Formation Damage Induced by Chemical Treatments: Case Histories

Nasr‐El‐Din, Hisham A.

doi:10.1115/1.1924464

Cited by 28 publications

(7 citation statements)

References 51 publications

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“…Coal seams are usually water or intermediate wet and water‐blocking problem prohibits the gas flow in coal seams. Fracturing process in CBM reservoirs also includes a mechanical interaction between the coal seam and the fracturing fluids 14‐17 . Therefore, it is of great significance to drain the water thoroughly and offer a high‐permeability channel for the gas flow.…”

Section: Introductionmentioning

confidence: 99%

Refracturing field tests for enhanced coalbed methane production with gas wettability alteration

Lin

Zhao

et al. 2021

Int J Energy Res

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Summary Gas wettability alteration (GWA) technology has been used for better methane drainage underground. Our previous field tests of underground fracturing demonstrated a large increase in coalbed methane (CBM) production compared with those in the boreholes fractured without GWA treatments. However, the general drainage rate of each fracturing borehole with GWA treatment is not high enough because no proppant was used in the underground fracturing. To this end, field tests of surface refracturing in two CBM wells (Wells A‐2 and 4) were conducted with an innovative fracturing measure with GWA treatments and elongated coal‐like proppants in XJ coal mine, Yangquan, China. The water and CBM production with the novel and the conventional fracturing technologies were compared and analyzed. The field test results showed that the CBM production with the novel refracturing technologies (29 697 and 26 844 m3 for Wells XJ‐2 and 4) is greater than those with conventional refracturing (22 746 m3 for Well XJ‐6) and initial‐fracturing (25 297.4 and 2847.2 m3 for Wells XJ‐2 and 4). The significant increase in CBM production demonstrates that the novel fracturing technology could be applied for enhanced CBM production.

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Section: Introductionmentioning

confidence: 99%

Refracturing field tests for enhanced coalbed methane production with gas wettability alteration

Lin

Zhao

et al. 2021

Int J Energy Res

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“…Different iron sulfide types will form because of this reaction. If HC1 used in such cases, it will react with the iron sulfide (iron to sulfur ration close to one) and it will produce H2S gas [10], Gupta [11] studied the use of abrasive-slurry-jet method tech nique to stimulate sandstone and carbonate reservoirs. He found that the use of this method will overcome the problems and chal lenges associated with the stimulation of heterogeneous and frac tured reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Challenges During Shallow and Deep Carbonate Reservoirs Stimulation

Mahmoud

Nasr‐El‐Din

2014

Journal of Energy Resources Technology

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Carbonate reservoir stimulation has been carried out fo r years using HCl or HCl-based fluids. High HCl concentration should not be used when the well completion has Crbased alloy in which the protective layer is chrome oxide which is very soluble in HCl. HCl or its based fluids are not recommended either in shallow reservoirs where the fra c ture pressure is low (face dissolution) or in deep reservoirs where it will cause severe corrosion problems to the well tubular. Different chelating agents have been proposed to be used as alternatives to HCl in the cases that HCl cannot be used. Chelating agents, such as HEDTA (hydroxyl ethylene diamine triacetic acid) and GLDA (glutamic -N, N-diacetic acid), have been used to stimulate carbonate cores. The benefits o f chelating agents over HCl are the low reaction, low leak-off rate, and low corrosion rates. In this study, the different equations and parameters that can be used in matrix acid treatment were summarized to scale up the laboratory conditions to the field conditions. The condi tions where HCl or chelating agents can be used were optimized and in this paper. The leak-off rate was determined using the data from coreflood experiments and computed to mography (CT) scans. Indiana limestone cores o f average permeability o f 1 md and core lengths o f 6 and 20 in. were used in this study. Chelating agents will be used at pH value o f 4 and at concentration o f 0.6M, and their performance will be compared with the 15 wt.% HCl. The experimental results showed that HCl has high leak-off rate and caused face dissolution at low injection rate. The model to scale up the linear coreflood results to radial field conditions was developed and can be used to design fo r the optimum condi tions o f the matrix acid treatments. Chelating agents can be used to stimulate shallow reservoirs in which HCl may cause face dissolution, because they can penetrate deep with less volume and also they can be used in deep reservoirs where HCl may cause severe corrosion to the well tubular.

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“…The increase in pH can be explained as follows: during the fresh water shock with the core initially saturated with NaCl, there is an exchange between the adsorbed Na'^ and the H^ ions in solution [4]. Formation damage due to fines dislodgment, induced by chemical treatment was examined [8][9][10]. A rapid and drastic decrease in the permeability was observed due to the injection of high pH fluids at a pH > 11.0 [5].…”

Section: Introductionmentioning

confidence: 99%

An Al/Zr-Based Clay Stabilizer for High pH Applications

El‐Monier¹,

Nasr‐El‐Din

2013

Journal of Energy Resources Technology

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An Al/Zr-Based Clay Stabilizer for High p\\ ApplicationsSandstone formations are exposed to a variety of high pH fluids, including: hydraulic fracturing using high pH borate gels, alkaline-based chemical enhanced oil recovery (EOR) methods, water-based drilling fluids, and cementing filtrate. High pH values can trigger fines migration, and subsequent loss of permeability and well productivity. An aluminumlzirconium-based (Al/Zr) clay stabilizer was developed to control fines migration at high pH applications. The objective of this study is to assess the effectiveness of this new stabilizer and compare its performance with commercially available stabilizers. Laboratory studies were performed using Berea sandstone (8 wt. % clays; mainly kaolinite) cores, 6 in. length and 1.5 in. diameter. Tetramethyl ammonium chloride (TMAC) and choline chloride were used for comparison as two commercial clay stabilizers. Various coreflood experiments were conducted to determine the effect of the three stabilizers on core permeability {from 64 to 100 niD) at various temperatures up to 300°F. In these experiments, a preflush that included 2 wt. % stabilizer was injected, followed by injection of 2 wt. % NaOH solution. The latter represented high pH filtrate that can invade the formation during any treatment that includes alkaline fluids. The pressure drop across the core was measured and samples of the core effluent were collected. Inductively coupled plasma optical emission spectrometry (wtNLAB32 software) was used to measure the concentrations ofAl, Zr, Fe, Ca, andMg. ZetaPALS (BIC software) was used to measure the surface charge on the kaolinite particles. Lab results indicated that the new clay stabilizer worked effectively up to 300 F following 2 wt. % NaOH. No reduction in permeability was noted in any of coreflood tests using sandstone cores of various initial permeabilities. The concentrations of various cations were found to be a function of core mineralogy. TMAC and choline chloride were not effective when followed by fresh water and incompatible with the high pH fluids. The new stabilizer is environmentally friendly, and can be used in hydraulic fracturing, and alkaline-based chemical EOR methods to mitigate clay related problems.

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Formation Damage Induced by Chemical Treatments: Case Histories

Cited by 28 publications

References 51 publications

Refracturing field tests for enhanced coalbed methane production with gas wettability alteration

Refracturing field tests for enhanced coalbed methane production with gas wettability alteration

Challenges During Shallow and Deep Carbonate Reservoirs Stimulation

An Al/Zr-Based Clay Stabilizer for High pH Applications

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