TY - GEN
T1 - Evaluation of a new environmentally friendly chelating agent for high-temperature applications
AU - Mahmoud, M. A.
AU - Nasr-El-Din, H. A.
AU - De Wolf, C. A.
AU - LePage, J. N.
AU - Bemelaar, J. H.
PY - 2010
Y1 - 2010
N2 - Matrix acidizing is used in carbonate formations to create wormholes that connect the formation to the wellbore. Hydrochloric acid, organic acids, or mixtures of these acids are typically used in matrix acidizing treatments of carbonate reservoirs. However, the use of these acids in deep wells has some major drawbacks including high and uncontrolled reaction rate and corrosion to well tubulars, especially those made of chrome-based tubulars (Cr-13 and duplex steel), and these problems become severe at high temperatures. To overcome problems associated with strong acids, chelating agents were introduced and used in the field. However, major concerns with most of these chemicals are their limited dissolving power and negative environmental impact. Glutamic acid diacetic acid (GLDA) a newly developed environmentally friendly chelate was examined as a replacement for acid treatments in deep oil and gas wells. The solubility of calcium carbonate in the new chelate was measured over a wide range of parameters. Core flood tests were conducted using long Indiana limestone cores 1.5-inch in diameter and 20 inches in length, which allowed us to better understand the propagation of this chemical in carbonate rocks. The cores were scanned with X-ray before and after the injection of chelate solutions into the cores. The concentration of calcium and chelate were measured in the core effluent. To the best of our knowledge, this is the first study to examine the fate and propagation of chelating agents in coreflood studies. GLDA has a very good ability to dissolve calcium from carbonate rocks over a wide pH range by a combination of acid dissolution and chelation. The addition of 5 wt% sodium chloride did not affect the GLDA performance at pH= 13, but significantly accelerated the reaction at pH= 1.7. Compared to other chelating agents, GLDA dissolved more calcium than EDG but less than HEDTA at high pH values. GLDA of pH = 1.7 was able to form wormholes at 2 and 3 cm3/min. GLDA was found to be thermally stable at temperatures up to 350°F.
AB - Matrix acidizing is used in carbonate formations to create wormholes that connect the formation to the wellbore. Hydrochloric acid, organic acids, or mixtures of these acids are typically used in matrix acidizing treatments of carbonate reservoirs. However, the use of these acids in deep wells has some major drawbacks including high and uncontrolled reaction rate and corrosion to well tubulars, especially those made of chrome-based tubulars (Cr-13 and duplex steel), and these problems become severe at high temperatures. To overcome problems associated with strong acids, chelating agents were introduced and used in the field. However, major concerns with most of these chemicals are their limited dissolving power and negative environmental impact. Glutamic acid diacetic acid (GLDA) a newly developed environmentally friendly chelate was examined as a replacement for acid treatments in deep oil and gas wells. The solubility of calcium carbonate in the new chelate was measured over a wide range of parameters. Core flood tests were conducted using long Indiana limestone cores 1.5-inch in diameter and 20 inches in length, which allowed us to better understand the propagation of this chemical in carbonate rocks. The cores were scanned with X-ray before and after the injection of chelate solutions into the cores. The concentration of calcium and chelate were measured in the core effluent. To the best of our knowledge, this is the first study to examine the fate and propagation of chelating agents in coreflood studies. GLDA has a very good ability to dissolve calcium from carbonate rocks over a wide pH range by a combination of acid dissolution and chelation. The addition of 5 wt% sodium chloride did not affect the GLDA performance at pH= 13, but significantly accelerated the reaction at pH= 1.7. Compared to other chelating agents, GLDA dissolved more calcium than EDG but less than HEDTA at high pH values. GLDA of pH = 1.7 was able to form wormholes at 2 and 3 cm3/min. GLDA was found to be thermally stable at temperatures up to 350°F.
UR - http://www.scopus.com/inward/record.url?scp=77954228768&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:77954228768
SN - 9781615679072
T3 - Proceedings - SPE International Symposium on Formation Damage Control
SP - 554
EP - 569
BT - SPE International Symposium and Exhibition on Formation Damage Control 2010
ER -
