Влияние неустановившегося режима эксплуатации на снижение коэффициента продуктивности скважин с трещинами гидроразрыва пласта

В данной выпускной квалификационной работе было исследовано влияние неустановившегося режима течения на количественное снижение коэффициента продуктивности скважин с гидроразрывом пласта. Анализ, проводимый в рамках данной работы показал, что длительность выхода на установившийся режим может достигать несколько месяцев, в течение которых продуктивность скважин с трещинами ГРП может снижаться более чем в два раза. В ходе выполнения проекта была подобрана аналитическая модель расчета снижения коэффициента продуктивности, основанная на геометрии трещины, которая имеет меньшую погрешность по сравнению с существующей формой расчета технологических показателей ГТМ и может использоваться на практике для прогнозирования геолого-технических мероприятий.In this work the estimation of productivity index decline was made. The analysis showed that the duration of transient period may last for a few months. During this period productivity index decline may be very significant. According to calculations, developed method has shown good matching between estimated and actual productivity index values. As it was estimated, this algorithm allows making prediction and forecasting of well behavior and accurate business planning

The partial equilibration of garnet porphyroblasts in pelitic schists and its control on prograde metamorphism, Glen Roy, Scotland

Garnet porphyroblasts in sillimanite-bearing pelitic schists contain complex textural and compositional zoning, with considerable variation both within and between adjacent samples. The sillimanite-bearing schists locally occur in regional Barrovian garnet zone assemblages and are indicative of a persistent lack of equilibrium during prograde metamorphism. Garnet in these Dalradian rocks from the Scottish Highlands preserves evidence of a range of metamorphic responses including initial growth and patchy coupled dissolution- reprecipitation followed by partial dissolution. Individual porphyroblasts each have a unique and variable response to prograde metamorphism and garnet with mainly flat compositional profiles co-exists with those containing largely unmodified characteristic bell-shaped Mn-profiles. This highlights the need for caution in applying traditional interpretations of effective volume diffusion eliminating compositional variation. Cloudy garnet with abundant fluid inclusions is produced during incomplete modification of the initial porphyroblasts and these porous garnet are then particularly prone to partial replacement in sillimanite-producing reactions. The modification of garnet via a dissolution-reprecipitation process releases Ca into the effective whole rock composition, displacing the pressure-temperature positions of subsequent isograd reactions. This represents the first report of internal metasomatism controlling reaction pathways. The behaviour of garnet highlights the importance of kinetic factors, especially deformation and fluids, in controlling reaction progress and how the resulting variability influences subsequent prograde history. The lack of a consistent metamorphic response, within and between adjacent schists, suggests that on both local and regional scales these rocks have largely not equilibrated at peak metamorphic conditions

Fe-Mg interdiffusion rates in clinopyroxene: Experimental data and implications for Fe-Mg exchange geothermometers

Chemical interdiffusion of Fe-Mg along the c-axis [001] in natural diopside crystals (XDi = 0.93) was experimentally studied at ambient pressure, at temperatures ranging from 800 to 1,200 °C and oxygen fugacities from 10-11 to 10-17 bar. Diffusion couples were prepared by ablating an olivine (XFo = 0.3) target to deposit a thin film (20-100 nm) onto a polished surface of a natural, oriented diopside crystal using the pulsed laser deposition technique. After diffusion anneals, compositional depth profiles at the near surface region (~400 nm) were measured using Rutherford backscattering spectroscopy. In the experimental temperature and compositional range, no strong dependence of DFe-Mg on composition of clinopyroxene (Fe/Mg ratio between Di93-Di65) or oxygen fugacity could be detected within the resolution of the study. The lack of fO2-dependence may be related to the relatively high Al content of the crystals used in this study. Diffusion coefficients, DFe-Mg, can be described by a single Arrhenius relation with (Formula presented). DFe-Mg in clinopyroxene appears to be faster than diffusion involving Ca-species (e.g., DCa-Mg) while it is slower than DFe-Mg in other common mafic minerals (spinel, olivine, garnet, and orthopyroxene). As a consequence, diffusion in clinopyroxene may be the rate-limiting process for the freezing of many geothermometers, and compositional zoning in clinopyroxene may preserve records of a higher (compared to that preserved in other coexisting mafic minerals) temperature segment of the thermal history of a rock. In the absence of pervasive recrystallization, clinopyroxene grains will retain compositions from peak temperatures at their cores in most geological and planetary settings where peak temperatures did not exceed ~1,100 °C (e.g., resetting may be expected in slowly cooled mantle rocks, many plutonic mafic rocks, or ultra-high temperature metamorphic rocks)

Das Theater : sein Wesen, seine Geschichte, seine Meister

von Karl Borinsk