WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS [report]

Jill S. Buckley, Norman R. Morrow
2005 unpublished
Given the extreme ecological sensitivity of the Arctic region, new environmentally friendly synthetic oil-base muds (SBM) are likely to be used for drilling wells. Oil company experience using SBM has shown that it can change the wettability of cores, causing great uncertainty in estimates of secondary recovery. For example, the uncertainty in waterflood residual oil saturation due to invasion of SBM has been found to be in excess of 20% PV, which significantly impacts the economics of
more » ... ding. It is vital that the recovery from different schemes be evaluated accurately so that the Arctic reserves are developed efficiently. Lowinvasion coring, which is used to minimize alteration of core properties, is not always viable due to drilling considerations or if the formation is very permeable. This research will improve our fundamental understanding of the factors that cause SBM to change the wettability of cores. Wetting changes due to SBM components will be tested on smooth mineral surfaces and in cores that have previously been exposed to reservoir fluids; cleaning and restoration procedures specific to different oils, surfactants, and mineralogy will be developed. The immediate focus is on finding methods to clean and restore cores to the in-situ condition for rocks and fluids that are relevant to arctic reservoirs. However, we expect this research will also serve to guide industry efforts to design muds that are both environmentally friendly and non-damaging with respect to core wettability.
doi:10.2172/840110 fatcat:xrjh6xcz5vgyhb3njgymo2hzrm