Layered petroleum reservoirs with cross-flows

Studied is a cylindrical reservoir consisting of three layers: a water-containing bottom layer, and two oil-containing top layers from whose upper layer oil is produced. For its solution, a corrected version of the finite Hankel transform for Neumann-Neumann boundary conditions was used together with numerical inversion of the Laplace transform. The effects of the water zone on the unsteady state pressure in the reservoir were evaluated at distances away from the well and at the well-bore itself. We found that the vertical pressure drop increases gradually with time and is more significant in the vicinity of the well-bore. For constant production and at any time t, smaller reservoirs experience higher pressure drops than larger ones. For the reservoir investigated, we found that for nondimensional time t _Dw <10⁴ the presence of a second fluid (water) has no effect on the pressure drop. Of all the formation and fluid properties investigated, porosity has the largest effect on pressure.Nomenclature c ₁, c ₂ Oil and water compressibilities, vol/vol/atm, vol/vol/psi - h Height of water zone from bottom of reservoir, cm, ft - h _D h/r _w , non-dimensional - H Height of reservoir, cm, ft - H _D H/r _w, non-dimensional - J ₀, J ₁ Bessel functions of the first kind, zero and first-order - K _r2, K _r1 Oil and water zones, horizontal permeabilities, darcies, md - K _z2, K _z1 Oil and water zones, vertical permeabilities, darcies, md - k ₁ n=1, 2, 3... - k ₂ n=1, 2, 3... - k _1,0 - k _2,0 - p(r, z, t) P(r, z, 0)–P(r, z, t), atm, psi - P(r, z, t) Pressure at any layer in the reservoir, atm, psi - P(r, z, 0) Initial pressure at any layer in the reservoir, atm, psi - P _D , non-dimensional - q Constant production rate of well, cc/sec, barrels/day - r Radius of reservoir, cm, ft - r _D r/r _w , non-dimensional - r _e Drainage radius, cm, ft - r _eD re/r _w , non-dimensional - r _w Well-bore radius, cm, ft - t Time, sec, hr - _Dw (k _r2 t)/( _{2 2} c ₂ r _w ² ), non-dimensional - Y ₀, Y ₁ Bessel functions of the second kind, zero and first-order - z Distance z measured vertically upward from bottom of reservoir, cm, ft - Z _D z/r _w , non-dimensional - z ₁ Height of the bottom of the producing layer, cm, ft - z _1D z ₁/r _w , non-dimensional - z ₂ Height of the top of the producing layer, cm, ft - z _2,D z ₂/r _w , non-dimensional - _n nth positive root of equation (18) - ₁ k _z1/k _r1, non-dimensional - ₂ k _z2/k _r2, non-dimensional - _{1 1 1} c ₁/k _r1, hydraulic diffusivity of layer I - _{2 2 2} c ₂/k _r2, hydraulic diffusivity of layers II and III - ₂, ₁ Viscosity of oil and water, cp, cp - _{n n} /r _w , l/cm, l/ft - ₂, ₁ Porosity of oil and water-filled zones, fraction - ( ₁/ ₂) (k _z2/k _z1), non-dimensional     

A sequential injection spectrophotometric method for the determination of penicillamine in pharmaceutical products by complexation with iron(III) in acidic media

A simple, robust and sensitive sequential injection spectrophotometric method for the assay of penicillamine (PA) in pharmaceutical formulations is developed. The method was based on the complex formation when PA is reacted with iron(III) solution in hydrochloric acid media. The deep blue colored PA-iron(III) complex produced is monitored at a maximum wavelength of 600 nm. A five level orthogonal array design coupled to genetic algorithm was employed to obtain the optimum experimental conditions for the determination of PA using peak absorbance as the measure of the system's performance criterion. A linear dynamic range for the determination of PA of 25-300 ppm was obtained with a sampling frequency of 50 h⁻¹ and a relative standard deviation of less than 0.98%. The method was successfully applied to the determination of PA in pharmaceutical formulations.     

A novel synthesis of organic diselenapolysulfides

A family of organic polychalcogenides with a common structure of RSeS_xSeR (with x=1, 2, 3 and R=CH₃, Ph, PhCH₂, O₂NC₆H₄CH₂) as well as cyclic 5,5-dimethyl-1,2-dithia-3,7-diselenacycloheptane were synthesized in good yield and high purity from the reaction of Ph₃CS_xCl with corresponding diselenides in chloroform at room temperature. Mechanistic aspects of the insertion involving the formation of an intermediate (RSeS_xCPh₃) are discussed.     

Reconstruction of physics objects at the Circular Electron Positron Collider with Arbor

After the Higgs discovery, precise measurements of the Higgs properties and the electroweak observables become vital for the experimental particle physics. A powerful Higgs/Z factory, the Circular Electron Positron Collider (CEPC) is proposed. The Particle Flow oriented detector design is proposed to the CEPC and a Particle Flow algorithm, Arbor is optimized accordingly. We summarize the physics object reconstruction performance of the Particle Flow oriented detector design with Arbor algorithm and conclude that this combination fulfills the physics requirement of CEPC.     

