LWD Density-Neutron Image Logs in Clastic Facies Evaluation - Example From Offshore Niger Delta

Mohammed Doghmi¹, Taofeek Ogunyemi¹, and Peter Schlicht^2
1 Schlumberger Oilfield Services, Port-Harcourt, Nigeria
² Schlumberger, Lagos,

Improvements in technology are enabling use of high resolution density-neutron imaging logs for identification of sedimentary facies in clastic reservoirs. This paper will highlight the value of these logging-while-drilling (LWD) logs in clastic reservoir evaluation, particularly when they are fully integrated with other measurements such as nuclear magnetic resonance, core and seismic data. Some guidelines for using the data in reservoir model construction will also be presented.

Specific aspects highlighted in this paper are lithofacies discrimination and structural applications using LWD data recently acquired offshore Niger Delta. Continuous "image facies" interpretations, calibrated initially with core, were generated over all the reservoir-bearing intervals and compared with conventional electrofacies identification from open hole LWD logs. The model was then propagated to other wells where no cores were acquired using neural networks. Calibration of interpreted dip data from the image with seismic will significantly enhance well-to-seismic calibration and highlights subseismic structures that may have been overlooked in reservoir modeling.

This method, although at an early development stage, can add significant insight to reservoir description and charcterization in development wells where typically no or few wireline imaging tools are run and reduce significantly coring costs. var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));