Method for measuring saturation of rock core bound fluid based on centrifugal method

Abstract

The invention discloses a method for measuring saturation of rock core bound fluid based on a centrifugal method. The method comprises the following steps of: S1, obtaining the dry weight of a rock sample; S2, pressurizing and saturating the rock sample to obtain the mass of the saturated rock sample; S3, dehydrating the rock sample by adopting a centrifugal method; S4, carrying out heat treatment on the rock sample, and recording the mass of the rock sample after each temperature increase; S5, calculating the saturation degree of the pore bound fluid of the rock sample; S6, carrying out derivation on the bound fluid saturation Swi in a Swi-Ti relation curve; S7, deriving a first-order derivative Swi'of Swi in a Swi'-Ti relation curve, and drawing a Swi''-Ti relation curve; S8, obtaining cut-off temperatures of the two types of bound fluids according to the Swi''-Ti relation curve; and S9, calculating to obtain the saturation of the two types of bound fluids. The processing method is simple and easy to operate; and the interval of the two types of bound fluids is obvious in expression, and division accuracy is high.

Description

technical field [0001] The invention relates to the technical field of exploration and development, in particular to a method for measuring the saturation of rock core bound fluid based on a centrifugal method. Background technique [0002] For typical tight rocks, the pore space is filled with free fluid FF (free fluid), capillary bound fluid CAF (capillary bound fluid) and clay bound fluid CBF (clay bound fluid). Free fluid exists in the form of a free state and can flow freely in the pores, and the corresponding storage space is also called free pores. In the process of oil and gas reservoir formation, affected by the difference in wettability of the pore wall surface and the capillary force of small pores, oil and gas cannot displace all the water during the migration process, and the water that cannot be displaced out of the pores becomes The bound fluid in the pores; the distribution and remaining in the contact position of fine non-clay minerals in the rock, in the m...

AI Technical Summary

Problems solved by technology

But using experience T 2C The value cannot correctly characterize the pore size of all rock types, and may produce large errors in the pore division of some rock types

In early studies, some scholars used centrifugal method to determine the two T 2C However, experiments have shown that the fluid displaced by centrifugation is usually only free fluid, and there are still a large amount of capillary-bound fluid and clay-bound fluid in the pores; multistage centrifugation is used to determine the double T 2C To divide the pore structure, it is still unable to accurately divide the free fluid, capillary-bound fluid and clay-bound fluid

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