Clariant Oil Services Prevents Asphaltene Deposits in Subsea Flowlines
- Successful prevention of asphaltene deposits ensure flow assurance integrity
- Field optimization led to a 40% reduction of the chemical dose rate creating logistical cost savings
- Decrease in overall chemical cost spend as a result of injection optimization
- No application challenges or evidence of asphaltene deposits since treatment began
A major producer in the UK sector of the North Sea was evaluating start-up requirements for a new offshore subsea field. All production was to flow via an 8” flowline to the host FPSO located 1.5 km away, in 100 m water depth with a reservoir temperature of 102oC and pressure of 5,000 psi.
In-depth assessments of the field characteristics were undertaken by independent third party laboratories and consultants to assess possible flow assurance challenges. An initial SARA analysis (tabled below) shows that this crude oil had the potential for unstable asphaltene deposition.
Further studies determined that, while the colloidal instability index and asphaltene/resin levels were low, the density and bubble point conditions were considered favorable for asphaltene deposition. As a result, deployment of an asphaltene inhibitor was recommended.
As the incumbent chemical solutions provider with more than 10 years of continuous support to the operator’s other North Sea assets, Clariant Oil Services was invited to evaluate and recommend a suitable product that would prevent any problems from occurring. Due to the subsea nature of the application, the product was required to meet stringent stability requirements, as well as compatibility with materials and cleanliness specification (<NAS-6) prior to injection down the subsea umbilical.
Clariant Oil Services Solutions and Value Delivered
After a thorough review and system analysis, Clariant Oil Services developed FLOTREAT DF 3167, an asphaltene inhibitor, to meet all of the operator’s requirements. Laboratory tests indicated an initial treatment of FLOTREAT DF 3167 to be 50 ppm, injected continuously from field start-up. See Figure 1 on page 3.
After two years of successful operation, a field optimization trial was undertaken to determine if a lower dose rate of FLOTREAT DF 3167 would maintain performance level, while also decreasing costs; results indicated a successful dose rate reduction of 40% (see Figure 2 on page 3). Additionally, since its application, no further problems or evidence of asphaltene deposits have been reported.
Figure 1: Performance of FLOTREAT DF 3167 vs. Blank in laboratory tests
Figure 2: Dose rate reduction during FLOTREAT DF 3167 field optimization trial
This information corresponds to the present state of our knowledge and is intended as a general description of our products and their possible applications. Clariant makes no warranties, express or implied, as to the information’s accuracy, adequacy, sufficiency or freedom from defect and assumes no liability in connection with any use of this information. Any user of this product is responsible for determining the suitability of Clariant's products for its particular application.*Nothing included in this information waives any of Clariant’s General Terms and Conditions of Sale, which control unless it agrees otherwise in writing. Any existing intellectual/industrial property rights must be observed. Due to possible changes in our products and applicable national and international regulations and laws, the status of our products could change. Material Safety Data Sheets providing safety precautions, that should be observed when handling or storing Clariant products, are available upon request and are provided in compliance with applicable law. You should obtain and review the applicable Material Safety Data Sheet information before handling any of these products. For additional information, please contact Clariant. *For sales to customers located within the United States and Canada the following applies in addition: NO EXPRESS OR IMPLIED WARRANTY IS MADE OF THE MERCHANTABILITY, SUITABILITY, FITNESS FOR A PARTICULAR PURPOSE OR OTHERWISE OF ANY PRODUCT OR SERVICE.
Copyright © Clariant International Ltd, 2013.