SPE 49542

Case History in Solving ESP Problems in Oil and Water Wells

Hesham A.Abdou - Agiba Petroleum Co.
Copy right 1998, Society or Petroleum Engineers
Grade of Tubing Material
This paper was selected for presentation at the 8 OJ Abu Dhabi International Petroleum Previously, tubing material grade; 1-55 was used. This
Exblbltlon and Coar....nce beld In Abu Dhab~ U.A.E., 11-14 October 1998.
grade was of lower yield and tensile strengths than N-80 or
This paper was selected for presentadon by the SPE Program Commillee following review of
bdormatloa coatalDed hi an abstract lubmlned by the author(s). Contents of the paper as
L-80. Moreover, running in hole with new tubing joints was
preseated, bave DOt been reviewed by tbe society or Petroleum Engineers and are subject to the solution to minimize corrosion possibility.
correction by author(l). The material, al presented, doe. no. necessarily reOed any position of
the Society of Petroleum Engineer. or I•• members. Papers presented at SPE meetings are Generally, corrosion rate now recorded a moderate rate (as
subject 10 publkadon review by Editorial committee of the Society of Petroleum Englnrer$.
PennI..ioo 10 copy I, restrkted to an abstract of not more than 300 words. lIIustntions may
low as 4 MPY) after the treatment program application.
not be copied. The abstract should contain conspicuous acknowledgment of where and by while before application, it was in the severe margin (as
whom the paper was preseated. Write Librarian. SPE. P.O.BOX 8333836, Richardson, TX
7508~38J6 U.S.A., rax OI-ZI~95~'435. high as 70 MPY). To get more development for the tubing
material, a feasibility study is undergoing to differentiate
Abstract between the following modern technologies to select up the
This paper discusses the technical problems encountered in best one from cost and technical contribution:
Agiba wells using ESP as an artificial lifting system in both - Modified epo:".)' coating
water source wells (WSW) and oil wells. in addition to the - Ceramic coating
applied solutions to overcome these problems. - Stainless steel

Introduction Modification of ESP Material

ESP is used in Agiba as an artificial system in some of oil In the past, material of ESP string was manufactured from
wells as well as in WSW to produce water to be reinjected carbon steel and so each of flat and power cables were of
in other water injector wells for compensating reservoir galvanized coating. As a way of fighting corrosion, ESP
pressure decline. Resulting problems of using this system in string was exchanged by a ferritic one and cables also were
WSW in the past (four years ago) was mainly in the exchanged by monel coating.
frequent failures due to corrosion which led to failure any
part of the ESP string (motor, pump, seal, etc.). Corrosion Abrasive Sand Problem
problem is referred to the sweet corrosive environment in Failure analysis were performed to investigate the reasons
which these pumps work due to presence of CO2 . This for failure cases of ESP(s) of WSW. In one well, it was
problem was overcome in two ways: concluded that the abrasive nature of the fluid is behind
- Injecting corrosion inhibitor Amine type base. such cases. abrasive action caused:
- Using pump string manufactured from special alloy - Impeller and diffuser wear acceleration
resistant to corrosion effects . -Vibration transfer to the seal where shaft seal started
leaking which led to flow well fluid into the motor,
In oil wells, the following problems were faced: subsequently burnt out.
- Mechanical problems created by deposition of fine ESP are usually as compression type pumps, in a
debris on pump shaft bringing to over loaded and compression pump all of the thrust generated by the stages
burnt out motor. as well as the pressure acting downwards on the pump
- Gassy conditions pumping wells. shaft. must be absorbed by the seal thrust bearing. As all of
the stages are in compression, it is essential that the pump
Factors Causing Tubing Corrosion Problems shafts are shimmed to the seal shaft, prior to installation.
Dissolved COz.Corrosion problems are caused mainly in The shimming of the shafts. lifts the impellers off the
WSW by the presence of dissolved CO2 in water. While diffusers and prevents any metal to metal wear during start
mist CO2 affected on that part of tubing above fluid level up. More importantly, the shimming of the shafts ensures
which is not effectively protected by Amin type corrosion that the generated thrust by the pump is transferred to the
inhibitor film treatment program which is applied and is seal thrust bearing, if the pump shafts were not shimmed.
injected in the tubing / casing annulus to protect the the pump would soon fail. In this manner, the Abrasion
internal and external tubing walls Resistance Zirconia (ARZ) bearings were suggested. These
bearings are known as Zirconia which is non metallic based

