A Calculation Method of Fracturing Fluid Loss Velocity Considering Natural Fractures

Abstract

The invention discloses a method for calculating a fracturing fluid leak-off speed by taking a natural fracture into account. The method comprises a step (A) of dividing the natural fracture with a fracture length of L into N unit bodies with an equal length, and dividing total calculation time T into M time nodes with the same intervals; a step (B): provided that a pressure estimated value at the position of a natural fracture inlet at a K-th time node is ; a step (C) of calculating pressure of the i-th unit body and width of the natural fracture at the k-th time node; a step (D) of calculating a leak-off speed of fracturing fluid at the k-th time node through the natural fracture; a step (E) of calculating a width of a hydraulic fracture at the position of the natural fracture inlet at the k-th time node; a step (F) of determining a pressure calculation value at the position of the natural fracture inlet at the K-th time node; a step (G) of setting solving precision as epsilon, calculating a solving error alpha, and if alpha<=epsilon, causing obtained through the step (D) to be the leak-off speed of the fracturing fluid at the k-th time node through the natural fracture. The leak-off speed of the fracturing fluid in the hydraulic fracture process can be calculated accurately, and effective guidance is provided for fraction scheme design.

Description

Technical field: [0001] The invention relates to the field of petroleum and natural gas exploration and development, in particular to a method for calculating the filtration rate of fracturing fluid considering natural fractures in the field of hydraulic fracturing. Background technique: [0002] Hydraulic fracturing technology is an important measure for stimulation of low permeability oil and gas reservoirs. Hydraulic fracturing is to use the ground high-pressure pump group to pump the fracturing fluid into the formation with a displacement exceeding the absorption capacity of the formation to generate hydraulic fractures, and then continue to inject the fracturing fluid with proppant (sand grains) to make the fracture continue to extend and Fill it with proppant, and when the fracturing fluid flows back, under the formation pressure, the proppant will support the fracture in the fracture and prevent the fracture from closing, thus forming a sand filling with a certain len...

AI Technical Summary

Problems solved by technology

[0006] Regarding the calculation method of fracturing fluid loss rate in natural fractures, scholars at home and abroad have done many related studies, most of which use the theory of seepage mechanics to describe the fracturing fluid loss in natural fractures, but the fracturing fluid in natural fractures The flow in the fracture has exceeded the seepage category, so these methods can not reflect the actual fluid loss of fracturing fluid well

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