Wellbore Radius (rw) This radius is used to determine the sandface area (2rwh), which represents the area through which all the produced reservoir fluids must flow. A reasonable value to use can be the drill bit radius, or the outside diameter of the casing.

### How do you calculate the radius of a drain?

Estimate drainage radius Rd, defined as the distance from the well to the point at which pressure change becomes less than the cutoff tolerance of 0.05 psia, at the end of the test. 1000 x-direction blocks, dx=10, dy=dz=100, producer in (1,1,1), Q=200 rb/d,.

How is skin factor calculated?

Parameters of the formation and the well obtained from interpretation are as follow: Permeability k = 0.65 mD. Half-length of hydraulic fractures xf = 74.1 meters. Fracture skin factor Sf = 1.02.

What is radial flow in reservoir?

Radial flow. Figure 4 Pressure distribution in a radiai reservoir. Darcy’s law can be applied to an ideal well model producing a constant steady-state production rate. The model assumes cylindrical flow in the reservoir where flow across the formation is horizontal and fluid moves radially toward the wellbore.

For a positive skin effect, effective wellbore radius is smaller than actual wellbore radius. For a negative skin effect, such as often obtained after well stimulation, effective wellbore radius is larger than actual well radius.

### What is skin factor in oil well?

1. n. [Well Testing] A numerical value used to analytically model the difference from the pressure drop predicted by Darcy’s law due to skin. Typical values for the skin factor range from -6 for an infinite-conductivity massive hydraulic fracture to more than 100 for a poorly executed gravel pack.

How do you calculate the drainage area of a vertical well?

Calculate the possible number of horizontal wells that will drain the lease effectively. Assume that a single vertical well effectively drains 40 acres. If rev is a drainage radius of a vertical well, then a 40 acre vertical well drains an area of a circle = prev2 = 40 acres x 43,560 sq ft/acre, rev = 745 ft.

What is drainage area of reservoir?

1. n. [Well Testing] The reservoir area or volume drained by the well. The terms drainage area, reservoir area, and drainage volume are often incorrectly used interchangeably. When several wells drain the same reservoir, each drains its own drainage area, a subset of the reservoir area.

## What is wellbore storage?

Wellbore storage is a function of the wellbore fluid and the completion size. The wellbore storage coefficient is defined as: C = Cf Vf with Cf the fluid compressibility and Vf the fluid volume. It is measured in units of bbl/psi.

### What is a radial flow?

Definition of radial-flow : having the working fluid flowing mainly along the radii of rotation a radial-flow turbine — compare axial-flow.