Page 188 - CW E-Magazine (8-10-2024)

Special Report Special Report

of O-rings or by selecting a more are high quantities of sand formation, bon dioxide and hydrogen sulphide. cause of failure. Fractured surfaces dis- premature failure of down-hole equip- unwanted substance causes an increase
corrosion-resistant material for the corrosive wells, scaling, asphaltenes, Figure-19 shows the detailed descrip- played an initial zone of intergranular ment. in the pressure drop.
shaft sleeves(9). and paraffi n deposition. tion of sub-assemblies of an ESP fractures promoted by pitting corro-
system deployed in an oil well. sion and a propagation zone with trans- A combination of a scale-resistant Mitigating asphaltene and paraffi n
Corrosion prevention in electric The natural presence of sand and granular fractures due to the presence coating and a scale inhibitor can prevent challenges requires proper materials of
submersible pump other solids results in an abrasive fl uid Case study of localized corrosion in of mechanical load. the formation of scale deposits such construction for the pump’s seals and/
Electric submersible pumps in oil that induces wear on the wetted sur- ESP system: as calcium carbonate. The continuous or applying a paraffi n inhibitor-chemi-
and gas wells are subject to corrosive faces of the ESP. One possible solution In 2014 a failure analysis was con- High concentrations of sulphur (S) treatment injection rate can be adjusted cal treatment. Inhibitor selection must
conditions, but the dangers can be miti- is to lower the fl uid velocity, but it is ducted on bolts (made from Monel and chlorine (Cl) were identifi ed on the based on scaling tendency results deter- take the following factors affecting wax
gated with coatings, corrosion inhibi- not ideal as it can lead to lower volumes K-500) that serve to support and join corrosion layers, revealing that an ag- mined from a scale and water analysis. inhibition performance into consideration:
tors and remote monitoring and control. and a reduction in monetary revenue. critical components of an electrical gressive electrochemical reaction took A scale-resistant coating together with fl ow regimes, temperature and wax
Figure-18 shows the cross-section of a submersible pump. The component was place. Under these layers, small pits a scale inhibitor can keep the scale in a content.
typical electric submersible pump used Corrosive operating condition also located in a stagnant area of saline solu- of 10-30 micrometers in depth were liquid phase and safely fl owing through
in oil and gas wells. threatens the reliability of pumps. A tion that promoted localized corrosion. found. It was inferred that the pits initi- the ESP system. Under laminar fl ow the solid de-
corrosive environment can arise from ated the cracking path that eventually posit will result in a low-paraffi n con-
high-temperature and saline conditions The experimental results concluded caused complete fractures. Controlling corrosion in ESPs tent wax. While in a turbulent fl ow, the
with an elevated concentration of car- that pitting corrosion was the primary The best corrosion mitigation strategy deposit solid will have a high-paraffi n
Maximizing the long-term produc- for ESPs in corrosive environments content wax deposit. When the tempera-
tivity of a well requires solutions that includes the combination of proper ture increases, the deposited wax mass
are customized to the well – its produc- metallurgy, protective coating, corro- decreases while the critical carbon
tion profi le, fl uid composition, tem- sion inhibitor, and biocide treatment. number increases.
perature and pressure – and chemical Abrasion resistant and corrosion resis-
Fig. 18: Cross section of a typical Electric treatments that mitigate the challenges. tant alloys may suffi ce for some wells Future advancements
Submersible Pump but other more corrosive wells may Because operators are looking to opti-
Artifi cial lift is considered the In some cases, proper material se- require incorporating a corrosion mize production, service providers must
backbone for maximizing producti- lection can be suffi cient to extend the inhibitor system. innovate to improve the effi ciency of the
vity from oil wells. There are several equipment’s service lifetime in high- artifi cial lift and chemical treatment sys-
types of artifi cial lift pumps, including solids environments. Abrasive-resistant Wells with high CO and/or H S tems. Automated solutions and remote
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sucker rod pumps, gas lift, hydraulic tungsten carbide-fl anged sleeves and require continuous injection of a cor- surveillance and control are one area of
pumps, progressive cavity pumps, jet bushings can decrease both radial wear rosion inhibitor. The proper inhibitor major advancement. Real-time platform
pumps and electric submersible pumps and down thrust. Abrasion-resistant in- product and the required concentration communication enables fast collabora-
(ESPs). serts can further help protect the inter- are selected through laboratory testing. tion between engineers and operators
nals of the pump from abrasive wear. The inhibitor must maintain its effi cacy with real-time diagnostics and analytical
The selection of a suitable type of With these materials of construction, under the operating temperatures and capabilities. Informed operators are able
artifi cial lift is based on the reservoir the pump can be expected to withstand stress experienced by the component. to make decisions with fewer trips to the
profi le, which are parameters such as the well’s highly abrasive down-hole fi eld, thus reducing downtime.
water production, sand production, conditions. Run time can typically in- An on-going monitoring system
solution gas-oil ratio and surface area crease by up to 800% compared to can be installed to adapt the dosage On the chemical treatment front,
available at the surface. Due to its capa- the run life of non-abrasion-resistant requirement should production condi- remote chemical automation and tank
bility in handling huge volumes of oil, pumps. tions change. A monitoring system that monitoring services improve effi ciency
electrical submersible pumps are one of can provide a fast response time such with minimal human interaction.
the most familiar types of artifi cial lifts Mitigating scale deposition as electric resistance (ER) is recom- Chemical pumps can be programmed to
in the industry. However, due to the Scale deposition occurs when the mended. automatically adjust the chemical feed
harsh nature of the well environment, solution equilibrium of the water is rate based on the changes in down-hole
ESP operators are faced with various disturbed by pressure and temperature Minimizing asphaltene and paraffi n conditions. In addition, chemical us-
operating challenges. changes. Scale deposits are the most impacts age in a storage tank can be wirelessly
common and most troublesome dam- Paraffi ns are as a class of i-alkanes monitored from any secure internet
Operating challenges in oil & gas age problems in the oil fi eld and can and n-alkanes characterized by a long connection.
industry occur in both production and injection hydrocarbon chain attached via single
Operating challenges that often lead wells. Scale deposition can cause a loss bonds. Paraffi n deposition is a major CONCLUSION
to costly repairs or replacement of ESPs Fig. 19: Description of sub-assemblies of a ESP system deployed in an oil exploration industry in production, pressure reductions and problem in which the deposition of the The corrosion risk of water pumps

188 Chemical Weekly October 8, 2024 Chemical Weekly October 8, 2024 189

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