Lab report drilling fluids lab

PETE 3265: Drilling Fluids Laboratory

Experiment #1 omponents o! "asi $"%: mud preparation and property measurement &

'eport by Laura Louise Demar( Lab Partners: )ustin *+ %ar,ue%ar. Don.or  /tation #3

Date Experiment Per!ormed: 015201 Date 'eport /ubmitted: 022201

*bstrat

The drilling fluid is one of the most important tools in well engineering so it is important to know if its rheological comportment and constitution attends certain requisites. These characteristics involve the mud weight, its viscosities and its pH, in addition to others. The mud used was made with water and bentonite. To measure these properties, some types of tests are recommended. The most common physical measurements, and executed in this procedure, are the mud weight, Marsh Funnel test, apparent viscosity, plastic viscosity, yield point, initial gel strength and pH measure. The technique

followed is recommended by !".

The

results

were

satisfactory,

corresponding to theorical values. The tests are well known, tested and approved by most of petroleum engineers.

Purpose

This experiment intends to promote the ability of mixing mud used in drilling operations, also measures the properties of the prepared mud, as well as let the students come into contact with equipment for measurement of some mud properties.

&ntrodution

The drilling fluid is an important tool in #rilling $ngineering. The main purpose of  the drilling fluid is remove the cuttings that the bit produces while drilling and carry them to the surface, so the bit can keep advancing in depth. nother purpose for the drilling fluid is to exert enough hydrostatic pressure in the formations that are being drilling to prevent that the fluids in the formation enter in the well. The mud has other important attributions, but these two are the most important.

"n order to achieve this specifications, the mud has to have some particular  characteristics. Most of the used drilling mud are water%base and its compositions consist in solids, liquids and chemicals. For this experiment, the mud is very simple, composed by water and bentonite, a clay that increase the viscosity of the water. There are many types of commercial bentonites, the most important is &yoming bentonite. The drilling fluid is a non%newtonian fluid, and for this reason it presents different types of viscosity, which depends on the flow rate. The merican !etroleum "nstitute '!"( recommends some tests to help determinate if the drilling fluid is performing its functions properly. The Mud )alance is a test to determine density o! t(e mud . The test consists in fill the cup of the balance and read the density directly from the balance, which gives the density in pounds per gallon 'ppg(. The Marsh Funnel test is basic used for detect an unwanted mud onsisteny, and consist in fill a funnel with mud sample and measure the time of * quart of the mud flow through the funnel. The time is measured in seconds per quart 's+qt(. This measurement does not give the accurately viscosity of the mud because it is a non% newtonian fluid. The viscosity indeed is measured by a rotational viscometer, in this case the Fan iscometer. There are some tests in different rotational speeds made with the same viscometer. The apparent 4isosity '( is read at speed of - rpm, it depends on what type of viscometer is measured, but with the Fan iscometer is measured in centipoise with the equation -.* $quation -.*

 AV  =

600 RPM reading 2

The rheological parameters of the mud are measured also, and !" recommends that the drilling fluid must follow the )ingham plastic rheological model. To confirm this

behavior, the mud has to be characteri/ed by the plasti 4isosity '!(, measured in centipoise given by the equation -.0 $quation -.0

 PV =600 RPM reading− 300 RPM reading

and also characteri/ed by the yield point  '1!(, measured in lbf per hundred square feet 'lbf+* sq( and given by the equation -.$quation -.-

YP=300 RPM reading − PV 

 nother important rheological parameter measured is the gel strength. There are two types of gel strength that !" recommends to measure, the initial gel , consisting in let the mud rest for * seconds after stable rotation, and then note the maximum deflection when the rotating presents a very low speed, generally - rpm. The same measurement is made letting the mud rest for * minutes, and it is called 10 minutes gel.

2ther important parameter measured is the p, consisting in the concentration of  hydrogen ions in an aqueous solution, and can be measured using pH paper or pH meter. "n this process, it was used the pH paper.

E,uipment and %aterials

To mix the mud it was used3 • • • • • •

4raduated cylinder of 056 spatula6 common balance6 blender6 water, *.756 bentonite 'Mel 4el(, 8g.

To weight the mud it was used3

•

Mud balance that includes cup, lid, level glass, rider, fulcrum, base, fulcrum and knife edge.

To measure the funnel viscosity of the mud it was used3 • •

The Marsh Funnel and the measuring 9ug6 chronometer.

To measure the other viscosities it was used3 •

The Fann iscometer, that includes the viscometer and the sample cup.

To measure the pH it was used3 • • • • •

pH paper6 caustic solution6 spatula6 graduated cylinder6 graduated pipet with pipet controller.

Proedure

To do the mud, the ratio of bentonite was *: lbs of gel per bbl of water, thus was used 7 lab bbl of water, which meas*.7 liter of water was measured in a graduated cylinder, then placed in the blender. The bentonite was taken from the bentonite bag and 8 grams were measured in the common balance, then displaced in the bender. The blender was turned on at low speed, and the mixture was stirred for five minutes. To measure the weight of the mud, the cup of the mud balance was filled with the mixed mud, closed with the lid, attached in the balance, and then measured moving the rider until the air bubble in the level glass was stabili/ed in the center of the marking. To measure apparent and plastic viscosities as well as the yield point, the cup of  the Fann iscometer was filled with the mixed mud, then the cup was displaced in the appropriated platform, raised until the mud cover the marking. The Fann iscometer 

was turned on in the speed of 8 rpm, then turned off. nother measurement was made with the speed of - rpm. To measure the initial gel, the Fann viscometer was turned on, with the speed of  - rpm, then turned off. &hen the Fann iscometer stopped spinning, the chronometer  was used to counter ten seconds. fter that, the Fann iscometer was turned on with the speed of - rpm, marked as ;gel speed>.pdf