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2 CASE HISTORY IN SOLVING ESP PROBLEMS IN OIL AND WATER WELLS 49542

ceramic material with main components of Magnesium rig utilization so it is costly, while the short term solution is
Oxide. This material is characterized by its high hardness to bleed off gas periodically .
and high corrosion resistance. Although all Ceramics are
brittle, Zirconia is toughened to make it resistant for surface Pumping Debris Condition
fatigue. Fig.l, shows method of supporting ARZ bearing It is well known that circulating debris emitted from
formation increases specific gravity of the pumped fluid So,
Deposit Analysis motor got burnt out where horsepower is increased on
Three samples of deposit are analyzed using X-ray continuous overloading.Fig.5 shows debris condition well.
diffraction which revealed that the major deposit Periodic back flushing was the short term solution to solve
composition is Fe203 with a minor part of iron silicate and this problem to get rid of settled debris and to avoid rig
iron hydroxide . utilization in pulling out of hole with ESP. This solution
was performed three times a month.
Visual Inspection On the other hand, there are wells working without
From the visual inspection of the pulled parts of the pump, remarkable problems because of the following reasons:
it is evident that impeller stages were subjected to - Good water injection supporting reservoir pressure
severe erosion due to sand and iron cuttings as shown in realized by raising the capacity of water injection
Fig.2 plant up to 4770 m3/D.
- Good proper selection and design for ESP equipment,
Solving Abrasive Sand Problems starting with selection the pump which down hole
The following actions are taken aiming to minimize failure pumping rate at best efficiency equals to the well
times of ESP of abrasive sand well: production rate :
-Using standard 'pump intake instead of gas separator to Q= ~o Qf ---------------------------------- (I)
avoid erosion by sand resulting from rotating turbine . As shown in Fig.6, head per stage (lIPS) is determined,
- Following the right start up procedures to avoid subsequently total number of stages (SN) is determined :
entertainment of sand due to turbulence during pump SN=[0.102 (WHP / p ) + (D-L) +
2 5
start up. 11068.6 fD Q /d ]/HPS ------------------- (2)
- Keeping the well pressurized during shut down to Then to estimate total HP required from the following
avoid oxygen entrance . equation:
HP=[1.2 (lOr 5 (Q) (WHP)]+[1.l354 (lOr4 p Q
Problems of ESP Oil Wells (D - L) ] + [1.2568 P fQ3 D / d5] -----------------(3)
Two major problems were faced. First one was the gassy From Fig.6 Tlov is detcnnined and I3P is calculated as:
conditions and second was pumping debris condition BP = HP / TJov --------------------------- (4)
MP is determined from the equation :
Gassy Condition MP = (BP / TIM) + HPs ---------------------- (5)
The pump was kept operating near design levels (minimum HPs = 4.5 kW
and maximum limits), but handling some gas as shown in Data of Wells are tabulated in table. I
Fig.3, the fluctuation is caused by entrained and free gas in (p) for oil and water are 0.85 & 1.05 respectively
the produced fluid, this condition is usually accompanied by PIP = 9.8063 p (D - L) ----------------------------------- (6)
a reduction in total fluid production (actual stock tank cubic
meter). Pump attempt to pump whatever is present at the· Main Conclusions
pump intake, hence attempt to pump the predesigned - Applying modified chemical treatment program, assisted
number of cubic meter of whatever fluids available, in corrosion fighting in WSW and so, extended
including gas. Taking into consideration that one cubic tubing service life.
meter of gas represents a very small stock tank contribution, - Modification of ESP string material and cables into
but represents a substantial volume through the pump. This ferritic and monel coating respectively was the
released gas is referred to one of the following reasons : solution
- Low efficiency of down hole fixed type separator, in for the repeated ESP failures in WSW.
addition to plugging of its internal parts that could be - Using of Abrasion Resistance Zirconia (ARZ) bearing
overcome by the application of rotary type separator which in abrasive sandy wells, would minimize impeller failure
is an efficient mean of reducing or eliminating problems in - Selection of the proper separator size for the gassy
well (s) having relatively high gas liquid ratio. wells and proper sizing of ESP, kept most of oil wells
- Pump intake pressure (PIP) is too low under bubble point working with good conditions.
pressure .(l.6 & 3.1 MPa for Aman & Meleiha fields Nomenclatures
respectively), the solution is to increase PIP to exceed p Liquid Specific gravity
bubble point pressure by lowering pump setting depth, 110v Pump overall efficiency, %
hence evolved gas cQuld be minimized. This solution needs TIM Motor efficiency, %

