Hydrate Management with Real-Time Data Visualization

Abstract

Hydrate is a common issue in the natural gas production, which can be accelerated by the presence of H₂S and CO₂. This paper is to present the current experience in a gas project in Sichuan, including application of several surveillance technologies for the benefit of hydrate prevention and management, to support production optimization. This sour gas project has high H₂S and CO₂ content. With the high deliverability at the wells, the project has used a two-choke configuration in the surface system to manage the surface pressure to feed the gas into the production process. Given a design of the two-choke system, the sour gas is choked, heated, and then choked again, and finally flows to the tri-ethylene glycol (TEG) dehydration unit. Hydrate formation risk normally exists downstream of the first choke and the second choke if the heater is not efficient, and at the filtration process upstream of the dehydration. Hydrate prevention had been considered during the design phase of the surface production facilities. Methyl-ethylene glycol (MEG) is therefore selected and injected to the upstream of the first choke to mix with the gas flow stream. Real-time data surveillance (i.e., pressure and temperature) with digital gauges are installed in the areas with high probability of hydrate formation. The most important next step is the real-time data (i.e., gas rate, water rate, pressure, temperature, and MEG injection rate), which are updated, and the hydrate formation curves are plotted to display on the central control computer. Based on the relative position of the pressure and temperature, the integrated digital control system can be used to optimize production by controlling gas rate, heater temperature, and MEG injection. In brief, with this visualized monitoring system in place, hydrate prevention has been visually and effectively managed and MEG consumption has been optimized to minimize the operational cost.

Copyright 2017, Unocal East China Sea Ltd., UECSL.

This paper was prepared for presentation at the 2017 International Petroleum and Petrochemical Technology Conference in Beijing, China, 20–22 September 2017.

This paper was selected for presentation by the IFEDC&IPPTC Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the IFEDC&IPPTC Committee and are subject to correction by the author(s). The material does not necessarily reflect any position of the IFEDC&IPPTC Committee, or its members. Papers presented at the Conference are subject to publication review by Professional Committee of Petroleum Engineering of Shaanxi Petroleum Society. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of Shaanxi Petroleum Society is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words: illustrations may not be copied. The abstract must contain conspicuous acknowledgment of IFEDC&IPPTC. Contact email: paper@ifedc.org or paper@ipptc.org.