Annular capacity volume can be defined as the volume contained between the outside of the pipe and the open hole (Fig. 1) or between the outside of the drill pipe or tubing and the inside of the casing (Fig. 2). Annulus Capacity volumes calculation might be estimated by a formula calculating the cross-sectional area between the open hole or casing ID and the drill pipe OD and then by multiplying it to its length. In this article also, you can download the annular capacity volume calculator excel sheet & tables PDF.

## Annular Capacity Volume Formula

The Annular Capacity Volume Formula is simply solved by calculating the annular area and multiply it on the length you want to calculate the volume for as below. (check also Pipe Capacity Calculation)

**Annular volume in bbl = annular capacity (bbl/ft) x length of annulus (ft)**

**volume in m ^{3 }= annular capacity (m^{3}/m) x length of annulus (m)**

To calculate annulus capacity, you will simply subtract the square of OD for internal cylinder from the square of ID for the outside diameter then divide the resultant on a certain figure according to your units as following:

**Annular capacity in bbl/ft = (Dh2 “in” – Dp2 “in”) ÷1029.4**

**in gal/ft = (Dh ^{2} “in”– Dp^{2} “in”) ÷ 24.51**

**capacity in m ^{3}/m **

**= (Dh**^{2}“mm” – Dp^{2}“mm” ) ÷1,273,240**in ****m ^{3}/m **

**= (Dh**^{2}“mm”– Dp^{2}“mm”) ÷1,273.24## Using Halliburton Red Books Annular Capacity Tables For Volume Calculations

Rather than calculating cross-sectional areas to perform annular volumes calculation, you could go back to the Halliburton Red Book PDF Download, which provides factors that you simply can multiply by the length of the annulus to more simply reach volumes.

There are two sections within the Red Book that you should become conversant with regarding annular volumes calculation:

- Firstly, section 122 consists of a set of tables of annular volume and annular fill-up factors with tubular goods in various size holes. It also contains lists of the factors for multiple strings of tubular goods in many hole sizes.

- Secondly, section 221 contains lists of factors for pipe strings inside other pipes. There are also tables for tubing, drill pipe, and casing inside of bigger casing. As Section 122, you will find also tables for multiple tubing strings inside casing.

## Problem 1

Perform annular capacity volume calculation, in barrels, between 5400 ft of 2 3/8 in. (2.375 in.), 4.7 lb/ft tubing and a 6-1/4 in. hole. Use Section 122-A of the Red Book (see Figure 1).

**Solution**:

**Annular Capacity /Volume Factor** = 0.0325 bbl/ft (from the Red Book)

**Annular Volume **= 0.0325 bbl/ft × 5400 ft = 175.5bbl

## Problem 2

Perform annular capacity volume calculation, in barrels, for 1000 ft of 51/2 in., 17 lb/ft casing inside 9-5/8 in., 36 lb/ft casing? Use Section 221 of the Red Book.

**Solution: **

**Annular Volume Factor** = 0.0479 bbl/ft

**Annular Volume **= 0.0479 bbl/ft × 1000 ft = 47.9 bbl

These tables can be utilized to estimate the length that a given volume of fluid will fill.

**Problem 3**

Calculate the number of feet of annular space between 4 1/2 in., 10.5 lb/ft casing and a 6 in. hole will 100 bbl of cement fill? Use Section 122 of the Red Book.

**Solution: **

**Annular Fill-up Factor **= 65.3597 ft/bbl

**Annular Fill-up** = 65.3597 ft/bbl × 100 bbl = 6535.97 ft

Another way of annular capacity volume calculations in between any size of the casing string and the ID of the open hole is by using Section 210 of the Red Book. This includes the factors for any size cylinders or holes with a length of 1 foot. Annular volume can be determined by subtracting the annular volume factors for one foot of height and then multiplying it by a certain annular height.

**Problem 4**

Perform annular capacity calculations, in barrels, between 2-3/8 in., 4.7 lb/ft tubing and a 6-1/8 in. hole. Utilize Section 210 of the Red Book.

**Solution: **

**Volume Factor for 6-1/8 in. hole** = 0.0364 bbl/ft

**Volume Factor for 2-3/8 in. hole (OD of the tubing)** = 0.0055 bbl/ft

**Annular Volume Factor** = 0.0364 bbl/ft – 0.0055 bbl/ft = 0.0309 bbl/ft

**Annular Volume** = 6000 ft × 0.0309 bbl/ft = 185.4 bbl

The differences between this way of estimating annular capacity volume and utilization of Section 122 can be explained by the methods used when rounding off of decimals in establishing the tables.

## Download Annular Capacity Volume Formula Calculator Excel Sheet

In this simple excel sheet, you will just insert some data concerning well depth, hole diameter, pipe OD & ID and it will calculate by formula the annular capacity volume.

Download Annular Volume Calculation Excel Sheet

**Download Annular Capacity Volume Tables**

I have also prepared for you all the tubular Annular capacity volume tables in one PDF file from Drilling data Handbook PDF Download to assist you in your calculations.

Download Now Annular Capacity Volume Tables

**Ref**: Applied Drilling Engineering Book , Halliburton Red Book