High-temperature and high-pressure unsteady-state equilibrium condensate oil gas-phase permeation test method

Abstract

The invention relates to a high-temperature and high-pressure unsteady-state equilibrium condensate oil gas-phase permeability test method. The method comprises the following steps: extracting, cleaning and drying a rock core; testing the maximum condensate oil saturation Som, the corresponding pressure PSom and the balance oil volume coefficient Bop of the constant volume failure; preparing a balanced oil gas sample; transferring the balanced oil gas sample; establishing bound water for the rock core; continuously performing balance oil displacement on the rock core under the pressure PSom and the formation temperature; carrying out balanced gas displacement on the rock core to obtain accumulated oil production O (t) and accumulated gas production G (t) on the ground; converting into accumulated oil production O '(t) and accumulated gas production G' (t) under stratum conditions; and calculating the oil-phase relative permeability Kro, the gas-phase relative permeability Krg and the gas saturation Sge of the outlet end surface of the rock core at each moment. The influence of rock and oil gas fluid under the stratum high-temperature and high-pressure conditions is considered, themeasurement result better conforms to production practice, and a simpler, more convenient, more accurate and more effective relative permeability curve testing method is provided for condensate gas reservoir development.

Description

technical field [0001] The invention relates to a high-temperature and high-pressure unsteady-state equilibrium oil-gas phase permeability testing method in the oil-gas reservoir development process in the field of petroleum and natural gas exploration and development. Background technique [0002] Oil-gas phase permeability is an important basic data in gas field development. The current standard practice for oil-gas phase permeability testing is to use simulated gas ( Nitrogen) and simulated oil (kerosene) are measured by steady-state method or unsteady-state method, and the test conditions are normal temperature and low pressure. Studies have shown that under the conditions of high temperature and high pressure in real equilibrium oil and gas reservoirs, the gas-oil interfacial tension is much smaller than the standard method, and the viscosity ratio is also very different. The fluids involved in seepage are not in phase equilibrium, resulting in great differences in test...

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Problems solved by technology

This method is in line with the field practice, and the results can explain the problem that formation condensate oil is easy to flow, but this method is very complicated, mainly as follows: (1) Two core experiments are required, one is depletion experiment to determine the criticality Flow saturation, the other is multiple balanced oil and gas displacement experiments, the experimental workload is heavy; (2) the steady state method requires two pumps, and the difficulty of the experiment increases; (3) the steady state method needs to determine the condensate oil saturation under high temperature and high pressure, NMR CT and CT have limitations on high temperature and high pressure conditions. The ultrasonic test currently used can only be determined by calibration experiments, and the accuracy is not high; (4) Generally, a single interpenetration test requires more than one month of continuous testing at high temperature and high pressure, and the test time is very long

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