Lecture 6 Summary and Notes

Important concepts for the day:

1. Petroleum reserviors are so rare because:

a. out of all of the organisms that live (and die) most decompose

b. out of all of the sedimentary rocks that form, <1% are "organic rich" = >5% organic material

c. out of all of the organic rich potential source rock that forms, not all is going to "make it to the kitchen" be buried to the depths (and heat) required for the formation of oil and gas)

d. out of all of the oil and gas that forms, <10% is trapped in reservoirs

e. ...

2. Seismic imaging is the "workhorse" of petroleum exploration. Seismic imaging allows us to see layers and structures within the Earth. Layers are "visible" in seismic imaging when one layer propagates seismic waves at a different speed than another; the wave is reflected and refracted at this boundary and this is indicated by a darker line on the seismic image.
3. The history of the seismic profile for our homework assignment is as follows:

a. deposition of horizontal, laterally continuous sheets of sedimentary strata (limestone then layered organic-rich shale, then coarse-grained sandstone, then well-cemented mudstone, then massive sandstone, then layered sandstone)

b. differential stress from a tectonic event folded the existing layers into an anticline fold

c. the top of this fold was eroded.

d. deposition of horizontal, laterally continuous sheets of sedimentary strata (conglomerate, then layered sandstone, then layered siltstone) occurred over top of the eroded anticline.

4. Divisions within the oil industry are described as being "upstream" or "downstream" such that:

upstream (aka E&P sector) involves exploration (finding oil) and production (drilling and operating wells)

midstream involves getting the oil from the oilfield to the refinery and

downstream involves refining, selling, and distributing the oil

5. The term "crude oil" describes oil as it is after being pumped out of the ground; crude oil from different oil fields can have a different composition. "Average" crude oil composition is mostly C with some H and trace S, N ,O< metals and salts. Kerogen from different source material (algae vs. zoooplankton and phytoplankton vs. land plants) will have different compositions with regard to H, C, and O. As petroleum matures from kerogen to oil to gas to graphite, its carbon content increases.

6. Most refineries are big and the biggest are, um, really big.

Slides shown in lecture today are available on Sakai. Monday, we will continue with our discussion of oil refineries and the organic chemistry of petroleum and begin our discussion of unconventional petroleum reserves. Your reading assignment for Monday is The Colonization of Kern County by Jeremy Miller.