A Non-Damaging Gelled Acid System Based on Surface Modified Nanoparticles

2021 ◽  
Author(s):  
Rajendra Kalgaonkar ◽  
Mohammed Bataweel ◽  
Mustafa Alkhowaildi ◽  
Qasim Sahu

Abstract Gelled acid systems based upon gelation of hydrochloric acid (HCl) are used widely in acid stimulation treatments to prevent fluid leak-off into the high permeable zones of a reservoir. The gelled-up fluid system helps retard the acid reaction to allow deeper acid penetration for hydrocarbon productivity enhancement. Conventional in-situ crosslinked gelled acid systems are made up of polyacrylamide gelling agent, iron-based crosslinker, and a breaker chemical in addition to other additives, with the acid as the base fluid. The polymer-based systems can lead to damage to formation due to a variety of reasons including unbroken polymer residue. Additionally, the iron-based crosslinker systems can lead to scaling or precipitation after the acid reacts with the formation, resulting in formation damage and lowering of hydrocarbon productivity. In this paper, we showcase a new nanoparticles-based gelled acid system that does not contain any polymer or iron-based crosslinker that can potentially damage the formation. It comprises nanoparticles, a gelation activator, acidizing treatment additives along with HCl. The new in-situ gelled acid system has low viscosity at surface making it easy to pump. With increase in the temperature and as the acid spends there is a viscosity increase. The viscosification and eventual gelation of the new system can be achieved as the acid reacts with a carbonate formation. As the acid further reacts and continues to spend, the gel demonstrates reduction of viscosity. This assists in a better cleanup post the acidizing treatment. Various experimental techniques were used to highlight the development of the nanoparticle-based acid diversion fluid. The gelation properties of the acid system, as a function of acid strength and temperature, are investigated. Static and dynamic gelation studies as a function of time, temperature and pH are reported. It is demonstrated that the viscosification property is a function of pH and the gelation occurs in a pH widow from 1 to 5 pH units. The gelation performance of the new system is evaluated at temperatures up to 300°F. The effect of different types of surface modification chemistries on the gelation properties is investigated. It is also shown that the gelation and viscosity reduction is entirely a pH dependent phenomenon and does not require any additional breaker chemistry; and therefore provides more control over the system performance. The new gelled acid system overcomes the inherent challenges faced by conventional in-situ crosslinked gelled acid systems; as it is based upon nanoparticles making it less prone to formation damage as compared to a crosslinked polymer-based system.

2022 ◽  
Author(s):  
Rajendra A. Kalgaonkar ◽  
Qasim Sahu ◽  
Nour Baqader

Abstract Gelled acid systems based upon gelation of hydrochloric acid (HCl) are widely used in in both matrix acidizing and fracture acidizing treatments to prevent acidizing fluid leak-off into high permeable zones of a reservoir. The gelled up fluid system helps retard the acid reaction to allow deeper acid penetration for hydrocarbon productivity enhancement. The in-situ gelation is typically achieved by using crosslinked polymers with the acid. Conventional in-situ crosslinked gelled acid systems are made up of polyacrylamide gelling agent, iron based crosslinker and a breaker chemical in addition to other additives, with the acid as the base fluid. However, the polymer-based systems can lead to damaging the formation due to a variety of reasons including unbroken polymer residue. Additionally, the iron-based crosslinker systems can lead to scaling, precipitation and or sludge formation after the acid reacts with the formation, resulting in formation damage and lowering of hydrocarbon productivity. In this paper we showcase a new nanoparticles based gelled acid system that overcomes the inherent challenges faced by conventional in-situ crosslinked gelled acid systems. The new system can work in 5 to 20 % HCl up to 300°F. The new system does not contain any polymer or iron based crosslinker that can potentially damage the formation. It comprises nanoparticles, a gelation activator, acidizing treatment additives along with HCl. The new in-situ gelled acid system has low viscosity at surface making it easy to pump. It gels up at elevated temperatures and pH of 1 to 4, which helps with diverting the tail end acid to tighter or damaged zones of the formation. We demonstrate that the viscosification and eventual gelation of the new system can be achieved as the acid reacts with a carbonate formation and the pH rises above 1. As the acid further reacts and continues to spend there by increasing the pH beyond 4, the gel demonstrates reduction of viscosity. This assists in a better cleanup post the acidizing treatment. Various experimental techniques were used to showcase the development of the nanoparticle based acid diversion fluid. Static and dynamic gelation studies as a function of time, temperature and pH are reported. The gelation performance of the new system was evaluated at temperatures up to 300°F and discussed in the paper. Comparative performance of different types of gelation activators on the gelation profile of the nanoparticles is evaluated. It is also shown that the gelation and viscosity reduction is entirely a pH dependent phenomenon and does not require any additional breaker chemistry, and therefore provides more control over the system performance. The novelty of the new gelled acid system is that it is based upon nanoparticles making it less prone to formation damage as compared to a crosslinked polymer based system.


