The spread of COVID-19 within a region in South East Asia has been modelled using a compartment model called SEIR (Susceptible, Exposed, Infected, Recovered). Actual number of sick people needing treatments, or the number active case data was used to obtain realistic values of the model parameters such as the reproduction number (R0), incubation, and recovery periods. It is shown that at the beginning of the pandemic where most people were still not aware, the R0 was very high as seen by the steep increase of people got infected and admitted to the hospitals. Few weeks after the lockdown of the region was in place and people were obeying the regulation and observing safe distancing, the R0 values dropped significantly and converged to a steady value of about 3. Using the obtained model parameters, fitted on a daily basis, the maximum number of active cases converged to a certain value of about 2500 cases. It is expected that in the early June 2020 that the number of active cases will drop to a significantly low level.
Developing a steady operation of gas and condensate value chain is an important task to maintain stable productions of oil & gas industries. In this regard, PETRONAS continues to improve its production facilities by utilizing process modelling and simulation via Symmetry iCON® as one of its main engineering tools. In this work, Symmetry iCON® pipe network solver was used to build a dynamic simulation model for gas and condensate pipeline network in Malaysian Peninsular region. One-month data of December 2018 has been used to validate the model. Then it was utilized to predict the data in January 2019 to further evaluate the applicability of the model. Some valuable observations included the significance of properties estimation of a pseudo component of C6+ in terms of thermodynamic and transport properties. Due to lack of data monitoring of the condensate in some terminals, this property estimation became very crucial while at the same time difficult to validate. Nonetheless, the model can predict the data within the range of error of 4-6%. In the future, when more data is available, the properties can be easily tuned to better represent the reality.
Optimizations of oil productions in current practices have been done separately in both subsurface and surface facilities. This approach might not lead to an optimum state when the whole system is interconnected. In this work, a superstructure model of an existing integrated subsurface and surface facilities was developed and evaluated to maximize the oil productions. In subsurface facilities, well performance data were taken from PROSPER well simulations. Operating variables such as downstream pressures of choke valves and gas lift flowrates, which influence the flow of oil, gas, and water from reservoirs, were considered. Based on these variables, performance correlations of the wells were then developed. On the evaluated surface facility, three pressure levels of vessels on the platform (high-, medium-, and low-pressure vessels) and their current designs were also considered. The optimization result shows that to reach optimum oil production, one well should be connected to the high-pressure vessel, four wells to the medium-pressure vessel, and the rest goes to the low-pressure vessel. Several choke valves and gas lift flowrates also need to be adjusted accordingly.
Proper design of LNG loading lines and verification of emergency shutdown (ESD) interlock systems are critical in ensuring overall safety of the LNG facility. During an emergency, ESD interlock is activated with ESD valves closure initiated simultaneously with all loading pumps trip and the kickback valves open. During the ESD valves closure, the pipeline can be exposed to a risk of high surge pressures exerted onto the wall. A pressure surge or liquid hammering phenomenon in piping systems can be caused by a fluid in motion forced to stop or change direction suddenly (rapid momentum change) and also due to cavitation effect. Cavitation is caused by the formation and instantaneous collapse of vapour bubbles. The collapsing bubbles exert severe localized impact forces that can result in pressure surges. This paper discusses the methodology used to evaluate any potential occurrence of surge and the peak pressure associated with it, using several case studies for analysis. This paper also shares best practice identified from the study to facilitate with safe operations at an LNG loading facility.
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