Offshore EOR Implementation – LPS Flooding

Skauge, Tormod; Djurhuus, Ketil; Hetland, S.; Spildo, Kristine; Skauge, Arne

doi:10.3997/2214-4609.201404784

Cited by 5 publications

(11 citation statements)

References 8 publications

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“…The LPS system exhibits good injectivity as demonstrated in filter tests and core floods, and the crosslinking reaction took place within a few hours (Skauge et al, 2011).…”

Section: Polymer Qualificationmentioning

confidence: 93%

“…These solutions referred to as either linked polymer solutions (LPS) or colloidal dispersion gels (CDG) contain nano-sized particles of cross-linked polymers (Skauge et al, 2010), which can induce increased microscopic sweep efficiency and thereby improved oil recovery (Skauge et al, 2011). Both polymer injection, as well as LPS/CDG injection are considered possible EOR measures on the Heidrun field and both systems were tested separately in the offshore injection test.…”

Section: Polymer and Lps Flood Conceptsmentioning

confidence: 99%

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Offshore Polymer/LPS Injectivity Test with Focus on Operational Feasibility and Near Wellbore Response in a Heidrun Injector

Selle

Fischer

Standnes

et al. 2013

SPE Annual Technical Conference and Exhibition

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Increased oil recovery technologies are very important for the large Heidrun field located in the Norwegian Sea. Very harsh climate and stringent environmental regulations render enhanced oil recovery (EOR) projects challenging. One EOR method evaluated for the field is polymer/LPS (Linked Polymer Solution) with the objective to improve the reservoir sweep. An offshore polymer and LPS injectivity test was performed with the objectives to determine the logistical and operational feasibility of handling polymers and to observe the near wellbore response during polymer and LPS injection.Prior to the offshore test, laboratory work was performed to qualify a polymer and a LPS system. A yard test was conducted to test necessary instrumentation and mixing/pumping equipment in preparation for the offshore test. The operation was performed by mixing a 5000 ppm polyacrylamide mother solution onshore, which was then shipped and stored offshore in completion tanks on the platform. The polymer mother solution was then injected downstream the choke on the injection well at a final polymer concentration of 300 ppm and 600 ppm, respectively. The test was done with a stepwise rate increase to switch from matrix to fracture injection. Aluminum citrate (AlCit) cross-linker was added at 300:10 and 600:20 polymer-tocross-linker ratio.A comprehensive sampling and analysis program was performed both onshore and offshore to secure high-quality polymer solution throughout the logistical chain. High-pressure sampling equipment was constructed to sample polymerized injection water at the wellhead. Furthermore, high-quality injection data was obtained through installation of a bottomhole memory gauge into the injector prior to the test.The main results from the offshore test proved the feasibility of storing, mixing, transport and injection of polymer solutions without contamination or unwanted shear degradation of the polymer. Good mixing was obtained by feeding the polymer mother solution into the injection stream. Polymer sampling at the wellhead showed good polymer quality based on viscosity and filter ratio results. Well injectivity improved under polymer/LPS injection compared to water injection due to the opening of existing fractures at lower injection rates.

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“…The LPS system exhibits good injectivity as demonstrated in filter tests and core floods, and the crosslinking reaction took place within a few hours (Skauge et al, 2011).…”

Section: Polymer Qualificationmentioning

confidence: 93%

Section: Polymer and Lps Flood Conceptsmentioning

confidence: 99%

Offshore Polymer/LPS Injectivity Test with Focus on Operational Feasibility and Near Wellbore Response in a Heidrun Injector

