Representation method and representation system of tight sandstone oil-water relative permeability information

Abstract

The invention belongs to the technical field of petrochemical engineering, and discloses a representation method and a representation system of tight sandstone oil-water relative permeability information. Effective connection with a core holding unit device is realized through a nuclear magnetic resonance device, and a tight sandstone displacement of oil by water process under nuclear magnetic resonance device is completed; and heavy water is used for displacement of oil; an oil and water relative permeability curve is solved and drawn through signals in a T2 spectrum of detected n-dodecane and port discharged liquid quantity; then, the displacement of oil by water process in a stratum is analyzed comprehensively in combination with geological conditions. In the method provided by the invention, oil content and water content in the core are solved through the T2 spectrum, and the finally drawn oil and water relative permeability curve is more accurate than that drawn by other methods;in an experiment process, a nuclear magnetic resonance test can be executed at any stage, the core is free from being taken out, and an experiment result obtained meets actual conditions better; the method is more convenient to operate, the whole process of the displacement of oil by water can be highly represented through the nuclear magnetic resonance test, so the method has actual significancein development of tight oil.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a method and system for characterizing tight sandstone oil-water relative permeability information. Background technique [0002] Currently, the closest prior art: [0003] In recent years, with the gradual reduction of conventional oil and gas reserves, tight oil has become a key field of oil and gas exploration and development at home and abroad. Among them, tight sandstone reservoirs have great development potential and development difficulty, and have gradually become the focus of research by domestic and foreign oil and gas field geology and development experts. Tight sandstone reservoirs generally have a porosity of less than 10% and a permeability of less than 0.1mD. The low-ultra-low porosity and permeability characteristics of tight sandstone reservoirs make the water flooding process different from conventional reservoirs. Relative permeabi...

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Problems solved by technology

[0006] (1) The pore structure of tight sandstone is complex, the pore space is narrow, water flooding experiments are not easy to carry out, and the calculation of oil-water two-phase permeability is complicated

[0007] (2) Based on the existing experimental equipment, the requirements for core permeability are very high. Generally, only cores with a permeability greater than 0.2md can be used to measure and calculate the relative oil-water permeability, while the porosity of tight sandstone is generally around 10%, and the permeability is lower than 0.1 mD, so the current experimental device cannot meet the experimental needs

[0010] The porosity and permeability of tight sandstone is very low, and the unsteady method needs to establish a large enough displacement pressure or displacement speed, so as to reduce the end effect caused by capillary force. Many researchers have explored different methods to weaken the end effect, although have some effect, but further research is needed

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