Objectives/Scope This paper covers the Shwe Offshore Platform (SHP) MEG Regeneration System upgrade works implemented to reduce excessive MEG losses and improve operation of the System. Methods, Procedures, Process The SHP MEG Regeneration System processes MEG used in the topsides for hydrate inhibition in the Low Temperature Separators (LTS) and at the four subsea wells. Since start-up of production in 2013, SHP has suffered from excessive MEG losses and operational difficulties. Later in the field life, MEG injection to subsea wells was discontinued due to contamination with salts from formation water, and Kinetic Hydrate Inhibitor (KHI) injection was introduced. Extensive evaluation of data, laboratory tests and field trials were carried out to investigate the causes of the excessive MEG consumption and operational difficulties. The upgrade of the MEG Regeneration System was finally completed and put in service since May 2018. Results, Observations, Conclusions The followings have been identified as the direct causes for MEG losses and operational difficulties; Poor efficiency of Glycol-Glycol Heat Exchangers (HEXs), causing low operating temperature of the Rich MEG Flash Drum and poor condensate/Rich MEG separation, resulting in MEG losses via Flash Drum condensate outlet.Excessive condensate in the Rich MEG reaching the Reboiler and resulting in contamination of the Lean MEG and downstream section (injection spray bars).Low water loading in the MEG Regeneration System resulting in lack of reflux and MEG losses via Reflux Drum.MEG carryover from LTS to the Export Gas Compressor (EGC) Suction Scrubbers, caused by foaming in the LTSs. In order to resolve the issues above, a number of modifications were implemented. New Glycol-Glycol HEX and a Liquid-Liquid Coalescer Filter were installed to provide better separation of condensate from Rich MEG. Also re-routing of the EGC Suction Scrubbers liquid outlet back to the MEG Regeneration System to recover the carried over MEG. Significant reduction of MEG losses was achieved, in the range of 70%, and overall system performance has improved. The main outcome of such improvement is that the condensate content in Rich MEG has been significantly decreased to below 500ppmV from above 1vol% due to the increase of Rich MEG Operating Temperature in Flash Drum and introduction of the Liquid-Liquid Coalescer Filter. Novel/Additive Information This paper was written to describe the method used for resolving the problems with MEG losses, excessive condensate in the Rich MEG, and MEG carryover. It also explains the data evaluation, preparation, execution, and the results of the MEG Regeneration System Upgrade work.
Objectives/Scope This paper describes the successful replacement of Mono Ethylene Glycol (MEG) by Kinetic Hydrate Inhibitor (KHI) to guarantee flow assurance in the Shwe field subsea production system, offshore Myanmar. It covers the initial difficulties experienced with MEG, specific field conditions, the comprehensive KHI selection process and testing up to field application and operation. Methods, Procedures, Process MEG used for hydrate inhibition in the field's subsea flowline was originally regenerated in the topside facility, however contamination of the MEG with salts from formation water was causing process upsets. The option of installing a reclamation package presented many challenges and, after review of field conditions, the application of a KHI was considered as a promising alternative to MEG. With the engagement of specialist chemical suppliers a broad and challenging series of laboratory, as well as field tests, was carried out to select a suitable product. Finally a dedicated permanent injection skid was installed to guarantee stable KHI delivery and production. Results, Observations, Conclusions The difficulties caused by salt contamination of the MEG system, combined with the intricate field logistics at the remote site offshore Myanmar, entailed a speedy solution. This combined with suitable operating parameters of the field; i.e. low water content, high wellhead flowing temperatures, subcooling within known KHI operating range, ensured KHI was an economical solution. Nevertheless from desktop study to successful field application a series hurdles had to be crossed, including performance and compatibility tests, simulating all the expected Shwe Offshore Platform (SHP) operating conditions: Determination of Hydrate Equilibrium Temperature (HET); Induction Time Autoclave test for the required residence time in the presence of Corrosion Inhibitor (CI); Hot Injection ests at wellhead operating temperature; Thermal stability tests for topsides and condensate disposal system; Umbilical material compatibility tests; Compatibility of KHI with incumbent products (MEG and CI). Testing of a range of products, carried out by specialist chemical supplier, resulted in the selection of a qualified product, followed by a successful field application testing programme. Seven years after its introduction, KHI has helped achieve optimum field uptime and reduced operational costs as well as eased logistics constraints. Novel/Additive Information KHI is not new to the Oil & Gas industry, however information on its selection and application is not widely available. This paper sheds light on the steps to be considered when evaluating KHI as a suitable hydrate inhibitor, as well as the detailed laboratory tests for proper selection of a product. The intent is to help operators who are facing challenges with hydrate inhibition and could revert to KHI as an alternative.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.