RU2055179C1 - Method for determination of productivity factor of gas-condensate wells - Google Patents

Abstract

FIELD: gas producing industry. SUBSTANCE: bottom-hole pressure and production rate are measured on well under operating practices. Well is shutdown at wellhead, and curve of pressure regaining on well bottom up to formation in time is registered. After full regaining of pressure, formation pressure is measured. Obtained results are used for graphical processing of pressure regaining curve and angular factor of rectilinear section and time characteristic of intersection of initial and rectilinear sections are determined. Then, radius of bottom-hole zone is determined by the respective formula. EFFECT: higher efficiency. 2 dwg, 4 tbl

Description

 The invention relates to the gas industry, in particular to field research of the productive characteristics of gas and gas condensate wells.

Closest to the invention is a method of research at stationary modes of formation gas filtration, which consists in measuring reservoir pressure, bottomhole pressures and production rates of the investigated well in 5-6 stationary modes and then determining the coefficients a and b from the inflow equation P $\genfrac{}{}{0ex}{}{\text{2}}{\text{<figure-callout id="2" label="pl R" filenames="00000015.png,00000016.png" state="{{state}}">pl </figure-callout>}}$ R $\genfrac{}{}{0ex}{}{\text{2}}{\text{zab}}$ a · Q + b · Q ² by the least squares method.

 The disadvantage of this method is the impossibility of using this method in wells operating with a minimum flow rate, ensuring the removal of fluid from the bottom due to the fact that when changing the mode in such wells, the principle of stationarity that underlies the method is violated.

 The objective of the invention is to create such conditions in the implementation of the method, which would allow the study of gas condensate wells mainly low production.

 It is impossible to conduct research in 5-6 stationary modes in such gas condensate wells, which can significantly reduce the accuracy of measuring the productivity coefficient of wells, and in some cases it becomes impossible to determine the productivity coefficient of low-yield wells.

• ln

(1) где β^I- угловой коэффициент, определяемый по прямолинейному участку кривой восстановления давления (КВД), обработанный в координатах Р $\genfrac{}{}{0ex}{}{\text{2}}{\text{заб}}$ от lgt;
Q_о дебит скважины перед остановкой скважин для записи КВД, тыс·м³/сут;
0,889 коэффициент пропорциональности;
R_с радиус скважины по внутреннему диаметру эксплуатационной колонны, м;
R_пр.з. радиус призабойной зоны, м, определяемый из соотношения
R_пр.з=

(2)
κ- величина, характеризующая скорость восстановления давления в зоне дренирования скважин, м³/с;
t_н.у. время восстановления начального участка КВД, с;
κ

(3) где V_др дренируемый объем, м³;
h эффективная толщина вскрытия интервалов, м;
t_в время восстановления пластового давления, с;
π- коэффициент ≈3,14.The essence of the invention lies in the fact that the method of determining the coefficient of productivity of gas condensate wells, including changing the filtration mode at the bottom of the investigated well and measuring wellhead and bottomhole parameters, while before changing the filtration mode, measure the flow rate of wellhead and bottomhole pressure of the studied well in the technological mode, and changing the non-stationary filtration regimes are produced by stopping the well, while recording the pressure recovery curve at the wellhead and bottom hole important, and the coefficient of productivity is determined in accordance with the following mathematical expression:
a 0.889 •

• ln

(1) where β ^I is the angular coefficient determined by the straight-line portion of the pressure recovery curve (HPC) processed in coordinates P $\genfrac{}{}{0ex}{}{\text{2}}{\text{zab}}$ from lgt;
Q _{about the} flow rate of the well before shutting down the wells for recording the pressure flow, thousand · m ³ / day;
0.889 coefficient of proportionality;
R _{c is the} radius of the well along the inner diameter of the production string, m;
R _pr.s. bottomhole radius, m, determined from the ratio
R _pr.s. =

(2)
κ is a value characterizing the rate of pressure recovery in the well drainage zone, m ³ / s;
t _n.a. recovery time of the initial section of HPC, s;
κ

(3) where V _dr is the drained volume, m ³ ;
h is the effective thickness of the opening intervals, m;
t _in the recovery reservoir pressure, with;
π- coefficient ≈3.14.

 The invention is industrially applicable, as it can be used in industry, in particular gas for field research of gas condensate wells.

 The proposed method for determining the productivity coefficient allows, by recording the parameters in one technological mode of the well and by transferring the well to an unsteady filtration mode with subsequent registration of the pressure recovery curve and processing the data from the above dependencies, determine the productivity coefficients of any low-production well.

(МПа² сут/тыс·м³) от Q_г.с. (тыс·м³/сут).In FIG. Figure 1 shows the processing of the pressure recovery curve (HPC) in coordinates P $\genfrac{}{}{0ex}{}{\text{2}}{\text{zab}}$ from lgt; in FIG. 2 addiction

(MPa ² days / thousand m ³ ) from Q _g.s. (thousand m ³ / day).

 Line 1 (Fig. 2) characterizes the research results of the proposed method, line 2 studies in stationary filtration modes.

 The method is as follows.

In a well operating at a technological mode, the bottomhole pressure P _{z.o. is measured.} and flow rate Q _about , then stop the well at the wellhead and register the HPC-curve of the pressure recovery at the bottom in time P _s (t) _i to the reservoir R _pl .

After the complete restoration of pressure, the formation pressure R _{pl is} measured.

