Drlling Fluids design lab final

8/17/2019 Drlling Fluids design lab final

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Drilling Fluids Lab – PETE 3265 – Section 1.

Spring 2015.

Lab partners: Briana Dodson, Aziz Al-Umairy

Report by: Alan Alexeyev

Experiments #8.1 and 8.2: Final Design

8 : Design a cement-contaminated Bentonite Mud and

treat it with SAPP

8 2

: Create a PHPA Mud and decontaminate it with SAPP

Date performed: 4/22 and 4/29/2015

Date submitted: 5/6/2015

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Purpose:

The purpose of the final two experiments was to re-create an 18ppb bentonite mud

that was created in lab 7.1 and contaminate it later with a 1% cement, after that to use

SAPP to see how much of it would be needed to decontaminate the mud in order to

achieve a viscosity of 10 and 15 cp for AV 300 and AV 600 respectively. The second part

of the experiment was to re-create a PHPA mud that was first created in lab 7.2 and again

to see how it would react to SAPP treatment until a 10 and 15cp viscosity levels are

reached. The 2nd sub-purpose was to compare what type of mud reacts better to SAPP

treatment and draw conclusions.

Abstract:

The final experiment was supposed to be an independent group project that is

designed for active learning and testing the skills in drilling mud preparation and analysis

that were acquired throughout the semester. The lab experiment that was proposed by

our group included a combination of almost all the procedures that were introduced in

this drilling lab course, from various physical measurements, chemical tests to mud

mixing, contaminations and treatments. Our emphasis was to do an experiment on how a

contaminated mud would react to a chosen treatment, and what doses of the treatmentmaterials are needed. For that, 2 different muds were made: one with bentonite and one

with PHPA, and a comparison between them was done at the end. Our contaminant was

class H cement. The comparison should lead us to draw some conclusions as to what

expect in the real-world applications when mud engineers are dealing with

contaminations and treatments and need to know which methods to use for better

results. Our group decided that one of parameters that tells the condition of a mud is the

viscosity, thus, our target was to achieve a viscosity of about 10 cp and 15 cp for AV300and AV600 respectively after the contamination treatment.

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Introduction:

The introduction of various types of contaminations and ways to treat them was

introduced in the previous labs [3].

Our chosen contaminant, Class H cement, is intended for use at a depth of around

8000 ft and is available only in moderate sulfate-resistant type. “It can be used with

accelerators or retarders to cover wide range of well depths and temperatures” [1].

Adding a cement can serve as a filtration control additive. If there is too much cement

then it will act as a contaminant, where the viscosity is too high and therefore the mud

treatment (decontamination) is required. In the lab conditions adding a cement is a

reasonable and easier choice to test the decontamination techniques.

PHPA stands for partially-hydrolyzed polyacrylamide. PHPA is “a class of water muds

that use partially-hydrolyzed polyacrylamide (PHPA) as a functional additive, either to

control wellbore shales or to extend bentonite clay in a low-solids mud”. It is designed to

be a shale-control mud. In low-solids muds, PHPA interacts with small concentrations of

bentonite to link particles together and improves rheology [2].

SAPP (Sodium Acid Pyrophosphate) is one of the deflocculants, the thinners that

reduce the tendency of the mud to flocculate. The introduction of SAPP to the mud is a

good choice for treating the flocculation caused by cement contamination. Flocculation

can be seen in the bigger viscosity values, thus the goal is to reduce the viscosity, and

SAPP can achieve that [1].

Caustic is NaOH, is being used to alter the mud pH. A high pH is desired in the mud

to suppress corrosion rate, hydrogen embrittlement, and solubility of Ca and Mg ions [1].

Higher pH is also favorable for viscosity control additives.

By introducing the abovementioned materials and their applications the engineer can

construct a mud that is applicable to the specific conditions he’s working on, and he will

know the ways on how to detect the problems and how to solve them.

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Equipment and Materials used:

• Beakers, pH Meter, Blender, Marsh Funnel, Stopwatch,

• Mud balance by OHAUS

•

OFITE – manufactured 8-speed Rotational Viscometer Model 800

• Shearometer

• OFITE filter press

• OFITE-manufactured CHLORIDE, ALKALINITY & HARDNESS DETERMINATION

kit

• Water, Wyoming bentonite, Cement class H, caustic solution, PHPA, Bio-

Lose, SAPP

•

Towel, safety glasses, lab coat, gloves

Procedures:

The procedures similar to the experiments 5, 6 and 7 were performed in this lab [3].

We started with 99g of bentonite and 1925mL of water and 20g of Cement class H. The

procedures of mud preparation, water loss test, shear strength test and others were

described in the previous labs [3]. Chemical tests were also performed at the end of this

lab. For PHPA mud, the following components were added: 71.5g of bentonite, 2.75g of

PHPA, 0.55g of Bio-Lose, and 0.55g of caustic solution.

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Results:

Table 1. Lab #8.1: Mud A: SAPP treatment of cement contaminated mud:

The mud contained: 1925 mL of water, 99g of bentonite, 20g of Cement H.

