A direct method of making large model fractured cores to maintain original oil-water saturation

Abstract

The invention discloses a direct production method for maintaining the original oil-water saturation of a large model fractured core, including: (1) determining the volume V, porosity, permeability K, oil saturation So, water saturation Sw, etc. of the fabricated fractured core; 2) Prepare the simulated oil and determine the quality of the oil used; (3) When the oil saturation is not considered, the quality of the water, cement, and quartz sand used are respectively a, b, and c; (4) When the oil saturation is established, the core is obtained (5) Mix oil, water and emulsifier evenly to prepare an oil-in-water emulsion; (6) Add cement and quartz sand to the emulsion and stir evenly to obtain cement slurry; (7) Wait for the cement to be tested When the sample is in a semi-solidified state, cut the cement sample with a steel wire according to the crack direction required by the experiment; (8) wait until the cement sample is consolidated. The invention is low in cost and easy to operate, can control the distribution of fractures in the rock core, and realize simultaneous establishment of models and saturation.

Description

technical field [0001] The invention relates to a direct manufacturing method for maintaining the original oil-water saturation of a large-model fractured rock core in an indoor simulation experiment of petroleum exploration and development. Background technique [0002] Physical simulation is an important means to simulate the development of oil and gas reservoirs. Practice shows that the larger the geometric size of the model, the closer the experimental results are to the actual mine field. Experimental cores are divided into natural and man-made. It is difficult to obtain natural cores, and the cost is relatively high. Therefore, artificial cores are commonly used for physical simulation of large models. The sand-packing model has low working pressure and cannot simulate fracture-porous reservoirs. Epoxy resin and aluminum phosphate are commonly used as cementing agents for existing cementation models, most of which require high-temperature sintering. In order to be...

AI Technical Summary

Problems solved by technology

For fractured cores, the procedure of creating fractures first and then establishing saturation is generally adopted. When the fluid is saturated, the fluid will channel through the fractures, so the original water saturation cannot be established.

There are two main methods for making cracks on artificial large cores. One is to insert a metal sheet before the core is formed, and then pull it out to form cracks, but it is difficult to grasp the timing of pulling out.

The second is to use specific materials to be placed in the model in advance, to melt, dissolve, volatilize, etc. by physical means, but there will be residues and the process is more cumbersome

Due to the existence of fractures in the fractured core, the water saturation is often higher than the required value, and the required oil-water saturation cannot be established