Skip to Main Content
GEOREF RECORD

Hydrates on the subsea wellhead in deepwater wells; study on the growth mechanisms, impacts on drilling safety, and possible solutions

Zhang Bailing, Yang Jin, Ali Takbiri-Borujeni, Sun Ting, Ali Reza Edrisi, Hojatollah Takbiriboroujeni, Wu Xudong, Liu Hexing and Bo Zhou
Hydrates on the subsea wellhead in deepwater wells; study on the growth mechanisms, impacts on drilling safety, and possible solutions
Interpretation (Tulsa) (November 2018) 6 (4): T1081-T1093

Abstract

Hydrate formation poses a risk to deepwater drilling operations. Most current studies on the hydrate formation and its impact on deepwater drilling operations have focused on the risk associated with hydrates inside the wellbore. Few researchers have studied the risk of hydrate formation outside the wellbore, and the risks to deepwater drilling are still unclear. In the South China Sea, there have been several events of hydrate growth on the outer surfaces of the subsea wellhead. The mechanisms of hydrate growth on the outer surface of the subsea wellhead are analyzed, and the gas source is predicted by analyzing the logging data of the adjacent wells. A model for the wellhead stability is developed, and the impacts of hydrate formation on the stability of the subsea wellhead are analyzed. The gas source, temperature, pressure, solid surface roughness, and relative static subsea environment are found to be the key factors in the formation of hydrate in the marine environment. The risk of hydrate formation to wellhead stability is subtle, but to blowout preventer (BOP) could be significant. Hydrates may cause BOP control failure in which the BOP could not be closed in the event of emergency; hydrate formation between the BOP and the wellhead may cause BOP not to be separated from the bottom of the wellhead. A tool was designed for controlling the formation of hydrates, with particular tilt angle and surface roughness. Because the appropriate tilt angle can divert the gas bubbles to avoid the hydrate formations at the wellhead. The designed hydrate control tool successfully mitigates the risks to drilling operations.


ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 6
Serial Issue: 4
Title: Hydrates on the subsea wellhead in deepwater wells; study on the growth mechanisms, impacts on drilling safety, and possible solutions
Affiliation: China University of Petroleum, Beijing, China
Pages: T1081-T1093
Published: 201811
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 17
Accession Number: 2019-007380
Categories: Economic geology, geology of energy sources
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables
N00°00'00" - N25°00'00", E99°10'00" - E122°00'00"
Secondary Affiliation: West Virginia University, USA, United StatesNicholls State University, USA, United StatesIsfahan University, IRN, IranChina National Offshore Oil Corporation, CHN, ChinaChina National Petroleum Corporation, CHN, China
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 2019
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal