scholarly journals Polyelectrolyte complex nanoparticles for protection and delayed release of enzymes in alkaline pH and at elevated temperature during hydraulic fracturing of oil wells

2012 ◽  
Vol 126 (2) ◽  
pp. 587-592 ◽  
Author(s):  
Reza Barati ◽  
Stephen J. Johnson ◽  
Stan McCool ◽  
Don W. Green ◽  
G. Paul Willhite ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Hydraulic Fracturing ◽  
Polyelectrolyte Complex ◽  
Oil Wells ◽  
Alkaline Ph ◽  
Delayed Release

Swelling Behavior and Drug Release of Polymer Coated Nano Iron Oxide Embedded Hydroxyapatite

2019 ◽  
Vol 829 ◽  
pp. 108-113
Author(s):  
Yoshiyuki Yokogawa ◽  
Rina Ohkura ◽  
Yoko Inoue ◽  
Atsumasa Shishido ◽  
Ereath Beeran Ansar ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Elevated Temperature ◽  
Ambient Temperature ◽  
Polyelectrolyte Complex ◽  
Elevated Temperatures ◽  
Release Behavior ◽  
Swelling Properties ◽  
Gel Beads ◽  
Calcium Alginate Gel ◽  
Ca Alginate

Spherical calcium-alginate gel beads containing HAIO, iron oxide (IO) nanoparticles embedded on hydroxapatite (HA), were prepared along with and poly (N-isopropylacrylamide) (PNIPAAM) or chitosan. These spheres, HAIO, HAIO-PNIPAAM and HAIO-chitosan spheres, were used as carriers of 5-fluorouracil (5-FU), one of the drugs for cancer chemical therapy, and the 5-FU release behavior in PBS solution was investigated at ambient and elevated temperatures using U-V spectrometry. The amount of the released 5-FU from the HAIO spheres was somewhat higher than that from HAIO-PNIPAAM and HAIO-chitosan spheres at ambient temperature. At elevated temperature, HAIO spheres showed an increase in quantity of released 5-FU. The amount of released 5-FU from HAIO-PNIPAAM spheres was almost the same, and that from HAIO-chitosan spheres was reduced compared to those at ambient temperature. These spheres, HAIO, HAIO-PNIPAAM and HAIO-chitosan spheres, show the similar swelling properties at elevated temperature. However, the combinations of Ca-alginate - PNIPAAM or Ca-alginate - chitosan may produce the different structures, which are core-shell network for HAIO-PNIPAAM spheres and or a polyelectrolyte complex for HAIO-chitosan spheres, leading to a different release behavior of 5-FU.

Near-Tip-Screenout Hydraulic Fracturing Of Oil Wells In The Bach Ho Field, Offshore Vietnam

1995 ◽  
Author(s):  
L.V. Hung ◽  
N.T. San ◽  
A.G. Shelomentsev ◽  
J.A. Tronov ◽  
D.D. Lam ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Oil Wells

Performance of 15 Years of Hydraulic Fracturing of Oil Wells in South of Oman

2022 ◽  
Author(s):  
Mathieu M. Molenaar ◽  
Ali Al-Ghaithi ◽  
Said Kindi ◽  
Fahad Alawi
Keyword(s):  
Hydraulic Fracturing ◽  
Low Cost ◽  
Oil Wells ◽  
Regression Methods ◽  
Coiled Tubing ◽  
New Concepts ◽  
Business Objective ◽  
Large Growth ◽  
Multivariable Regression ◽  
Production Increase

Abstract The first application of Hydraulic Fracturing in the South Oman started in 2000 to enhance water disposal wells. In 2004 the first oil wells were frac'ed. Although the technology was deployed many times, it never grew into a conventional practice. From 2004 to 2017 on average 5 Oil Wells were hydraulically fractured on yearly basis. In November 2017, a Hydraulic Fracturing Maturation & Expansion Workshop was conducted with the vision of growing the application by applying new frac concepts. A focused effort was initiated to drastically reduce cost, and simultaneously increase the scope by executing larger frac campaigns. The first hydraulic fracturing campaign introducing the frac new concepts, started end 2018 and a rapid growth from 5 wells per year to 45 wells per year was anticipated in the next three years. This large growth of scope relied on a steady supply of frac candidates and needed to be supported by screening and selecting processes that are fit for purpose in finding candidates. Although more than a hundred wells had already been frac'ed wells, selection of the most appropriate wells for stimulation was and remains one of the greatest challenges. A frac performance database was created for over 100 wells that had been hydraulically fracture stimulated to date. Recognizing that the frac performance depends on many variables ranging from subsurface properties to surface execution of the frac job, the size of the dataset proved to be too small to find correlations using sophisticated multivariable regression methods. Instead, the dataset was analyzed through careful investigation and evaluation of each frac job. In this paper the net oil gain will be used as the key success criteria i.e., value driver to demonstrates how effective the frac is achieving its business objective. Some 40% of the producers had been producing from the same zone before the hydraulic fracture stimulation. This provided the opportunity to understand the efficiency of the stimulation in terms of the "stimulation ratio" i.e., measuring the net oil gain. This paper will focus on investigating the suitability of frac'ing the reservoir based on the initial production variables; Gross Rate and BS&W. Also, this paper will discuss benefits and impacts of Hoist versus Coiled-Tubing clean-out on the frac delivery process and compare the frac performance. To date, the project demonstrated that hydraulic fracturing at low cost, can be applied as a viable development concept for producing oil wells, with the potential unlock additional and new reserves. Significant folds in production increase are possible from 2x to 7x.

scholarly journals Numerical Models for Hydraulic Refracturing on Vertical Oil Wells

2018 ◽  
Vol 7 (4.26) ◽  
pp. 279 ◽  
Author(s):  
Vladimir Bratov
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Hydraulic Fracturing ◽  
Numerical Models ◽  
Fracture Initiation ◽  
Time Profile ◽  
Oil Wells ◽  
Fracture Event ◽  
History Of

The paper presents an approach for simulation of refracturing treatment on vertical oil wells. The model is accounting for filtration of hydraulic fracturing fluid through the proppant packed inside the crack formed during previous hydraulic fracturing treatments. The simulations provide a possibility to estimate history of stress intensity factor appearing at the tip of the existing crack once the time profile of pressure within the wellbore is given. Introducing critical value of the stress intensity factor for the fractured media, time-to-fracture initiation (after pressure increase start) can be estimated and compared to instance of fracture event registered in real conditions. Also, the possibility of fracture reorientation through formation of new fractures at the region adjacent to the wellbore is studied. 

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