Method for evaluating reservoir pore type based on pore replacement

Abstract

The invention relates to a method for evaluating reservoir pore type based on pore replacement. The method includes the following steps: based on longitudinal wave speed, transverse wave speed, and density of a known reservoir stratum, calculating saturated rock elastic modulus of an original pore type 1 contained in the reservoir stratum; selecting the elastic modulus of a reservoir rock matrix mineral component and the elastic modulus of a pore fluid composition component, in combination with porosity, saturation and mineral component volume content, calculating the elastic modulus of the reservoir rock matrix; calculating a rock skeleton elastic modulus of the original pore type 1 contained in the reservoir stratum; conducting inversion on a pore aspect ratio of the reservoir stratum when the pore type 1 is contained; replacing the original pore type 1 with a pore type 2 through a given new pore aspect ratio; calculating the new longitudinal wave speed and transverse wave speed of the replaced reservoir stratum; comparing the longitudinal wave speed and transverse wave speed of the original reservoir stratum and the replaced reservoir stratum, and conducting reservoir pore type evaluation. According to the invention, the method can depict reservoir pore type and is more suitable for actual reservoir stratum.

Description

technical field [0001] The invention relates to the technical field of oil and gas resource exploration, in particular to a method for evaluating reservoir pore types. Background technique [0002] With the continuous deepening of oil and gas exploration and development, complex reservoirs such as carbonate rock salt, igneous rock and shale have become key areas for increasing oil and gas reserves and production. These complex reservoirs often develop multiple pore types, such as matrix pores, fractures, and vugs. The difficulty of complex reservoir prediction is to find high-quality reservoirs with high recoverable reserves and high economic value, and pore type is an important factor affecting the oil and gas reserves and productivity of complex reservoirs. Therefore, pore type evaluation is the key to complex reservoir prediction and fluid identification. [0003] However, the relationship between velocity and pore type in complex reservoirs is very complex. For exampl...

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Problems solved by technology

However, the classical critical porosity model does not establish the relationship between the reservoir rock skeleton and the pore type, so it cannot characterize the influence of the pore type on the elastic modulus of the reservoir rock skeleton, and thus cannot evaluate the reservoir pore type

In addition, these empirical models or empirical formulas may only be suitable for a certain type of reservoir, and cannot be extended to other reservoirs. Simply applying the empirical model will bring large errors; at the same time, the assumptions of these empirical models are too simple, which is inconsistent with the actual reservoir pore type. Inconsistent, it is difficult to reflect the pore type characteristics of the actual reservoir

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