Effect of Presence of Crude Oil on the Performance of Emulsified Acids

Sayed, Mohammed; Assem, Ahmed I.; Nasr‐El‐Din, Hisham A.

doi:10.2118/152844-ms

Cited by 5 publications

(2 citation statements)

References 38 publications

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“…Mahmoud et al (2011) evaluated the effect of water, oil, and gas while acidizing calcite cores using 0.6 M concentration of GLDA, HEDTA, and EDTA at a pH of 4 and a temperature of 300°F. Sayed et al (2012) studied the effect of the presence of crude oil in the formation on the performance of emulsified acid in stimulating carbonate formations. The authors also noted the absence of face dissolution at low GLDA injection rates and high temperatures.…”

Section: Introductionmentioning

confidence: 99%

New Insights on the Effect of Oil Saturation on the Optimum Acid Injection Rate in Carbonate Acidizing

Kumar

Nasr‐El‐Din

2014

SPE Improved Oil Recovery Symposium

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The existence of an optimum injection rate for wormhole propagation and face dissolution at low injection rates during matrix acidizing are well established. However, little has been documented that describes how the presence of residual oil affects carbonate acidizing. This study demonstrates the impact of oil saturation on wormholing characteristics while acidizing field and outcrop cores under reservoir conditions (200°F). Knowledge of the effect of different saturation conditions on acid performance will contribute towards the design of more effective acid treatments.Coreflood experiments at flow rates ranging from 0.5 to 20 cm 3 /min were performed to determine the optimum acid injection rate for wormhole propagation when acidizing homogeneous limestone reservoir cores, low permeability Indiana limestone cores, and homogeneous dolomite cores with dimensions 3 and 6 in. of length and 1.5 in. of diameter. The study involved acidizing cores saturated with water, oil, and waterflood residual oil using 15 wt% HCl. The viscosity of the crude oil used was 3.8 cp at 200°F. CT scans were used to characterize wormholes through the cores. The concentrations of the dissolved calcium and magnesium ions were measured using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and the effluent samples were titrated to determine the concentration of the acid.At injection rates 0.5 to 20 cm 3 /min, 15 wt% HCl was effective in creating wormholes with minimal branches for cores with residual oil (S or =0.4-0.5). Compared to brine and oil saturated cores, waterflood residual oil cores took less acid volume to breakthrough. Additionally, the wormholing efficiency of regular acid improved with increased acid injection rates in the presence of residual oil. A decrease in acid pore volumes to breakthrough for oil saturated cores was noted at high acid injection rates, which could be attributed to viscous fingering of acid through oil. Unlike brine saturated and oil saturated cores, waterflood residual oil cores showed no face dissolution at low acid injection rates. Conclusions from this work will aid in the design of better acid jobs by highlighting the impact of oil saturation on the wormholing characteristics of acid while acidizing carbonate rocks.

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Section: Introductionmentioning

confidence: 99%

New Insights on the Effect of Oil Saturation on the Optimum Acid Injection Rate in Carbonate Acidizing

Kumar

Nasr‐El‐Din

2014

SPE Improved Oil Recovery Symposium

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“…Sayed et al (2012) studied the effect of the presence of crude oil in the formation on the performance of emulsified acid in stimulating carbonate formations. Emulsified diesel was mixed with 36.8 wt% HCl, de-ionized water, and corrosion inhibitor to prepare the acid solution which was used to treat acidized high permeability Indiana limestone cores.…”

mentioning

confidence: 99%

Effect of Oil Saturation on Acid Propagation during Matrix Acidization of Carbonate Rocks

Kumar

Nasr‐El‐Din

2014

SPE Latin America and Caribbean Petroleum Engineering Conference

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The existence of an optimum injection rate for wormhole propagation and face dissolution at low injection rates during matrix acidizing are well established. However, little has been documented that describes how the presence of residual oil affects carbonate acidizing. This study demonstrates the impact of oil saturation on wormholing characteristics while acidizing field and outcrop cores under reservoir conditions (200°F). Knowledge of the effect of different saturation conditions on acid performance will contribute towards the design of more effective acid treatments. Coreflood experiments at flow rates ranging from 0.5 to 20 cm3/min were performed to determine the optimum injection rate for wormhole propagation when acidizing homogeneous limestone reservoir cores and low permeability Indiana limestone cores of dimensions 3 and 6 in. length and 1.5 in. diameter. The absolute permeability of the cores ranged from 1 to 78 md. The study involved acidizing cores saturated with water, oil, and waterflood residual oil using 15 wt% HCl. The viscosity of the crude oil used was 3.8 cp at 200°F. CT scans were used to characterize wormholes through the cores. The concentrations of the dissolved calcium and magnesium ions were measured using Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES) and the effluent samples were titrated to determine the concentration of the acid. At injection rates 0.5 to 20 cm3/min, 15 wt% HCl was effective in creating wormholes with minimal branches for cores with residual oil (Sor=0.4–0.5). Compared to brine and oil saturated cores, waterflood residual oil cores took less acid volume to break through. Additionally, the wormholing efficiency of regular acid improved with increased acid injection rates in the presence of residual oil. A decrease in acid pore volumes to breakthrough for oil saturated cores was noted at high acid injection rates, which could be attributed to viscous fingering of acid through oil. Unlike brine saturated and oil saturated cores, waterflood residual oil cores showed no face dissolution at low acid injection rates. Conclusions from this work will aid in the design of better acid jobs by highlighting the impact of oil saturation on wormholing characteristics of acid while acidizing carbonate rocks.

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New Non-aromatic Non-ionic Surfactants to Form a Stabilized Emulsified Acid for Efficient HP/HT Stimulation

Sokhanvarian¹,

Stanciu²,

Fernández³

et al. 2019

Proceedings of the International Petroleum and Petrochemical Technology Conference 2019

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Effect of Presence of Crude Oil on the Performance of Emulsified Acids

Cited by 5 publications

References 38 publications

New Insights on the Effect of Oil Saturation on the Optimum Acid Injection Rate in Carbonate Acidizing

New Insights on the Effect of Oil Saturation on the Optimum Acid Injection Rate in Carbonate Acidizing

Effect of Oil Saturation on Acid Propagation during Matrix Acidization of Carbonate Rocks

New Non-aromatic Non-ionic Surfactants to Form a Stabilized Emulsified Acid for Efficient HP/HT Stimulation

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