WoPhO 2012, Теория — Задача 2. Vertical Well

Theoretical 2: Physics of the Oil and Gas Production

Условие

Often the reservoir can be modeled as a cylinder (see Figure 7). For this problem all properties were averaged out as in the previous part, so the reservoir is assumed homogeneous with uniform permeability kk. Oil can be viewed as an incompressible fluid with viscosity μ\mu. Because the rocks above and below the reservoir are impermeable and the height of the cylinder is much less than its radius (h≪Rh \ll R), one can conclude that the fluid flows only in the radial direction.

A flat cylindrical reservoir of radius R=1000 m and height h=10 m with a vertical well of radius r_w=0.1 m drilled in the center; pressure P_b at the outer boundary and P_w at the bottom of the well.
Figure 7: Cylindrical reservoir with a vertical well drilled in the center

(a) Find the velocity of the oil vwv_w inside the well with radius rw=0.1r_w = 0.1 m, if the flow rate is 30 m3day\frac{m^3}{day}. Estimate the fluid velocity in the reservoir near the well vrv_r. [0,4 т.]

(b) The calculated fluid velocity in the reservoir is rather small therefore the reservoir pressure can be treated as a constant for several months or even years, especially if the reservoir is connected with an underground source of water. Let PbP_b be the pressure at the outer boundary of the reservoir and PwP_w be the pressure at the bottom of the well. In this part assume that both PbP_b and PwP_w are constants (time-independent values), as well as the radial pressure distribution.

Calculate pressure drop Pb−PwP_b - P_w , which is required to produce oil with flow rate qq. [1 т.]

(c) Make a sketch of pressure distribution in the reservoir P(r)P(r) as a function of the distance from the well. [0,4 т.]

Отговори

Решение


Оригинал в Архива: WoPhO_2012_Q12.pdf · официални решения: WoPhO_2012_S12.pdf