Geol 404 1st Edition Lecture 7 Outline of Last Lecture I. Stress RegimesII. FaultsIII. FoldsIV. Geometrical FoldV. Mechanical FoldOutline of Current Lecture VI. GeophysicsVII. DHI Gas EffectVIII. Drilling Rig SystemsIX. LoggingX. Borehole EnvironmentXI. Salinity and TemperatureCurrent LectureVI. Exploration Geophysicsa. Uses logging as a method to understand the reservoirb. Gravity and Magnetic Responcesi. Show the angles of the faults and sand barsii. Basement Fault1. Gravity responds2. Magnetic respondsiii. Reef1. Gravity responds2. Magnetic doesn’t iv. Minor Intrusion1. Gravity doesn’t 2. Magnetic respondsv. Salt DomeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Gravity responds best2. Magnetic responds sortofc. R=p*v (Reflection Time)=(density of rock*velocity of rock)i. Highest to Lowest Density Velocity rocks1. Limestone, Anhydrite, Dolomite, Salt, Shale, Sandstone, Coald. Stacked Tracei. Depositional Environments –Stratigraphic Trapsii. Seismic Facies Analysis – Internal Reservoir Propertiesiii. Seismic Attribute Analysis – Internal Reservoir PropertiesVII. DHI Gas Effecta. 4 Classificationsi. Bright Spot -Occurs in very porous sandstone (Bright Red)ii. Polarity Reversal -Occurs in moderately porous sandstoneiii. No Reflection -Occurs in porous limestoneiv. Dim Spot -Occurs in Less porous limestoneVIII. Drilling Rig Systemsa. Hoisting, Rotary, Fluid Circulating systemb. Kelly -Pipe that connects to the Kelly bushing or rotary tablec. Kelly Bushing -Rotating piece of metal attached to drilling rig.d. Circulating systemi. Shale shaker to desander to desilter to mud tanks to mud pumpse. Drilling Mudi. Formation fluid/gas that tries to enter a wellbore can damage the wellbore, and may cause a blowout IX. Logginga. During Drillingi. Mud Log1. Record cuttings depth, oil, gas, and lithological dataii. LWD (Log while drilling)b. After Drillingi. Wireline Logging: formation evaluation, perforation, hole integrityii. Spontaneous Potential1. Shows lithology, bed shaliness, qualitative permeability2. Shale Baseline to the right3. Sand baseline to the leftiii. Resistivity Log1. Shows lithology, hydrocarbons, pressure predictionX. Borehole Environmenta. Mudcakeb. Flushed Zone (invaded zone)c. Transition Zoned. Uninvaded ZoneXI. Salinity and Temperature a. Salt solution can dissolve in water to ionsb. Higher salinity=higher ion concentration in the water=higher conductivityc. Expressed in ppm parts per milliond. 200ppm to
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