Calculation method of temperature, pressure and dryness of injected steam and nitrogen mixture

Abstract

The invention provides a method for calculating the temperature, pressure and dryness of the injected steam and nitrogen mixture. The outlet is the initial calculation point, and the step size can be set arbitrarily to calculate the wellhead temperature, wellhead pressure and wellhead dryness distribution at the wellhead of the surface pipeline; the wellhead is the initial calculation point, and the step size can be set arbitrarily to calculate the wellbore temperature, wellhead pressure and wellhead dryness distribution at the wellhead. Wellbore pressure and wellbore dryness distribution; based on the wellbore temperature, the wellbore pressure and the wellbore dryness distribution, guide the implementation of corresponding processes on the oilfield site. The invention has good calculation stability and high calculation accuracy, and provides reliable calculation means for the optimal design of injection parameters of the steam+nitrogen mixed system in the wellbore.

Description

technical field [0001] The present invention relates to the field of steam injection development in thermal recovery of heavy oil, in particular to the calculation of the relevant parameters of injected steam and nitrogen mixture in surface pipelines and well bores in heavy oil thermal recovery, specifically, the temperature, temperature and temperature of injected steam and nitrogen mixture. Calculation method of pressure and dryness. Background technique [0002] Steam injection is an effective and economical method for producing heavy oil. However, the steam injection technology itself has some shortcomings: the cost of simple steam injection is high; The steam in the reservoir channeled along the high-permeability layer, resulting in a large loss of injected steam and a decrease in volumetric sweep coefficient. Therefore, a thermal oil recovery process using nitrogen assisted steam injection is proposed. The process can reduce steam heat loss, improve steam injection e...

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Problems solved by technology

[0004] The invention provides a method for calculating the temperature, pressure and dryness of the injected steam and nitrogen mixture. Under the condition that the steam temperature, steam pressure and steam dryness at the outlet of the steam boiler are known, the steam+nitrogen binary system is deduced. The calculation formula and calculation process of the temperature, pressure, and dryness distribution of the two-phase mixture in the surface pipeline and the wellbore solve the problem that the existing steam injection parameter calculation model cannot calculate the temperature field, pressure field, and dryness of the nitrogen and steam mixture in the wellbore. Problems with correct calculation of fields

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