Advanced Log Interpretation in Field Development
- Richard Merkel (Denver Petrophysics) | Margaret Lessenger (Rimrock Petrophysics)
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- Publication Date
- October 2016
- Document Type
- Journal Paper
- 479 - 491
- 2016. Society of Petrophysicists & Well Log Analysts
- 2 in the last 30 days
- 279 since 2007
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The authors were involved in a project in the Monument Butte field in the Uinta Basin, to evaluate the potential of reducing well spacing from 20 to 10 acres in a field where a secondary waterflood has been in effect for a number of years. Water injection is commingled in highly discontinuous sand intervals in more than 25 stratigraphic units.
Our objective was to test if dielectric logs in infill wells could identify where the low-salinity waterflood breakthrough occurred. Since dielectric log interpretation gives bulk volume water (BVW) somewhat independent of water salinity, we hoped to identify sands when breakthrough of low-salinity injection water occurred. Reservoir sands are highly discontinuous and regional waterflood-injection maturity highly variable. We hoped to identify zones of water breakthrough for improved field development. If identified, completions engineers could avoid these zones when completing the infill producing well. We designed an initial testing program using dielectric, NMR, and triple-combo log data.
The additional logging, core, and pressure data on infill wells partially met the original objectives, but also were used to determine pay interval (1) wettability, (2) relative permeability, (3) saturation, and (4) reservoir pressure (depleted, native state, and waterflood over pressure). The log and core measurements also were instructive in determining clay-bound water parameters including volume, Archie m, and salinity. These results narrowed down which shaly sand petrophysical models could be used in the field. Each of these factors provided input in the completion of the infill oil producers, as well as which wells and intervals should be converted from producer to injector. Examples show the log response, analysis, and results in many of the independent and/or isolated producing sands in Monument Butte, and how RFT downhole pressure measurements and core analysis aided and verified the interpretation.
|File Size||32 MB||Number of Pages||13|