According to the data obtained, the HPC is graphically processed in coordinates P $\genfrac{}{}{0ex}{}{\text{2}}{\text{s}}$ (t) from lgt (Fig. 1) and determine the angular coefficient β ^{I of the} rectilinear section and the time characteristic of the intersection of the initial and rectilinear sections (t _n.u. ).

где t_н.у. время восстановления начального участка КВД, с;
κ- величина, характеризующая скорость восстановления давления в зоне дренирования скважины, м²/с;
κ

, где V_др дренируемый объем, м³;
h эффективная толщина вскрытых интервалов, м;
t_в время восстановления пластового давления, с;
π- коэффициент 3,14.Then we determine the radius of the bottomhole zone R _pr.s. according to the formula
R _pr.s. =

where t _n.o. recovery time of the initial section of HPC, s;
κ is the value characterizing the rate of pressure recovery in the well drainage zone, m ² / s;
κ

where V _dr drained volume, m ³ ;
h is the effective thickness of the opened intervals, m;
t _in the recovery reservoir pressure, with;
π- coefficient of 3.14.

• ln

, где 0,889 коэффициент пропорциональности;
β^I- угловой коэффициент, определяемый по прямолинейному участку КВД обработкой в координатах Р $\genfrac{}{}{0ex}{}{\text{2}}{\text{заб}}$ от lgt;
Q_о дебит скважины перед остановкой для записи КВД, тыс.м³/сут;
R_с радиус скважины по внутреннему диаметру эксплуатационной колонны, м;
R_пр.з. радиус призабойной зоны, м.The coefficient of filtration resistance a is determined by the formula
a 0.889 •

• ln

where 0.889 is the coefficient of proportionality;
β ^I - the angular coefficient determined by the straight section of the HPC by processing in coordinates P $\genfrac{}{}{0ex}{}{\text{2}}{\text{zab}}$ from lgt;
Q _{about the} flow rate of the well before stopping to record the pressure-response pressure, thousand m ³ / day;
R _{c is the} radius of the well along the inner diameter of the production string, m;
R _pr.s. bottomhole radius, m

где Р_пл пластовое давление, МПа;
Р_з.о. забойное давление перед остановкой скважины для записи КВД, МПа;
Q_о дебит скважины перед остановкой для записи КВД, тыс·м³/сут.Then, substituting the value of the coefficient a in the equation of the inflow P $\genfrac{}{}{0ex}{}{\text{2}}{\text{pl}}$ - R $\genfrac{}{}{0ex}{}{\text{2}}{\text{s}}$ aQ _o + bQ $\genfrac{}{}{0ex}{}{\text{2}}{\text{o}}$ , we determine the coefficient b by the formula
b

where R _PL reservoir pressure, MPa;
R _z.o. bottomhole pressure before shutting down the well to record the pressure drop, MPa;
Q _{about the} flow rate of the well before stopping to record the pressure-response pressure, thousand · m ³ / day.

PRI me R. The proposed method was tested on sixteen wells of the Vuktylsky, one Yugidsky, West Soplesssky and Vasilkovsky fields and two wells of the Pechoro-Kozhvinsky field. In the table. 1,2,3 and FIG. 1 and 2 as an example, the results of field studies of wells are presented. 133-Vuktyl using the proposed method and in stationary filtration modes. The coefficients of filtration resistance, determined by the study of the proposed method, amounted to
a 2.1 x 10 ^-3 MPa ² days / thousand m ³ ;
b 1.26 x 10 ^-5 (MPa ² days / thousand m ³ ) ² .

According to the results of studies on stationary filtration modes, these coefficients are significant
a 1.95 x 10 ^-3 MPa ² days / thousand m ³ ;
b 1.33 x 10 ^-5 (MPa day / thousand m ³ ) ² .

 Table 4 presents the main results of determining the coefficient a and b for the three studied wells. Comparison of the filtration resistance coefficient determined by the proposed method with the results of studies on stationary filtration modes gives satisfactory convergence.

 The invention in comparison with the prototype allows you to determine the productivity coefficients of the studied wells.

Claims (1)

METHOD FOR DETERMINING THE PRODUCTIVITY COEFFICIENT OF GAS-CONDENSATE WELLS, including changing the filtration mode at the bottom of the studied well and measuring wellhead and bottomhole parameters, characterized in that before changing the filtration mode, the flow rate, wellhead and bottomhole pressure of the studied well are measured in the process mode, and the mode of filtering is not produced by stopping the well, while recording the pressure recovery curve at the wellhead and at the bottom of the well, and the product coefficient the properties are determined in accordance with the following mathematical expression:

where β ′ is the angular coefficient determined by the straight-line section of the pressure recovery curve (HPC) processed in the coordinates P $\genfrac{}{}{0ex}{}{\text{2}}{\text{zab}}$ from lgt;
Q _about - well flow rate before shutting down the well to record the well pressure, thousand • m ³ / day;
0.889 - coefficient of proportionality;
R _with - the radius of the well along the inner diameter of the exploitation of the column, m;
R _{f p. h} - radius of the bottomhole zone,

κ is a value characterizing the rate of pressure recovery in the well drainage zone, m ² / s;
t _{n. y} is the recovery time of the initial section of the HPC,

where V _{d p} - drained volume, m;
h is the effective thickness of the opened intervals, m;
t _in - time of reservoir pressure recovery, s.

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