- By: Paul Parsons
- In: Blog
In previous posts, we explained why horizontal drilling and hydraulic fracturing is needed in unconventional shale and tight-rock formations (here) and we presented an example of the drilling and casing program for a horizontal well (here). In this post, we will address how a horizontal well is hydraulically fractured. We'll focus on the "plug-and-perf" method, which is by far the most common method. We’ll illustrate the process with a video we created but will provide some context first. If you prefer, you can skip straight to the video further down.
Overview
Hydraulic fracturing involves pumping fluid under high pressure to create a series of fractures extending out from the lateral section of the wellbore into the surrounding formation. “Proppant” (usually sand) is added to the fluid to fill the fractures and keep them open after pumping has stopped. The fractures create a multitude of easy-flow pathways for oil and/or gas to reach the wellbore, which increases both the total recoveries and the rate of recovery from the low-permeability rock.
Stages
Hydraulic fracturing is done in a series of “stages” starting at the toe of the well. The length of stages can vary by area, by formation and by operator but are commonly around 250’. Stages are necessary because it takes a tremendous amount of pumping horsepower to create fractures so it is only practical to do a limited amount at a time. Also, fracture patterns are easier to control in small stages and can be implemented more uniformly. The number of stages will depend on the length of the lateral and the length of the stages. A 10,000 foot lateral with 250’ stage length would have about 40 stages.
- By: Paul Parsons
- In: Blog
In this post we’ll present an example of the drilling program for a horizontal well in the Bakken formation in the North Dakota portion of the Williston Basin. The Bakken is one of the larger unconventional oil development areas in the US. Drilling designs differ by area and by company, and evolve over time as experience is gained and new technologies and capabilities are developed. However, the well we will review here has strong similarities with wells currently being drilled in other unconventional oil areas such as the Permian Basin and parts of the Eagle Ford. The example we'll use is modeled after an actual, recent well plan that was submitted for approval to the state regulatory agency by a large Bakken operator.
- By: Paul Parsons
- In: Blog
The term "unconventional" oil and gas refers to oil and gas produced in a manner different than the traditional (conventional) way. The traditional way, which we covered last week, is drilling vertical wells into subsurface structures/features identified on seismic ("prospects") that may have trapped sizable accumulations of migrating oil and gas.
In this post, we will deal with the type of unconventional production that involves producing oil and/or gas from shale or other types of "tight" rock using horizontal drilling and hydraulic fracturing. We will address other types of unconventional production in future posts, including coalbed methane and the Canadian oil sands.
- By: Paul Parsons
- In: Blog
By now, almost everyone has heard the terms "conventional" and "unconventional" oil and gas. This week we will focus on the conventional/traditional method of oil and gas exploration, which involves searching for subsurface features in porous and permeable rock layers that may have trapped accumulations of oil and gas. These "prospects" can be explored and produced using simple vertical wells, but there is substantial risk of drilling a "dry hole." Next week we will address unconventional development of shale and tight rock formations using horizontal drilling and hydraulic fracturing.
- By: Paul Parsons
- In: Blog
In order to produce oil and gas from a property, the producer must have legal rights to produce, called “mineral rights.” There are multiple forms of mineral rights ownership, and the form most-commonly used by oil and gas companies is to “lease” exploration and production rights from “mineral estate” owners.
- By: Paul Parsons
- In: Blog
Oil and gas are molecules composed of hydrogen and carbon atoms and are thus called “hydrocarbons.” Hydrocarbons are flammable/combustible and can be used to make a variety of fuels, but they are also highly versatile for other uses such as the manufacture of plastics and a wide variety of other petrochemical products. Hydrocarbons gain their exceptional versatility primarily from their carbon atoms. Carbon atoms bond exceptionally well with other atoms, are easy to modify into other chemical and structural variations, and can form more compounds than any other element. Carbon is also a critical component of all lifeforms and the carbon and hydrogen remains of organisms that lived in the ancient past are the source of oil and gas.
- By: Energy Training Resources
- In: Blog
The world in general, and the U.S. in particular, have a lot of room for improvement in oil and gas consumption. However, modern life relies on oil, gas, and derived products in countless ways that mostly don't yet have suitable or scalable alternatives. You are relying on computer and telecommunications components derived from oil and gas just to read this post, and if you look around you right now, you will likely spot many products that involved oil and gas in some way, such as the materials that they are made from, the power used to manufacture them, or the packaging that they came in. In addition to products themselves, we are served by an oil-and-gas-fueled global transportation network that continuously operates to efficiently distribute materials, equipment, supplies, consumer goods, and food products around the world.