Selle

Fischer

Standnes

et al. 2013

SPE Annual Technical Conference and Exhibition

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“…Their use has been proposed for stabilization of CO 2 -foams, as nanofluids for wettability change, , as nanosensors for well applications, , and as flooding agents . We have studied nanoparticles in the form of cross-linked polyacrylamide polymers − and well-defined silica particles . The polymer particle system has been called Linked Polymer Solution (LPS) and applied as a flooding agent in onshore fields in China .…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles for Enhanced Oil Recovery: Influence of pH on Aluminum-Cross-linked Partially Hydrolyzed Polyacrylamide-Investigation by Rheology and NMR

et al. 2014

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New methods are continuously being evaluated for Enhanced Oil Recovery (EOR). Nanoparticle flooding is an intriguing new approach in which one of the main applications is microscopic diversion. Linked polymer solution (LPS) is a nanoparticle system that consists of partially hydrolyzed polyacrylamide (HPAM) cross-linked by aluminum(III). The source of aluminum is an aluminum citrate (AlCit) complex, where citrate serves as a carrier ligand. The large size and flexibility of HPAM as well as the multicomponent species of AlCit present at most relevant reservoir conditions make the system highly complex and challenging to characterize. In the literature, there is a lack of systematic and consistent data describing the various chemical species involved in LPS. This work used nuclear magnetic resonance (NMR) spectroscopy and dynamic rheology to investigate the reaction between HPAM and Al 3+ as a function of solution pH. The results of NMR spectra indicate that AlCit is more reactive at near neutral pH and cross-linking reactions should preferably be performed at this condition. Structural conformation and viscoelastic properties of the HPAM-Al complex appear to be dominated by the protonation−deprotonation state of the carboxylic acid groups as result of pH changes.

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“…17 However, LPS is different with regard to the method of preparation and purpose of application. 18 In fact, LPS has been implemented successfully on onshore fields in China. 19−22 Furthermore, laboratory core floods under offshore condition have shown an increase in oil recovery on the order of 19− 61%.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Systems similar to LPS have been investigated using a high molecular weight and a high concentration of HPAM and AlCit, which is known as colloidal dispersion gels (CDGs) . However, LPS is different with regard to the method of preparation and purpose of application . In fact, LPS has been implemented successfully on onshore fields in China. − Furthermore, laboratory core floods under offshore condition have shown an increase in oil recovery on the order of 19–61% .…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles for Enhanced Oil Recovery: Phase Transition of Aluminum-Cross-Linked Partially Hydrolyzed Polyacrylamide under Low-Salinity Conditions by Rheology and Nuclear Magnetic Resonance

et al. 2014

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There is booming interest in the application of nanoparticles for enhanced oil recovery. In this work, a polymer nanoparticle that is generated by cross-linking a high-molecular weight partially hydrolyzed polyacrylamide with aluminum(III) and known as linked polymer solution (LPS) has been studied. The size and conformational state of LPS particles are influenced by the concentration of Al(III). To the best our knowledge, there is no current established method for determining the conformational state, i.e., single coiled particle, coil aggregates, or gel, for a polymer solution with a high molecular weight (>10 × 106 Da) and a low concentration (<1000 ppm). In this work, therefore, the phase transition of LPS is investigated by employing two-dimensional 1H–1H nuclear magnetic resonance (nuclear Overhauser effect spectroscopy and diffusion ordered spectroscopy), UV–visible spectroscopy, and oscillatory rheological methods. Each method is limited to determining the conformational state; however, the combined methods provided a consistent tool for mapping various interactions regarding the conformational changes of LPS as a function of Al(III) concentration. The results of our study revealed that the phase transition is a stepwise process; the transition from a random polymer coil to structured coils (intramolecular cross-linking) was observed by reduction of the hydrodynamic radius and an increase in the rate of diffusion, followed by coil aggregates as a function of Al3+ concentration. Ultimately, networked weak gels are formed by coil aggregates (intermolecular cross-linking) above the threshold concentration.

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Offshore EOR Implementation – LPS Flooding

Cited by 5 publications

References 8 publications

Offshore Polymer/LPS Injectivity Test with Focus on Operational Feasibility and Near Wellbore Response in a Heidrun Injector

Offshore Polymer/LPS Injectivity Test with Focus on Operational Feasibility and Near Wellbore Response in a Heidrun Injector

Nanoparticles for Enhanced Oil Recovery: Influence of pH on Aluminum-Cross-linked Partially Hydrolyzed Polyacrylamide-Investigation by Rheology and NMR

Nanoparticles for Enhanced Oil Recovery: Phase Transition of Aluminum-Cross-Linked Partially Hydrolyzed Polyacrylamide under Low-Salinity Conditions by Rheology and Nuclear Magnetic Resonance

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