FORMATION EVALUATION

CHAPTER 1PART 220/03/20131CGE 674 FORMATION EVALUATION

Shorter tool length meansless rat hole required

Less tool components means shorter rig up andrig down time

TYPICAL LOGGING TOOL20/03/20133

TYPICAL LOGGING TOOL20/03/20134

TOOL CONFIGURATION20/03/20135

WIRELINE UNIT20/03/20136SPONTANEOUS POTENTIAL (SP) 20/03/20137SP TOOL

SP is a recording of the difference between the electrical potential of a movable electrode in the borehole and the electrical potential of a fixed surface electrode20/03/20138

SP TOOLSource: DG Bowen, 2005

Principle of Spontaneous Potential SP LogSource: Halliburton

Source: HalliburtonLiquid junction effectsLiquid junction potential

Source: HalliburtonSP due to membrane potentialResultant SP from liquid junction and membrane potentials20/03/201312Application of SP tool:1. Permeable zone identification2. Fluid type identification 3. Connate water salinity determination Across shales, SP curve defines a more or less straight line to represent shale baseline.Across permeable formation , SP curev show defelection from shale baseline. If the deflection is positive, Rmf