Study for gravel slection and pack operation for oil production well on Song Doc oil field

Sand control by gravel packing is by far the most reliable and effective sand control method and is being used worldwide. One of the most important factor for successful operation is gravel size selection which is suitable with properties of well and particle size of sand from the reservoir, also the operation method needs to be considered during study. Due to the variety of different oilfield, the selections of gravel size and operation method are challenges for petroleum engineer and manager. Oil production wells in Song Doc oil field are producing in Miocene and Oligocene with very high rate of sand production; some of the wells were plugged by sand. Therefore, the study on the selections of gravel size and operation method is needed and important. In this study, theory analyzing was used in order to yield advantage and disadvantage of each gravel packing method and their operation. Based on the operating condition on Song Doc field and the availability of equipment on site, gravel packing method by thru-tubing with vent screen was selected. The coil tubing was chosen as the operation method. This is the best sand control method for the Song Doc oil field with low cost and high effectiveness sand control.

Effect of Tailings Fine Content on the Properties of Cemented Paste Backfill from the Perspective Packing Density

In order to quantitatively study the influence of tailings fine content on the properties of cemented paste backfill (CPB) and further understand the mechanism of tailings fine content acting, the concept of packing density was introduced in this study. The packing density of each tailings sample was measured by the wet packing method after the samples with various fine contents were prepared. Moreover, CPBs with different tailings fine contents were tested by the mini slump test, rheological test, uniaxial compressive strength (UCS) test, and mercury intrusion porosimetry test. The results demonstrated that the flow spread and UCS both increase first and then decrease with the increase of tailings fine content, while the yield stress shows an opposite trend. The fine content of tailings affects the flowability of fresh CPB mainly through the packing density. When the fine content is high, the influence of the specific surface area of tailings cannot be ignored. The packing density is an important factor affecting the strength of CPB, and there is an obvious linear relationship between the packing density and UCS. The pore structure of CPB samples with different tailing fine contents is significantly different, and the macroscopic packing density changes the strength of CPB by affecting the microscopic pores.

The Influence of Packing Methods and Storage Time of Poultry Sausages with Liquid and Microencapsulated Fish Oil Additives on Their Physicochemical, Microbial and Sensory Properties

The aim of the study was to evaluate the influence of refined fish oil additives in liquid and microencapsulated forms, packing method (VP—vacuum packing, MAP—modified atmosphere packing) and storage time (1, 7, 14, 21 days) on selected physicochemical, microbiological and sensory characteristics of minced poultry sausage. Principle component analysis (PCA) showed that the fish oil additive, packing method and storage time significantly influenced some of the physicochemical characteristics of the sausages. The pH value was negatively correlated with the type of sample and packing method. The water activity decreased along with the storage time. The sausages with microcapsules had distinguishable hardness, gumminess and chewiness than the other samples. This tendency increased in the subsequent storage periods. The packing method and storage time of the samples had a statistically significant influence on the growth of the total colony count and count of lactic acid bacteria (p < 0.05). The most aerobic bacteria were found in the control sample, and the least in the sample with microcapsules, regardless of the packing method. The use of MAP and the addition of microcapsules resulted in the lowest microbiological contamination of the sausages. The sensory analysis made by a trained panel did not show any significant differences between the samples. After 21-day storage of the sausages there was a slight decrease in some of the sensory parameters, e.g., color, smell, taste. The liquid oil and microencapsulated oil additives in the meat filling did not negatively affect the taste or any physicochemical characteristics of the meat products. From the microbiological perspective, there were better effects from the MAP method.

Efficient Private Conjunctive Query Protocol Over Encrypted Data

Conjunctive queries play a key role in retrieving data from a database. In a database, a query containing many conditions in its predicate, connected by an “and/&/∧” operator, is called a conjunctive query. Retrieving the outcome of a conjunctive query from thousands of records is a heavy computational task. Private data access to an outsourced database is required to keep the database secure from adversaries; thus, private conjunctive queries (PCQs) are indispensable. Cheon, Kim, and Kim (CKK) proposed a PCQ protocol using search-and-compute circuits in which they used somewhat homomorphic encryption (SwHE) for their protocol security. As their protocol is far from being able to be used practically, we propose a practical batch private conjunctive query (BPCQ) protocol by applying a batch technique for processing conjunctive queries over an outsourced database, in which both database and queries are encoded in binary format. As a main technique in our protocol, we develop a new data-packing method to pack many data into a single polynomial with the batch technique. We further enhance the performances of the binary-encoded BPCQ protocol by replacing the binary encoding with N-ary encoding. Finally, we compare the performance to assess the results obtained by the binary-encoded BPCQ protocol and the N-ary-encoded BPCQ protocol.

Analysis of physical properties of granular materials on their numerical models (2D case)

The paper describes a method for determining the density and specific surface of the package of rock particles represented by discs with the size corresponding to the size of the rock fragments of real dump massifs (2D case). The packing method of the particles corresponds to the schemes of dumping used in open-pit mining - areal and peripheral ones. The influence of boundaries, in which the dump is located, on the physical characteristics of this massif - density and porosity - is revealed. It was revealed that the way of formation of the bulk of particles affects its density, especially at the boundaries of the massif. The massif of particles formed in accordance with the area technology of dumping has a denser composition and is less affected by the effect of its boundaries than the massif formed in accordance with the peripheral technology of dumping. The applied method of determining the physical characteristics of the bulk medium differs from the statistical methods (e.g., Monte Carlo) and is well-proven for static media, such as dumps and filtering massifs in open-pit mining.

On some methods of researching the structural, physical and mechanical parameters of granular media as applied to the modeling of rock dumps

The physical properties of the artificial disjointed rock massifs (the filling massifs and arrays of collapsed rocks and dumps) formed during mining operations, are largely determined by the geometry of the structure of pore space and the mineral phase, i.e. particle size, shape and packing method. In this case, the conditions for the arrangement of the particles relative to each other (the distances between the centers of the particles, the orientation, the number of contacts, the angles between the segments connecting the particle centers, etc.) have a decisive influence on the macroscopic characteristics of the rock mass (specific surface, bulk density, load capacity, etc.) and the behavior of such media under the applied stresses. Thus, in order to manage the state of disjointed technogenic rock massifs of bedrock, the question of applying modern methods for modeling bulk media for determining these parameters is considered. The article provides an overview of methods for modeling granular media to determine their structural, physical and mechanical parameters.