South Texas Oil Fields

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Texas is, of course, famous for being the primary locations of oil in the continental United States. It remains the leading producer of both oil and gas. In January 2013, over 70 million barrels of crude oil (MBO) were produced in Texas, more than 3 times the next highest state, (North Dakota with 22.8 MBO).

The state’s oil boom began with the famous Spindletop gusher in 1901. In the years since, the state’s petroleum regulators (The Texas Railroad Commission) used to control oil prices by installed price quotas on Texas oil producers, although this was lifted in the early 1970s when the state’s production peaked.

Texas is also the heart of our country’s Gulf Coast refining hub, with 27 refineries with an estimated capacity of 4.7 MBO/day. These refineries process oil from Texas, the Gulf of Mexico, or international blends imported at any of a variety of southern shipping ports. Naturally, product is used as feedstock for an extensive petrochemical industry.

One of the bigger recent developments in Texas was the reversal of the famous Seaway Pipeline to Cushing, Oklahoma, the location where the oft-cited West Texas Intermediate blend is physically delivered.

Oil-bearing formations have been observed in areas listed below.

- The Wilcox formation is mostly observed in the north eastern part of texas and pinches off towards the southern parts of the state. The Lower Wilcox Group part of the Eocenepaleocene series of the Tertertiary System. The Wilcox has an overlying relationship with the Midway formation through most of Texas. In other words, the Wilcox is on top of the Midway. In the northern parts, the Wilcox tends to be thicker than the Midway, while in the southern parts the Midway is thicker than the thin Wilcox layer above it.

- The Midway oil and gas formation is closely related to the Wilcox formation and is also part of the Eocenepaleocene series of the Tertertiary System in Texas.

- The Navarro oil formation is typically found above the Taylor systems. The Navarro formation is classified as part of the Maastrichtian Group of the Gulfian Series of the Cretaceous age. The Nacatoch, which is typically a prolific formation in Louisiana along with the eastern part of Texas, has been recorded to have great oil potential throughout history. Where the Nacatoch pinches off, the Corsicana formation, otherwise known as the Navarro, begins. In the southernmost parts of Texas it is often referred to as the Escondido Upper or the Olmos Lower.

- The Taylor oil formation is part of the Campanian Group of Gulfian Series of the Cretaceous System. Other formations closely related to the Taylor are the Pecan Gap, Wolf City, San Miguel, Anacacho and Upson.

- The Austin Chalk oil formation is part of the Santonian Coniacian Group of the Gulfian Series of the Cretaceous System. The chalk parts of the Austin formations have been largely sought after over time.

- The Eagle Ford oil formation, which lies below the Austin Chalk, is part of the Turonian and Cenomanian Groups of the Gulfian Series of the Cretaceous age. Most often found as a shale, the Eagleford tends to bear more natural gas in the eastern parts of the state and, as one moves to the west, more condensate and crude oil is found. Some of the most profitable areas have been observed in between the dry gas and oil-bearing areas of Texas. Other formations related to these two time periods are the Subclarksville, Coker, Harris, Lewisville, Dexter and Woodbine.

- The Buda oil formation and the Grayson, Georgetown, Fredericksburg, Edwards, Person, Kainer, Salmon Peak, Mcknight, West Nueches, and Stuart City are classified as the Albian unit of the Comanchean Series of the Cretaceous age and have been known to bear hydrocarbons such as crude oil throughout parts of Texas.

- The Glen Rose, Mooringsport, Bacon Limestone, Rodessa, James Limestone, Pine island have been classified as Glen Rose Group of the Aptian and Albian Series of the Comanchean and Coahuilan Series of the Cretaceous System.

- Buckner, Smackover, Gilmer-Haynesville, Cotton Valley, Schulter, Bossier, Norphlet, Louann Salt4, and the Werner are some of the deepest formations that have been known to bear rich hydrocarbons. These formations are generally very tight in terms of permeability and porosity due to their depths and, therefore, tend to require very large fracs. These formations are all part of the Jurassic age which is composed of the Lower, Middle and Upper Series. At this time, nothing has been found in the Lower Jurassic … yet

The Gulf of Mexico and parts of Texas have always had a complex structural history of all oil- and natural gas-bearing systems.

The supercontinent Rodinia which was thought to contain all the earth’s land mass, was thought to exist 1.1 billion to 750 million years ago. As this supercontinent began to break up in parts of what we know as the Gulf Coast, particularly with Mexico, Texas, Louisiana, Mississippi, Alabama, Florida and including the Gulf of Mexico itself, it began to go through periods of trying to create rifts. But failed systems, or aulacogens, began to form during the 150 million year intervals which have now have been associated with many different types of oil- and gas-bearing structures. These structures are known today by a variety of different names including, in Texas, the Delaware Rift, which runs along the Rio Grande River; the Wichita Oklahoma Aulacogen, closely related to the Red River; and the Mississippi Lineament, or Reelfoot Rift, which runs along the modern Mississippi River system.

During the Pennsylvanian and Permian periods, the earth’s super continent, Pangea, created several different faults as the plates associated with Africa, South America and North America separated from one another. These geological movements created oil- and gas-bearing formations related to the Paleozoic period.

in the Triassic period, South America and Africa separated from North America and formed a series of rift basins along the North American continent. During this time it has been thought that the area known today as the Gulf of Mexico was a stretched low basin that flooded in the late Jurassic period. This lowly flooded land was then further divided in the area underlain by the Middle Jurassic Salt, which is associated with the Oceanic crust of that time period, while the Upper Jurassic Carbonate and Clastic areas were deposited over the entire basin. The Upper Jurassic Smackover formation has been thought to be the source rock of many of the oil and gas formations that originally consisted of shelf carbonates and deeper marine shales.

Few tectonic events are thought to have happened in Gulf of Mexico Basin during the Cretaceous Period. This caused the perfect environment for life to flourish. During this time, known as the early Cretaceous period, shelf-edge reefs developed along the breaks between the continental shelf. The southern parts of these shelf-building events have been classified as the Aptian Reef-building Event, and was thought to ¬†occur where prehistoric life forms deposited lime mudstone and shale. These reefs then started to be formed landward, and stratigraphically above the earlier reefs. The shelf’s edge also influenced the deposition of the Upper Cretaceous Unit, which formed the Austin Chalk and Eagle Ford formations, and are thought to be the source rock of Cretaceous and early Tertiary anticline and syncline systems.

* The photos on this page do not represent any specific locations, projects, or company and are shown for visual purposes only. This is not a project for sale or a solicitation to purchase any oil wells for sale or natural gas wells for sale. This is not a presentation or offer to sell securities or to sell any other product whatsoever. This post is only for informational purposes to aid individuals who wish to develop oil and gas assets in the southern part of this state.

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