Calculation of fluid high pressure physical parameters: The calculation of high pressure
physical property parameters of fluid domestic and abroad is summarized, which can be used
to calculate oil, gas and water viscosity, compression coefficient, volume coefficient and
density, etc. Gas provides a variety of non-hydrocarbon gas correction methods; oil phase
provides saturated and unsaturated physical properties calculation; two phases provide
tension calculation, etc.
This paper provides the calculation of gas-liquid two-phase flow
pattern in wellbore: For gas-liquid two-phase fluid, the pressure conversion methods from
wellhead to bottom hole (single-phase liquid, single-phase gas, gas-liquid uniform flow,
Hagedorn-Brown, Harsan-Kabir, Begges-Brill, Dons-Ros, Orkiszewski, Aziz, Mukherjee-Brill)
are provided, and the calculation modules of pressure change at different depths are
provided at the same time.
The Hagedorn-Brown method:
Hagedorn-Brown (1965) establishes a pressure gradient model for the three-phase flow of oil
water and gas in a vertical well, based on single-phase fluid and mechanical energy
conservation law; In a 457m depth test well with 1, 11/4", 11/2 "tubes, a large number of
field tests have been carried out on the mixture of 10, 30, 35 and 110 mPa.s natural gas,
water and oil are used, and the relation of pressure drop of the two-phase vertical rising
pipe under various flow patterns is put forward by the reverse calculation of liquid-holding
ratio.
Harsan-Kabir method: The method of
judging each of the flow type is obtained by means of the mechanism analysis for the
transition of the gas-liquid two-phase flow type in the lead straight circular pipe, and a
method for judging the flow type is put forward, and the calculation method of the pressure
gradient under various flow types is also given.
The Beggs-Brill method: Beggs-Brill
(1973) obtained a pressure gradient equation based on the energy conservation equation of
the homogeneous flow energy, and conducted a large amount of experiments with water and air
in a tilted transparent tubes with diameters of 1 ", 11/2" and 13.7 m length, The relative
law of liquid holdup and drag coefficient of gas-liquid two-phase flow in different inclined
pipes is obtained.
Duns_Ros method: The calculation of the
gas-liquid two-phase pipe flow is mainly carried out through the judgment of the flow
pattern, and the main task of the related formula is to judge the distribution of the flow
pattern in each section of the well bore. In general, the vertical multi-phase flow can be
divided into four different flow modes, including a bubble flow, a slug flow, a slug flow
elastic transition (stirring flow), and elastic flow.
Orkiszewski method: Orkiszewski (1967)
used 148 wells measured data to compare the gas-liquid two-phase flow models and picked the
optimal one based on different flow types. The pressure drop calculation method of four flow
patterns is obtained by synthesizing his research results.
Aziz method: The flow pattern is
determined according to the proposed flow pattern distribution map, and then the liquid
holdup and pressure drop are calculated.
Mukherjee-Brill method: Mukherjee and
Brill (1985) improve the experimental conditions on the basis of the research work of Beggs
and Brill (1973). The flow pattern of two-phase flow in inclined tube is deeply studied, and
a more suitable criterion for judging the flow pattern of two-phase flow in inclined tube
(including horizontal tube) and the application convenience empirical formula of liquid
holdup and friction coefficient are put forward.
Productivity prediction and node analysis of oil and gas wells:
According to the seepage equation of oil and gas wells, the dynamic IPR curves of oil, gas
and water at different times are provided, the production of oil and gas wells varies with
time under given bottom hole pressure, the bottom hole pressure varies with time at constant
flow rate is provided, and the sensitive parameters analysis of formation permeability, skin
and gas component and so on to pressure and flow rate are provided.
The calculation of wellbore pressure and temperature is provided:
According to wellbore pipe flow, both the variation of wellbore pressure and temperature can
be calculated by simultaneously considering formation heat conduction and wellbore thermal
convection, and various flow patterns of vertical well and horizontal well can be
considered.
Provide the gradient conversion of oil and gas wells,
productivity well testing function: According to different types of productivity well
testing (conventional, isochronous and modified isochronous well testing, etc.) to predict
productivity curves; According to wellbore test pressure and temperature gradient data,
wellbore pressure and temperature gradient conversion are obtained.
Multi-component mixed phase state calculation: For condensate gas
well and gas-bearing mixture, RK, SRK, PR and PT equation of state are used to calculate the
phase diagram of multicomponent mixture according to the phase equilibrium theory, and the
bubble point and dew point pressure of the mixture are calculated at the same time.
