Tom Tat Tienjjo
Transcript of Tom Tat Tienjjo
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MINISTRY OF EDUCATION AND TRAINING
HANOI UNIVERSITY OF MINING AND GEOLOGY------------***-----------
PHAM DUC THIEN
Research on drilling fluid flow in well
drilling to enhance drilling efficiency
Major: Drilling and completion oil and gas wells
Code : 62.53.50.01
ABSTRACT OF THESIS
OF DOCTORATE IN ENGINEERING
HANOI - 2012
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Research finished at Department of Surface Mining
Engineering, Faculty of Mining,
Hanoi University of Mining and Geology
Supervisors:
1. Assoc. Prof. Dr. Cao Ngoc Lam,
Hanoi University of Mining and Geology
2. Assoc. Prof. Dr. Vo Xuan Minh,
Hanoi University of Mining and Geology
Examiner 1: Dr. Khieu Huu Bo
Examiner 2: Dr. Nguyen Van Minh
Examiner 3: Dr. Nguyen Van Ngo
This thesis is going to be defended at the council of doctorate thesis
examiners of Hanoi University of Mining and Geology(Dong Ngac commune, Tu Liem district, Hanoi)
On ……Date……
This thesis can be found at Hanoi National Library
or Library of Hanoi University of Mining and Geology
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PREFACE
1. Necessary requirement of research
In drilling well, there are many paramerters effect of drillingefficiency, as kind of drilling rig, application technology, driling
fluid. A mong of them there is a respect which effect on drillingefficiency is driling fluid circulation to separate and cutting transport
out of the hole.
Research on driling fluid circulation to know clean capable
bottom hole and cutting transport. If the regime of driling fluid floware sensible, the cutting are separated and transported efficiency out
of the hole.
For this reason, “Research on drilling fluid flow in wellbore toenhance effective drilling” is imperative and have sience and reality
meaning.
2. The research purpose of thesis
The thesis reseach on drilling fluid flow with three respect are:- Reseach on flow regime of drilling fluids in annulus and
drillingpipe, application of drilling fluids used in Nam Con Son and
Cuu Long basin.
- Reseach on cutting transport capable of drilling fluids flow invertical annulus segment and effect of paramaters on cutting
transport efficiency, application for drilling in Nam Con Son andCuu Long basin.
3. Objectives and Scope of Research - Reseach on flowing Newtonian and non Newton fluid flow in
annulus and drillingpipe.- Reseach on flowing of drilling fluids used to drilling well in
Nam Con Son and Cuu Long basins.- Reseach on cutting transport in annulus and effecting
parameters, application for drilling well in Nam Con Son and Cuu
Long basins.
- Reseach on cleaning bottom hole base on optimum bithydraulic with maximum horsepower and impact force.
4. Content and Mission of Research
- Reseach on flowing of drilling fluid flow in annulus and
drillingpipe, following:
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+ Establish friction pressure equtions of drilling fluid in lamilar
flow in annulus and drillingpipe, Newtonian equivalent viscousity of
now Newton fluid and regime flow;
+ Drilling fluid flowing in eccentric annulus;+ Determine friction pressure of drilling fluids in lamilar and
turbulent flow in annulus and drillingpipe;+ Collect pratical drilling data to determine flowing of drilling
fluids in annulus and drillingpipe;
- Reseach on cutting transport in vertical annulus segment with
respects:+ Determine essence of cutting transport in vetical segment
annulus;
+ Simulate determination effect of paramerters, as annulusvelocity, fluid rheology, fluid density, parlical density, cutting size,
rate of penetration on cutting transport and losses of pressure.
- Reseach on cleaning bottom hole of drilling fluid flow,
contents:+ Establish horsepower hydraulic and impact force optimum
equations of drlling fluid flow through bit nozzoles;
+ Simulate determination horsepower hydraulic and impact
force optimum with change of paramerters as flowrate, fluidrhealogy, rate of pemetration.
5. Research methodsTo perform the reseach contents, the thesis used some method of
reseach:
1- Theorytical of reseach: used some consumes, laws,
mathemathic to reseach on flowing of drilling fluids in annulus anddrillingpipe.
2- Collection and treatment pratical data wich used to drill in Nam Con Son and Cuu Long basins.
3- Build program and simulate determination by matlab sofware
to perform:
- Reseach on effecting of paramerters as annulus velocity, fluidrheology, cutting density, fluid density, and rate of pemetration on
cutting transport and friction pressure losses;
- Reseach on optimum cleaning bottom hole base on two
criterion are horsepower and impact force hydraulic of drilling fluidflow through bit nozzoles.
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6. Basic literature of thesis
- The thesis was build base on basic literatures hydraulic,
drilling fluids, drilling hydraulic, cutting transport, multiflow, and jet
flow wich were pushlished in and out counting.- In building thesis, the author used many literature about
drilling fluid, fluid rheology, cutting transport in vertical, deviate,horizontal well, bit hydraulic, eg, wich were published on journals in
and out the country.
- Base on knowledge and personal experience of the author in
science reseach and employment history in University of Mining andGeology
7. Defended points of thesis
1. In drilling wells in Nam Con Son and Cuu Long basin, mostdrilling fluid are lamilar flow in annulus and turbulent flow in
drillpipe.
