CN-115754219-B - Method for judging migration similarity in propping agent seam

CN115754219BCN 115754219 BCN115754219 BCN 115754219BCN-115754219-B

Abstract

The invention discloses a method for judging migration similarity in a proppant slit, which comprises the steps of obtaining a surface similarity ratio according to the length and the height of an actual flow field slit and the slit length and the slit height of a simulated flow field slit, calculating a proppant single particle sedimentation speed, a concentration correction coefficient and a wall correction coefficient, obtaining particle sedimentation speeds of the actual flow field and the simulated flow field, calculating particle movement speeds and horizontal movement speeds of the actual flow field and the simulated flow field, obtaining a sedimentation speed similarity ratio, obtaining a migration similarity ratio, a fluid Reynolds number similarity ratio, a particle Reynolds number similarity ratio and a particle Frudes number similarity ratio of the actual flow field and the simulated flow field, judging whether the surface similarity ratio, the sedimentation speed similarity ratio, the migration similarity ratio, the fluid Reynolds number similarity ratio, the particle Reynolds number similarity ratio and the particle Frudes number similarity ratio are between 0.9 and 1.1, and if the particle Reynolds number similarity ratio is completely similar.

Inventors

XU HONGXING
ZHANG MIAN
WANG ZUWEN
CAO XIN
WEN YAKUI
YIN GUOYONG
LI YANHONG

Assignees

中国石油天然气集团有限公司
中国石油集团川庆钻探工程有限公司

Dates

Publication Date: 20260508
Application Date: 20211216

Claims (10)

