Crosslinked Acid as an Effective Diversion Agent in Matrix Acidizing

Runtuwene, Michael; Fasa, Muhammad Hilmi; Rachmawati, Fitria Dewi; Wijanarko, Muhammad; Kadarsyah, Arief; Komalasari, Novi; Gurnito, Nuratas

doi:10.2118/133926-ms

Cited by 9 publications

(3 citation statements)

References 1 publication

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“…Calcite (calcium carbonate) reacts with HCl to produce calcium chloride, water and carbon dioxide (Eq.1), while dolomite reacts with HCl to produce calcium chloride, magnesium chloride, water and carbon dioxide (Eq.2). The reaction rate for calcium carbonate is rapid, while the reaction with dolomite is slower (Patton et al 2003 Using HCl may significantly increase oil and gas production (Runtuwene et al 2010), despite lowering Young's modulus and resulting in wellbore instability.…”

Section: Effect Of Low Ph Solutions On Mineral Dissolutionmentioning

confidence: 99%

Imbibition Characteristics of the Barnett Shale Formation

Morsy¹,

Sheng²

2014

SPE Unconventional Resources Conference

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In order to understand the effect of injected stimulation fluids on nano-darcy permeability, naturally fractured shale reservoirs, an integrated study of spontaneous imbibition has been performed. In this study, oil recovery during spontaneous imbibition in naturally fractured shale samples was improved using different water formulations. Different water solutions were formulated by adding different amounts of HCl and NaOH to either distilled water or 2 wt% KCl-base brine solution. Eight water formulations, distilled water, 2% KCl brine, low pH HCl solutions (0.74-1.2), and high pH alkaline solutions (11.7-12.4) were examined to recover oil from shale rocks. Outcrop samples from the Barnett shale formation were used in this study. The samples were 2.54 to 3.81 cm in diameter and 0.762 to 5.08 cm in length. Firstly, we studied the average porosity of the used samples using CT Scanning. The average porosity was around 7%. Secondly, we studied the rock stability and spontaneous imbibtion of the different Barnett samples in distilled water, 2 wt% KCl, low pH solutions (0.74-1.2), and high pH alkaline solutions (11.7-12.4). During the spontaneous imbibition, the maximum oil recovery was 24% using distilled water and low pH solution of pH0.74 (3 wt% HCl in 2 wt% KCl base brine solution). Clay swelling can contribute to the Barnett oil recovery improvement by creating along bedding cracks. Oil recoveries from the Barnett shale can be improved by 56% when used 2 wt% NaOH solution and 88% when used 3 wt% HCl when added to 2 wt% KCl simulation base fluid. High pH solutions did not improve oil recoveries from the Barnett samples when added to distilled water due to pore plugging resulted from the combination of clay swelling with mineral dissolution. Low pH solutions showed along bedding cracks similar to distilled water effect on the Barnett shale samples that helped recovery accelerations, while higher pH solutions showed sever samples damage with higher alkaline concentrations (2 wt% NaOH).

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Section: Effect Of Low Ph Solutions On Mineral Dissolutionmentioning

confidence: 99%

Imbibition Characteristics of the Barnett Shale Formation

Morsy¹,

Sheng²

2014

SPE Unconventional Resources Conference

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“…The severity of fractured pore networks in carbonate reservoir increases the barrier for fluid flow (Jones 1975;Popov et al 2007;Philip et al Philip et al 2005). Matrix acidizing is introduced by injecting acid stimulated fluid, i.e., HCl, into reservoir below fracture pressure to enhance reservoir conductivity and improve the flow rate through dissociation of the reservoir rock (Izgec et al 2008;Chang et al 2008;Raj and Pal 2014;Morsy et al 2015;Company 2013;Gomez 2006;Kalia and Balakotaiah 2010;Al-Hadhrami and Blunt 2000;Rahim et al 2014;Runtuwene et al 2010). The HCl acid spreads efficiently in carbonate formation compared to homogeneous reservoir due to the flow properties, which varies from small (micron) to larger (centimeter) scale (Izgec et al 2008).…”

Section: Carbonate Reservoirs and Matrix Acidizingmentioning

confidence: 99%

Experimental study of nanoparticles as catalyst in enhancing matrix acidizing for carbonate reservoir