Trial

SAPPContent,

lb/bbl

Mud

Weight pH AV 300 AV 600

10sec

GS Sheareometer

1 0 7.8 20 25

2 2 7.6 16 19

3 4 8.7 ppg 7.4 11 15 6 cp 5.5 lb/100ft2

Water Loss, min Volume, mL

2.5 17

5 267.5 33

Cake thickness 1/3”

Hardness Test : 9mL; Chloride Ion Determination : 0.3 mL; Silver Nitrate : 0.0282

Table 2. Lab #8.2: Mud B: PHPA mud and SAPP treatment:

0.55g of Bio-Lose and Caustic each, 71.5g Bentonite, 2.75g of PHPA, 1925mL of Water

Trial

SAPP

Content,

lb/bbl MW pH AV300 AV600

10sec

GS Shearometer

1 0 - - 24 33

2 2 - - 15 22

3 3 - - 14 21

4 5 8.7 ppg 8.5 10 15 2 0

Water Loss, min Volume, mL

2.5 3

5 5

7.5 6

Cake thickness 2/64”

Hardness Test : No hardness; Chloride Ion Determination : 0.3 mL; Silver Nitrate : 0.0282

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0

5

10

15

20

25

30

0 1 2 3 4 5 6

V I S C O S I T Y ( C P )

SAPP CONCENTRATION (BBL)

SAPP Concentration(bbl) vs Apparent Viscosity 300

(cp)

8.1&8.2: Mud A & Mud B Results Compared

SAPP Concentration (bbl) vs. Mud A AV 300 (cp) SAPP Concentration (bbl) vs. Mud B AV 300 (cp)

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6

V I S C O S I T Y ( C P )

SAPP CONCENTRATION (BBL)

SAPP Concentration vs Apparent Viscosity 600 (cp)

8.1&8.2: Mud A & Mud B Results Compared

SAPP Concentration (bbl) vs. Mud A AV 600 (cp) SAPP Concentration (bbl) vs. Mud B AV 600 (cp)

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Discussions:

From the graph and results, it is observed that the viscosity drops with each portion of

SAPP added to the mud. It does confirm that SAPP is indeed working to reduce the

viscosity. Our purpose was to see how much SAPP needs to be added to each type ofmud to achieve similar viscosity at the end. As we can see, the amount of SAPP that was

needed to achieve the viscosities of 10 and 15cp for mud A was 4 lb/bbl, and 5 lb/bbl for

mud B. Also, judging from the initial conditions with no SAPP, mud B had higher initial

viscosity than mud A. Therefore, it is sort of expected that it took more amount of SAPP

for mud B to achieve 10/15cp viscosity than mud A.

Mud A (of lab 8.1) experienced a much bigger water loss than Mud B (of lab 8.2). Since

caustic solution is present in mud B, it serves as a good viscosity control additive and

maintains higher pH – this is exactly what is seen there; the pH was higher than in mud A

and a water loss was a lot smaller.

Increments of 2 lb/bbl were chosen because we wanted to replicate the similar

experiment in the past labs [3]. Also, we noticed that with each 2lb/bbl portion of SAPP

the viscosity decreased by about 4-5 cp. The only surprising moment was with mud B,

when going from 2 lb/bbl to 3 the viscosity almost didn’t decrease, therefore after that we

added another 2 lb/bbl to make a total of 5 lb/bbl of SAPP. I’m guessing we could’ve

achieved the similar results also with just 6 lb/bbl total.

Mud A had a much larger cake thickness, of about a third of an inch, while mud B

exhibited a very small cake. The 10-sec gel strength was also larger with mud B. My guess

is that because there are additional chemicals in the mud B, such as caustic and Bio-Lose,

they keep the filtration control better, and thus the water loss, gel strength and cake

thickness are smaller than in mud A.

Chemical tests produced almost the identical results on chloride ion determination and

silver nitrate, but mud B had no hardness. I believe that overall mud B would be more

favorable in drilling situations. It showed better water loss results, no hardness, and

higher pH value. It only required one more lb/bbl of SAPP to get the same viscosity at the

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end. PHPA is used in the low solids environments, and since mud B had no shear strength,

it’d useful for that. Mud A showed lower viscosity in the beginning but had too big of a

water loss; it could be suitable for a bit different environments, like high solids one.

Overall, I’d give the slight edge to mud B as the overall winner here.

Safety Comments:

Regarding the safety, we were using the goggles, gloves, and lab coats. One needed

to be careful when measuring, filling up the water to avoid spilling or break the

equipment. Another important thing was to pour the fluids very carefully to avoid

spillage, so that we will not lose any amount of fluids for further measurements.

Conclusions:

Upon concluding this final experiment, our group was able to summarize all the

learnings that happened in this drilling mud course. This lab had a combination of all the

procedures and tests required to do an extensive analysis on a drilling mud. Two muds

were compared, and the analysis on how they react to a contamination treatment was

made.

In was a great experience doing those drilling labs. For that I wanted to thank the

instructor, teaching assistant and the grader for being with us all this semester and

assisting us in learning about drilling muds.

References:

1. Pages 45-75. Adam T. Bourgoyne, Martin Chenevert, Keith Millheim, F.S.

Young Jr., Applied Drilling Engineering, Vol.2, SPE, Richardson, TX. 1986

2. http://glossary.oilfield.slb.com/

3. Drilling fluids lab 1, 2, 3, 4, 5, 6, 7 by Alan Alexeyev. February – April 2015.

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http://glossary.oilfield.slb.com/http://glossary.oilfield.slb.com/http://glossary.oilfield.slb.com/http://glossary.oilfield.slb.com/

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Drlling Fluids design lab final