2012 ◽  
Author(s):  
Prajakta Ratnakar Patil ◽  
Anjali Sarda ◽  
Shoy George ◽  
Yogesh Kumar Choudhary ◽  
Rajendra Kalgaonkar
Keyword(s):  

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 600
Author(s):  
Thomas Ferrand ◽  
Damien Deldicque

Tectonic plates are thought to move above the asthenosphere due to the presence of accumulated melts or volatiles that result in a low-viscosity layer, known as lithosphere–asthenosphere boundary (LAB). Here, we report experiments suggesting that the plates may slide through a solid-state mechanism. Ultrafine-grained aggregates of Mg2GeO4 and minor MgGeO3 were synthetized using spark plasma sintering (SPS) and deformed using a 1-atm deformation rig between 950 °C and 1250 °C. For 1000 < T < 1150 °C, the derivative of the stress–strain relation of the material drops down to zero once a critical stress as low as 30–100 MPa is reached. This viscosity reduction is followed by hardening. The deformation curves are consistent with what is commonly observed in steels during the shear-induced transformation from austenite to martensite, the final material being significantly harder. This is referred to as TRansformation-Induced Plasticity (TRIP), widely observed in metal alloys (TRIP alloys). It should be noted that such enhanced plasticity is not necessarily due to a phase transition, but could consist of any kind of transformation, including structural transformations. We suspect a stress-induced grain-boundary destabilization. This could be associated to the transient existence of a metastable phase forming in the vicinity of grain boundaries between 1000 and 1150 °C. However, no such phase can be observed in the recovered samples. Whatever its nature, the rheological transition seems to occur as a result of a competition between diffusional processes (i.e., thermally activated) and displacive processes (i.e., stress-induced and diffusionless). Consequently, the material would be harder at 1200 °C than at 1100 °C thanks to diffusion that would strengthen thermodynamically stable phases or grain-boundary structures. This alternative scenario for the LAB would not require volatiles. Instead, tectonic plates may slide on a layer in which the peridotite is constantly adjusting via a grain-boundary transformation.


2021 ◽  
Vol 63 (7) ◽  
pp. 630-638
Author(s):  
Mustafa Kaptanoglu ◽  
Mehmet Eroglu

Abstract In the study for this contribution, production of in situ synthesized TiB2 particles in iron-based composite coatings using four different submerged arc welding powders (fluxes) containing increasing amounts of ferrotitanium and ferroboron with S1 welding wire, were targeted. For this purpose, coating deposition was carried out to improve the hardness and wear properties of the AISI 1020 steel surfaces using hybrid submerged arc welding. In hybrid submerged arc welding, the welding pool is protected by both welding powders and an argon gas atmosphere. To examine the composite coatings, visual, chemical, microstructural analyses and hardness and wear tests were carried out. With the use of increasing amounts of ferrotitanium and ferroboron in the welding powders, it was observed that the microstructure of the coatings changed in terms of TiB2 particle geometries such as rectangular and hexagonal; volume fractions of TiB2 particles in the coating microstructures increased; hardness values of coatings were enhanced from 34 HRC to 41 HRC; the wear resistance of the coatings improved, and worn surface images of the coatings caused by the counter body changed from continuous with deep scratches to discontinuous with fine scratches and crater cavities.


