Shale gas wells typically
have steep production decline curves
in the first few years of operation. Therefore, if such reduction
in production is not accounted for, much of the supporting infrastructure
within the shale gas field owned by the exploration and production
(E&P) company will be grossly oversized after only a few years
of production. Instead of the conventional approach of utilizing spatially
fixed processing facilities, this work proposes the use of modular
and transportable processing plants. This in turn allows the processing
facilities to be composed of multiple modular plants operating in
parallel. These modular plants can be reallocated within the field
to other processing facilities by the E&P company to combat the
uncertainty in production that comes with developing a shale gas field.
A superstructure is developed to aid in formulating the capacity planning
and allocation problem as a multi-stage stochastic program with uncertain
production forecasts. We incorporate a novel recourse function that
allows the operator of the E&P company to quantify the effect
of postponing the processing of the influent to a later time due to
insufficient processing capacity. The proposed approach and solution
technique are illustrated through a case study. For a set of randomly
generated scenarios, the modular and transportable system shows major
cost and operational benefits over the traditional permanent plants
with fixed capacities.
We present a spectrophotometric calibration system that will be implemented as part of the DES DECam project at the Blanco 4 meter at CTIO. Our calibration system uses a 2nm wide tunable source to measure the instrumental response function of the telescope from 300nm up to 1100nm. The system consists of a monochromator based tunable light source that is projected uniformly on a Lambertian screen using a broadband "line to spot" fiber bundle and an engineered diffuser. Several calibrated photodiodes strategically positioned along the beam path will allow us to measure the throughput as a function of wavelength. Our system has an output power of 0.25 mW, equivalent to a flux of approximately 100 photons/s/pixel on DECam. We also present results from the deployment of a prototype of this system at the Swope 1m at Las Campanas Observatory for the calibration of the photometric equipment used in the Carnegie Supernova Project.
Traditional color and airmass corrections can typically achieve ∼0.02 mag precision in photometric observing conditions. A major limiting factor is the variability in atmospheric throughput, which changes on timescales of less than a night. We present preliminary results for a system to monitor the throughput of the atmosphere, which should enable photometric precision when coupled to more traditional techniques of less than 1% in photometric conditions. The system, aTmCam, consists of a set of imagers each with a narrow-band filter that monitors the brightness of suitable standard stars. Each narrowband filter is selected to monitor a different wavelength region of the atmospheric transmission, including regions dominated by the precipitable water absorption and aerosol scattering. We have built a prototype system to test the notion that an atmospheric model derived from a few color indices measurements can be an accurate representation of the true atmospheric transmission. We have measured the atmospheric transmission with both narrowband photometric measurements and spectroscopic measurements; we show that the narrowband imaging approach can predict the changes in the throughput of the atmosphere to better than ∼10% across a broad wavelength range, so as to achieve photometric precision less than 0.01 mag.
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