2. The sensible annulus fluid velocity when cutting transport of
wells in Nam Con Son and Cuu Long basins are 0.7 to 1.3 m/s, theminimum annulus fluid velocity should not lower 0.4 m/s.
3. The optimum horsepower hydraulic criterion are only used for
low and medium deep of drilling, the optimum hydraulic impact
force criterion can use for high deep of drilling.8. Innovations of thesis
1. Propose logic mathermatic menthod to establish equationsfriction pressure loss for Newtonian, non Newtonian fluid flowing
through drillpipe and annulus well in lamilar regime. This from
translate non Newtonian fluid to Newtonian fluid by equivalent
Newtonian viscosity.2. When reseach on flowing of drilling fluid in annulus and
drillingpipe of drilling wells in Nam Con Son and Cuu Long basins,the author discovered most drilling fluids are lamilar flow in annulusand turbulent flow in drillpipe.
3. Propose a model and program simulate determination
efficiently of cutting transport, from that can to easy evaluateeffecting of parameters on cutting transport.
4. When simulate determination pressure gradient in annulus,
the author discovered in cutting transport drilling wells in Nam Con
Son and Cuu Long basin as the annulus velocity is increase up to 1.3m/s, the pressure gradient decrease and strong decrease at lower 0.4
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m/s. The interval annulus velocity have low pressure gradient is 0.7
to 1.3 m/s. The minimum shoud not lower 0.4 m/s.
5. The first time simulate determination optimum bit hydraulic
and propose condition application of optimum criterions, that is theoptimum horsepower hydraulic criterion are only used for low and
medium deep of drilling, the optimum hydraulic impact forcecriterion can use for high deep of drilling.
9. Scientific and Practical Significances
1- Scientific significances
- The thesis was reseached logic and full about mathermaticalwhen establish friction pressure losses equations of drilling fluid in
lamilar regimes flow. From that define flow regime of non
Newtonian fluids base on Newtonian equivelent viscousity.- Evaluation and illustration effect of annulus velocity, fluid
rheology, fluid density, cutting density, cutting size, and rate of
pemetration cutting transport in vertical segment well.
- Propose optimum hydraulic condition of drilling fluid flowthrough bit nozzoles and application range optimum bit hydraulic.
2 - Practical significances
- The thesis is basic for drilling engineer plan drilling program
10. Thesis structureThe thesis are content prefere, four chater, conlusions and
recommendations, and references. All the thesis are performed in150 page. There are 45 figures, 89 tables and appendix
Chapter 1
Literature review of reseaching on drilling fluid flow1.1. Introducion
Cutting transport and cleaning well is important in drillinginsustrial. According to history devlopment, there are many scientist
to be interested in reseaching. The reseaching to concentrate onflowing of fluid, kind of cutting transport, drilling fluid flow through
bit nozzoles.
There are mumerous mathematical and empirical models for the
prediction and interpretation of hydraulics of cutting transportmechanism. Common problems with most of these cutting transport
models include inaccurate prediction, when compared with the
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experimental results or insitu drilling results. Thus, a new
mathematiacl model is necessary to overcom some of the limitation
of the existing hydraulic model.
1.2. Literarure Review1.2.1. Experimental study
The literatures experimental study care about mud rheology,flow rate in annulus, cutting size, fluid viscousity, rate of penetration
in cutting transport and bottom hole cleaning.
1.2.2. Theoretical Study
The literatures theoretical study carried out cutting transportmodels include two layer, three layer hydraulic model in vertical,
transit and horizontal segment.
1.2.3. Jet bit hydraulic literaturesThe jet bit hydraulic literatures care about optimum hydraulic
paramerters and consumption pumb hydraulic horsepower.
1.3. Sumary and evaluate
Base on literature review about drilling fluid flow. There aresome problems need studying:
- General method to define flow regimes of drilling fluid with
dfferent rheology;
- Theoretical and general reproduce effective of paramerters oncutting transport in annulus.
- Reseach on flowing regimes of drilling fluids in drillingpipeand annulus.
- Determine pressures gradient of flowing drilling fluids when
cutting transport in annulus.
- Mathermatical development to find optimum bit hydrauliccondition and application condition.
- Determination sensible range of annulus fluid velocity and pratical application.
Chapter 2
Drillling fluids and flowing of drilling fuids in drillingpipe
and annulus2.1. Drilling fluids and rheology
2.1.1. Drilling fluids rheologyRheology is correlation of fluid shear tress and shear rate.
Almost drilling fluids are non Newtonian fluids, general following:
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2.1.1.1. Newtonian fluids
The Newtonian fluids are defined by equation:s
where: τ
- shear tress; s - shear rate; µ - Newtonian viscousity.2.1.1.2. Non Newtonian fluids1- Bingham fluid
The Bingham fluid is defined by equation
s py
where: y - yield point; s- shear rate; p - plastic viscousity.
2- Power law fuid
The Power law fluid is defined by equation:nks
where: k - consistence factor; n - flow index.
3 - Herschel Bulkley fluid (yield Power Law fluid)The Herschel Bulkley fluid is defined by equation:
n
y ks The API considered the power law fluid is standard fluid use in
oil field.