1. A method for judging migration similarity in a proppant slit, comprising: Obtaining a similar ratio of a seam length to a seam height of the simulated flow field crack according to the length and the height of the actual flow field crack; calculating the single-particle sedimentation velocity, the concentration correction coefficient and the wall correction coefficient of the propping agent; Acquiring the particle sedimentation velocity of an actual flow field and a simulated flow field according to the single particle sedimentation velocity, the concentration correction coefficient and the wall correction coefficient; calculating the particle moving speed and the horizontal moving speed of the actual flow field and the simulated flow field; obtaining a similar sedimentation velocity ratio according to the particle movement velocity, the particle sedimentation velocity and the horizontal movement velocity of the actual flow field and the simulated flow field; Obtaining a similar migration ratio, a similar fluid Reynolds number ratio, a similar particle Reynolds number ratio and a similar particle Froude number ratio of an actual flow field and a simulated flow field; Judging whether the surface similarity ratio, the sedimentation velocity similarity ratio, the migration similarity ratio, the fluid Reynolds number similarity ratio, the particle Reynolds number similarity ratio and the particle Froude number similarity ratio of the actual flow field and the simulated flow field are between 0.9 and 1.1, and if so, completely similar the actual flow field and the simulated flow field.
2. The method for judging the migration similarity in a proppant joint according to claim 1, wherein the surface similarity refers to the fact that the lengths and heights of an actual flow field and a simulated flow field crack are correspondingly proportional, and the proportionality coefficients are the same, and the calculation formula of the surface similarity ratio is as follows: wherein, i.e. 、 Is the length, height and m of the actual flow field crack; 、 To simulate the length, height and m of the flow field crack.
3. The method for determining the intra-proppant-seam migration similarity according to claim 1, wherein the concentration correction factor calculation formula is: Wherein, C is the sand ratio,%; Sand ratio, i.e., surface sand ratio, refers to the ratio of the volume of proppant to the volume of fracturing fluid; the wall correction coefficient calculation formula is: Wherein: the particle size of the propping agent is m, w is the width of the crack and m; The calculation formula of the single particle sedimentation velocity is as follows: When (when) When (1): When (when) When (1): When (when) When (1): Wherein, the For the reynolds number of the particles, 、 Proppant density and fracturing fluid density, ; Is the particle size, m, of the propping agent; In order to achieve the viscosity of the fracturing fluid, G is the gravity acceleration rate of the gravity, ; The formula for calculating the Reynolds number of the particles is as follows: Wherein: In order to achieve a speed of movement of the particles, , Is the horizontal movement speed of the particles.
4. The method for judging the intra-slit migration similarity of a proppant according to claim 3, wherein the sedimentation velocity of particles in the actual flow field slit is the same as the method for calculating the sedimentation velocity of the simulated flow field, and the sedimentation velocity of particles in the actual flow field slit has a formula: Wherein: for the settling velocity of single particles in an actual flow field slit, 。
5. The method for judging the intra-slit migration similarity of a proppant according to claim 1, wherein the movement speed of the particles in the actual flow field slit is the same as the calculation method for simulating the movement speed of the particles in the flow field slit, and the calculation formula of the movement speed of the particles in the actual flow field slit is as follows: Wherein, the For the horizontal movement velocity of the particles in the actual flow field cracks, Is the settling velocity of the particles in the actual flow field cracks.
6. The method for determining intra-slot migration similarity as claimed in claim 5, wherein the horizontal movement velocity of the particles in the actual flow field fracture Equal to the fluid horizontal movement speed; simulating horizontal movement velocity of particles in a flow field Equal to the fluid horizontal movement speed.
7. The method for determining the migration similarity in a proppant slot of claim 6, wherein the sedimentation velocity similarity ratio is calculated by the formula: Wherein: 、、 For the movement speed, sedimentation speed and horizontal movement speed of the particles in the actual flow field cracks, ; 、、 To simulate the movement speed, sedimentation speed and horizontal movement speed of particles in the flow field cracks, 。
8. The method for judging the intra-slit migration similarity of a proppant according to claim 1, wherein the migration similarity refers to a ratio of a time required for a particle in an actual flow field and a simulated flow field to move a unit distance in a horizontal direction to a time required for a particle to move a unit distance in a vertical direction, and the migration similarity is calculated by: Wherein, the 、 Respectively the horizontal migration time and the sedimentation time of particles in an actual flow field crack, s; 、 Respectively simulating horizontal migration time and sedimentation time of particles in a flow field crack, and s; 、 Respectively the length and the height of an actual flow field crack, m; 、 respectively simulating the length and the height of a flow field crack, and m; 、 the true sedimentation velocity and the horizontal movement velocity of the particles in the actual flow field cracks are respectively, ; 、 The true sedimentation velocity and the horizontal movement velocity of particles in the simulated flow field cracks are respectively, ; The fluid Reynolds number equality refers to the corresponding equality of Reynolds numbers generated by fluid horizontal movement in two flow fields, and the fluid Reynolds number equality calculation formula is as follows: Wherein, the 、 For the fracturing fluid density of the actual flow field and the simulated flow field, ; 、 For the fluid horizontal displacement velocity of the actual flow field and the simulated flow field, ; 、 To simulate the fracturing fluid viscosity of the actual flow field and the simulated flow field, ; The equal reynolds numbers of the particles refer to the corresponding equal reynolds numbers generated by the traction of the particles in the two flow fields by the fluid, and the equal reynolds numbers of the particles are calculated by the following formula: Wherein, the 、 For the actual flow field and the velocity of movement of the particles in the simulated flow field, ; 、 The proppant particle size for both the actual flow field and the simulated flow field, m; The particle Froude number equality means that Froude numbers generated by the action of gravity of particles in two flow fields are correspondingly equalized, and the particle Froude number equality calculation formula is as follows: wherein g is the gravity acceleration, , To be the rate of movement of the particles in the actual flow field cracks, ; To simulate the velocity of movement of the particles in the flow field cracks, 。
9. The method for judging the migration similarity in a proppant slot according to claim 1, The relation formulas of the moving speed, the sedimentation speed and the horizontal moving speed of particles in the actual flow field and the simulated flow field cracks and the crack width ratio are as follows: Where a is the width ratio of the actual flow field slit to the simulated flow field slit.
10. The method for judging the intra-slot migration similarity of the propping agent according to claim 1, wherein if not, the experimental parameters of the simulated flow field are finely adjusted according to the construction parameters of the known actual flow field or the actual flow field construction parameters are finely adjusted according to the experimental parameters of the known simulated flow field until the ratio of the parameters of the similarity result is between 0.9 and 1.1; The construction parameters comprise the length and height of the crack, the sand ratio, the width of the crack, the sedimentation speed of single particles, the horizontal movement speed of the particles, the sedimentation speed of the particles, the density of fracturing fluid, the horizontal migration speed of fluid, the particle size of propping agent particles and the acceleration of gravity.

