Marcellus Shale Fracking – Transloading Bulk Materials for Marcellus Shale Drilling

Archive for the ‘Well Drilling’ Category

The horizontal drilling and hydraulic fracturing that is involved in the natural gas and oil exploration fields in America is done to improve the amount of energy reserves that are being extracted from the ground.

The horizontal drilling is done to increase the amount of surface exposure a wellbore has with the subsurface rock formation. With more exposure to this surface area, the process of hydrofracking or fracking can be done with a greater amount of efficiency.

The hydrofracking is a process where a slurry is made with small amount of acid, frac sand, and water. The ratio of water to sand is 99.5: 0.5. This slurry is then pumped into the wellbore and down into the subsurface rockbed at a rate of up to 265 liters per second. Pressure is then applied to the slurry, which can reach upwards of 15,000 psi.

This pressurized slurry forms cracks in the brittle rockbed where energy reserves are trapped. The oil and natural gas is allowed to escape after the slurry pressure is released because the frac sand that is left behind in these cracks are keeping them open.

The frac sand’s density and crush limit is generally greater than the pressure being exerted on it from the rockbed, which makes it the ideal medium for holding open the fractures.

The water and excess frac sand is then recovered after the fracking process, and the additional natural gas and oil reservoirs can then be extracted and collected for use in the American market.

This is how horizontal drilling and hydraulic fracturing is contributing in a positive manner in making America less dependent on foreign energy imports.

Here is more about well drilling.

The Marcellus horizontal drilling is legal and practical due to the way the formation of shale rock has formed. When a drilling company just drills straight down, or what is called vertical drilling, their borehole only intersects the shale layer that is a small and limited area.

The shale layer in the Marcellus shale region is not vertical but horizontal, like nearly all layers of the earth’s mantle. The horizontal drilling is vertical drilling at the top, but a directional drill head changes the course and direction of the borehole during the drilling process.

The main advantage of this process is that a greater area of the shale rock bed is exposed in the borehole. This increases the possibilities of the drilling to intersect with a natural gas pocket. Because of this increased area of exposure when fracking is needed to increase the amount of natural gas or oil from the shale rock bed, a better result is achieved.

The secondary advantage is that multiple boreholes can be started on the same platform, but go in different directions. This allows for more underground area that can be covered without a greater impact on the surface environment.

Horizontal drilling is accomplished by starting a vertical shaft downward. As the hole is being drilled, the direction is guided sideways. This is not a 90-degree turn like on a street, but a slow curving arch that could take hundreds of feet before the corner is achieved.

With this style of drilling, most wells are capable of extracting up to 5 times more natural gas and oil than with a vertical borehole alone. The time it takes to drill a horizontal well is comparable to a vertical well, which is only 30 to 45 days. The time is dependent on the depth the well is to penetrate to.

In the region of Marcellus, horizontal drilling is the most common and economically practical application for the extraction of natural gas and oil from below the surface.

The term horizontal drilling is also called directional drilling and slant drilling. This type of drilling is nothing new and has been around since the early 1900s.  The early methods were achieved through the use of bent or curved piping.

The true horizontal drilling did not occur until the development of the downhole drill motors that were developed in the 1970s. They used a stationary pipe for power with a rotating drill head and a piece of bent pipe or snub pipe that allowed for the direction of the hole to be changed.

The latest technological advances have come with the rotary steerable tools that allow the operator to drill in the direction they desire with more accuracy.

Compared to vertical drilling, the benefits of this type of hole boring are a greater access and exposure of a reservoir, along with more options on the placement of a drilling platform. This method is how energy companies are recovering oil and gas reserves that are located under towns and villages.

This process has also changed the way many companies now approach drilling. There are instances where up to 40 different drilling platforms are placed closely together. Each one heads off in a different direction underground to recover the energy reserves that are trapped below ground. Because the platforms are located in a smaller area, the environmental impact is reduced.

In years to come, more wells will use the horizontal drilling techniques to recover more energy to meet the demands of consumers.

The process of well drilling is nothing new to the natural gas and oil industries, but these were not the first types of wells that were used. Water was the first resource that mankind drilled into the ground in an attempt bring it to the surface and recover it. These early wells were dug by hand and not very deep.  To support the sides many were lined with masonry block.

The modern process of drilling a borehole is much more complicated. The shafts are longer and narrower. Because of the number of wells being drilled and the increased companies performing this process, regulations and regulating agencies have been established to set limits and define the process.

Today, there is the International Association of Drilling Contractors (IADC) that has defined the process to help guide and standardize the industry. The limits on the downhole pressure and hydraulic pressure profiles can be found in the Managed Pressure Drilling (MPD).

Part of this process is the use of the appropriate drill bit. The soil is generally categorized into one of three conditions. There is soft, medium, and hard.

The soft condition is generally made up of sand, clays, shale, and soft limestone. The soil is considered medium when calcites, hard limestone, hard shale, and dolomites are present. Hard soil conditions are when hard shale, mudstones, and cherty limestone are in the ground being drilled.

For the most part when drilling a well for the natural gas and oil industry, one of two types of bits will be used. The drag bit is a polycrystalline diamond compact hammer bit (PDC bit) that is used in the soft soil conditions. The second, used on deep holes, is the roller bit that has teeth on wheels that crush the rock in the path of the borehole.

One little known fact of well drilling is that this is the most widely known use of diamonds in the world.  They will never look good on a finger, but they can cut through rock like butter.

You might be wondering what well drilling has to do with Transloading.  This blog is sponsored by TranZ a freight handling company that specializes in delivering goods and materials to the Marcellus Shale fracking sites.  You may contact TranZ by CLICKING HERE.