Dispersion Of Oil In Water Research Articles

Incorporation, distribution and fate of saturated petroleum hydrocarbons in sediments from a controlled marine ecosystem

A simulation of a chronic input of petroleum into an estuarine environment was investigated using the facilities at the Marine Ecosystems Research Laboratory at the University of Rhode Island. An oil-water dispersion of No. 2 fuel oil was added to the system (twice weekly for 24 weeks) and the saturated hydrocarbons from this oil were measured in suspended material and sediments. After the initial chronic oil addition, trace amounts of hydrocarbons were detected in the sediments within two weeks, but substantial accumulation was not detected for approximately 135 days. The oil appeared to enter the sediment via the suspended material, with most of the saturated hydrocarbons associated with smaller size sediment particles (< 45 μm to > 0·3 μm). With time, the fuel oil saturated hydrocarbons in the sediments were mixed to a depth of 3 to 4 cm. Although only 12% of the total saturated hydrocarbons added to the system were found in the sediments, these hydrocarbons appear to be relatively stable and were still detectable in these sediments for at least six months after the last oil addition.

On the structure of transparent water and oil dispersions stabilized by polymeric emulsifiers

An investigation has been made of transparent oil-water dispersions stabilized by amphiphilic polymeric substances. The samples are well-defined polyethylene oxide — polystyrene graft copolymers with various lengths of backbone and side chains. The domain for existence of microemulsions and the phase diagrams were determined turbidimetrically by titration with 2-propanol for water/toluene/graft copolymer systems. Results are generalized to several amphilic copolymers of different chemical structure using various polar oils. A behavior markedly different is observed depending on whether soaps or copolymers are used for these systems. In particular, polymeric microemulsions form only when there is a mutual solubility for the ternary solvent mixture. A simple model is proposed, based on particles which consist of two concentric spheres having a PS part solvated by toluene and a PEO part by water, the continuous medium being composed of the ternary solvent mixture at mutual solubility. The size of the particles was determined by light scattering spectroscopy.

ROLE OF GEOMICROBIOLOGY IN ENHANCED RECOVERY OF OIL: STATUS QUO

The forthcoming decrease in availability of known, presently economical deposits of crude oil in the foreseeable future, makes it imperative that the search for new oil deposits be intensified and the present methods of oil recovery be improved or new ones introduced. From the work reported in the literature it is obvious that microbiology may play a significant role in both cases. Among many parameters influencing oil recovery, viscosity of the oil and the surface tension between the rock, oil and water are of great importance. Microorganisms growing in the reservoir produce gases and surfactants, which may, to some extent, regenerate the endogenous energy of the reservoir and facilitate movement of the crude oil to the well. The composition of the crude oil may become altered by biodegradation of asphaltic, napthenic and/or paraffinic components of the oil. The fraction being biodegraded varies according to the microbiological population present. In general terms mixed populations are more effective in biodegradative processes and production of surfactants. A combination of sewage microorganisms and reservoir microorganisms adapted to 95°C and high pressure, was found satisfactory. Molasses is a suitable supplementary substrate for the growth of such a mixed population. A decrease of viscosity of oil, resulting from biological degradation, may be a composite effect of degradation of highly polymerised hydrocarbons, precipitation of asphaltenes and solution of biologically produced gases in the oil. Such biogenic gases dissolved in the reservoir water may, in combination with biologically produced acids, contribute to the slow solution of the sedimentary rock, thus increasing the rock's permeability and facilitating migration of the oil through the reservoir.The biological activity in the reservoir is influenced by a number of parameters (pH, Eh, temperature, pressure, oil-water dispersion, mineralisation). The permeability of the reservoir rock is of primary importance. Rocks of permeability less than 150 md are not suitable for biologically enhanced recovery. Field tests indicate that biological activity in a reservoir may result in a drop of 50 per cent in the oil viscosity, a three-fold increase of oil production over several months, increase in water acidity and additional production of gas with a recorded pressure increase from 2 atm to 27 atm. The area affected by the biological activity depends on the mineralogy and permeability of the reservoir rock, sandstone and limestone of permeability higher than 600 md being most suitable.Further properly controlled and documented laboratory and field experiments are urgently required before the feasibility of microbiologically enhanced oil recovery can be firmly established.

