TY - GEN
T1 - Optimum injection rate of a new chelate that can be used to stimulate carbonate reservoirs
AU - Mahmoud, M. A.
AU - Nasr-El-Din, H. A.
AU - De Wolf, C. A.
AU - LePage, J. N.
PY - 2010
Y1 - 2010
N2 - Different chelating agents were used as alternatives for HCI in matrix acidizing to remove near wellbore damage and create wormholes in carbonate formations. Previous studies have demonstrated the use of ethylenediaminetetraacetic acid (EDTA), hydroxy ethylenediaminetetraacetic (HEDTA) and glutamic acid-N,N- diacetic acid (GLDA) as an alternative for HCl to stimulate carbonate reservoirs. The main problem with EDTA and HEDTA is the low biodegradability. GLDA was introduced as alternative for HCl for stimulating deep carbonate reservoirs at which HCl will cause corrosion and face dissolution problems. In this study calcite cores, 1.5 in. diameter with 6 and 20 in. length were used to determine the optimum conditions where the GLDA can breakthrough the core and form wormholes. GLDA solutions with pH values of 1.7, 3, and 3.8 were used. The optimum conditions of flow rate and pH were determined using the coreflood experiments. CT scan was used to determine the wormholes length and diameter to determine of optimum Damköhler number. GLDA was compared with chelates that are used in the oil industry such as EDTA and HEDTA. GLDA also was used to stimulate parallel cores with different permeability ratios (up to 6.25) to assess its ability on diversion. GLDA was found to be very effective in creating wormholes at pH = 1.7, 3, and 3.8 at different injection rates at temperatures of 180, 250, and 300°F. Increasing the temperature increased the reaction rate and less amount of GLDA was required to breakthrough the core and form wormholes. Unlike HCl and EDTA, there was no face dissolution or washout in the cores even at very low rates. Also, an optimum flow rate and Damköhler number were found at which the pore volume required to create wormholes was the minimal. GLDA at pH 1.7 and 3 created wormholes with a small number of pore volumes. Compared with acetic acid the volume of GLDA at pH 3 required to create wormholes was less than that required with acetic acid at the same conditions. GLDA was found to be effective in stimulating parallel cores with different permeabilities.
AB - Different chelating agents were used as alternatives for HCI in matrix acidizing to remove near wellbore damage and create wormholes in carbonate formations. Previous studies have demonstrated the use of ethylenediaminetetraacetic acid (EDTA), hydroxy ethylenediaminetetraacetic (HEDTA) and glutamic acid-N,N- diacetic acid (GLDA) as an alternative for HCl to stimulate carbonate reservoirs. The main problem with EDTA and HEDTA is the low biodegradability. GLDA was introduced as alternative for HCl for stimulating deep carbonate reservoirs at which HCl will cause corrosion and face dissolution problems. In this study calcite cores, 1.5 in. diameter with 6 and 20 in. length were used to determine the optimum conditions where the GLDA can breakthrough the core and form wormholes. GLDA solutions with pH values of 1.7, 3, and 3.8 were used. The optimum conditions of flow rate and pH were determined using the coreflood experiments. CT scan was used to determine the wormholes length and diameter to determine of optimum Damköhler number. GLDA was compared with chelates that are used in the oil industry such as EDTA and HEDTA. GLDA also was used to stimulate parallel cores with different permeability ratios (up to 6.25) to assess its ability on diversion. GLDA was found to be very effective in creating wormholes at pH = 1.7, 3, and 3.8 at different injection rates at temperatures of 180, 250, and 300°F. Increasing the temperature increased the reaction rate and less amount of GLDA was required to breakthrough the core and form wormholes. Unlike HCl and EDTA, there was no face dissolution or washout in the cores even at very low rates. Also, an optimum flow rate and Damköhler number were found at which the pore volume required to create wormholes was the minimal. GLDA at pH 1.7 and 3 created wormholes with a small number of pore volumes. Compared with acetic acid the volume of GLDA at pH 3 required to create wormholes was less than that required with acetic acid at the same conditions. GLDA was found to be effective in stimulating parallel cores with different permeabilities.
UR - https://www.scopus.com/pages/publications/78651112173
M3 - Conference contribution
AN - SCOPUS:78651112173
SN - 9781617389641
T3 - Proceedings - SPE Annual Technical Conference and Exhibition
SP - 1034
EP - 1055
BT - Society of Petroleum Engineers - SPE Annual Technical Conference and Exhibition 2010, ATCE 2010
ER -