to the high-pressure inlet end of the differential pressure gauge, the pressure measuring hole 13 is connected to the pressure sensor, and the pressure measuring hole 14 is connected to the low-pressure inlet end of the same differential pressure gauge connected to the pressure measuring hole 13.

[0169] The following is a detailed description of the segmented sand laying using 20 / 40 mesh quartz sand, 40 / 70 mesh quartz sand, and 70 / 100 mesh quartz sand proppants in a volume ratio of 1:1:1.

[0170] A method for testing flow conductivity in a segmented sand-laying mode based on a standard API flow chamber comprises the following steps in sequence:

[0171] 1) According to the calculated proppant mass, weigh the corresponding mass of proppant and filler for use.

[0172] The bulk density of 20 / 40 mesh quartz sand, 40 / 70 mesh quartz sand, and 70 / 100 mesh quartz sand proppants is 1.53 g / cm 3 , 1.47g / cm 3 , 140g / cm 3 ; Overall sand thickness: w = 5mm; Actual pressure measurement area:

[0173] A e =12.7×3.81=48.39cm 2

[0174] According to formula (3), the mass of each proppant required for the actual pressure test area is:

[0175]

[0176] Among them, M a1The quality of 20 / 40 mesh quartz sand; M a2 The quality of quartz sand of 40 / 70 mesh; M a3 The quality of quartz sand is 70 / 100 mesh.

[0177] According to the principle of optimal selection of filling materials for the invalid pressure measurement area, 20 / 40 mesh quartz sand is selected as the filling material for this area. According to formula (4), the mass of the filling material for the single-sided invalid pressure measurement area that needs to be weighed is:

[0178]

[0179] 2) Install the lower piston of the API diversion chamber with a square sealing ring to a suitable position near the pressure measuring hole, and tighten the fastening screws below;

[0180] 3) Place the metal plate into the API flow chamber so that it fits the lower piston;

[0181] 4) Spread the weighed proppant evenly on the metal plate of the diversion chamber. It is recommended to mark the positions of the proppant in the actual pressure measurement area and the filling materials in the invalid pressure measurement area in advance. Use a paper funnel to slowly move the proppant components and filling materials into the middle of the marked area, and then use a paving ruler to carefully scrape it flat. The distribution of the proppant after paving is as follows: Figure 4 shown.

[0182] 5) Take another metal plate and place it on top of the laid proppant filling layer, then put the upper piston with the square sealing ring installed into the diversion chamber until it contacts the metal plate above the proppant filling layer.

[0183] 6) Place the assembled API flow chamber on the stage 5 of the pressurizing device, and rotate the turntable 9 to make the lower plate surface of the pressurizing cover plate 6 contact the upper surface of the upper piston 16 of the API flow chamber.

[0184] 7) Precompacting the proppant filling layer. Apply pressure through the hydraulic force applying device 4 and load the closing pressure to 5 MPa.

[0185] 8) Connect the pipeline. Figure 4 As shown, the pressure measuring hole 12 is connected to the high pressure inlet end of the differential pressure gauge, the pressure measuring hole 13 is connected to the pressure sensor, and the pressure measuring hole 14 is connected to the low pressure inlet end of the same differential pressure gauge connected to the pressure measuring hole 13. Figure 5 As shown, the inlet end 7 is connected to the liquid displacement device, the outlet end 8 is connected to the outlet pipeline, and the outlet pipeline is connected to the back pressure valve, balance and other equipment.

[0186] 9) Vacuuming operation. Use a vacuum pump to evacuate the inside of the diversion chamber to a negative pressure of 0.1 MPa, and maintain this pressure for 30 minutes; after turning off the vacuum pump, the negative pressure of 0.1 MPa can still be maintained for 5 minutes; if the vacuum degree decreases, repeat step (9).

[0187] 10) Set the water displacement flow rate of the displacement pump to 5 ml / min and start the pump for displacement.

[0188] 11) The closing pressure is applied to the preset closing pressure point through the hydraulic force applying device 4. After the closing pressure and flow rate are stable, the pressure difference Δp is recorded, and the sampling interval is 30 seconds.

[0189] 12) The closing pressure is increased step by step, and step 11) is repeated. The conductivity of the proppant packing layer under different closing pressures is calculated according to formula (5).

