METHOD FOR DETERMINING DYNAMIC BOTTOMHOLE PRESSURE OF DEEP GAS CONDENSATE WELL Russian patent published in 2023 - IPC E21B47/06 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to methods for calculating dynamic bottomhole pressure in deep gas condensate wells with a complex spatial arrangement of the wellbore and opening formations with a high condensate content. The method for determining the dynamic bottomhole pressure of a deep gas condensate well is characterized by the use of known data on well inclinometry, inner diameter and run-down depth of lift pipes. Formation gas flow rate corresponding to current values of wellhead pressure and temperature is determined by hydrodynamic studies of wells. Initial data are determined based on the results of primary gas condensate studies and PVT studies of the formation fluid, including the construction of a model of the formation gas condensate mixture with ten-degree fractions. As the initial composition, the component-fractional composition is taken, corresponding to the bottomhole pressure determined during the primary gas condensate surveys of the well. For the obtained model, computational CVD experiments are carried out with a decrease in pressure with a step of one megapascal and an array of component-fractional compositions of the fluid is formed, corresponding to the calculated steps of reducing the reservoir pressure as the reservoir is depleted. The bottomhole pressure is determined in the first approximation based on the obtained values and initial data on the formation gas flow rate, wellhead pressure and temperature. The composition corresponding to the bottomhole pressure in the first approximation is selected from the calculated array of component-fractional composition of the fluid. Next, the component-fractional compositions of the vapor and liquid phases of the well fluid are calculated, followed by determination of their physical properties to establish the flow structure at each calculated step along the wellbore. Using mechanistic modelling of the calculation of pressure losses along the wellbore, the pressure gradient is calculated, which is taken constant for the calculated step along the wellbore. According to a certain value of pressure loss at the calculated step along the wellbore and calculated using the geothermal temperature gradient, the calculation of the value of pressure loss for the next calculated step along the wellbore is repeated. Calculation is carried out until reaching the mark of the well head according to inclinometry. The obtained value of the calculated wellhead pressure is compared with the initial one, the bottomhole pressure is adjusted by this value and the calculation is repeated until the calculated wellhead pressure converges with the initial one to the required accuracy.

EFFECT: improved accuracy of determining dynamic bottomhole pressure in deep gas condensate wells with a complex spatial arrangement of the wellbore.

1 cl, 3 dwg, 1 ex -