2.1.2. Paramerters practice rheology of driliing fluidsThe result of experimental [44]:
The water based mud has: τy = 2.2 Pa, k = 2.15 Pa.sn; n = 0.3858
The oil based mud has: τy = 4.35 Pa, k = 4 Pa.sn; n = 0.3561
Mojis [44] studied the water based fluids with two main typesare: water base mud with Bentonite and added, and Brines with
polymer and added. Water based mud with Bentonite base on basic
fluid (CLN). CLN: 15g Bentonite in 350 ml water + caustic soda.
Table 2.1. Rheology of drilling fluidsDrilling fluids
density
(kg/m3)τy (N/m
2) n k (Pa.sn)
CLN+KCl 1290 7.9033 0.48 1.612
CLN+KF 1171 9.74 0.3 2.71
KCl+PHPA 1200 1.62 0.74 0.06
KCl+Xanthan 1166 12.02 0.412 2.117
KF+PHPA 1166 0.91 0.763 0.03
KF+Xanthan 1172 13.172 0.478 1.491
The two types of salts used are KCL and KF, two types of
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polymers are Xanthan and PHPA, paramerters and drilling fluid
rheology were shown in table 2.1.
In VietNam, acording to data presented drilling fluids has many
kinds and performance in Bingham plastic model.Table 2.2. Rheology of drilling fluids in Nam Con Son basinOrdinal Drilling fluids Fluid density,
kg/m3
YP, N/m2
PV,Pa.s
1 SW/GEL/PAC 1114 8.1 0.0120
2 SW/GUAR GUM 1084 6.7 0.0210
3 VISKOPOL 1042 4.8 0.0235
4 VISKOPOL/PRE.BENTONITE 1090 8.1 0.0440
5 SW/POLYMER 1078 7.2 0.0120
6KCL/PHPA
1108 8.4 0.01607 PAC/CMC 1132 7.2 0.0190
8 GEL/VISKOPOL/PRE.BENTONIT 1120 9.1 0.0475
9 GEL/CMC 1048 5.7 0.0325
10 ANCO 2000 1132 7.4 0.0175
11 KCL/POLYMER 1084 6.0 0.0185
12 ULTRADRIL 1174 11.3 0.0305
Table 2.3. Rheology of drilling fluids in Cuu Long basinOrdinal Drilling fluids Fluid density,
kg/m3
YP, N/m2
PV,Pa.s
1 ULTRADRIL 1210 5.3 0.0315
2 SW HIVIS SWEEP 1042 1.0 0.0030
3 KCL/POLYMER/IDCAP D 1282 6.2 0.0235
4 KCL/IDCAP/MUD 1174 6.5 0.0180
5 SPUD MUD 1078 5.3 0.0080
6 SOBM 1234 8.1 0.0180
7 OLEFIN SOBM 1234 11.3 0.0175
8 SBM 1318 14.6 0.0200
9 NaCl/BRINE 1150 3.4 0.006010 RDIF 1150 8.6 0.0225
11 KCL/POLYMER 1108 6.9 0.0235
12 PREHYDRATED/BENTONITEHIVIS PIL
1019 4.6 0.0175
13 KCL/POLYMER/LCM 1108 8.4 0.0270
14 SW/GUA GUM/CMC 1150 10.3 0.0380
15 SW/GUA GUM/GEL/CMC 1090 6.7 0.0155
16 GEL/POLYMER 1090 4.8 0.0245
17GEL/CMC
1078 5.5 0.0155
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L
2
ip
ms2
v
D
l p
Re
7,18
D
2lg274,1
1
ip
9,0ip Re
25,21
Dlg214,1
1
2.2. Friction pressures losses in drilliingpipe and annulus
2.2.1. Friction pressures losses in drilliingpipe and annulus when
lamilar flow
To define relatively friction pressure with shear tress and piperadius, we considered the force active independent on fluids, fluid
flow in drilling pipe and annulus are concentric cylindrical shell.By force balance equations and develop mathermatical to define
friction pressure equations, the result obtained friction pressures
equations of Newtonian, Bingham, Power Law, Herschel- Bulkley
fluids in lamilar flow in drillingpipe and annulus.
2.2.2. Equivalent viscousity
By balance friction pressures equations of Newtonian and non
Newtonian fluids in lamilar flow, we obtain equivalent viscosityequations of non Newtonian fluids.
2.2.3. Flow regimes of non Newtonian fluids
The drilling fluid is lamilar flow when the Reynolds number
with equivalent viscousity lower 2320 and turbulent flow higher2320.
2.2.4. Friction pressure in lamilar flow
The Darcy-weisbach equation to define friction pressure losses
the Newtonian fluids in pipe:
where: pms - friction pressure losses; - friction factor; L - fluid
density.
When fluid flow lamilar, the friction factor is define byequation:
Re/64 2.2.5. Friction pressure losses when turbulent flow
There are some equations to define the Darcy friction factor, but
two equations used usually are:
Colobrook equation [30]:
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Tomita equation [30]:
where:ε
- rough of pipe.2.2.6. Friction pressure losses in eccentric annulus
2.2.6.1. Hydraulic diamerterIn lamilar flow, the hydraulic eccentric annulus contens two
area: lamilar and turbulent area. Heigh of the lamilar area depend on
eccentricity and radius ratio. In one area the hydraulic diamerters
equations are established.2.2.6.2. Friction pressure losses
Base on the hydraulic diamerters equations, the Reynolds
numbers and friction factors are determined.
