Wells pumped dry later replenished.
The 195-210-million-year-old specimen was found 2.3km (1.4 miles) below the floor of the North Sea by an offshore oil drilling platform.
In September 2009, the rig (Deepwater Horizon) drilled the deepest oil well in history at a vertical depth of 35,050 ft (10,683 m) and measured depth of 35,055 ft (10,685 m) in the Tiber field at Keathley Canyon block 102, approximately 250 miles (400 km) southeast of Houston, in 4,132 feet (1,259 m) of water.
what wells? Where? how much? how long?
Originally posted by ANNED
Wells pumped dry later replenished.?!
In many cases where this has happened the oil is thick or the oil deposit has other deposits below it.
bad practises like perforating in multiple layers can cause oil from one layer to migrate to the other pumped out layers.
In thick oil fields steam/water flooding and/or solvent flooding on one part of a field may cause increased flow in other parts of the field years later.
They may also cause increased flow in other oil layers if there are wells perforated in multiple oil layers.
Originally posted by makeitso
Here is the PNAS information. Dated 2002.
PNAS The genesis of hydrocarbons and the origin of petroleum
Conclusions from the PNAS: The pressure of 30 kbar, at which the theoretical analyses of section 4 predicts that the Hydrocarbon system must evolve ethane and heavier hydrocarbon compounds, corresponds to a depth of more than 100 km. The results of the theoretical analysis shown in Fig. 2 clearly establish that the evolution of the molecular components of natural petroleum occur at depth at least as great as those of the mantle of the Earth, as shown graphically in Fig. 4, in which are represented the thermal and pressure lapse rates in the depths of the Earth.
Here is the followup testing (Again) Dated 9-2004
Physicsweb - Petroleum under pressure
Scientists in the US have witnessed the production of methane under the conditions that exist in the Earth's upper mantle for the first time. The experiments demonstrate that hydrocarbons could be formed inside the Earth via simple inorganic reactions -- and not just from the decomposition of living organisms as conventionally assumed -- and might therefore be more plentiful than previously thought.
And the PNAS for it:
Generation of methane in the Earth's mantle: In situ high pressure?temperature measurements of carbonate reduction
Conclusions: The study demonstrates the existence of abiogenic pathways for the formation of hydrocarbons in the Earth's interior and suggests that the hydrocarbon budget of the bulk Earth may be larger than conventionally assumed. The wide pressure?temperature?composition stability field of methane documented here has broad implications for the hydrocarbon budget of the planet and indicates that methane may be a more prevalent carbon-bearing phase in the mantle than previously thought, with implications for the deep hot biosphere (25). In particular, isotopic evidence indicating the prevalence of biogenic hydrocarbons pertains to economically exploited hydrocarbon gas reservoirs, largely in sedimentary basins (2); these observations and analyses do not rule out the potential for large abiogenic reservoirs in the mantle. Moreover, the assumption that CO2 is the sole carrier of mantle-derived noble gasses (26, 27) should be reevaluated. Finally, the potential may exist for the high-pressure formation of heavier hydrocarbons by using mantle-generated methane as a precursor.
From the Oak Ridge National Laboratory. Dated 1999
Abiogenic methane formation and isotopic fractionation under hydrothermal conditions
These results, combined with the increasing recognition of nickel-iron alloy occurrence in oceanic crusts, suggest that abiogenic methane may be more widespread than previously thought.
Department of Earth and Planetary Sciences, Nagoya University, Japan. Dated 1994.
Mantle hydrocarbons: abiotic or biotic?
Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) arid peridotite xenoliths in alkali basalts contain heavier hydrocarbons (n-alkanes), whereas igneous rocks produced by magmas such as gabbro arid granite lack them. The occurrence of hydrocarbons indicates that they were not derived either from laboratory contamination or from held contamination; these compounds found in the mantle-derived rocks are called here "mantle hydrocarbons."
It appears that hydrocarbons may survive high pressures and temperatures in the mantle, but they are decomposed into lighter hydrocarbon gases such as CH4 at lower pressures when magmas intrude into the crust; consequently, peridotite cumulates do not contain heavier hydrocarbons but possess hydrocarbon gases up to C4H10.
Another instance that leads me to believe that oil is abiotic is the symptoms that clean up workers suffered from after the Exxon Valdez spill. Most of the symptoms are consistent with radation exposure.