DOUBLESLICING: a non-iterative single profile multi-exponential curve resolution procedure. Application to time-domain NMR transverse relaxation data

A new non-iterative curve resolution technique for resolving single decay profiles is proposed. The new technique, called DoubleSlicing, is based on the Decra (Direct Exponential Curve Resolution Algorithm) principle. While the original Decra was designed to resolve several decay curves simultaneously and thus fitting common pure exponentials, DoubleSlicing can resolve single decay profiles by a simple double data transformation followed by an analytical and unique three-way decomposition. The new approach is successfully demonstrated on experimental NMR CPMG relaxation data, measured on combinations of unmixed paramagnetic CuSO(4) solutions. Decay signals of the water component were acquired following an innovative experimental design that ensured no interaction between the components present in each sample under observation. DoubleSlicing proved to be accurate in estimating relaxation times differing in one order of magnitude (range: 19.6-159.4ms). Its performance was comparable to discrete exponential fitting with the advantage of being much faster - in terms of computation time, DoubleSlicing outperformed exponential fitting by a factor of four.     

Pressure dependence of the electrical resistivity and the ionization energy of Cr In n-type InP

The electrical resistance of chromium-doped, n-type InP has been found to increase exponentially with hydrostatic pressure (up to 4.7 kbar) at 273 K, 301 K, and 344 K. The resistivity activation energy increases by 6.5 × 10^-6 eV/bar. This rate equals the difference between the pressure dependences of the lowest conduction band minimum at $\text{k}$ = (000) and the <111> subsidiary minima determined by others. Our results indicate that pressure increases the ionization energy of a Cr donor level whose wave function has a large contribution from the <111> minima. It is suggested the Cr donor level is due to Cr⁺³ occupying an indium site.     

Energy Levels of Neutral Atoms Via a New Perturbation Method

The energy levels of neutral atoms supported by potential V (r) = -Zexp(-ar)/r (Yukawa potential) are studied, using both dimensional and dimensionless quantities, via a new analytical methodical proposal (devised to solve for nonexactly solvable Schrödinger equation). Using dimensionless quantities, by scaling the radial Hamiltonian through y = Zr and = /Z, we report that the scaled screening parameter is restricted to have values ranging from zero to less than 0.4. On the other hand, working with the scaled Hamiltonian enhances the accuracy and extremely speeds up the convergence of the energy eigenvalues. The energy levels of several new eligible scaled screening parameter values are also reported.     

Supply chain optimization of petroleum organization under uncertainty in market demands and prices

A multi-period stochastic planning model has been developed and implemented for a supply chain network of a petroleum organization operating in an oil producing country under uncertain market conditions. The proposed supply chain network consists of all activities related to crude oil production, processing and distribution. Uncertainties were introduced in market demands and prices. A deterministic optimization model was first developed and tested. The impact of uncertainty on the supply chain was studied by performing a sensitivity analysis in which ±20% deviations were introduced in market demands and prices of different commodities. A stochastic formulation was then proposed, which is based on the two-stage problem with finite number of realizations. The proposed stochastic programming approach proved to be quite effective in developing resilient production plans in light of high degree of uncertainty in market conditions. The anticipated production plans have a considerably lower expected value of perfect information (EVPI). The main conclusion of this study is that for an oil producing country with oil processing capabilities, the impact of economic uncertainties may be tolerated by an appropriate balance between crude exports and processing capacities.     

Determination of polyphenol component fractions and integral antioxidant capacity of Syrian aniseed and fennel seed extracts using GC–MS,HPLC analysis,and photochemiluminescence assay

The chemical components of both Syrian aniseed and fennel seeds collected from Idlib and Aleppo regions were identified using GC/MS spectrometry. Thirty-four component fractions representing an average of 98.5% of anise seed extract were characterized. The major average components were (E)-Anethole, Estragole, Limonene, Fenchone, Linalool, para-Anisaldehyde, (Z)-Anethole, and methyl chavicol. Also, thirty-one component fractions representing an average of 99.46% of fennel seed extract were identified. The major components were α-Pinene, α-Phellandrene, Fenchone, Methyl chavicol, Estragole, (Z)-Anethole, Limonene, 1,8-Cineole, Anisole-p-allyl, E,E-Farnesene, Estragole, (E)-Anethole, Anisaldehyde, and Carvacrol. The extract of aniseed was characterized by higher amounts of trans-anethole (52.2%) than fennel extract (38.3%). The integral antioxidant capacity (IAC) of two different extracts from both aniseed and fennel seeds have been determined using photochemiluminescence assay (PCL). The sum of antioxidant capacity (IAC) of hydrophilic and hydrophobic components in both aniseed and fennel seeds was determined, as a total equivalent per gram of dry material (nmolTE/gDM) at 166.69 ± 0.42 and 363.28 ± 1.11 nmol for hydrophilic and hydrophobic components, respectively. Eight major phenolic compounds known as possible antioxidant sources with their concentrations have been identified in both aniseed and fennel seeds by HPLC and GC–MS analysis.