Natural gas hydrate stratum attenuation modeling method and device

Abstract

The invention provides a natural gas hydrate stratum attenuation modeling method and device. The method comprises the steps that solid matrix components, hydrate and pore water parameters of a work area, stratum porosity at different depths and a logging curve are obtained; hydrate saturations at different depths are determined based on the logging curve of the work area and the stratum porosity at different depths, and then the permeability at different depths is determined in combination with the stratum porosity at different depths; determining the elasticity modulus and density of the solid matrix; determining the bulk modulus and density of the mixed fluid at different depths; determining the elasticity modulus of the dry marine sediment skeleton at different depths; and based on thestratum porosity at different depths, the elasticity modulus of the dry marine sediment skeleton at different depths, the elasticity modulus and density of the solid matrix, and the bulk modulus and density of the mixed fluid at different depths, obtaining a change model of the longitudinal wave speed along with the depth and / or a change model of the longitudinal wave inverse quality factor alongwith the depth.

Description

technical field [0001] The invention belongs to the field of petrophysical modeling, in particular to a method and device for modeling attenuation of natural gas hydrate formations. Background technique [0002] Natural gas hydrate, referred to as hydrate, also known as "combustible ice", is an ice-state and crystalline clathrate compound formed by natural gas and water under high-pressure and low-temperature environmental conditions. As an unconventional energy source, it has become a hot spot in current energy research because of its huge resources. [0003] Gas hydrates generally exhibit different effects from mineral and fluid components. Natural gas hydrate can not only show the properties of fluid, but also show the properties of solid skeleton. These properties have been discovered in laboratory studies (Buffett and Zatespina, 2000; Tohidi et al., 2001; Winter et al., 2004; Yun et al., 2005; Priest et al., 2009). A variety of isotropic petrophysical theories suitab...

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Problems solved by technology

[0004] However, at the present stage, the decay simulation process often focuses on the study of the decay mechanism caused by hydrate occurrence, while ignoring the influence of hydrate-induced fluid viscosity changes, rock permeability changes, etc. on the decay characteristics, and the attenuation of other reservoir factors. Influenced by characteristics, the research on the attenuation mechanism of hydrate reservoirs is not accurate and in-depth

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