2.3. Flow regimes of drilling fluids in drillingpipe and annulus
2.3.1. Pratical paramerters of drilling in VietNam
By studying the data about drilling paramerters from 2003 to
2010, contents 34 well in Nam Con Son basin, 73 well in Cuu Long basin, The paramerters are shown in table 2.4
Table 2.4 Drilling paramerters in Viet NamWell diameter Drillingpipe diameter Flow rate
inch mm inch mm gpm l/s26 660.4 5 127 10001100 63.169.4
17 ½ 444.5 5 127 6931033 43.765.212 ¼ 311.15 5 127 628855 39.653.98 ½ 215.9 5 127 500606 31.538.26 152.4 3 ½ 88.9 230245 14.515.5The average velocity in drillingpipe and annulus are determined,
the result are shown in table 2.5.
Table 2.5 The average velocity of drilling fluids flow indrillingpipe and annulus
Drillingpipe diameter,
mm
Fluid velocity, m/sWell diameter, mm
ouside inside va v p 660.4 127 108.5 0.19 0.21 6.83 7.51444.5 127 108.5 0.31 0.46 4.73 7.06311.15 127 108.5 0.63 0.85 4.29 5.83215.9 127 108.5 1.32 1.6 3.41 4.13152.4 88.9 70.2 1.21 1.29 3.75 4.01
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1n
n
n2n
e
8
n4
1n3k
vDRe
2.3.2. Determination of flow regimes of drilling fluids in drillingpipe
and annulus
Base on the average velocity of drilling fluid in table 2.5, fluidsrheology in table 2.1 to 2.3, equivalent viscosity, Reynolds number
of Dodge and Metzner. Determination program is shown inappendix. The Reynolds number of Dodge and Metzner for non
Newtonian fluids are define by equation [22]:
2.3.2.1.Drilling fluids with rheology n < 1- Drilling fluids flow in annulus
Table 2.7: Flow regimes of drilling flluid CLN+KCl in annulusDrilling
fluidva Equivalent
viscousity, Pa.sReynolds
number
Dodge and
Metzner
Reynolds
number
Flowregimes
0.19 0.21 0.5451-0.5175 240-279 125-145 lamilar
0.31 0.46 0.3566-0.2904 356-469 205-372 lamilar0.63 0.85 0.2146-0.1837 697-1100 463-729 lamilar1.32 1.6 0.1288-0.1165 1175-1575 1004-1345 lamilar
CLN+KCl
1.21 1.29 0.1139-0.1101 871-960 748-825 lamilar- Drilling fluids flow in drillingpipeTable 2.14: Flow regimes of drilling flluid CLN+KCl in drillingpipe
Drillingfluid v p
Equivalentviscousity, Pa.s
Reynoldsnumber
Dodge andMetzner
Reynolds
number
Flowregimes
6.83 7.51 0.0356-0.0339 26867-31037 13434-15518 turbulent4.73 7.06 0.0431-0.0350 15371-28255 7685-14127 turbulent4.29 5.83 0.0453-0.0386 13251-21121 6625-10561 turbulent3.41 4.13 0.0511-0.0462 9347-12507 4674-6253 turbulent
CLN+KCl
3.75 4.01 0.0388-0.0374 8763-9703 4382-4852 turbulent
2.3.2.2. Drilling fluids wich used in Nam Con Son and Cuu Long basins
- Drilling fluids flow in annulus
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L
Ls
D
p
sC
gd
3
4v
Table 2.25: Flow regimes of drilling flluid SW/GEL/PAC in annulus
Drilling fluid va Equivalentviscousity, Pa.s
Raynoldsnumbers
Flowregimes
0.19 0.21 0.08550.0834 13211497 lamilar0.31 0.46 0.20140.0194 544839 lamilar0.63 0.85 0.55020.5452 235319 lamilar1.32 1.6 2.29672.2934 5769 lamilar
SW/GEL/PAC
1.21 1.29 4.49334.4915 1921 lamilar- Drilling fluids flow in drillingpipe
Table 2.32: Flow regimes of drilling flluid SW/GEL/PAC in
drillingpipe
Drilling fluidv p Equivalent
viscousity, Pa.sRaynoldsnumbers
Flowregimes
6.83 7.51 0.09780.0900 844210084 turbulent4.73 7.06 0.13590.0950 42088934 turbulent4.29 5.83 0.14860.1125 34906264 turbulent3.41 4.13 0.18380.1539 22423244 turbulent
SW/GEL/PAC
3.75 4.01 0.11310.1065 25932944 turbulent
Acording to the simulation results from table 2.4 to 2.19 for
drilling fluids with rheology three parameters, table 2.20 to 2.43 for
drilling fluids used in Nam Con Son, Cuu Long basins with rheologytwo parameters, table 2.44 to 2.45 for water show that drilling fluid
lamilar flow in annulus, turbulent flow in drillingpipe. The water and
drilling fluid with viscousity equivalent water turbulent flow in
annulus.
