Evaluation of Alkali-Surfactant Effectiveness by Single Well Test Pilot in a Malaysian Offshore Field Environment

Manap, Arif Azhan Abdul; Chong, Mizan Omar; Sai, Rithauddin M.; Zainal, Suzalina; Yahaya, Abdul Wafi; Othman, Mohamad

doi:10.2118/144150-ms

Cited by 17 publications

(2 citation statements)

References 11 publications

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“…Even with expansion of the waterflood to multiple inverted nine-spots, the reservoir had only produced 6.5% original oil in place by 2013 (Khan et al 2014). Effective well spacing in the waterflood is relatively large: approximately 250 acres (Al-Ajmi et al 2007 Description of Traditional One-Spot ASP Pilots in SAMA Four one-spot ASP pilots were conducted in SAMA. The first three occurred in Wells A, B, and C and used traditional SWTT design.…”

Section: Sama Reservoir and Historymentioning

confidence: 99%

“…Reactive, partitioning SWTTs are used to measure the saturation of an immobile phase (oil, water, or gas) near a wellbore Carlisle, 1986, 2007;Hernandez et al 2002;Jerauld et al 2010;Abdul Manap et al 2011;Carlisle et al 2014). To measure the ROS to water (S orw ) with an SWTT, a large volume of water must first be injected into a producing well until oil in the investigated region is immobile.…”

Section: Introductionmentioning

confidence: 99%

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Design and Demonstration of New Single-Well Tracer Test for Viscous Chemical Enhanced-Oil-Recovery Fluids

et al. 2016

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Single-well-partitioning-tracer tests (SWTTs) are used to measure the saturation of oil or water near a wellbore. If used before and after injection of enhanced-oil-recovery (EOR) fluids, they can evaluate EOR flood performance in a so-called one-spot pilot. Four alkaline/surfactant/polymer (ASP) one-spot pilots were recently completed in Kuwait's Sabriyah-Mauddud (SAMA) reservoir, a thick, heterogeneous carbonate operated by Kuwait Oil Company (KOC). UTCHEM (Delshad et al. 2013), the University of Texas chemical-flooding reservoir simulator, was used to interpret results of two of these one-spot pilots performed in an unconfined zone within the thick SAMA formation. These simulations were used to design a new method for injecting partitioning tracers for one-spot pilots. The recommended practice is to inject the tracers into a relatively uniform confined zone, but, as seen in this work, that is not always possible, so an alternative design was needed to improve the accuracy of the test.The simulations showed that there was a flow-conformance problem when the partitioning tracers were injected into a perforated zone without confinement after the viscous ASP and polymer-drive solutions. The water-conveyed-tracer solutions were being partially diverted outside of the ASP-swept zone where they contacted unswept oil. Because of this problem, the initial interpretation of the performance of the chemicals was pessimistic, overestimating the chemical residual oil saturation (ROS) by up to 12 saturation units. Additional simulations indicated that the oil saturation in the ASP-swept zone could be properly estimated by avoiding the post-ASP waterflood and injecting the post-ASP tracers in a viscous polymer solution rather than in water. An ASP one-spot pilot using the new SWTT design resulted in an estimated ROS of only 0.06 after injection of chemicals (Carlisle et al. 2014). These saturation values were obtained by history matching tracer-production data by use of both traditional continuously-stirred-tank (CSTR) models and compositional, reactivetransport reservoir models.The ability of the simulator to model every phase of the onespot pilot operation was crucial to the insight of modified SWTT design. The waterflood, first SWTT, ASP flood, and the final SWTT were simulated using a heterogeneous permeability field representative of the Mauddud formation. Laboratory data, field-ASP quality-control information, and injection strategy were all accounted for in these simulations. We describe the models, how they were used, and how the results were used to modify the SWTT design. We further discuss the implications for other SWTTs.The advantage of mechanistic simulation of multiple aspects of a one-spot pilot is an important theme of this study. Because the pore space investigated by the SWTTs can be affected by the previously injected EOR fluids (and vice versa), these interactions should be accounted for. This simulation approach can be used to identify and mitigate design problems during each phase of a challenging one-s...

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Section: Sama Reservoir and Historymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design and Demonstration of New Single-Well Tracer Test for Viscous Chemical Enhanced-Oil-Recovery Fluids

et al. 2016

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ASP Process and Field Results

Chang

2013

Enhanced Oil Recovery Field Case Studies

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Design of a Surfactant/Polymer Process in a Hard Brine Context: A Case Study Applied to Bramberge Reservoir

et al. 2012

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Bramberge reservoir is a low temperature (40°C), high permeability (∼1 Darcy) sandstone reservoir located in Germany. Waterflooded during several decades, oil production has been declining for the past few years. These conditions make this reservoir a good candidate for surfactant-polymer flooding. Despite favourable attributes, the use of production brine, which exhibits very high hardness, as a re-injection fluid makes this project challenging and unique. In this paper, we illustrate how this specific hurdle can be managed using a new strategy specifically developed for hard brines. We show that surfactant/polymer formulations can be optimized in Bramberge re-injection brine despite its hardness with adequate properties for SP flooding (ultra-low interfacial tension and good solubility). The high level of divalent ions, and especially calcium ions, makes alkalis irrelevant for this project. We demonstrate using coreflood experiments that conventional injection strategies, successfully applied in soft brines (salinity gradient, etc…), and brine management options fail in these specific conditions because of the high chemicals adsorption. This high adsorption is showed to be strongly related to divalent ions. We finally propose a successful alternative based on a careful selection of adsorption inhibitors. Using these additives, high oil recovery (94 %OOIP) was obtained together with low anionic surfactant and polymer adsorption. The overall technical performance is in line with conventional alkali-surfactant-polymer strategy in soft brine making this project very attractive and promising. The process is currently in an optimization phase for pilot and field scale simulations allowing technical and economical optimization.

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Evaluation of Alkali-Surfactant Effectiveness by Single Well Test Pilot in a Malaysian Offshore Field Environment

Cited by 17 publications

References 11 publications

Design and Demonstration of New Single-Well Tracer Test for Viscous Chemical Enhanced-Oil-Recovery Fluids

Design and Demonstration of New Single-Well Tracer Test for Viscous Chemical Enhanced-Oil-Recovery Fluids

ASP Process and Field Results

Design of a Surfactant/Polymer Process in a Hard Brine Context: A Case Study Applied to Bramberge Reservoir

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