WaterFrac Application in Injectors Improves Waterflooding - An Innovative
Approach

Nainwal, S.P.; Das, Rajarshi; Singh, C. B.; Singh, Sanjai

doi:10.2523/101156-ms

Cited by 2 publications

(1 citation statement)

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“…It is quite common to inject water at high wellhead pressures in a well with the intention of creating certain fractures in the reservoir rock that will increase the overall injectivity of the well (Nainwal et al, 2006). Another option is to intentionally fracture the reservoir using proppants.…”

Section: Fracture Treatments/ Injection With Increased Wellhead Pressurementioning

confidence: 99%

Re-establishment of the proper injectivity of the CO2-injection well Ktzi 201 in Ketzin, Germany

Zettlitzer

Moeller

Morozova

et al. 2010

International Journal of Greenhouse Gas Control

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The onshore CO 2 -storage site Ketzin consists of one CO 2-injection well and two observation wells. Hydraulic tests revealed permeabilities between 50 and 100 mD for the sandstone rock units. The designated injection well Ktzi 201 showed similar production permeability. After installation of the CO 2 -injection string, an injection test with water yielded a significantly lower injectivity of 0.002 m 3 /d*kPa, while the observation wells showed an injection permeability in the same range as the productivity. Several possible reasons for the severe decline in injectivity are discussed. Acidification of the reservoir interval, injection at high wellhead pressure, controlled mini-fractures and back-production of the well are discussed to remove the plugging material to re-establish the required injectivity of the well. It has been decided to perform a nitrogen lift and analyse the back-produced fluids. Initially during the lift, the backproduced fluids were dark-black. Chemical and XRD analyses proved that the black solids consisted mainly of iron sulphide. Sulphate-reducing bacteria (SRB) were detected in fluid samples with up to 10 6 cells/ml by fluorescent in situ hybridisation (FISH) indicating that the formation of iron sulphide was caused by bacterial activity. Organic compounds within the drilling mud and other technical fluids were likely left during the well completion process, thus providing the energy source for strong proliferation of bacteria. During the lift, the fraction of SRB in the whole bacterial community decreased from approximately 32 % in downhole samples to less than 5 %. The lift of Ktzi 201 succeeded in the full restoration of the well productivity and injectivity. Additionally, the likely energy source of the SRB was largely removed by the lifting, thus ensuring the long-term preservation of the injectivity.2

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Section: Fracture Treatments/ Injection With Increased Wellhead Pressurementioning

confidence: 99%

Re-establishment of the proper injectivity of the CO2-injection well Ktzi 201 in Ketzin, Germany

Zettlitzer

Moeller

Morozova

et al. 2010

International Journal of Greenhouse Gas Control

View full text Add to dashboard Cite

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Enhancing Reservoir Productivity in Carbonate Formations Propped vs Acid Fracturing Strategies at Lekhwair Area

Al Malki,

Al Manthari,

Al Aamri

et al. 2024

Day 2 Tue, February 13, 2024

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This paper represents a follow-up to a previous hydraulic study conducted in the same area, with the inclusion of acid fracturing treatment execution and evaluation to conclude a comprehensive comparison study with the earlier propped fracturing campaign. In the Lekhwair satellite fields, the reservoir properties of Cretaceous carbonate formations (Natih C1 and Shuaiba) oil reservoirs were found to exhibit lower mobility than initially projected. In response, post-drilling matrix stimulation was performed using 20% HCl, albeit with limited success. To address these challenges, we initiated a hydraulic fracturing study aimed at assessing the response of these tight permeability carbonate rocks to stimulation. An integrated multidisciplinary approach was developed to compare the design of propped fracturing and acid fracturing treatments in carbonate settings. This approach involved the integration of acoustic borehole imaging data, geomechanical analysis, petrophysical logs, mineralogy, and other factors to optimize the design. A range of well candidates, including oil producers and water injection wells, with both vertical and highly deviated cased hole completions and open-hole horizontal wells, were selected. During the candidate selection process, the primary challenge in carbonate formations was to ensure that the design contained the fracture height and half-length within optimal parameters. This was crucial to prevent lateral uncontrolled fracture propagation towards nearby water injection wells and producers, as well as to safeguard the integrity of the cap rock (natural barrier) within the carbonate setting. The study also compared post-fracture well performance between propped fracturing and acid fracturing, utilizing advanced technologies such as self-consolidated proppant, retarded emulsified acid, and degradable particulate diverters. Prior to the fracture treatment, the selected wells had minimal production due to poor inflow, resulting in very low gross and net oil production. These wells were operated on an ON/OFF schedule to manage reservoir pressure and address issues with Electric Submersible Pump (ESP) reliability caused by the extremely low flow rates. Post-fracture well treatment results indicated a significant improvement in gross and net oil production, with production increasing by up to 20-fold, and the ESP lifetime extended in comparison to the pre-fracture period. These wells could now operate continuously within the optimal ESP operating range and were no longer subject to ON/OFF scheduling. The uptime of these wells improved from 25% to 100%. Notably, this paper serves as a sequel to a previous hydraulic study, with a focus on the inclusion of acid fracturing. The results of this study contribute to a comprehensive comparison of acid fracturing method on this carbonate reservoir, with the earlier propped fracturing campaign. Even though several treatment fluid system has been studied, including linear and cross-linked gel acid, retarded emulsified acid system for acid fracturing and borate cross-linked guar fluid for propped fracturing, the main intention of this paper is rather to concentrate on method comparison than fluid discussion, therefore the section covering the laboratory and fluid discussion is limited to critical design related information. The findings represent a significant step forward in the understanding of stimulation techniques in carbonate formations and offer valuable insights for future field development plans. In conclusion, this study builds upon previous research, offering a deeper understanding of hydraulic fracturing techniques in carbonate formations and providing valuable insights for some novel technologies advancement.

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WaterFrac Application in Injectors Improves Waterflooding - An Innovative Approach

Cited by 2 publications

References 0 publications

Re-establishment of the proper injectivity of the CO2-injection well Ktzi 201 in Ketzin, Germany

Re-establishment of the proper injectivity of the CO2-injection well Ktzi 201 in Ketzin, Germany

Enhancing Reservoir Productivity in Carbonate Formations Propped vs Acid Fracturing Strategies at Lekhwair Area

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