Investigation of Wax Depositional Behaviour in Straight and Curved Pipes – Experiments and Simulation
PhD Thesis
Makwashi, N. (2020). Investigation of Wax Depositional Behaviour in Straight and Curved Pipes – Experiments and Simulation. PhD Thesis https://doi.org/10.18744/lsbu.8v4yv
Authors | Makwashi, N. |
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Type | PhD Thesis |
Abstract | Deposition wax is one of the chronic flow assurance problems that continue to attract attention in the oil and gas field, particularly as the hydrocarbon explorations and productions in recent years move into a colder environment. The accumulation of the wax deposit in the pipeline reduced or interrupted the production, and in the worst-case completely clogged the pipeline, resulting in equipment failure or field abandonment. Although significant progress has been made in mitigating the problem, many questions about the full understanding of the factors and the physical process mechanisms of deposition remain unanswered. Predominant researches are being conducted in straight pipes. The impact of pipe curvatures such as pipe bends, elbows, and inclinations (found in production and transportation systems) on the increased severity of the deposition is not well studied, only very limited studies being reported. In this thesis, the deposition of wax was studied in a single-phase flow using a novel laboratory-scale flow loop accommodating three different pipes configurations: a straight pipe and curved pipes with 45°and 90°bends. Series of experiments were carried out using a crude blend with and without chemical inhibitor at different flow rates–under laminar(Q!"#; 3, 5, 7 l/min) and turbulent flow (Q!"#; 9, 11 l/min) conditions and at different ambient cooling temperatures of 10, 15, 25 °C(T$!!#≤pour point temperature of the oil) and 30, 35, 40 °C(T$!!#≥WAT of oil). The experimental period was varied from 2, 4, 6, 8 hours. Prior to the flow loop studies, three different waxy crude oil samples and four commercial wax inhibitors are screened and characterised through different standard techniques. The wax content of crude oil samples A, B,and C was found to be 12.05, 20.05,and 14wt%, n-paraffin distributions ranges from C15-C74, WAT and pour point respectively. Similarly, SARA (saturated/aromatic/resin/asphalte)fractions, wax appearance temperature, viscosity, pour point, and the colloidal instability index of the samples was obtained. Anew wax inhibitor was developed by blending different fractions of commercial inhibitors improved the performance and transformed the needle-like or rod-like crystals structure of the oil samples into an agglomerate with small particles dispersed in the oil matrix. |
Year | 2020 |
Publisher | London South Bank University |
Digital Object Identifier (DOI) | https://doi.org/10.18744/lsbu.8v4yv |
File | File Access Level Open |
Publication dates | |
29 May 2020 | |
Publication process dates | |
Deposited | 19 Nov 2020 |
Funder/Client | Nigerian Petroleum Technology Development Fund |
https://openresearch.lsbu.ac.uk/item/8v4yv
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