Fracturing With a High-Viscosity, Cross-Linked GelContinuous Fracturing Technique

Introduction Highly viscous fracturing fluids that could be pumped at relatively high rates with acceptable friction pressure were first introduced 18 years ago. This viscous fluids were oil-water dispersions that created some problems because they required special mixing and pumping techniques. The fluids did, however, prove their value by creating wide, deeply penetrating fractures and by carrying high concentrations of propping agents. Since then, other high viscosity fluids have been introduced and their properties and effectiveness reported. Such fluids now properties and effectiveness reported. Such fluids now are used commonly in all areas. Because there is some variation in fluid requirements of different areas and formations, several types of fluids have evolved. All can be classed as viscous fracturing fluids. While these fluids have been used successfully, most have the same primary disadvantage: they must be batched mixed before use. Batch mixing requires that all water gelling agents be premixed in fracturing tanks before pumping. Often this premixed in fracturing tanks before pumping. Often this leads to additional rig-time expense for the operator and additional rig-time expense for the operator and additional equipment time and man hours for the service company. Also, if the procedure is not completed as planned, there can be considerable expense in preparation planned, there can be considerable expense in preparation of fluid that is not used. These expenses can become prohibitively high on large jobs, such as the prohibitively high on large jobs, such as the "massive-fracturing" type treatment. To overcome the disadvantages of batch mixing, specially prepared materials for gelling water have been developed that can be mixed continuously as the fluid is pumped down hole. These materials, first prepared from guar gum polymers, have been in use for 3 years and have proved polymers, have been in use for 3 years and have proved highly successful. More recently, lower residue guar derivatives have been used successfully. Cross-Linked Guar Gels Very high viscosities can be achieved by cross-linking the guar gels. However, preparation of cross-linked guar gels at the well location on a large volume basis has been troublesome and time consuming in the past because of the required batch-mixing technique. That is, the guar gelling agent and cross-linker are premixed in the fracturing water. Adjustments of the fluid's pH are often necessary and present problems in achieving a uniform pH in large fracturing tanks. The guar gelling agent hydrates and produces a high-viscosity solution. JPT P. 119

Larvicidal activities of N, N'-dialkylalkylenediamines and other fatty diamines in oil films and water dispersions.

Symmetrically disubstituted fatty diamines were synthesized by the reaction of alkyl bromides, H3C-(CH2)7-11-Br, with alkylenediamines, H2N-(CH2)2-6-NH2 or 1,3-diamino-2-propanol. Various formulations of these compounds and commercial compounds were tested against 4th-stage larvae of mosquitoes. In each series of homologues tested activity generally reached a peak with the N, N' -didecyl homologue and diminished as the alkyl chains were lengthened or shortened. The 48-hr LD50 values for Anopheles albimanus Weidemann, Culex pipiens quinquefasciatus Say, and Aedes aegypti (L.) were 0.1, 0.14, and 0.31 ppm when 1.9, 2.5, and 5.6 µl, respectively, of Richfield Larvicide oil containing 5.5% N.N' -didecylputrescine and 4% oleic acid were applied to the 0.5ft2 surface of 1 liter of water containing larvae, The oil plus oleic acid control gave LD50 values of 34, 26, and 34 µl, respectively. The dialkyldiamines showed high activity when dispersed in water by a procedure involving heating and shaking to provide, on cooling, floating needles or fibers of minute size. Against A. albimanus and C. p. quinquejasciatus, best results were obtained with a dispersion of N, N' -didecylputreseine which gave 48-hr LC50 values of 0.041 and 0.014 ppm, respectively, 22 and 35 times that given by Abate® O, O' -(thiodi- p -phenylene) O, O, O', O' -tetramethyl phosphorothioate dispersed in water. Against A. aegypti N, N' -dinonylpropylenediamine was most effective and gave an LC50 of 0.05 ppm, 28 times that given by Abate.

Structure of Water in Microemulsions: Electrical, Birefringence, and Nuclear Magnetic Resonance Studies

Microemulsions, which are optically transparent oil-water dispersions, were produced by mixing hexadecane, hexanol, potassium oleate, and water. As the amount of water is increased, the microemulsion exhibits a clear to turbid to clear transition. In contrast to the clear regions, the turbid region possesses birefringence. The development of birefringence is also accompanied by a sharp decrease in the electrical resistance. The high-resolution (220 megacycle) nuclear magnetic resonance data suggest that water exists in two distinct molecular environments in the birefringent region; the first environment is characterized by relatively less mobile water molecules than oil molecules, whereas in the second environment oil molecules are less mobile than water molecules. The electrical, birefringence, and nuclear magnetic resonance data are in agreement with the proposed mechanism of change in the structure of water from water spheres to water cylinders to water lamellae. The chemical shift of water protons suggests that the molecular environment of water in spheres is different from that of water in cylinders or that of water in lamellae.