759
49542 HESHAM AABDOU 3

~o Oil fonnation volume factor

BP Brake power, MI}rr3, kW
D Pump setting depth, L, m
d Tubing internal diameter, L, mm
f Modified hydraulic friction loss factor
BP Hydraulic power, Merr3, kW
BPs Power loss in seal section, ML2/T3, kW
L Dynamic fluid level, L, m
MP Motor break power, ML2/T3, kW
PIP Pump intake pressure, kPa
Q Gross production flow rate at reservoir
conditions, L3rr, m3/d
Qf Gross production flow rate at surface
3
conditions, err, m /d
Qo Oil flow rate, L rr, m3/d
3
BPS Head per stage from ESP chart, L, m
w.c Water cut percentage, %
WHP Well head pressure, kPa

Subscripts
ov Overall
M Motor
o Oil
s Seal
f Fluid

Acknowledgments
The author wishes to thank the management of Agiba
petroleum co. for permission to publish this paper and
valuable assistance given by. petroleum engineering
depru1ment in collection the required data and materials to
finalize this paper .

References
1-"Electric Submersible Pumping System Applications Course",
Centrilijt, Claremore, Oklahoma; ApriI26-30,1993
2- M.H.EI-Hakim : "The Benefits ofARZ "Abrasion Resistant
Zirconia" Applied in Water Wells- Case Study, AGIP Corrosion
& Maintenance Convention, Milano-Italy; lillie (9-11), 1998 .

SI Metric Conversion Factors

bbl x 1.589873 E -01 = m3
hp x 7.46043 E- 01 = kW
psi x 6.894757 E+OO =kPa
in x 25.4 E+OO= mm
ft x 3.048 E -01 = m

Hesbam A.Abdou
Works for Agiba petroleum company as workover
department manager, his total experience length is thirteen
years. He holds a B.Sc degree in petroleum engineering
from Al-Azhar University (1982). In addition that he holds
a Diploma in design of pipelines, pumps & turbines (1991)
and an MS degree in turbo machines (1996), both from
Cairo University, also he is continuing now his higher
studies for doctoral degree.

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4 CASE HISTORY IN SOLVING ESP PROBLEMS IN OIL AND WATER WELLS 49542

Table I : Production and well data of oil & water source wells

well Qr w.e Q. WHP L D PIP

M-14 150 0 150 330 1280 1768 4068
M-31 164 24 125 760 1226 1676 3751
M-35 82 38 51 190 1323 1772 3743
A-5 93 25 70 860 1460 1779 2659
A-8 64 0 64 760 1600 1716 967
A-18 80 85 12 760 1573 1687 950
A-28 110 0 110 670 1400 1615 1792
NE-L3 118 34 73 480 1240 1789 4576
AG-3 596 49 304 2100 0 1672 13940
AG-5 137 56 60 830 222 914 6786
AG-6 216 49 110 970 90 753 5526
AG-7 287 74 75 1520 0 1615 13460
M-17 1765 100 0 2400 274 1364 11220
M-20 1272 100 0 2400 274 671 4090
M-21 1765 100 0 2400 274 899 6440
Z-9 382 100 0 9500 193' 1065 8980 Fig.3 Gassy Condition Well

' . "

P~l!sl~!q~~ign.pfOvidihg ~xtra
downlhrV$t.·pad·.StJPport ..........-----g~;;;;;;;as~W

Fig.l Supporting ARZ bearing

Fig.2 Severe Erosion in Impeller & Diffuser

Fig.4 Rotary Gas Separator

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49542 HESHAM AABDOU
5

Fig.5 Debris Condition Well

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