Sorption and Fate of Phosphonate Scale Inhibitors in the Sandstone Reservoir: Studied by Laboratory Apparatus With Core Material

Kan, A.; Yan, L.; Bedient, P.B.; Oddo, J.E.; Tomson, M.B.

doi:10.2523/21714-ms

Cited by 6 publications

(3 citation statements)

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“…Indeed, the adsorption of phosphonates onto reservoir rocks is the desired result of well squeeze treatments with scale inhibitors [Kan et al, 1991: Jordan et al, 1994 mixed in the pores of the core. The phosphate scales form hard bone-like deposits, whereas the hydroxide forms gels in aqueous solutions.…”

Section: Discussionmentioning

confidence: 99%

Exposure to Phosphate-based Completion Brine Under HPHT Laboratory Conditions Causes Significant Gas Permeability Reduction in Sandstone Cores

Downs

2011

All Days

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High-density potassium phosphate and potassium/cesium formate brines were tested in an advanced core flood test rig for their compatibility with low-permeability sandstone containing simulated formation water under HPHT conditions. The tests were carried out at a temperature of 175 o C (347 o F) and pore pressure of 5,800 psi. Compatibility was determined by comparing the relative gas permeability of the cores before and after exposure to the brines under HPHT conditions.The 10-20mD sandstone core plugs, containing simulated North Sea HPHT gas reservoir water at residual water saturation, were flooded with 10 pore volumes of test brine and subsequently equilibrated with the brine for 48 hours to allow chemical interaction. Drawdown pressures of up to 100 psi were then created on the wellbore side of the core to create gas flow. Gas permeability was measured after flowing 4,000 ml (approx. 2,000 pore volumes) of humidified gas through the core.The results showed that flooding this core with the potassium phosphate brine reduced the gas permeability by more than 90%.By comparison, flooding with cesium formate brine created a modest improvement in the permeability of the core to gas.Examination by SEM of the core damaged by the phosphate brine showed that its pores were partially obstructed with a thick layer of scale. The scale was particularly plentiful in areas of the core where illite clays were present. The scale was examined in situ by EDS and found to contain potassium and phosphorus. It is known that phosphates in aqueous solution are strongly adsorbed onto mineral surfaces where they can form precipitates and complex insoluble salts from exposure to multivalent cations. Aqueous phosphate solutions are also known to react with clays to form solid precipitates. It is possible that the scale formed in the core as a result of interactions under hydrothermal conditions between the invading phosphate brine and, inter alia, the pore-lining illite clay deposits naturally present within the rock.The scale modeling software, DownHoleSAT, predicted a significant risk of various phosphate scales being formed as a result of mixing of the formation water and phosphate brine inside the core under the experimental conditions. Such scales may have contributed to the formation damage observed in the core flooded with the phosphate brine.

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Section: Discussionmentioning

confidence: 99%

Exposure to Phosphate-based Completion Brine Under HPHT Laboratory Conditions Causes Significant Gas Permeability Reduction in Sandstone Cores

Downs

2011

All Days

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“…[2][3][4][5][7][8][9][10][11][12] The precise form of the isotherm describing this adsorption process determines the squeeze lifetime, as is described in detail elsewhere. For phosphonates, it is known that adsorption is a function of pH, temperature, mineral substrate, and involves cations such as Ca 2 +.…”

Section: Introductionmentioning

confidence: 99%

Phosphonate Scale Inhibitor Adsorption/Desorption and the Potential for Formation Damage in Reconditioned Field Core

Jordan¹,

Sorbie²,

Jiang³

et al. 1994

Proceedings of SPE Formation Damage Control Symposium

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Scale inhibitor "squeeze" treatments are used extensively to control problems with downhole carbonate and sulphate scale formation. The return curve from an adsorption/desorption squeeze is governed by the inhibitor/rock interaction which, in tum, is described by the adsorption isotherm. Several factors, such as pH, [Ca 2 +], temperature, rock mineralogy etc, affect the adsorption level and the shape of the adsorption isotherm. However, these same factors may also lead to deleterious effects in terms of both formation damage and inhibitor solution effectiveness; the latter effect is referred to in this work as "fluid damage".In this paper, results and discussion are presented on the potential for formation damage and inhibitor fluid damage when acid phospho nates are applied in clastic reservoir formations. Results are presented from an extensive series of phospho nate (DETPMP) scale inhibitor core flooding experiments using Brent Group (North Sea) sandstone cores as the adsorbing substrate. Careful effluent analysis along with detailed petrography and permeability measurement before and after core flooding are shown to be invaluable in assessing the degree of formation damage (and "fluid damage") arising due to several factors. Most of the points raised here are quite general and they are illustrated by the specific field results. This work therefore contributes to the development of safer field applications of scale inhibitor squeeze treatments in the light of individual reservoir petrography.

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“…Sandstone is predominantly silica mineral that is negatively charged at neutral pH, but dolomite is a carbonaceous rock, rich in calcium and magnesium, with a net positive charge. 21 Both rock types are common in oil-rich environments. The materials used in this work were obtained from actual field samples.…”

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confidence: 99%

Engineered nanoparticles for hydrocarbon detection in oil-field rocks

Berlin

et al. 2011

Energy Environ. Sci.

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Sorption and Fate of Phosphonate Scale Inhibitors in the Sandstone Reservoir: Studied by Laboratory Apparatus With Core Material

Cited by 6 publications

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Exposure to Phosphate-based Completion Brine Under HPHT Laboratory Conditions Causes Significant Gas Permeability Reduction in Sandstone Cores

Exposure to Phosphate-based Completion Brine Under HPHT Laboratory Conditions Causes Significant Gas Permeability Reduction in Sandstone Cores

Phosphonate Scale Inhibitor Adsorption/Desorption and the Potential for Formation Damage in Reconditioned Field Core

Engineered nanoparticles for hydrocarbon detection in oil-field rocks

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