Performance Evaluation of Synthetic-Based Drilling Fluid with Flat Rheology
Tie Geng,
Zhengsong Qiu,
Hailong Miao,
Wei Zhang,
Ke Lei
Issue:
Volume 7, Issue 5, October 2018
Pages:
54-58
Received:
12 October 2018
Accepted:
31 October 2018
Published:
19 November 2018
Abstract: In offshore deepwater drilling, because of the low temperature aroud seafloor, the conventional synthetic-based drilling fluid becomes very thick, resulting in severe loss of drilling fluid during drilling through the deepwater formations with a narrow safe-density window. Therefore, it is important to improve the rheological properties of drilling fluid at deepwater drilling conditions. In this work, by investigating the effects of the key components including the base oil, emulsifier, wetting agent and rheology modifier on the rheological properties of synthetic-based drilling fluid at 4°C to 65°C, the optimal additives were selected, and a synthetic-based drilling fluid with flat-rheology characteristics was developed. It was found that the gas-to-liquid oil had low viscosity at a low temperature, and was suitable for preparing deepwater drilling fluids. The evaluation experiments show that at 4°C to 65°C, the drilling fluid could maintain stable yield point, 10-min Gel and 6 r/min reading value at a density of 0.9-1.5 g/cm3 even after high temperature aging, while the rheological properties of the conventional synthetic-based drilling fluid were significantly influence by the low temperature. Moreover, it showed excellent performance in filtration reduction and shale inhibition, and could maintain good properties even being contaminated by seawater. Therefore, its stable rheological properties at the deepwater drilling temperature range can effectively control the equivalent circulating density, thus reducing the risk of drilling fluid loss during deepwater drilling.
Abstract: In offshore deepwater drilling, because of the low temperature aroud seafloor, the conventional synthetic-based drilling fluid becomes very thick, resulting in severe loss of drilling fluid during drilling through the deepwater formations with a narrow safe-density window. Therefore, it is important to improve the rheological properties of drilling...
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Real Options: An Evaluation Tool for a Photovoltaic System for Self-consumption
Joana Fialho,
Pedro Pinto,
Ana Lúcia Gomes
Issue:
Volume 7, Issue 5, October 2018
Pages:
59-65
Received:
17 October 2018
Accepted:
1 November 2018
Published:
14 December 2018
Abstract: The use of renewable sources to produce energy is good for the planet and has economic value, that is, investing in the produce of green energy can be economically viable. This paper aims to conduct an evaluation, using real options tools, of a photovoltaic (PV) system, for self-consumption, at the Campus of Polytechnic Institute of Viseu, Portugal. A PV system produces electricity from sun and its investment can be viable, particularly in sunny countries like Portugal. This viability comes from the rapid recovery of the investment, since the energy produced is no longer bought to the electrical network. The utilization of real options, in this study, namely the decision trees, allows integrating uncertainty sources and operational flexibility. In this work, we considered the price of electricity tariff and the value of the initial investment as uncertain values. The operational flexibility is integrated by considering the options “invest”, “defer” and “not invest” in the PV system, for self-consumption. The results suggest that the Polytechnic Institute of Viseu should invest in a PV system, for self-consumption. The use of solar energy, especially in countries with high sun expose, such as Portugal, is economically viable.
Abstract: The use of renewable sources to produce energy is good for the planet and has economic value, that is, investing in the produce of green energy can be economically viable. This paper aims to conduct an evaluation, using real options tools, of a photovoltaic (PV) system, for self-consumption, at the Campus of Polytechnic Institute of Viseu, Portugal...
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