Description

Method for judging migration similarity in propping agent seam Technical Field The application relates to the technical field of proppant settlement migration, in particular to a method for judging migration similarity in a proppant joint. Background Hydraulic fracturing technology is one of the important technologies applied to unconventional resource exploitation. The method comprises the steps of injecting a front-end liquid into a shaft rapidly, holding high pressure at the bottom of the shaft, when the bottom-hole pressure is greater than the formation fracture pressure, the formation is pressed open to form a symmetrical crack, pumping a sand-carrying liquid containing propping agent in a subsequent pumping part to enable the crack to be closed on the propping agent to form an oil-gas flow channel with high diversion capacity, and finally pumping a displacement liquid to squeeze the sand-carrying liquid in the shaft into the formation. However, the underground situation is invisible and not easy to touch, and it is difficult to know accurately how the proppants migrate in the pressed-open cracks and how the formed sand bank is shaped. The similarity criterion is the only key point for combining the object model experiment with the field construction condition. The field construction effect is evaluated and optimized, and the object model experimental parameters obtained after optimization are converted into the field construction parameters through the similarity criteria to guide the follow-up fracturing construction. Most scholars skip the similarity part when carrying out proppant settlement migration experiments and directly carry out subsequent experiments, and although the experimental results have a certain guiding effect on the site, the supported credentials are insufficient, or part of scholars consider the problem, but only simply put forward the problem and do not have specific implementation. Aiming at the problem, the patent provides a brand new similarity criterion and a specific similarity method. The similarity criterion provided by the patent is simple and easy to implement, and the object model experiment and the field construction effect can be well combined. Disclosure of Invention The application provides a method for judging the similarity of migration in a proppant joint, which aims to solve the problem that the similarity research of the proppant settlement migration object model experiment and the on-site construction effect is weak. The technical scheme adopted by the application is as follows: the invention discloses a method for judging migration similarity in a proppant joint, which comprises the following steps: Obtaining a similar ratio of a seam length to a seam height of the simulated flow field crack according to the length and the height of the actual flow field crack; calculating the single-particle sedimentation velocity, the concentration correction coefficient and the wall correction coefficient of the propping agent; Acquiring the particle sedimentation velocity of an actual flow field and a simulated flow field according to the single particle sedimentation velocity, the concentration correction coefficient and the wall correction coefficient; calculating the particle moving speed and the horizontal moving speed of the actual flow field and the simulated flow field; obtaining a similar sedimentation velocity ratio according to the particle movement velocity, the particle sedimentation velocity and the horizontal movement velocity of the actual flow field and the simulated flow field; Obtaining a similar migration ratio, a similar fluid Reynolds number ratio, a similar particle Reynolds number ratio and a similar particle Froude number ratio of an actual flow field and a simulated flow field; Judging whether the surface similarity ratio, the sedimentation velocity similarity ratio, the migration similarity ratio, the fluid Reynolds number similarity ratio, the particle Reynolds number similarity ratio and the particle Froude number similarity ratio of the actual flow field and the simulated flow field are between 0.9 and 1.1, and if so, completely similar the actual flow field and the simulated flow field. Further, the surface similarity refers to that the lengths and heights of the actual flow field and the simulated flow field cracks are correspondingly proportional, and the proportionality coefficients are the same, and the calculation formula of the surface similarity ratio is as follows: Wherein L 1、H1 is the length and the height of an actual flow field crack, and m, L 2、H2 is the length and the height of an analog flow field crack, and m. Further, the concentration correction coefficient calculation formula is: Wherein, C is the sand ratio,%; Sand ratio, i.e., surface sand ratio, refers to the ratio of the volume of proppant to the volume of fracturing fluid. The wall surface correction system has the following calculation formula: Wherein d p is the par