2014 ◽  
Vol 7 (3) ◽  
pp. 1110 ◽  
Author(s):  
Aravamuthan Sundar Rajan ◽  
Srinivasan Sampath ◽  
Ashok Kumar Shukla
Keyword(s):  

1970 ◽  
Vol 1 (3) ◽  
pp. 43-49 ◽  
Author(s):  
Jovita Kanoujia ◽  
Kanchan Sonker ◽  
Manisha Pandey ◽  
Koshy M Kymonil ◽  
Shubhini A Saraf

The present research work deals with the formulation and evaluation of in-situ gelling system based on sol-to-gel transition for ophthalmic delivery of an antibacterial agent gatifloxacin, to overcome the problems of poor bioavailability and therapeutic response exhibited by conventional formulations based a sol-to-gel transition in the cul-de-sac upon instillation. Carbopol 940 was used as the gelling agent in combination with HPMC and HPMC K15M which acted as a viscosity enhancing agent. The prepared formulations were evaluated for pH, clarity, drug content, gelling capacity, bioadhesive strength and in-vitro drug release. In-vitro drug release data of optimized formulation (F12) was treated according to Zero, First, Korsmeyer Peppas and Higuchi kinetics to access the mechanism of drug release. The clarity, pH, viscosity and drug content of the developed formulations were found in range 6.0-6.8, 10-570cps, 82-98% respectively. The gel provided sustained drug release over an 8 hour period. The developed formulation can be used as an in-situ gelling vehicle to enhance ocular bioavailability and the reduction in the frequency of instillation thereby resulting in better patient compliance. Key Words: In-situ gelation; Gatifloxacin; Carbopol 940; HPMC K15M. DOI: http://dx.doi.org/10.3329/icpj.v1i3.9661 International Current Pharmaceutical Journal 2012, 1(3): 43-49


2020 ◽  
Author(s):  
Barbara Souza ◽  
Jin-Chong Tan

We report two solvent-free mechanochemical methods to achieve one‑pot encapsulation of anti-cancer drug 5‑Fluorouracil (5‑FU) in the iron-based MIL‑100 metal-organic framework (MOF). We compare the structural and physicochemical properties of drug@MIL‑100 systems derived from <i>in situ </i>manual and vortex grinding, where the former exhibits a slower drug release due to stronger guest-host interactions.


Author(s):  
Sanket Kumar ◽  
Mahesh Singh ◽  
Babulal Patel

Peptic ulcer, it is the most common type of stomach disease, according to the American Gastroenterology Association. “We know that ulcers occur because there has been a disruption in the balance of factors that injure the digestive tract and those factors that protect it from injury,” The present investigation deal with the formulation, optimization and evaluation of sodium alginate based in situ gel of ranitidine hydrochloride (R-HCl) in ulcer treatment. The in-situ formulation are homogenous liquid when administration orally and become gel at the contact site. The evaluation of the formulation is dependent upon accurate results obtained by analytical method used during the study. Accurate results require the use of standard and a calibration procedure. Hence, standard plots of Ranitidine hydrochloride were prepared in (0.1N HCL, pH 1.2) solutions. Two, sodium alginate and calcium carbonate used as a polymer and cross-linking agent respectively in the formulation of in-situ gel. From the IR studies it may be concluded that the drug and carriers used undergo physical interaction there is no chemical change, and thus the gelling agent, cross-linking agent and other excipient is suitable for formulation of in-situ gel of ranitidine hydrochloride. Indicate that the formulation, DKF9 which was prepared by the Sodium alginate (2 gm) with Ranitidine Hydrochloride showed minimum drug release (sustained drug release) after 8 hrs. It can be concluded that the In-situ gel was beneficial for delivering the drug which needs sustained release to achieve the slow action. Keywords: In-situ gel, Peptic Ulcer, Ranitidine Hydrochloride (R-HCl), Sodium alginate.


Sign in / Sign up

Export Citation Format

Share Document