Chapter 3
Reseach enhance efficiency of transport in drillingpipe and
annulus
3.1. Slip velocity and drag coefficient
3.1.1. Slip velocity
Slip velocity is falling of solids in static fluids. The forces on thesolids spheres falling in static fluidds content: Drag force, gravity
force, buoyancy force. By force balance equation, have:
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cosv
1v1
cosv
vR
a
s
a
tt
cosgAA
1Gradp ahd ms
a
where: vs- slip velocity, dp- solid diameter, CD- drag coefficient.
3.1.2. Drag coefficient
3.1.2.1. Newtonian fluidDrag coefficient is defined by three area with Shah’s equations.
3.1.2.2. Non Newtonian fluidsDrag coefficient is defined by three area with Mayer ’s equation.
3.2. Property of cutting transport in vertical segment well
Cutting transport in vertical segment well base on slip velocity
that performance of ratio transport:
Where: vt -transport velocity;va-annulus velocity; -deviation angle.3.3. Equations development
Balance force acting on flowing in annulus, have:
where: Gradp- pressure gradient;ms
-friction shear strees; - wetted
perimeter;hd
-effective density; g- gravity;Aa-annulus cross section.
3.4. Simulate determination effecting of paramerters on
efficiency of cutting transport3.4.1. Algorithm simulate determination
Step 1: Import the parameters: va, L , s , n, d p,
Step 2: Calculate the drag coefficient, solid Reynolds number,
slip velocity by iteration method.
1- Assume the particle Reynolds number in one of three are:2- Calculate the drag coefficient respect;
3- Calculate the slip velocity;
4- Calculate the particle Reynolds number;Iterate from 2 to 4 until the particle Reynolds number between
previous and present values are approximate.
Step 3: Calculate the transport velocityStep 4: Calculate the transport ratio
3.4.2. Simulate determination principle
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0
0.1
0.2
0.3
0.4
0.5
0.60.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Annu lu s velo ci ty Va, m /s
T r a n s p o r t r a t i o R
t
0
0.1
0.2
0.3
0.4
0.5
0.60.7
0.8
0.9
1
900 1000 1100 1200 1300 1400
Drill ing fluid density, kg/m3
T r a n s p o r t r a t i o
R t
The simulate determination is performed by matlab sofware and
base on basic data in table 3.1. When run program simulate
determination, the parameters: annulus velocity, rheology fluids,
cutting density, fluid density, cutting size are changed in turn, theother paramerters following the basic data. The results of running
program was presented under part.Table 3.1. The parameters of basic data
Paramerters Value
Yeild tresse y 7,18 N/m2
Flow behavior index n 0,32
Consitancy factor k 1,37 Pa.sn
Hole diameter 311,15 mmOutside drillingpipe diamerter 127 mm
Cutting density 2600 kg/m3
Drilling fluid density 1100 kg/m3
Average cutting size 5mm
Rate of penetration 0,005556m/s (20 m/h)
3.4.3. Results and discusstionTable 3.4a: Rheology of drilling fluids
Rheology CLCS Fluid A Fluid B Fluid Cy (N/m
2) 7.18 7.18 7.18 7.18
n 0.32 0.32 0.32 0.32
k (Pa.sn) 1.37 0.5 1.0 2.5
L(kg/m3) 1100 1100 1100 1100
tdN (Ns/m2) 0.5327 0.1944 0.3889 0.9721
Figure 3.3: Cutting transport
efficiency following va in vertical
Figure 3.3: Cutting transport efficiencyfollowing fluid density in vertical well
with va= 0.7m/s
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1600 1800 2000 2200 2400 2600 2800 3000 3200
Cutting density, kg/m3
T r a n s p o r t r a t i o
R t
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6 7 8 9 10
Cutting size, m m
T r a n s p o r t r a t i o R
t
From the result of simulation cutting transport efficiency when
change of paramerters showed that the increase in annulus velocity,
viscosity, flow behavior index, drilling fluid density leads to increase
cutting transport. The increase in cutting density, cutting size, rate of penetration leads to decreases cutting transport.
3.5. Simulate determination pressure gradient in annulus
3.5.1. Algorithm simulate determinationStep 1: Import the paramerters;
Step 2: Calculate Newtonian equivalent viscousity in annulus;Step 3: Calculate cross section annulus;
Step 4: Calculate the total of concentration;
Step 5: Calculate effective density;
Step 6: Calculate wetted perimeter;Step 7: Calculate the Reynolds number;
Step 8: Calculate friction factor;Step 9: Calculate friction shear tresseStep 10: Calculate pressure gradient
3.5.2. Simulate determination principle
The simulate determination is performed by matlab sofewareand base on basic data in table 3.1. When run program simulate
determination, the paramerters: annulus velocity, rheology fluids,
cutting density, fluid density, cutting size are changed in turn, the
other paramerters following the basic data. The result of running program was presented under part.
