Sand production is one of the major problems in sandstone reservoirs. Different mechanical and chemical methods have been proposed to control sand production. In this paper, we propose a chemical method based on using...Sand production is one of the major problems in sandstone reservoirs. Different mechanical and chemical methods have been proposed to control sand production. In this paper, we propose a chemical method based on using polyacrylamide/chromium triacetate hydrogel to investigate sand production in a synthetic sandpack system. To this end, a series of bulk experiments including the bottle test and rheological analysis along with compression tests were conducted. Experimental results indicated that the compressive strength of the sandpack was increased as much as 30 times by injecting 0.5 pore volume of hydrogel. Also, it was found that the increases in cross-linker and polymer concentrations exhibited a positive impact on the compressive strength of the sandpack, mostly by cross-linker concentration(48 psi). Hydrogel with a higher value of cross-linker could retain its viscoelastic properties against the strain which was a maximum of 122% for 0.5 weight ratio of cross-linker/polymer. The presence of salts, in particular divalent cations, has a detrimental effect on the hydrogel stability. The maximum strain value applied on hydrogel in the presence of CaCl_2 was only about 201% as compared to 1010% in the presence of distilled water. Finally, thermogravimetric analysis and its derivative showed that the hydrogel could retain its structure up to 300 °C. The results of this study revealed the potential application of the hydrogel to control sand production.展开更多
S Steam injection is commonly used for production of viscous crude oil.Reservoir rock often contains clay minerals.Reactive nature of steam and clay minerals may lead to formation damage.This work in-vestigates oil re...S Steam injection is commonly used for production of viscous crude oil.Reservoir rock often contains clay minerals.Reactive nature of steam and clay minerals may lead to formation damage.This work in-vestigates oil recovery and changes in petrophysical properties as a function of the mineralogy.Sand-packs with quartz,calcite,feldspar,kaolinite,smectite,and illite were prepared for steam injection experiments.Permeability of the steamed sandpacks was determined using coreflood experiments.Chemical composition of the produced aqueous samples was determined using ICP-OES(inductively coupled plasma-optical emission spectroscopy).Morphology of the rock samples was studied using SEM-EDs(scanning electron microscope-energy dispersive X-ray spectroscopy).Mineralogy and elemental content of the solid samples were determined using XRD(X-ray diffraction)analysis and XRF(X-ray fluorescence)respectively.It was found that aqueous phase samples produced from clay-rich sandpacks tend to have higher pH than samples produced from samples without clay minerals.Oil recovery factors for 100%quartz case was determined to be 65 wt%.Calcite-and feldspar-rich sandpacks produced 56 and 61 wt%of oil respectively.Sandpacks with clay fractions have shown the lowest oil recovery-39,29,and 28 wt%for kaolinite-,smectite-,and illite-rich samples respectively.Mineral dissolution and pre-cipitation were the dominant damaging mechanism for quartz and calcite cases.Feldspar-rich sandpack demonstrated signs of structural destruction of the mineral and fines release.Kaolinite's effect on oil recovery was found to be associated with fines migration.Smectite hydration and swelling in presence of steam was the dominant formation damage effect on the oil production.Steam interaction with illite-rich sandpack caused formation of amorphous silica.This paper presents oil recovery factors as a function of injected pore volume(PV)of steam for sandpacks of different mineralogy.Obtained results characterize petrophysical changes caused by steam interaction with 展开更多
基金support of the Iran National Science Foundation(INSF)with Project No.of 95849122
文摘Sand production is one of the major problems in sandstone reservoirs. Different mechanical and chemical methods have been proposed to control sand production. In this paper, we propose a chemical method based on using polyacrylamide/chromium triacetate hydrogel to investigate sand production in a synthetic sandpack system. To this end, a series of bulk experiments including the bottle test and rheological analysis along with compression tests were conducted. Experimental results indicated that the compressive strength of the sandpack was increased as much as 30 times by injecting 0.5 pore volume of hydrogel. Also, it was found that the increases in cross-linker and polymer concentrations exhibited a positive impact on the compressive strength of the sandpack, mostly by cross-linker concentration(48 psi). Hydrogel with a higher value of cross-linker could retain its viscoelastic properties against the strain which was a maximum of 122% for 0.5 weight ratio of cross-linker/polymer. The presence of salts, in particular divalent cations, has a detrimental effect on the hydrogel stability. The maximum strain value applied on hydrogel in the presence of CaCl_2 was only about 201% as compared to 1010% in the presence of distilled water. Finally, thermogravimetric analysis and its derivative showed that the hydrogel could retain its structure up to 300 °C. The results of this study revealed the potential application of the hydrogel to control sand production.
文摘S Steam injection is commonly used for production of viscous crude oil.Reservoir rock often contains clay minerals.Reactive nature of steam and clay minerals may lead to formation damage.This work in-vestigates oil recovery and changes in petrophysical properties as a function of the mineralogy.Sand-packs with quartz,calcite,feldspar,kaolinite,smectite,and illite were prepared for steam injection experiments.Permeability of the steamed sandpacks was determined using coreflood experiments.Chemical composition of the produced aqueous samples was determined using ICP-OES(inductively coupled plasma-optical emission spectroscopy).Morphology of the rock samples was studied using SEM-EDs(scanning electron microscope-energy dispersive X-ray spectroscopy).Mineralogy and elemental content of the solid samples were determined using XRD(X-ray diffraction)analysis and XRF(X-ray fluorescence)respectively.It was found that aqueous phase samples produced from clay-rich sandpacks tend to have higher pH than samples produced from samples without clay minerals.Oil recovery factors for 100%quartz case was determined to be 65 wt%.Calcite-and feldspar-rich sandpacks produced 56 and 61 wt%of oil respectively.Sandpacks with clay fractions have shown the lowest oil recovery-39,29,and 28 wt%for kaolinite-,smectite-,and illite-rich samples respectively.Mineral dissolution and pre-cipitation were the dominant damaging mechanism for quartz and calcite cases.Feldspar-rich sandpack demonstrated signs of structural destruction of the mineral and fines release.Kaolinite's effect on oil recovery was found to be associated with fines migration.Smectite hydration and swelling in presence of steam was the dominant formation damage effect on the oil production.Steam interaction with illite-rich sandpack caused formation of amorphous silica.This paper presents oil recovery factors as a function of injected pore volume(PV)of steam for sandpacks of different mineralogy.Obtained results characterize petrophysical changes caused by steam interaction with
