«Oilfield engineering»

NEW TECHNIQUE OF TESTING (RESEARCHING) GAS AND GAS CONDENSATE WELLS BASED ON AUTOMODELING MODES OF UNSTATIONARY NON-ISOTHERMAL NON-LINEAR FILTRATION

UDC: 622.279.5.001.42
DOI: 10.33285/0207-2351-2021-10(634)-39-46

Authors:

¹ National University of Oil and Gas "Gubkin University", Moscow, Russian Federation
² Baltic State Technical University "VOENMEH" named after D.F. Ustinov, Saint-Petersburg, Russian Federation

Keywords: reservoir parameters, non-linear non-isothermal gas filtration, reservoir productivity, gas flow rate, reservoir transmissibility factor, piezo conductivity of the formation, Multi-point boundary value problem, ordinary differential equations, continuity equations, pulse equations, equations of real gas state, non-stationary energy equation

Annotation:

The objects of research are gas and gas condensate wells. For the first time, the paper considers the determination of the reservoir properties of productive formations and wells flow rate based on the results of field gas-dynamic tests of wells in stationary and non-stationary modes (flow-pressure). The numerical solution of a multipoint boundary value problem for a system of ordinary differential equations was obtained on the basis of standard algorithms and test calculations with subsequent interpolation of the vector of the eigenvalues initial values during an iterative computational process based on the built-in package of mathematical programs for a PC. A system of 27 ordinary differential equations of the first order is considered, each equation of which contains seven unknown eigenvalues. For the non-isothermal nonlinear problem of gas filtration (gas-condensate mixture), a self-similar solution is obtained, which makes it possible to determine the lithological characteristics of productive deposits (layers) and the current gas flow rate. Examples of calculations are considered that show a significant difference in the values of the current gas flow rate when using the linear Darcy law (Q = 337,7 thousand m3/day) and using the non-linear Forchheimer - Darcy law (Q = 208,6 thousand m3/day) with the same lithological parameters of the productive formation, i. e. the difference is more than 60 %.

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