[0190] Embodiment 2

[0191] When the ratios of proppants of different types or specifications to be tested differ greatly, proppants are placed in multiple API diversion chambers with lower pistons installed, and multiple API diversion chambers are connected in series. (Note: Considering the difficulty of experimental operation, it is recommended that the number of API diversion chambers used should not exceed 3)

[0192] The actual pressure measurement area and the invalid pressure measurement area are divided as follows:

[0193] Take two standard API diversion chambers connected in series as an example. Figure 6 As shown, in the order in which the displacement fluid flows through the standard API diversion chamber, the first standard API diversion chamber through which the fluid flows is the first standard API diversion chamber 1, and the diversion chamber next to the first standard API diversion chamber is the second standard API diversion chamber 2. The actual pressure measuring area 101 includes the area from the center axis of the pressure measuring hole 12 of the first standard API diversion chamber 1 to the center axis of the pressure measuring hole 24 of the second API diversion chamber and the part surrounded by the inner side wall of the API diversion chamber cavity; all parts included in the invalid pressure measuring area 100 are: the area inside the cavities of the first standard API diversion chamber 1 and the second standard diversion chamber 2 except the actual pressure measuring area.

[0194] Take three standard API diversion chambers in series as an example. Figure 7 As shown, according to the order in which the displacement fluid flows through the standard API diversion chambers, the first standard API diversion chamber through which the fluid flows is the first standard API diversion chamber 1, the second standard API diversion chamber through which the fluid flows is the second standard diversion chamber 2, and the diversion chamber through which the fluid flows last is the third standard diversion chamber 3. Figure 7 As shown, the actual pressure measurement area 101 includes the area Figure 7The shaded part in the middle is composed of three parts, namely, the part from the central axis of the pressure measuring hole 12 of the first standard API diversion chamber 1 to the outlet end of the internal cavity of the first standard API diversion chamber and the inner side wall of the cavity, the entire second API standard diversion chamber 2, and the part from the central axis of the pressure measuring hole 34 of the third API diversion chamber 3 to the outlet end of the internal cavity of the third standard API diversion chamber 3 and the inner side wall of the API diversion chamber cavity; the part included in the invalid pressure measuring area 100 is: the area inside the cavity of the first standard API diversion chamber 1 and the third standard API diversion chamber 3 except the actual pressure measuring area.

[0195] Because there are many API diversion chambers, in order to prevent sand blockage at the inlet and outlet of the diversion chamber and maximize the success rate of the segmented sand diversion test, a filter with a certain mesh size is placed at the filter screen holes at the inlet and outlet of the diversion chamber or filled with proppant with large particle size. The actual pressure measurement area is paved according to the designed proppant ratio, and the invalid pressure measurement area is filled with appropriate materials according to certain filling rules.

[0196] How to place multiple API diversion chambers on the hydraulic press stage: Multiple diversion chambers can be placed at the same height or stacked up and down. The specific placement method is mainly determined by the area and size of the hydraulic press stage. Considering the conventional model of the press stage, it is recommended that the diversion chambers be stacked up and down. If two standard API diversion chambers are used, the placement method and the pipeline connection method between the diversion chambers are as follows: Figure 8 As shown; if three standard API diversion chambers are used, the placement method and pipeline connection method between the diversion chambers are as follows Fig. 9 shown.

[0197] The pressure measuring pipeline connection method is: according to the direction of the displacement fluid flowing through the API diversion chamber, the fluid flows through the pressure measuring hole of the first API diversion chamber and is connected to the high-pressure inlet end of the differential pressure gauge, the fluid flows through the third pressure measuring hole of the last API diversion chamber and is connected to the low-pressure inlet end of the differential pressure gauge, and the remaining pressure measuring holes are closed.

[0198] A flow conductivity test procedure based on a standard API flow chamber with a large difference ratio and a segmented sand spreading method, comprising the following steps in sequence:

[0199] 1) Calculate the mass of each proppant in the actual pressure measurement area and the mass of the filling material in the invalid pressure measurement area, and weigh the corresponding mass of proppant and filling material for use.

