An investigation of the use of surface-active agents in the secondary recovery of oil by water flooding

The importance of producing oil cannot be emphasized enough in this modem world. Therefore, when primary methods of production seemingly exhaust the oil reservoirs, a secondary method of producing more oil is a necessity. At the present time, secondary methods of oil recovery have developed into a large industry. They are not a new development. The need of introducing compressed air or air-gas mixtures into the wells to increase production was quickly realized. Water flooding methods followed, and at first were restricted to the Eastern fields. Later, about 1935, systematic water flooding methods were developed and applied all over the country. The system of water flooding involves applying water under pressure to oil-bearing formations by means or injection wells, generally ringed around a production well. These formations are fine-grained, tightly-packed sands, which contain oil left in the formation after the primary method of\u27 production. The mechanics of the flooding involves the formation of an oil bank ahead of the advancing water and its removal through the production well. Water flooding at the present time is a very inefficient process, due to the fact that approximately 25 per cent of the oil is left in the formation after the flood. If this oil, or even a part of it, could be removed by a special kind of water drive it would greatly increase the income of the operator but also would reduce the amount of oil left in the formation which now is unobtainable by any present methods of production. The use of wetting agents or surface-active chemicals has been prominent among the methods which have been proposed to reduce the amount of residual oil by water flooding. It is theoretically possible to sweep more oil out of the sand by using surface-active chemicals to lower the surface tension of the water and the interfacial tension between the oil and water. This fact has been known for some time. The principal feature cited in argument against the use of wetting agents has been excessive adsorption onto the reservoir rock surface. The advancing water front of the flood, therefore, has been depleted of these agents before beneficial effects could be realized. The amount and cost of the chemicals required to permit an effective penetration of the reservoir has been entirely out of proportion to the value of the additional oil that might be obtained. However, almost all of the early experiments were conducted using cationic and anionic wetting agents. During the past few years non-ionic surface-active agents have become available at a low enough price to make their use in water flooding a practical matter. In laboratory tests these chemicals have shown a negligible tendency to become adsorbed by siliceous or clay minerals. From these results, it seems that the problem of excessive adsorption has been solved by the use of non-ionic wetting agents. Most investigators of this subject have agreed that not all reservoirs respond in the same manner to the same chemical. The reasons why a certain surface-active agent is very effective on one type of reservoir formation and only moderately so or not at all on a different reservoir formation are not known completely at the present time. Therefore, to establish the effectiveness of a certain surface-active chemical upon a particular reservoir, laboratory flooding tests as well as a pilot flood test should be carried out. The subject matter of this thesis is the experimental investigation of the effects which certain surface-active chemicals have upon the residual oil content after water flooding or cores taken from Shell-Saunders No. 1 Well, located in the Canary Field, Washington County, Oklahoma. All surface-active agents tested were of the nonionic water-soluble type. To the author\u27s knowledge, no such investigation has been made using these surface-active chemicals, nor have cores from this field been tested in this manner --Introduction, pages 1-3

Measurement of the Casimir Effect in the Cylinder-Sphere Geometry

The Casimir effect originates from the boundary effects on the quantum vacuum. The boundary modifies the allowed modes of zero-point, or virtual, photons. Current studies of the Casimir effect have taken place primarily between simple geometries such as the sphere-plate configuration. More complicated geometries will introduce modifications in the collective charge fluctuation anisotropy. In this work, we examine the Casimir force between a cylinder and a sphere in a UHV environment, examining the effects of the 1-D dimensionality of the cylinders. To reduce the ellipticity of the cylinders involved, we have used a glass optical fiber, coated with Au to provide a conductive surface. Co-location of the sphere and cylinder was achieved using a piezoelectric stage with a capacitive sensor controlled PID loop. To maintain cleanliness of the samples and minimize the effect of surface adsorbates, we utilize Ar ion bombardment and UV cleaning. We examine our results using the Proximity Force Approximation (PFA). The Casimir effect has broad implications for MEMS devices operating in the submicron regime

Mapping Sex Offender Addresses: The Utility of the Alaska Sex Offender Registry as a Research Data Base

The registration of sex offenders was part of a national effort to enhance public safety by permitting law enforcement officials to track the location of convicted sex offenders after their release. All fifty states have enacted legislation requiring persons convicted of various sex-related offenses to register with law enforcement agencies; many states also grant public access to all or a portion of their registries. This document reports on the Alaska Statistical Analysis Center's efforts to improve data accuracy in the Alaska Sex Offender Registry, maintained by the Alaska State Troopers, and to assess the registry's utility as a research tool.Bureau of Justice Statistics, Grant No. 1999-RU-RX-K006Background of the Project / Research Methodology / Results / Utility: Spatial Justice Research / APPENDICES / A. Alaska’s Sex Offender Registration Law / B. Establishment of a Central Registry of Sex Offenders in Alaska / C. Definitions of Offenses for which Convicted Persons Must Register as Sex Offenders in Alask

Pulvinar-Cortex Interactions in Vision and Attention

The ventro-lateral pulvinar is reciprocally connected with the visual areas of the ventral stream that are important for object recognition. To understand the mechanisms of attentive stimulus processing in this pulvinar-cortex loop, we investigated the interactions between the pulvinar, area V4, and IT cortex in a spatial-attention task. Sensory processing and the influence of attention in the pulvinar appeared to reflect its cortical inputs. However, pulvinar deactivation led to a reduction of attentional effects on firing rates and gamma synchrony in V4, a reduction of sensory-evoked responses and overall gamma coherence within V4, and severe behavioral deficits in the affected portion of the visual field. Conversely, pulvinar deactivation caused an increase in low-frequency cortical oscillations, often associated with inattention or sleep. Thus, cortical interactions with the ventro-lateral pulvinar are necessary for normal attention and sensory processing and for maintaining the cortex in an active state. The pulvinar is often proposed to modulate cortical processing with attention. Zhou et al. find that beyond any role in attention, the pulvinar input to cortex seems necessary to maintain the cortex in an active state.National Institutes of Health (U.S.) (Grant R01 EY017292

Lesslie Newbigin\u27s understanding of the Holy Spirit and the church in mission

https://place.asburyseminary.edu/ecommonsatsdissertations/2087/thumbnail.jp

Aggregate and emulsion properties of enzymatically-modified octenylsuccinylated waxy starches

Sorghum and maize waxy starches were hydrophobically modified with octenylsuccinic anhydride (OSA) and treated with enzymes before being used to emulsify β-carotene (beta,beta-carotene) and oil in water. Enzyme treatment with β-amylase resulted in emulsions that were broken (separated) earlier and suffered increased degradation of β-carotene, whereas treatment with pullulanase had little effect on emulsions. Combinations of surfactants with high and low hydrodynamic volume (V) indicated that there is a relationship between V and emulsion stability. Degree of branching (DB) had little direct influence on emulsions, though surfactants with the highest DB were poor emulsifiers due to their reduced molecular size. Results indicate that V and branch length (including linear components) are the primary influences on octenylsuccinylated starches forming stable emulsions, due to the increased steric hindrance from short amphiphilic branches, consistent with current understanding of electrosteric stabilization. The success of OSA-modified sorghum starch points to possible new products of interest in arid climates