Search
Filters
Close

Save 20% on select titles with code HIDDEN24 - Shop The Sale Now

Downhole Sour Corrosion And Scale Deposition In Oil Wells

Sour corrosion and iron sulphide scale deposition are two common flow assurance issues encountered in oilfields. Sour oil wells typically produce crude along with produced water and a significant amount of acidic gases such as carbon dioxide and hydrogen sulfide. The high pressure and temperature conditions under the downhole tend to cause severe corrosion damage including metal loss and pitting, along with iron sulphide scale deposition. Iron sulfide deposition in sour wells is a corrosion induced scale problem. It potentially causes production decline, restricted well intervention, well shutdown, or even severe consequences towards to the abandoned wells.

Product Number: 51322-17694-SG
Author: Tao Chen, Frank Chang, Feng Liang, Steven Hochanadel
Publication Date: 2022
$0.00
$20.00
$20.00

A downhole corrosion and scale monitoring (DCSM) tool was developed and applied in sour oil wells to monitor the corrosion and scale formation under real downhole flow conditions. The cylindrical test coupon was made of T-95 carbon steel, which was identical to the metallurgy of the downhole completion tubing. The corrosion and scale deposited on the surface of the cylindrical test coupon effectively simulated the corrosion and scale deposited on the surface of downhole completion tubing.

The DCSM was installed at a desired depth in the downhole and retrieved after three months. The retrieved coupons were characterized thoroughly to assess the corrosion and scaling mechanisms using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) analyses, X-ray diffraction (XRD) and surface profilometer. The results showed that a thin layer (~300 micron in thickness) of deposit, mainly composed of pyrrhotite, was formed on the surface of the T-95 coupon. However, an overall weight loss (1.3194 g) due to the combined effects of the iron sulphide deposition (weight gain) and abrasion/corrosion of the outer layer from the surface (weight loss) was observed. After removing the scale deposition, both general corrosion and under-deposit pitting corrosion were detected by the surface profile scan on the T-95 coupon, where the under-deposit pitting corrosion was considered to be the major concern.

A downhole corrosion and scale monitoring (DCSM) tool was developed and applied in sour oil wells to monitor the corrosion and scale formation under real downhole flow conditions. The cylindrical test coupon was made of T-95 carbon steel, which was identical to the metallurgy of the downhole completion tubing. The corrosion and scale deposited on the surface of the cylindrical test coupon effectively simulated the corrosion and scale deposited on the surface of downhole completion tubing.

The DCSM was installed at a desired depth in the downhole and retrieved after three months. The retrieved coupons were characterized thoroughly to assess the corrosion and scaling mechanisms using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) analyses, X-ray diffraction (XRD) and surface profilometer. The results showed that a thin layer (~300 micron in thickness) of deposit, mainly composed of pyrrhotite, was formed on the surface of the T-95 coupon. However, an overall weight loss (1.3194 g) due to the combined effects of the iron sulphide deposition (weight gain) and abrasion/corrosion of the outer layer from the surface (weight loss) was observed. After removing the scale deposition, both general corrosion and under-deposit pitting corrosion were detected by the surface profile scan on the T-95 coupon, where the under-deposit pitting corrosion was considered to be the major concern.

Also Purchased
Picture for 00170 WIRELINE WEAR RESISTANCE OF POLYMERIC
Available for download

00170 WIRELINE WEAR RESISTANCE OF POLYMERIC CORROSION BARRIER COATINGS FOR DOWNHOLE APPLICATIONS

Product Number: 51300-00170-SG
ISBN: 00170 2000 CP
Author: N. Symonds, B. G. Mellor and R. J.K. Wood, S. Groves
$20.00
Picture for 96021 CORROSION RESISTANCE OF SOME DOWNHOLE
Available for download

96021 CORROSION RESISTANCE OF SOME DOWNHOLE TUBING MATERIALS AND INHIBITOR EFFECTIVENESS IN SWEET ENVIRONMENTS

Product Number: 51300-96021-SG
ISBN: 96021 1996 CP
Author: Shi-Liang Fu, John G. Garcia, Antoine M. Chiffln
$20.00
Picture for 96076 EFFECT OF ENVIRONMENTAL FACTORS ON
Available for download

96076 EFFECT OF ENVIRONMENTAL FACTORS ON DOWNHOLE SOUR GAS CORROSION

Product Number: 51300-96076-SG
ISBN: 96076 1996 CP
Author: Gerdt Wilken
$20.00