FLOW RATES

Measuring flow rate is a simple process which requires the use of a appropriately marked container such as a 20 litre drum and a stop watch or wrist watch. All it is, is recording the time it takes for the container to fill up with fluid.

 

Flow rate is measured in L/sec (litres per second).

 

Flow Rate (L/sec)= Volume of drum (Lt) / Fill Time (sec) e.g 20 litre drum / Takes 5 seconds to fill = 4L/sec

UP HOLE VELOCITY

Uphole velocity is the speed of air flowing through the annulus. Uphole velocity is crucial in determining if the hole being drilled has sufficient clearing pressure to extract all the cuttings. Likewise It can be used to determine if you have a loss in or gain of fluid from the formation.

CEMENTING CASING (CALCULATING THE VOLUME OF THE ANNULUS)

 

for this example we will assume that the hole is approx: 30meters in Depth and has a Diameter of 0.185meters. The outer Diameter of the casing is 0.150m.

 

The formula is VOLUME OF ANNULUS = VOLUME OF HOLE - VOLUME OF CASING

 

First we will find the volume of the hole:

Volume of hole (cubic meters) = 0.785 x (Diameter squared) x Depth = 0.785 x (0.185 x 0.185) x 30 = 0.806 cubic meters (1)

 

If we convert that into Litres: (1 cubic meter = 1000 litres) The answer is 0.806 x 1000 = 806 litres

 

Second we will find the volume of the casing:

 

Volume of Casing (cubic meters) = 0.785 x (Casing Diameter x Casing Diameter) x Depth = 0.785 x (0.150 x 0.150) x 30 = 0.530 cubic meters (2)

 

If we convert that into Litres: (1 cubic meter = 1000 litres) The answer is 0.530 x 1000 = 530 litres

 

Finally we put these answers into our first formula: VOLUME OF ANNULUS = VOLUME OF HOLE - VOLUME OF CASING

Volume of annulus (cubic meters) = Volume of Hole - Volume of Casing

= 0.806 (1) - 0.530 (2)

= 0.276 cubic meters of cement required

or 806 Litres - 530 Litres = 276 Litres of cement required.

CALCULATING THE VOLUME OF A CIRCULAR TANK

VOLUME CALCULATION OF A CONTAINER / MUD PIT

MARSH FUNNEL VISCOSITY

The marsh funnel viscosity is the ratio of the speed of the mud as it passes through the outlet tube, the shear rate, to the weight of the mud force that is causing the mud to flow, measuring the shear stress. The marsh funnel viscosity is measured in the number of seconds it takes for one quart of drilling mud to flow out of the marsh funnel. The Marsh Funnel is used for routine viscosity determinations on almost every well drilling rig. 

 

viscosities for muds 35 - 45 seconds (clay muds)

polymer muds 35 - 100 seconds

 

up hole velocities

low viscocities near water  0.6m/sec

medium 0.5m/sec

high over 50 secs 0.3 m/sec

MUD BALANCE

 

 

 

 

 

 

 

 

 

 

The BAROID Mud Balance provides a simple method for the accurate determination of mud density. An outstanding advantage of this balance is the fact that the temperature of the drilling mud does not materially affect the accuracy of readings. The durable construction of the Baroid Mud Balance makes it ideal for field use. It is very accurate and constructed with break resistant parts. Principally, the balance consists of a base, graduated arm and cup, lid, knife edge, rider, built in spirit level, and a counterweight. The constant volume cup is affixed to one end of the graduated arm and the counterweight is attached to the other end. A plastic carrying case is provided which holds the balance intact and in working position.