Method For Determination Of Permeability Research Articles

Modification of Pulse Decay Method for Determination of Permeability of Crystalline Rocks

An improvement of the pulse decay method of rock permeability measurement is presented. The technique is based on fitting experimental data to analytical and numerical solutions of the filtration equations derived with regard to the variation of flowing gas properties with temperature and pressure. A special apparatus and software for the implementation of this method were developed. A single experiment in which gas is used as a flowing medium enables determining both the permeability of a sample to water and the Klinkenberg constant. The permeability measurements on the samples of different types of rock with various reservoir properties were carried out and demonstrated satisfactory accuracy and efficiency of the method. An effective method for anisotropic permeability measurement is proposed as a development of this technique.

СУЧАСНІ ПІДХОДИ ДО ВИЗНАЧЕННЯ ПРОНИКНОСТІ ПОРІД-КОЛЕКТОРІВ ЗА ДАНИМИ ГЕОФІЗИЧНИХ ДОСЛІДЖЕНЬ

Permeability of rock is its physical property that describes its ability to conduct fluids under the pressure gradient. This paper presents short description and analysis of methods for determination of permeability of oil and gas reservoirs. Permeability is a function of different parameters that leads to difficulties during its estimation. Investigations of the void space structure of rocks, their anisotropy etc.were carried out in order to take into account all factors that have an influence on the permeability. Reservoir conditions could also be modeled for that purpose. Methods for determination of permeability of rocks can be divided into three groups: methods based on the laboratory studies of rocks; methods based on the well logging data; and methods based on the correlations between different parameters of rocks. The first two groups include methods for steady and unsteady fluid flow. Methods for the unsteady flow are usually more precise and rapid, thus prospects of extension of methods for permeability determination are mostly connected with them. Each of the presented methods to determine permeability is characterized by some pros and cons. The most appropriate method for the specific experiment is always chosen according to conditions and requirements and expected results. Further author's investigations will be related to the creation of petrophysical models of permeability of oil and gas reservoir rocks, including reservoirs of complex structure.

Effect of O-acetylation of O antigen of Escherichia coli lipopolysaccharide on the nonspecific barrier function of the outer membrane

Comparison of the methods for determination of permeability of the outer membrane of Escherichia coli strain 4s and its mutants was carried out. The studied isogenic strains E. coli 4s were obtained by selection of spontaneous mutants according to their sensitivity to bacteriophages recognizing the surface O antigen of the outer membrane lipopolysaccharide as a primary receptor. The variants differed in the presence and (de)acetylation of the lipopolysaccharide O antigen. A peptide antibiotic polymyxin, plasmid DNA, and lysozyme were used as probes. The role of acetylation of the O antigen of the lipopolysaccaride of E. coli outer membrane in modification of its permeability (correlating with bacteriophage sensitivity of the cells) was confirmed. Kinetic analysis using lysozyme was shown to be the optimal method for determination of the barrier function of E. coli outer membrane.