Расчёт притока флюида к многоствольной горизонтальной скважине

Аббасова Самира Вагиф гызы – доцент кафедры «Нефтегазовая инженерия» Азербайджанского Государственного Университета Нефти и Промышленности, Азербайджан, Баку.

Мирзоев Эльвин Азад оглу – магистр кафедры «Нефтегазовая инженерия» Азербайджанского Государственного Университета Нефти и Промышленности, Азербайджан, Баку.

Calculation of fluid inflow to a multilateral horizontal well.

The practice of operating MHL (multilateral horizontal wells) includes a wide range of methods for mathematical modeling of their productivity, which include such indicators as the inflow of formation fluid to the bottom of the wells, the shape of the area covered by the drainage process. Among others, it should be noted such calculation techniques as the method of Yu.P. Borisov, V.P. Pilatovsky, V.P. Tabakova, V.G. Griguletsky, V.P. Merkulov and B.A. Nikitin.

The earliest dependence that describes the inflow to the MHS is the Borisov-

Pilatovsky-Tabakov technique [1-4], represented by the following equation.

Q =

2 nkh ( P - P )

,  „   , l sin a h , h sin a ц In R, - In —+— In-----

[ ^k x ( n ) In     2nr_c

где

• ^k - permeability index, mkm²;

• ^h - the value of the effective thickness of the reservoir, m;

• ^ц - viscosity index of the fluid saturating the reservoir, Pa*sec;

• ^l - length of the horizontal section, m;

• ^Pk - value of contour pressure, Pa;

• P - bottom hole pressure, Pa;

• ^Rk - the value of the contour radius, m;

• ^a - an indicator of the angle of deviation of the trunk from the vertical direction,

• ⁿ - the number of trunks;

• ^rc - indicator of the radius of the horizontal section.

According to the data given in Table 1, the productivity indicators of horizontal and multilateral wells are compared in accordance with the condition for the formation of the studied field.

Table 1

Initial calculated data

Well Parameter/No.	1
Seam number	Yak 3-7
Effective length of a horizontal well - L, m	800
The radius of the circular feed loop - Rk, m	1500
Well radius - rc, m	0,0786
Effective formation thickness - hef, m.	19,1
Reservoir permeability -k, 10-3 µm2	480
Reservoir pressure – Pr., MPa	15,9
Downhole pressure - Pwh, MPa	10
Δp MPa	5,9
Reservoir fluid viscosity - µ, MPa*s	8,9
The ratio of horizontal to vertical permeability - ß	4,5
Volumetric coefficient - b, m3/m3	1,12
Saturation pressure	27,1

For this case, the value of the skin factor is assumed to be zero, i.e., S=0. In addition, a multilateral horizontal well is represented by shafts with a length (Lo) of 800 meters.

Next, a theoretical calculation is made in accordance with formula (1) for the case of horizontal and multilateral wells. It should be noted that the possibility of drilling a multilateral horizontal well with two sidetracks as an alternative to a horizontal one is considered for the case of a steady flow of fluid. Neglecting frictional pressure losses, flow rates (Q) are calculated.

For a horizontal well:

Q =

2nkh ( p - P )

,  „   , l sin a h , h sin a ц In R, - In —+— In-----

[ k      x ( n ) In     2nr

2 - 3,14 - 480 - 19,1 - 5,9

8,9

ln1500 - In

800 • sin 90

19,1,    19,1 - sin90

+-- In-----------------

800   2 ■ 3,14 - 0,0786

= 198,6 т / сут

For

a            multilateral

horizontal

well:

Q =

2nkh ( p - P )

,  „   , l sin a h , h sin a a In R, - In —+ — In-----

[ ^k      x ( n )    In     2nr

2 - 3,14 - 480 - 19,1 - 5,9

8,9

ln1500 - In

800 - sin90

19,L,n   19,1 ^{- sin90}

800 ■ 2   2 ■ 3,14 - 0,0786

= 283,1 т / сут

The result of the calculation is shown in table 2.

Table 2

Flow rates of horizontal and multilateral horizontal wells

Q hw , t/d	MHW , t/d	Q MHW -Q HW , t/d
198,6	283,1	84,5

According to the table above, it can be concluded that in the case of a multilateral horizontal well, the flow rate is much higher compared to a horizontal one. In particular, as can be seen from the calculation, this increase is about 40%, which indicates the feasibility of using MHS.

The technology of drilling multilateral horizontal wells allows for a significant reduction in the cost of produced hydrocarbons, an increase in the economic and technological efficiency of the development process.