Figure 3.8: Cutting transport efficiency
following cutting density in vertical wellwith va= 0.7m/s
Figure 3.10: Cutting transport efficiency
following cutting size in vertical well withva= 0.7m/s
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11000
11500
12000
12500
13000
13500
14000
0 0.3 0.6 0.9 1.2 1.5 1.8
Ann ulus v el oc ity Va, m /s
P r e s s u r e
g r a d i e n t i n
a n n u l u
s ,
P a / m
11000
11500
12000
12500
13000
13500
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Annulu s velo cit y Va, m/s
P r e s s u r e
g r a d i e n t i n a
n n u
l u s ,
P a / m
C LCS F luid A Fl uid B Fluid C
9000
10000
11000
12000
13000
14000
15000
16000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Annulus velocity, m/s
P
r e
s s u
r e
g
r a d
i e n
t
i n
a
n
n
u
l u
s ,
P
a
/ m
Fluid density 950 kg/m3 Fluid density 1100 kg/m3 Fluid density 1300 kg/m3
10000
10200
10400
10600
10800
11000
11200
11400
11600
1800 2000 2200 2400 2600 2800 3000 3200
Cutting density, kg/m3
P
r e s s
u
r e
g r a d
i e n t i n
a n
n u
l u s ,
P
a / m
10000
11000
12000
13000
14000
15000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Ann ulu s velo city , m /s
P r e s s u r e
g r a d i e n t i n
a n n u l u s ,
P a / m
Cutting density 2200 kg/m3 Cutting density 2600 kg/m3 Cutting density 3000 kg/m3
9000
10000
11000
12000
13000
14000
15000
16000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Annulu s velocity, m/s
P r e s s u r e
g r a d i e n t i n
a n n u l u s , P
a / m
ROP= 0,002778 m/s ROP= 0,005556 m/s ROP= 0,008333 m/s
3.5.3. Result and discussion
Figure 3.12: Presssure gradient in
annulus of vertical well following va
Figure 3.14: Presssure gradient in
annulus of vertical well following
drilling fluid rheology and va
Figure 3.19: Presssure gradient inannulus of vertical well following
cutting density with va= 0.7 m/s
Figure 3.20: Presssure gradient in
annulus of vertical well following
cutting density and va
Figure 3.22: Presssure gradient in
annulus of vertical well following rate
of penetration and va
Figure 3.17: Presssure gradient inannulus of vertical well followingdrilling fluid density and va
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From the result of simulation on figure, we showed that there is
one point similar: In the low range of annulus velocity when increasein annulus velocity, the pressure gradient decrease. The increase in
annulus velocity to 1,3m/s the pressure gradient to minimum value.If continuos increase in annulus velocity, the pressure gradient
increase. The range of annulus velocity from 0,7 to 1,3 m/s leads to
sensible low value of pressure gradient and this range are sensible
annulus velocity to cutting transport. The other respect when theannulus velocity increase reach to 0,4 m/s, the pressure gradient
significant decrease. As the annulus velocity higher 0,4 m/s, the
pressure gradient decrease slowly. This presented that the decrease inannulus velocity reach to 0,4 m/s, the pressure gradient significant
increase. We can concludation that in drilling should not using the
annulus velocity lower 0,4 m/s.
- Pressure gradient of drilling fluids use in Nam Con Son, CuuLong basins
To define rule of changing between pressure gradient and
annulus velocity, the author simulate determination pressure gradient
as changing annulus velocity for some drilling fluids used in NamCon Son and Cuu Long basins
Simulate determination principle base on basic data in table 3.1and rheology of drilling fluid in table 2.2, 2.3.
The results of simulate determination was presented in tables
and figues following.
Table 3.25: Pressure gradient in annulus in vertical wellGradp, Pa/mva,
m/sVISKOPOL/
PRE.BENTONITE
KCL/POLYMER ULTRADRIL KCL/POLYMER/
IDCAP D
GEL/POLYMER
0,1 13530 13438 14446 15049 13462
0,3 12113 11970 13113 13809 11981
0,5 11909 11724 12902 13627 11725
0,7 11904 11679 12879 13618 11673
0,9 11969 11703 12923 13671 11692
1,1 12068 11762 13000 13753 11747
1,3 12188 11840 13097 13854 11823
1,5 12321 11931 13209 13967 11914
1,7 12466 12032 13331 14090 12015
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2
d
2
t
2
cCgA2
Q p
9000
9250
9500
9750
10000
10250
10500
10750
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Annulus velosity, m/s
P
r e s
s u
r e
g
r a d
i e n
t
i n
a
n
n
u
l u
s ,
P
a / m
CLCS Fluid A Fluid C
10000
10500
11000
11500
12000
12500
13000
13500
14000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Ann ul us ve loci ty, m /s
P r e s s u r e
g r a d i e n t i n a
n n u l u s ,
P a / m
The tables and figures showed that rule of changing pressure
gradient drilling fluids with Bingham rheology same the drilling
fluids in part previous. This to asserted rule of changing between pressure gradient and annulus velocity.
- Pressure gradient in annulus with velocity when drilling fluidsnot cutting transport.
To addition clear, the author simulate determination pressure
gradient in annulus velocity when drilling fluids not bring cutting.
The result simulate determination showed that the increase in
annulus velocity, the pressure gradient increase.From this asserted that the equations were established to
determine effecting of paramerters on cutting transport areconfidency and essensibly.