[0200] 2) Install the lower piston of the API diversion chamber with a square sealing ring to a suitable position near the pressure measuring hole, and tighten the fastening screws below;

[0201] 3) Place the metal plate into the API diversion chamber so that it fits the lower piston of the diversion chamber;

[0202] 4) Spread the weighed proppant evenly on the metal plate of the diversion chamber. It is recommended to mark the positions of the actual pressure measurement area proppant and the invalid pressure measurement area filling material in advance. Use a paper funnel to slowly move each proppant component and filling material into the middle of the marked area, and then carefully scrape it flat with a paving ruler.

[0203] 5) Take another metal plate and place it on top of the laid proppant filling layer, then put the upper piston with the square sealing ring installed into the diversion chamber until it contacts the metal plate above the proppant filling layer.

[0204] 6) Place the assembled API flow chamber on the stage 5 of the pressurizing device, and rotate the turntable 9 to make the lower plate surface of the pressurizing cover plate 6 contact the upper surface of the upper piston 16 of the API flow chamber.

[0205] 7) Precompacting the proppant filling layer. Apply pressure through the hydraulic force applying device 4 and load the closing pressure to 5 MPa.

[0206] 8) Connect the pipeline. If two standard API diversion chambers are used, such as Figure 6 As shown, the pressure hole 12 is connected to the high pressure inlet of the differential pressure gauge, the pressure hole 24 is connected to the low pressure inlet of the same differential pressure gauge connected to the pressure hole 12, and the other pressure holes are closed. Figure 7 As shown, the pressure measuring hole 12 is connected to the high pressure inlet of the differential pressure gauge, the pressure measuring hole 34 is connected to the low pressure inlet of the same differential pressure gauge connected to the pressure measuring hole 12, and the other pressure measuring holes are closed. Figure 8 , Fig. 9 As shown, the inlet end 7 is connected to the liquid displacement device, the outlet end 8 is connected to the outlet pipeline, and the outlet pipeline is connected to the back pressure valve, balance and other equipment.

[0207] 9) Vacuuming operation. Use a vacuum pump to evacuate the inside of the diversion chamber to a negative pressure of 0.1 MPa, and maintain this pressure for 30 minutes; after turning off the vacuum pump, the negative pressure of 0.1 MPa can still be maintained for 5 minutes; if the vacuum degree decreases, repeat step (9).

[0208] 10) Set the water displacement flow rate of the displacement pump to the set flow rate and start the pump for displacement.

[0209] 11) The closing pressure is applied to the preset closing pressure point through the hydraulic force applying device 4. After the closing pressure and flow rate are stable, the pressure difference Δp is recorded, and the sampling interval is 30 seconds.

[0210] 12) The closing pressure is increased step by step, and step 11) is repeated. The conductivity of the proppant packing layer under different closing pressures is calculated according to formula (5).

[0211] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A method for testing the flow conductivity of a segmented sand-laying method based on a standard API flow chamber, characterized in that: The sand-paved area inside the API diversion chamber is divided into an actual pressure measurement area and an invalid pressure measurement area; Determine the filling size and sand concentration / thickness of the actual pressure measuring area and the invalid pressure measuring area; Calculating the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the filling amount is determined according to the filling size and the concentration / thickness of the sand in the actual pressure measuring area and the invalid pressure measuring area; Performing sand laying operation on the actual pressure measuring area and the invalid pressure measuring area according to the filling amount of the actual pressure measuring area and the invalid pressure measuring area, wherein the actual pressure measuring area is filled with proppant, and the invalid pressure measuring area is filled with filler, and the filler and the proppant are of the same type and specification; Place the API diversion chamber with sand on the loading platform of the hydraulic press, connect the pipeline, evacuate and saturate the displacement liquid, pressurize to the preset closing pressure point, and then conduct the diversion capacity test, and record the displacement liquid flow and pressure difference at different preset closing pressure points; The sand spreading operation for the actual pressure measurement area and the invalid pressure measurement area is divided into small difference ratio sand spreading and large difference ratio sand spreading, wherein the small difference ratio sand spreading is that the volume of the three components of large, medium and small to be tested does not exceed four times in sequence; If the sand is spread with a small difference ratio, use a single API diversion chamber to carry out the diversion capacity test under the segmented sand spreading method; The actual pressure measuring area and the invalid pressure measuring area are subjected to sand spreading operation, including large-difference-ratio sand spreading, wherein the large-difference-ratio sand spreading is that the volumes of the large, medium and small components to be tested are more than four times in sequence; If the sand is laid with a large differential ratio, two or three API diversion chambers are used to connect in series; Two or three API diversion chambers are placed on the same level or stacked up and down; The division rules of the actual pressure measurement area and the invalid pressure measurement area also include: If the sand is laid with a large differential ratio: the actual pressure measurement area includes the area between the high-pressure pressure measurement hole of the first API diversion chamber near the API diversion chamber inlet interface and the low-pressure pressure measurement hole of the terminal API diversion chamber outlet interface; the invalid pressure measurement area includes the area in the cavity of two or three API diversion chambers connected in series except the actual pressure measurement area; If the sand is laid with a large difference ratio, the actual pressure measuring area includes the semicircular area except the rectangular area in the first to the last API diversion chamber. Using the pressure drop equivalent principle, the semicircular area is equivalent to a rectangular actual pressure measuring area with the same width and different length as the actual pressure measuring area of ​​the adjacent rectangular area. The length calculation formula of the equivalent rectangular area is: In the formula, L is the length of the equivalent rectangular area, cm; W It is 1 / 2 of the width of the internal cavity of the API flow chamber, cm.

