What is well radius?

What is well radius?

In this work, the radius of investigation of a pumping well is qualitatively defined as the maximum distance from the well up to which aquifer properties have a significant influence on drawdown at the well (Fig. 1b).

What is effective wellbore radius how it is calculated?

The effective wellbore radius rwa is defined as. (5–22) If s is positive, the effective wellbore radius rwa is smaller than rw, then fluid must theoretically travel through additional formation to give the required pressure drop. If s is negative, the effective wellbore radius is larger than rw.

What is radius of influence of a well?

Radius of Influence means the radial distance from the center of a well bore to the point where there is no lowering of the water table or potentiometric surface because of pumping of the well; the edge of the cone of depression.

How can one determine the radius of influence of a well?

Solution to drawdown problem Radius of influence (R) for a well may be calculated using the following equation: R = b*(SQRT(K/(2*N))), where b is the thickness (100m), K is hydraulic conductivity (1e-5 m/sec), and N is the recharge (0.75 m/yr or 2.378e-8 m/sec).

How do you calculate the drainage radius of a well?

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,.

What is flow efficiency of a well?

A better relative index for determining the efficiency with which a well has been drilled and completed is the “flow efficiency,” the ratio of a well’s actual PI to ideal PI.

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

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.

How do you calculate drawdown on a well?

Subtract the measurements you collect as the pump is running from the static water level. The difference is the drawdown. For example, if the static water level is 1 foot below the top of the casing and the water level after one hour is 3 feet below the top of the casing, the drawdown at one hour of pumping is 2 feet.

What is meant by radius of influence and how is it determined?

How do you find the radius of influence for an unconfined aquifer?

R=√{1.9 Ksat h t / n}, for unconfined aquifers (Aravin and Numerov, 1953) “sichardt”: R=3000 s √{Ksat}, Sichardt formula for unconfined aquifers (Cashman and Preene, 2001)

What is the drainage radius of an offshore gas well?

1 mile drainage radius (~2,500 acres per well) would be exceptional for an offshore gas well. Gas wells have much greater drainage radius than oil wells. Deep onshore gas wells typically are spaced on 640 acres, big fracked horizontal wells often at 1,280 ac/well.

How much area does a horizontal well drain?

The methods to estimate drainage areas of horizontal wells generally give fairly similar results. As a rule of thumb, a 1,000 ft long horizontal well can drain twice the area of a vertical well, while a 2,000 ft long well will drain three times a vertical well, in a given time.

What is the drainage radius of a reservoir?

“Drainage Radius: The radius of the approximate circular shape around a single wellbore from which the hydrocarbon flows into the wellbore. The drainage radius of a single well will help determine how many wells will be needed (and where they should go) to most efficiently drain the reservoir.”

How do you calculate the effective wellbore radius?

The effective wellbore radius is defined by Eq. 3–8b. Assuming equal drainage volumes, r eh = r ev, and equal productivity indices, (q/Δ p) Vertical = (q/Δ p) Horizontal. This gives