Chapter 4
Reseach enhance bottom hole clean of drilling fluid flow
4.1. Reseach optimum condition to enhance bottom hole clean of
drilling fluids flow
4.1.1. Pressure loss across jet bitBy energy balance equation, we have:
Figure 3.28: Presssure gradient in
annulus of vertical well following
drilling fluid rheology and va when non bring solid
Figure 3.23: Presssure gradient in
vertical well annulus drilling fluid VISKOPOL/PRE.BENTONITE
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bmstu p1
1 p
bctu p1
p
where: pc- pressure loss across jet bit; Q - flow rate; At - total area ofthe bit nozzles;C- Constant.
4.1.2. Optimum drill bit hydraulics4.1.2.1. Maximum drill bit hydraulic horsepower, optimum velocity
and nozzoles diameter
Horsepower hydraulic of drilling fluid through bit is defined by
equation: Hc = (p b – pdc – pms).Qwhere: Hc-Horsepower bit hydraulic; p b-pump pressure; pdc- pressure
loss across mud motor; pms- friction pressure losses.
To simple and can define maximum horsepower hydraulic ofdrilling fluid through bit, the friction pressure loss is described:
Q.C pms where: α- flow exponent
yields1
dc bc CQQ pQ pH
The horsepower hydraulic is the denpendent variable and is a
function of flow rate Q
Thus, by use of differential caculus, taking the first derivative ofHc with respect to Q and setting the equal to zezo, we have:
where:pmstu - optimum friction pressure loss; pctu- optimum pressure
drop across the nozzoles.The literature had been published [1], if Hc is know, then
optimum pump can be calculated by equationP btu = 3 Pms
According ro previous chapter 2, chapter 3, the total friction
pressure loss is defined by equation:Pms = Pmsa + Pmsp
where:pmsa - friction pressure loss in annulus; pmsp- friction pressure
loss in drillingpipe.
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2
v
D
L
2
v
DD
L p
2
p
ip
L p
2
a
oph
hd ams
5
ip
2
L p
oph
22
op
2
h
2
hd a
2
msD
L8
DDDD
L8Q p
5
ip
2
L p
oph
22
op
2
h
2
hd a
mstutu
D
L8
DDDD
L8
pQ
.n
A2d tuntu
bd ctu p
1
g2Cv
Following Darcy-Weibach equation, friction pressure loss per
length L of hole well as
wherea
- friction factor in annulus in lamilar flow
p - friction factor in drillingpipe in turbulent flow
Substituting va; v p by Q, can be derived
When friction pressure is optimum, then flow rate is optimum, thus:
where Qtu; pctu are determined, we have:
ctu
2
d
2ctu
tu pgC2
QA
where:Atu- optimum total area of nozzoles
If drill bit have n nozzoles, the optimum nozzoles diamerter
Optimum velocity of drilling fluid through nozzoles bit is
4.1.2.2. Maximum jet impact force
Jet impact force of drilling fluid flow through bit nozzoles is
defined by Newtonian’second law of motion and give by
2
b CQQHBF
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2
1 p p btuctu
2
p p btumstu
where: B - fator, g/2CBd
After differentiating and setting to zero yields
By the literature had been published [1], if Hc is know, thenoptimum pump pressure can be calculate by equation
P btu = 2Pms
The optimum flow rate, firiction pressure, nozzoles size, jetvelocity are defined same over part.
4.2.Simulate determination optimum bit hydraulic
4.2.1. Algorithm simulate determination Step 1: Import parameters
Step 2: Calculate cross section annulus, flow rate, drillingpipe
fluid velocity, annulus fluid velocity
Step 3: Calculate total concentration;
Step 4: Calculate Newtonian equivalent viscousity in annulusand drillingpipe;
Step 5: Calculate effective densityStep 6: Calculate wetted perimerter
Step 7: Calculate Reynolds number in annulus and drilling pipe
Step 8: Calculate friction factor ;Step 9: Calculate friction pressure losses;
Step 10: Calculate optimum pump pressure;
Step 11: Calculate optimum friction pressure;
Step 12:Calculate optimum pressure drop across the bit nozzolesStep 13: Calculate optimum flow rate
Step 14: Calculate total optimum area of the nozzoles;
Step 15: Calculate optimumn nozzoles diamerters;Step 16: Calculate optimum fluid velocity through the nozzoles;
4.2.2. Simulate determination principle
The simulate determination is performed by matlab sofware and
base on basic data in table 3.1. When run program simulate
determination, the paramerters is changed. Simulate determination
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for bit three nozzoles. The result of running program was presented
under part.