2. The method for testing flow conductivity of segmented sand-laying method based on standard API flow chamber according to claim 1 is characterized in that: The division rules of the actual pressure measurement area and the invalid pressure measurement area include: If the sand is laid with a small difference ratio: the actual pressure measuring area includes the rectangular area between the high-pressure pressure measuring hole of the API diversion chamber close to the API diversion chamber inlet interface and the low-pressure pressure measuring hole close to the API diversion chamber outlet interface; the invalid pressure measuring area is the area of ​​the sand-paved area inside the API diversion chamber except the actual pressure measuring area in the rectangular area.

3. The method for testing the flow conductivity of the segmented sand-laying method based on the standard API flow chamber according to claim 1 is characterized in that: The actual pressure measuring area proppant and the invalid pressure measuring area filler dosage are calculated according to the sand spreading concentration or sand spreading thickness, including: If calculated according to the sand concentration, the actual weight of proppant a in the pressure measurement area is calculated as follows: The calculation formula for the amount of filler weighed in the single-side invalid pressure measuring area is: If calculated by sand thickness, the actual pressure measurement area proppant a The calculation formula for weighing amount is: The calculation method for the amount of filler weighed in the single-side invalid pressure measuring area is: In the formula, —The weight of a proppant in the actual pressure measurement area, g; —The mass of the filling material in the single-side invalid pressure measurement area, g; A e —Area of ​​actual pressure measurement area, cm 2 ; A f —Area of ​​the unilateral invalid pressure measurement area, cm 2 ; C a —Proppant sand concentration, kg / m 2 ; C f —Sand concentration of the filling material in the single-side invalid pressure measurement area, kg / m 2 ; —A certain proppant a As a percentage of all proppants, % ; w —Sand paving thickness, cm; —Density of one-side filling, g / cm 3 ; —A certain proppant a Density, g / cm 3 .

4. The method for testing flow conductivity of segmented sand-laying method based on standard API flow chamber according to claim 1 is characterized in that: If the actual pressure measuring area includes the semicircular area at the end of the API diversion chamber, the total length of the actual pressure measuring area in the rectangular area is calculated by adding the length of the rectangular actual pressure measuring area equivalent to the semicircular area. The specific calculation formula for the diversion capacity under the segmented sand laying method includes: If the sand is laid with a small difference ratio: the actual pressure measurement area includes the rectangular area in the API diversion chamber, and the flow diversion capacity calculation formula is: In case of large differential sand laying: When two API diversion chambers are used, the calculation formula for diversion capacity is: When the number of API diversion chambers used is three, the calculation formula for diversion capacity is: In the formula, —The conductivity of the proppant filling layer under the segmented sand spreading method, ; Q —Displacing fluid flow rate, mL / min; —The pressure difference between the high-pressure pressure measuring hole and the low-pressure pressure measuring hole, kPa; —Test liquid viscosity, mPa·s.

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