Manufacturing method for manmade rock sample for simulating real form of hydraulic fracturing crack

Abstract

The invention discloses a manufacturing method for a manmade rock sample for simulating the real form of a hydraulic fracturing crack. An original square rock plate is manufactured through an underground rock core or same-layer-position outcrop rock of an oil gas reservoir section; the rock plate is split in the length direction through a rock plate splitting device, and a three-dimensional laserscanner is used for obtaining split rock sample surface rough feature data; the rock sample surface roughness coefficient after splitting is calculated, and a pair of split rock samples capable of most representing the reservoir hydraulic fracturing crack surface feature are selected according to the roughness coefficient; according to the surface roughness feature data, a 3D printer is used for manufacturing a manmade rock sample manufacturing die; manmade rock sample manufacturing materials are prepared according to reservoir section rock mineral components, and a manmade rock sample for simulating the real form of the hydraulic fracturing crack is formed through pressing. According to the manufacturing method, the principle is simple, adopted equipment facilitates machining and manufacturing, rock samples consistent to reservoir rock mineral in component and real and uniform in surface rough feature can be manufactured in batches, and testing is conveniently conducted.

Description

technical field [0001] The invention relates to the technical field of oil and gas production enhancement and reformation, in particular to a method for making artificial rock samples for simulating the real shape of hydraulic fracturing fractures. Background technique [0002] Hydraulic fracturing is the main measure for increasing production of oil and gas reservoirs. During construction, fracturing fluid with relatively high viscosity is squeezed into the oil and gas reservoir through the wellbore. When the injection rate of fracturing fluid exceeds the absorption capacity of the reservoir, it will High pressure is formed on the reservoir, and when this pressure exceeds the fracture pressure of the reservoir rock near the bottom of the well, the reservoir rock will be pushed apart and fractures will be generated. The rock is formed by the mutual bonding of various mineral particles and cement, and hydraulic fracturing fractures mainly extend along the part of the cement w...

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Problems solved by technology

[0007] Although these methods can reproduce rock samples with a fixed rough surface to a certain extent, they have certain limitations in simulating the real shape of hydraulic fractures: (1) None of the above methods have analyzed the mineral composition of natural rock samples. Detailed analysis of basic information such as particles (particles, cement, etc.) and mineral particle size, resulting in a large difference in the basic components and pore structure characteristics of artificial rock samples and natural rock samples, so that it is impossible to obtain both porosity and permeability. Man-made rock samples whose physical properties such as density, compressive strength, elastic modulus, and shear strength are all consistent with natural rock samples

(2) The rough surface morphology of the rock sample produced by the direct pouring method has a large error from the original rock sample, resulting in a large deviation in its mechanical properties from the original rock sample

(3) The 3D printing method is sprayed and stacked layer by layer, and the produced rock samples have obvious layering, which does not match the structural characteristics of the original rock samples

(4) No research has been carried out on the selection method of rough surface topography representing the true shape of hydraulic fractures in a certain reservoir section

(5) No compression was performed during the preparation of the rock sample, and the strength of the prepared rock slab could not meet the requirements of the interaction between fracturing construction and formation pressure, and could not meet the effect of fracturing experiments

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