4.2.3. Results and discustion
4.2.3.1. Parameters of optimum horsepower hydraulic
0
10
20
30
40
50
60
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Deep of drill ing, m
P r e s s u r e ,
M P a
Friction pressure losses Optimum pump pressure
Optimum friction pressure losses Optimum pressure drop bit
Figure 4.7: Optimum parameters horsepower hydraulic following well deep
at va = 1,3 m/s
4.2.3.2. Parameters of optimum jet impact force
0
5
10
15
20
25
30
35
40
45
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Deep of dril ling, m
P r e s s u r e ,
M P a
Friction pressure losses Optimum pump pressure
Optimum friction pressure losses Optimum pressure drop bit
Figure 4.12: Optimum parameters jet impact force following well deep at va
= 1,3 m/s
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4.2.3.3. Discustion
Fllowing the result of simulate determination, have some
comments:
- As the well drilled deeper, the optimum pressure pump,optimum friction pressure, optimum pressure bit drop, optimum flow
rate increase.- As the well drilled deeper rate of increasing the optimum pump
pressure are maximum and rate of increasing continuous decrease are
optimum pressure bit drop, optimum friction pressure
- As the well drilled deeper the optimum pressure pump for theoptimum horsepower hydraulic criterion very biger as the impact
force maximum criterion
- The flow rate increase, the optimum pump pressure, optimumfriction pressure losse increase.
- From the upper commentations and data in tables, we show
that the value of optimum pump pressure is very big, special in high
deep of well drill. The questions bring out are what condition toaplication optimum bit hydraulic.
The Sunnda Corporation [3], the maximum pump pressure is
5000 PSI (350 at).
Compare the maximum pump pressure and optimum pressure,we show that when optimum horsepower bit hydraulic at va = 1,3m/s
and 2500m deep of drillings (table 4.5, p btu = 35 MPa), the optimum pump pressure reach maximum pump pressure. On the other, when
optimum jet impact force at = 1,3m/s and 3500m deep of well (table
4.15, p btu = 34,8 MPa), the optimum pump pressure reach maximum
pump pressure. Therefore, the optimum horsepower bit hydrauliccriterion were only applied in low deep and medium deep of well,
the optimum jet impact force criterion can apply in high deep ofwell.
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Conclusions and recommendatons
1. Conclusions
With results of research for drilling fluids flow in well drilling
base on two respect are improve cutting transport efficiency invertical segment well and cleaning cutting on bottomhole, the author
have some conclusions:1. Propose mathermatic menthod to establish equations friction
pressure loss for Newtonian, non Newtonian fluid flowing through
drillpipe and annulus well in lamilar regime. This from translate non
Newtonian fluid to Newtonian fluid by equivalent Newtonianviscosity.
2. In drilling wells in Nam Con Son and Cuu Long basin, most
drilling fluid are lamilar flow in annulus and turbulent flow indrillpipe.
3. The cutting transport efficiency increase as the annulus
velocity, fluid density increase. The cutting transport efficiency
decrease as the fluid viscousity, cutting density , cutting size, rate of penetration increase.
4. Significant parameters effect on cutting transport efficiency
are annulus fluid velocity and drilling fluid rheology. But cutting
transport efficiency are effected by parameters in situ as cuttingdensity, cutting size, and
5. Losses friction pressure of drilling fluid flow bring and non bring solid cutting are different. The drilling fluid flow bring solid
cutting as the annulus velocity is increase, the pressure gradient
decrease and then it increase. The drilling fluid flow non bring solid
cutting as the annulus velocity is increase, the pressure gradientincrease.
6. In cutting transport drilling wells in Nam Con Son and CuuLong basin as the annulus velocity is increase up to 1.3 m/s, the
pressure gradient decrease and strong decrease at lower 0.4 m/s. The
interval annulus velocity have low pressure gradient is 0.7 to 1.3 m/s.
The minimum shoud not lower 0.4 m/s.7. With parameters of circulation system was established, kind
of drilling fluid are known, we can find condition bit hydraulic
optimum base on three parameters are maximum horsepower
hydraulic, maximum hydraulic impact force, and velocity, diameterof jet bit optimum.
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8. The optimum pressure pumb following horsepower hydraulic
criterion large biger hydraulic impact force. The optimum
horsepower hydraulic through bit are used for low and medium
depth, The optimum hydraulic impact force through bit are used forhigh depth.
2. Recommendatons
Base on the result of reseach, the author recommend:
- Continuos develope and perfect program, Algorithm simulate
determination;- Build model sofware have interface with user.
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BIBLIOGRAPHY
1. Pham Duc Thien (2009). Application studied resultsdetermination of friction factor to calculate pressure losses of drilling
fluid flow though eccentric annulus. Scientific -Technical Journal of
Mining and Geology, No 27/ 7-2009. University of Mining and
Geology, Ha Noi.
2. Pham Duc Thien (2010). Effects of wellbore deviation on
cuttings bed formation in cuttings transport and cuttings bed anti-
sliding velocity. Meeting of Scientific 19th time, date 11/11/2010.
University of Mining and Geology, Ha Noi.
3. Pham Duc Thien (2011). Newtonian equivalent viscosity and
determination regime of non Newtonian fluid flowing through
drillpipe and annulus. Scientific -Technical Journal of Mining and
Geology, No 33/ 01-2011. University of Mining and Geology, Ha
Noi.4. Pham Duc Thien (2011). Optimum bit hydraulic. Scientific -
Technical Journal of Mining and Geology, No 34/ 4-2011.
University of Mining and Geology, Ha Noi.
5. Pham Duc Thien (2011). Effects of parameters on cuttings
transport in vertical and near vertical well. Scientific -Technical
Journal of Mining and Geology, vol 5, petroleum, No 34/ 4-2011.
University of Mining and Geology, Ha Noi.