Selvaraj

Maulianda

Wee

et al. 2019

J Petrol Explor Prod Technol

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Hydrochloric (HCl) acid is the most common stimulating fluid used in acidizing job due to its strong acidic property and low cost to create or enlarge existing wormhole within the reservoir. However, the HCl acid has rapid reaction with carbonate reservoir, and it is causing surface dissolution of the rock and lowering the penetration into the formation. Recent studies have shown the addition of nickel nanoparticles as catalyst to handle the problems in HCl acidizing. The nanoparticles are high-performance catalyst due to their high ratio of surface area to volume. The proposed method in this research is to mix the nanoparticles with the carbonate formation prior to the acid injection into the formation. The efficiency of the nanoparticles as catalyst depends on the thermodynamics property, which is surface energy of the materials used. The surface energy reduces as the size of particles become smaller. However, the effect of surface energy become insignificant on nanoparticles due to the small particles sizes, and the surface energy is based on the individual energy of the particles. Therefore, this research investigates the efficiency of silica, aluminum oxide, and zinc oxide besides nickel nanoparticles based on their thermodynamics property in accelerating the conversion of CO 2 gas into carbonic acid. The approach consists of investigating the efficiency of nanoparticles in different concentrations of carbonate and mass of nanoparticles. Suitable nanoparticles are proposed based on efficiency and cost in retarding the HCl reactivity and rapid formation of in situ carbonic acid. The concentration of carbonic acid (H 2 CO 3), bicarbonate ion (HCO 3 −), and carbonate ion (CO 3 2−) is analyzed based on Henry's law of solubility. The result shows that the silica has the best efficiency as catalyst in 6700 ppm Na 2 CO 3 solution due to its high stability and dispersion in aqueous solution. The silica engages into rapid dissociation of water molecules and bind with OH − group to react with CO 2 gas and form HCO 3 −. The nanoparticles reduce the reactivity of HCl through conversion of bicarbonate ions. However, ZnO gives better efficiency in 17,000 ppm of Na 2 CO 3. The efficiency of silica in this concentration increased at 0.7 g, proving the minimum amount required as catalyst. In contrast, ZnO and Al 2 O 3 have lower efficiency as acid retarder since changes in pH values affect the performance of the nanoparticles. The surface charge demonstrated by ZnO and Al 2 O 3 depends on pH changes which makes these nanoparticles to perform inefficiently. The silica is chosen as the best catalyst due to high efficiency versus cost ratio.

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Section: Hcl and Mineral Dissolutionmentioning

confidence: 99%

Improvement of Eagle Ford Shale Formation's Water Imbibition by Mineral Dissolution and Wettability Alteration

Morsy

Gomaa

Sheng

2014

SPE Unconventional Resources Conference

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In order to understand the performance of waterflooding in nano-darcy permeability, naturally fractured shale reservoirs, an integrated study of spontaneous imbibition has been performed. In this study, oil recovery during spontaneous imbibition in naturally fractured shale samples was improved using different water formulations. Different water solutions were formulated by adding different amounts of HCl and NaOH to either distilled water or 2 wt% KCl-base brine solution. Eight water formulations, distilled water, 2% KCl brine, low pH HCl solutions (0.74-1.2), and high pH alkaline solutions (11.7-12.4) were examined to recover oil from shale rocks. Reservoir core samples from Eagle Ford shale were used in this study. The samples were 2.54 to 3.81 cm in diameter and 0.762 to 5.08 cm in length. Firstly, we studied the porosity of the used samples using CT Scanning. The average porosity was 1.6% for Eagle Ford shale samples. Secondly, we studied the rock stability and spontaneous imbibtion of the different Eagle Ford samples in distilled water, 2 wt% KCl, low pH solutions (0.74-1.2), and high pH alkaline solutions (11.7-12.4). During the spontaneous imbibition, the maximum oil recovery was 37% for Eagle Ford using pH 0.74 (3 wt% HCl in 2 wt% KCl) and 44% using pH 11.7 (0.1 wt% NaOH in distilled water). The oil recovery was improved by mineral dissolution using low and high pH solutions along with wettability alteration. The rock hardness was significantly affected by using both high and low pH solutions, which resulted in 93-98% loss of its initial value. IntroductionIn shale reservoirs, oil is stored in a very tight matrix, with virtually all permeability concentrated in a large number of natural fractures (Fakcharoenphol et al. 2012). Due to these fractures, oil cannot be displaced from the matrix by means of conventional waterflooding. Channeling and bypassing through the fractures would result in extremely poor recovery (Guo et al. 1998). Primary oil production from such fractured reservoirs in which the storage occurs in the matrix and flow happens in fractures can be divided into three stages: 1) production from the fracture network at early time; 2) production from the fracture network and rock matrix at intermediate time; and 3) production from the rock matrix at a later time (Guo et al. 1998). Early production from the fracture network of shale formation declines rapidly because of a variety of reasons: increasing effective stress, proppant fatigue due to stress cycling, and digenesis. Most of the recovery of the intermediate and long-term stages of production depends on spontaneous imbibition of brine into the rock matrix and expulsion of oil via the fracture face. Spontaneous imbibition can add significant amount of oil recovery in fractured reservoirs with low matrix permeability depending on rock wetness quality. The rate of imbibition is mainly affected by the net effect of capillary pressure driving force and the opposing viscous resistance to flow. Because of the strong capillary forces, the small...

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Crosslinked Acid as an Effective Diversion Agent in Matrix Acidizing

Cited by 9 publications

References 1 publication

Imbibition Characteristics of the Barnett Shale Formation

Imbibition Characteristics of the Barnett Shale Formation

Experimental study of nanoparticles as catalyst in enhancing matrix acidizing for carbonate reservoir

Improvement of Eagle Ford Shale Formation's Water Imbibition by Mineral Dissolution and Wettability Alteration

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