Case Study - Equivalent-Circulating-Density Management Strategy Solves Lost-Circulation Issues on Complex Salt Diapirs/Paleocene Reservoir
- David A. Murray (Shell UK Limited) | Mark W. Sanders (M-I Swaco) | Kirsty Houston (M-I Swaco) | Hamish Hogg (Shell UK Limited) | Graeme J. Wylie (Shell UK Limited)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling & Completion
- Publication Date
- June 2014
- Document Type
- Journal Paper
- 194 - 207
- 2014.Society of Petroleum Engineers
- 4.1.2 Separation and Treating, 1.7.6 Wellbore Pressure Management, 1.11 Drilling Fluids and Materials, 1.6 Drilling Operations, 5.1.1 Exploration, Development, Structural Geology, 1.10.1 Drill string components and drilling tools (tubulars, jars, subs, stabilisers, reamers, etc), 6.5.2 Water use, produced water discharge and disposal
- low-ECD drilling fluid, HFHS pill, depleted reservoir, salt diapir, horizontal well
- 4 in the last 30 days
- 499 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
Drilling horizontal infill wells in the Pierce field in the UK Central North Sea (UKCNS) is challenging because of the narrow drilling window caused by depletion in a highly fractured reservoir, which is complicated further by water injection and the proximity of other production wells. Wellbore strengthening was attempted in the reservoir section of Pierce B5 (B5), although, when a preexisting fracture weakened further by depletion was encountered, losses occurred. During the next 10 days more than 5,000 bbl of nonaqueous fluid (NAF) was lost downhole. During the recovery from the losses event, 15 individual treatments with lost-circulation materials (LCMs) were made. More than 50 t of LCM was used without success; however, the well was stabilized enough to secure the drilled footage and to complete the well. Two additional horizontal wells in the same field were successfully drilled with a low-equivalent-circulating-density (ECD) management strategy combined with the development of a low- ECD drilling-fluid system and the use of a high-fluid-loss, high strength (HFHS) pill. The dual problems of barite sag and poor hole cleaning, which can be problematic when reducing ECD through a reduction in fluid rheology, were successfully managed. This low-ECD technique can be applied in other subsea depleted wells in which a narrow drilling window exists. This paper describes how a detailed analysis of the losses event on Pierce B5 provided an improved understanding of the loss mechanism that resulted in a revised ECD-management strategy. An engineered low-ECD NAF with an HFHS pill, combined with learnings on ECD awareness in the planning and execution phases, mitigated the drilling risks on subsequent wells. This has implications when encountering very large fractures that are difficult to overcome, not only on future Central North Sea wells, but also globally for wells drilled in similar geological settings.
|File Size||1 MB||Number of Pages||14|
Alberty, M.W. and McLean, M.R. 2004. A Physical Model for Stress Cages. Presented at the SPE Annual Technical Conference, Houston, Texas, 26–29 September. SPE-90493-MS. http://dx.doi.org/10.2118/90493-MS.
Bern, P.A., Zamora, M., Slater, K.S. et al. 1996. The Influence of Drilling Variables on Barite Sag. Presented at the SPE Annual Technical Conference, Denver, 6–9 October. SPE-36670-MS. http://dx.doi.org/10.2118/36670-MS.
Davison, J.M., Leaper, R., Cauley, M.B. et al. 2004. Extending the Drilling Operating Window in Brent: Solutions for Infill Drilling in Depleting Reservoirs. Presented at the IADC/SPE Drilling Conference, Dallas, Texas, 2–4 March. SPE-87174-MS. http://dx.doi.org/10.2118/87174-MS.
Dye, W., Hemphill, T., Gusler, W. et al. 1999. Correlation of Ultra-low Shear Rate Viscosity and Dynamic Sag in Invert-Emulsion Drilling Fluids. Presented at the SPE Annual Technical Conference, Houston, Texas, 3–6 October. SPE-70128-MS. http://dx.doi.org/10.2118/70128-MS.
Jachnik, R.P. and Marshall, D.S. 1989. Optimising Oil Muds for Offshore Drilling and Lower Environmental Impact. Presented at the 21st Annual Offshore Technology Conference, Houston, Texas, 1–4 May. OTC-5904-MS. http://dx.doi.org/10.4043/5904-MS.
Lummus, J.L. and Azar, J.J. 1986. Drilling Fluids Optimization—A Practical Field Approach. Tulsa, Oklahoma: Pennwell Publishing.
Sanders, M.W., Scorsone, J.T., and Friedheim, J.E. 2010. High-Fluid-Loss, High-Strength Lost Circulation Treatments. Presented at the SPE Deepwater Drilling and Completions Conference, Galveston, Texas, 5–6 October. SPE-135472-MS. http://dx.doi.org/10.2118/135472-MS.
Schutjens, P.M.T.M., Snippe, J.R., Mahani, J. et al. 2012. Production-Induced Stress Change in and Above a Reservoir Pierced by Two Salt Domes: A Geomechanical Model and Its Applications. SPE J. 17 (1): 80–97. SPE-131590-PA. http://dx.doi.org/10.2118/131590-PA.
Seymour, K.P., Rae, G., Peden, J.M. et al. 1993. Drilling Close to Salt Diapirs in the North Sea. Presented at the Offshore Europe Conference, Aberdeen, 7–10 September. SPE-26693-MS. http://dx.doi.org/10.2118/26693-MS.
van Oort, E., Friedheim, J., Pierce, T. et al. 2009. Avoiding Losses in Depleted and Weak Zones by Constantly Strengthening Wellbores. Presented at the SPE Annual Technical Conference, New Orleans, Louisiana, 4–7 October. SPE-125093-MS. http://dx.doi.org/10.2118/125093-MS.
Zamora, M. 2009. Mechanisms, Measurement and Mitigation of Barite Sag. Presented at the Offshore Mediterranean Conference, Ravello, Italy, 25–27 March. OMC-2009-105.
Zamora, M. and Bell, R. 2004. Improved Wellsite Test for Monitoring Barite Sag. Presented at the AADE Fluid Technology Conference, Houston, Texas, 6–7 April. AADE-04-HO-DF-19.