Basins, Tight Sand, & Shale Plays, Oh My!

While having a discussion in my office, I discovered I really don't understand the differences between basins, tight sand & shale plays.  Why are the resources that come from them different?   Do you have to drill through them differently?  New blog subject discovered!

Originally, I wanted to explain the geological differences between basins, tight sand and shale plays in one blog post. However, I realized, not only do I want to have a better grasp on the definition of these land formations, but I also want to see how they relate to the oil and gas industry.   

As I began researching, I found plenty of great information to squeeze into one week's blog, but combining all the information at once can contribute to a case of information overload.  So, I am dividing the blog into three parts.  Let's begin, shale we? (Sorry, that was too easy.)

Basins are geographically the largest of the three, so we will start there. 

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A basin is a dip or a depression in the earth's surface, a bowl if you will.  They generally have sides higher than the bottom.  Basins were not created overnight, more like thousands of years.  They are formed by forces above the ground, like erosion or below the ground, like earthquakes.  Of course, with the earth being so vastly different you know there must be different types of basins.  The map above shows basins that are in the United States.  The three major types are River Drainage Basins, Structural Basins, and Ocean Basins. Here is a quick breakdown of the three.


  • River Drainage Basin- The land that water must cross to reach a river.  The lowest part of a basin drains all the available water from various tributaries, creeks and streams in its area. 
  • Structural Basin-  It is formed by tectonic activity, the natural processes of weathering and/or erosion.  They are found in mostly dry regions.
  • Ocean Basin-  The larges of the three depressions. The picture below shows that to be true. The edges of the continents, known at the continental shelves, form the sides of the ocean basins.These basins are constantly changing due to tectonic activity, such as seafloor spread and subduction.  Ocean basins are at depths of thousands of feet below the ocean's surface. Because of this depth, they remain the most elusive to scientists.  


Now that we have learned what a basin is, let's discover how it is tied to the oil and gas industry.

The natural resources that the consumer craves in these basins are generally formed the same way, with organisms, sediment, pressure, heat and time. (Remember: I am not a scientist!)  The sediment, which are the remains of  plants, animals, that have been covered in salt and silt, have been pushed down deeper and deeper towards the earths crust.  The energy stored within these organisms, along with the immense pressure and heat created the sand.  More pressure and heat created rock. There are layers upon layers of this. Different levels of heat, pressure, and organic make-up are the deciding factor to the creation of crude oil or natural gas underground. If the rock surrounding the resources is porous they will travel through the rock.  If the rock is not porous the resources will be trapped in a reservoir beneath a basin, then the drilling begins.  

Deeper burial of rock layers in subsiding basin



Continued burial of sediment and rock layers in subsiding basin




I hope this first part of my three part series helps you to understand the definition of a basin and how the term is used within the oil and gas industry.  

I have a lot more knowledge to share on Tight Sand and Shale Plays coming soon.  


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Amy Jerina

Amy Jerina is an Account Representative with Croft Production Systems which is located in Needville, Texas. At Croft she focuses on growing existing customer relationships & helps to develop new client prospects. With a focus on increasing sales of the organization’s products & services. Amy also works with the marketing & business development team members in the office to ensure CROFT is meeting its client needs. She collaborates with field representatives & engineers as a liaison between the company & clients. Amy provides unlimited support to customers over the phone & is able to conduct field visits with clients located in the Continental United States. Amy has over 10 years of management, training & sales experience & over 15 years of customer service skills. She is using this experience to break into the oil & gas industry. By writing this weekly blog Amy is growing her oil & gas knowledge and hope to share that knowledge with anyone who wants to learn.