Significance of Time-Lapsed Hydrocarbon Saturations From Pulsed-Neutron-Capture (PNC) Logs and the Impact of Borehole-Environment Parameters on PNC-Derived Saturations
- Arfan Ali (Shell UK Limited) | Simon Small (Shell UK Limited) | Kamaljeet Singh (Schlumberger) | Andy Martin (Schlumberger)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- May 2017
- Document Type
- Journal Paper
- 285 - 292
- 2017.Society of Petroleum Engineers
- Reservoir surveillance, RST logging, Pulsed Neutron Capture, Time lapse sigma
- 4 in the last 30 days
- 294 since 2007
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Reservoir surveillance with pulsed-neutron-capture (PNC) logs has shown its importance historically in providing reservoir hydrocarbon saturations behind the casing. However, there is little in the literature to show the importance of PNC logs for contact tracking and accessing bypassed/moved hydrocarbons. In addition, no one has ever attempted to characterize the various borehole environments and subsequently understanding their impact on the PNC-derived hydrocarbon saturations.
This paper is divided into two parts. The first part shows the importance of time-lapse PNC logs in understanding reservoir fluid movement and chasing migrated hydrocarbons behind the casing. A case study from the UK Central North Sea is presented to highlight the importance of the PNC sigma data.
The second part of the paper shows the computation of borehole-environment parameters from simple to complex completions including multiple casing/tubing strings, varying hole sizes, and annuli fill. For the first time, the work presented in this paper shows the importance of having correct environmental parameters and the impact of using incorrect parameters on the PNC-derived hydrocarbon saturations. Not making such detailed checks may result in misinterpretation of the PNC data, leading to incorrect conclusions about fluid dynamics, and risky decisions in adding perforations and water-shut off (WSO) opportunities.
|File Size||1 MB||Number of Pages||8|
Fertl, W. H. 1987. Pulsed Neutron Capture Logs Evaluate Geopressure Environments. Presented at the 19th Offshore Technology Conference, Houston, 27–30 April. SPE-5572-MS. https://doi.org/10.2118/5572-MS.
Gournay, L. S. and Maute, R. E. 1982. Detection of Bypassed Gas Using Borehole Gravimeter and Pulsed Neutron Capture Logs. The Log Analyst 23 (3). SPWLA-1982-vXXIIIn3a3.
Hilchie, D. W., Mills, W. R., Dennis, C. L. et al. 1969. Some Aspects of Pulsed Neutron Logging. The Log Analyst 10 (2): 7–17. SPWLA-1969-vXn2a2.
Itter, D., Cedillo, G., Han, X. et al. 2015. Locating Bypassed Oil Through In-Well Surveillance in Prudhoe Bay. Presented at the 56th SPWLA Annual Logging Symposium, Long Beach, California, 18–22 July. SPWLA-2015-OOOO.
Madhavan, S., Al-Hashash, H., and Al-Arbash, A. 2015. Reservoir Characterization by 3D Modelling of Water Encroachment Using Time Lapse Pulsed Neutron Logs in Heterogeneous Shaly Sand Reservoir of Greater Burgan Field. Presented at the SPE Kuwait Oil and Gas Show and Conference, Mishref, Kuwait, 11–14 October. SPE-175408-MS. https://doi.org/10.2118/175408-MS.
Mickael, M. W. 1999. A New Algorithm for Correcting Neutron Decay Logs for Borehole and Diffusion Effects. The Log Analyst 40 (6): 471–478. SPWLA-1999-v40n6a1.
Morris, C., Aswad, T., Morris, F. et al. 2005a. Reservoir Monitoring With Pulsed Neutron Capture Logs. Presented at the Europec/EAGE Annual Conference, Madrid, 13–16 June. SPE-94199-MS. https://doi.org/10.2118/94199-MS.
Morris, F., Morris, C., and Quinlan, T. 2005b. Applications of Pulsed Neutron Capture Logs in Reservoir Management. Presented at the SPE Western Regional Meeting, Irvine, California, 30 March–1 April. SPE-93889-MS. https://doi.org/10.2118/93889-MS.
Murdoch, B. T., Hunter, C. J., Randall, R. R. et al. 1990. Diffusion Corrections to Pulsed Neutron Capture Logs: Methodology. Presented at the SPWLA 31st Annual Logging Symposium, Lafayette, Louisiana, 24–27 June. Paper Q.
Neuman, C. H., Sullivan, M. J., and Belanger, D. K. 1999. An Investigation of Density Derived From Pulsed Neutron Capture Measurements. Presented at the SPE Annual Technical Conference and Exhibition, Houston, 3–6 October. SPE-56647-MS. https://doi.org/10.2118/56647-MS.
Odom, R. C., Streeter, R. W., Hogan, G. P. et al. 1994. A New 1.625-in. Diameter Pulsed Neutron Capture and Inelastic/Capture Spectral Combination System Provides Answers in Complex Reservoirs. Presented at the SPWLA 35th Annual Logging Symposium, Tulsa, 19–22 June. SPWLA-1994-O.
Ortega, E., Torres-Verdin, C., William, E. et al. 2013. Multidetector LWD Sigma Logging Principles, Petrophysical Applications, and Environmental Effects. Presented at the SPWLA 54th Annual Logging Symposium, New Orleans, 22–26 June. SPWLA-2013-NNN.