Integrated Gas Hydrate Prediction in Design and Analysis of Gas Lifted Asset

Transcription

1 34 th Gas-Lift Workshop Singapore February 7-11, 2011 Integrated Gas Hydrate Prediction in Design and Analysis of Gas Lifted Asset Rajan Chokshi, Ashok Dixit, Subash Kannan Weatherford International This presentation is the property of the author(s) and his/her/their company(ies). It may not be used for any purpose other than viewing by Workshop attendees without the expressed written permission of the author(s).

2 Overview Hydrate Chemistry Hydrate Forming Conditions in GL Assets Prediction in Well Model Prediction in Network Model Hydrate Inhibition Real Time update of models - Iterative Process. Conclusion 2011 Gas-Lift Workshop 2

3 Hydrate Chemistry Gas Hydrates Ice like crystalline structures formed by water and stabilized by the presence of light gases and hydrocarbons It is a significant threat to the flow assurance of the production systems Can plug lines with little or no warning 2011 Gas-Lift Workshop 3

4 Hydrate Chemistry Hydrate Types Hydrate I - In presence of light gases methane, ethane Hydrate II In presence of heavier gases propane, butane Hydrate H Picture Courtesy : Gas-Lift Workshop 4

5 Hydrate Forming Conditions Some significant factors that influence hydrate formation are, Hydrate Structure Operating Conditions Pressure, Temperature Composition Injection Fluids/ Injection Conditions Joule Thompson Cooling 2011 Gas-Lift Workshop 5

6 Hydrate Typical Phase envelop Psia Below Injection Point HYDRATE FORMATION ZONE Temperature (deg F) 2011 Gas-Lift Workshop 6

7 Hydrate envelop with Injection gas Psia Above & Below Injection Point HYDRATE FORMATION ZONE Temperature (deg F) 2011 Gas-Lift Workshop 7

8 Gas lifted well model 2011 Gas-Lift Workshop 8

9 Hydrate envelop with PT Profile 2011 Gas-Lift Workshop 9

10 Hydrate envelop with PT Profile(above gas Injection point) 2011 Gas-Lift Workshop 10

11 Fluid composition and phase envelop Below Injection Point Above Injection Point 2011 Gas-Lift Workshop 11

12 Subsea Gas Lift Asset Gas injection Line FPSO Riser Subsea Wells 2011 Gas-Lift Workshop 12

13 Wells - Below injection point The hydrate envelop for all subsea wells above Injection point Well #1 Well #2 Well #3 Well #4 Well #5 Well # Gas-Lift Workshop 13

14 Wells - Above injection point The hydrate envelop for all subsea wells below Injection point Well #1 Well #2 Well #3 Well #4 Well #5 Well # Gas-Lift Workshop 14

15 Hydrate envelop with PT Profile (Riser) 2011 Gas-Lift Workshop 15

16 Common methods to prevent Hydrates Addition of Hydrate Inhibitors Industry standard inhibitors Methanol, Ethanol, Mono-Ethylene Glycol (MEG), Di-Ethylene Glycol (DEG), etc. How inhibitor works? They dissolve in water and thus alter the properties of water which reduces the tendency of hydrate formation Heat Flow-line to Increase the Fluid Temperature Dehydrate Gas 2011 Gas-Lift Workshop 16

17 Hydrate Inhibition 2011 Gas-Lift Workshop 17

18 Hydrate Prediction (Real Time) Flow Assurance Module Network Model This is an iterative Process which can update the well and network model to predict the Possible Hydrate Formation and help with calculation of Inhibitor Injection rates. 18

19 Conclusion The seamless integration between Well/Surface network module and Flow Assurance module facilitates fast and efficient analysis of multiple scenarios. The concurrent display of Hydrate curves and P&T profiles assist user in identifying the possible Hydrate formation location in the well / flowline quickly Module can Predict the Hydrates with the available Black Oil Data- No need of Compositional PVT (Internally translated) 2011 Gas-Lift Workshop 19

20 Conclusion The hydrate inhibitor functionality allows user to study the efficacy of various industry standard inhibitors and also optimize the inhibitor quantity. Real Time update of the models assure that the Possible Hydrate Formation can be predicted at any stage Gas-Lift Workshop 20

21 Copyright Rights to this presentation are owned by the company(ies) and/or author(s) listed on the title page. By submitting this presentation to the Gas-Lift Workshop, they grant to the Workshop, the Artificial Lift Research and Development Council (ALRDC), and the American Society of Mechanical Engineers (ASME), rights to: Display the presentation at the Workshop. Place it on the web site, with access to the site to be as directed by the Workshop Steering Committee. Place it on a CD for distribution and/or sale as directed by the Workshop Steering Committee. Other uses of this presentation are prohibited without the expressed written permission of the company(ies) and/or author(s) who own it and the Workshop Steering Committee Gas-Lift Workshop 21

22 Disclaimer The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas-Lift Workshop Web Site. The Artificial Lift Research and Development Council and its officers and trustees, and the Gas-Lift Workshop Steering Committee members, and their supporting organizations and companies (here-inafter referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Gas-Lift Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained. The views, opinions, and conclusions expressed in these presentations and/or training materials are those of the author and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content of the materials. The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, noninfringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose Gas-Lift Workshop 22