Dual Gradient Drilling Is Ready For Primetime: The Benefits Of A Retrofit System For Better Well Control, Enhanced Water Depth Capability And Flat Time Reduction

Author(s):  
Robert Ziegler
2006 ◽  
Vol 21 (04) ◽  
pp. 287-295 ◽  
Author(s):  
Jerome J. Schubert ◽  
Hans C. Juvkam-Wold ◽  
Jonggeun Choe

2015 ◽  
Author(s):  
E. Hauge ◽  
J.M. Godhavn ◽  
D.O. Molde ◽  
J.H Cohen ◽  
R.S. Stave ◽  
...  

Author(s):  
Brandee A. Elieff ◽  
Jerome J. Schubert

Currently the “Pump and Dump” method employed by Exploration and Production (E&P) companies in deepwater is simply not enough to control increasingly dangerous and unpredictable shallow hazards. “Pump and Dump” requires a heavy dependence on accurate seismic data to avoid shallow gas zones; the kick detection methods are slow and unreliable, which results in a need for visual kick detection; and it does not offer dynamic well control methods of managing shallow hazards such as methane hydrates, shallow gas and shallow water flows. These negative aspects of “Pump and Dump” are in addition to the environmental impact, high drilling fluid (mud) costs and limited mud options. Dual gradient technology offers a closed system, which improves drilling most simply because the mud within the system is recycled. The amount of required mud is reduced, the variety of acceptable mud types is increased and chemical additives to the mud become an option. This closed system also offers more accurate and faster kick detection methods in addition to those that are already used in the “Pump and Dump” method. It has the potential to prevent the formation of hydrates by adding hydrate inhibitors to the drilling mud. And more significantly, this system successfully controls dissociating methane hydrates, over pressured shallow gas zones and shallow water flows. Dual gradient technology improves deepwater drilling operations by removing fluid constraints and offering proactive well control over dissociating hydrates, shallow water flows and over pressured shallow gas zones. There are several clear advantages for dual gradient technology: economic, technical and significantly improved safety, which is achieved through superior well control.


2016 ◽  
Author(s):  
Zhaoguang Yuan ◽  
Dan Morrell ◽  
Paul Sonnemann ◽  
Colin Leach
Keyword(s):  

2015 ◽  
Author(s):  
John H. Cohen ◽  
Roger Stave ◽  
Espen Hauge ◽  
Dag Ove Molde

Author(s):  
Mikolaj Stanislawek

Permanent Plug and Abandon (PP&A) operations of the existing production and exploration wells continue to have a higher focus in drilling and well operations for Oil & Gas Companies. It is expected that they will play an important role in the future, and their further optimization and simplification is even more important. This paper describes a successful approach and execution of a challenging Permanent Plug and Abandon operation of a subsea well in the Norwegian Sea by Statoil. A subsea well at over 350 m water depth was being drilled, when a casing running tool was stuck at the subsea wellhead when running an intermediate casing string. This led to a temporary well abandonment, before permanent P&A operations could be resumed at a later stage. Several concepts and contingency scenarios were evaluated and risk assessed in the planning phase, which required implementation of nonstandard and innovative P&A solutions and equipment. They were developed in the planning phase and reviewed with planning and execution teams, and tested before the operational start-up. Main P&A operational goals were established in the planning phase, and successfully implemented during the operations: 1) well control — confirm there is no gas and no well control risk in the well before resuming P&A operations, 2) gain access to the well by retrieving stuck tool from subsea wellhead, and 3) establish permanent P&A barriers in the well. Both planning and execution of this operation is described in this paper, which includes main planned operations, and also a strategical approach with several contingency scenarios prepared in order to be able to P&A this well permanently.


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