Marcellus Shale Fracking – Transloading Bulk Materials for Marcellus Shale Drilling

Archive for the ‘Hydro Fracturing’ Category

The process of fracking can be natural and man made. Either way it is done, the result is the same. This is when a liquid is pressed up against a rock bed which causes it to break or fracture. The most common use for this process is in the oil and natural gas exploration field, but it can also be used to stimulate a groundwater well.

The first use of fracking rock was in North Carolina around 1903. At the Mount Airy quarry, fracking was and still is, used to separate the granite rock from the surrounding rock bed. This process was modified in 1947 to fracture the rock bed deep in the earth through the borehole of a well. It was so successful that it became common practice by 1949. Today, this practice is still used around the world to help extract additional trapped energy reservoirs.

Once the rock bed was cracked or fractured, a means was need to keep these newly developed openings from closing. This is the purpose of adding sand to the water. This slurry has worked very efficiently because the sand is porous enough to allow the water, oil, and natural gas to be released but has enough integrity to keep the rock from closing again once the pressure is released.

Microseismic monitoring is the way those causing the fracking to locate and identify where the fractures occurred in the borehole and surrounding rock bed. With the information from the monitors, a map can then be produced and used by the engineers of the well.

The injection rate of the slurry mixture of water and sand can be as high as 100 barrels a minute or 265 liters per second. The actual pressure that builds up, which causes the fracking of the rock bed, can be as great as 15000 psi.

The definition of microseismic is a faint earth tremor that is caused by a natural phenomenon like waves or wind, or by a manmade source called hydro fracking.

When compared to an earth quake by magnitude, the difference is clear. A 3 magnitude earthquake is the smallest that can be felt. This is when 4 cm of movement over a 0.03 km squared area occurs. This is equivalent to a 30 ton blast. A micro seismic is on a magnitude of 0 with a slip and area of 1 mm over 30 m squared. This is equivalent to 1 kg stick of dynamite. The smallest recordable movement is a -4 magnitude. This is when the slip and area are 10 micrometers and the area is 0.003 m squared. This is equivalent to a 1 mg blast of explosives.

To map out a possible gas reserve, the operators must know where to start boring their holes horizontally. This is where microseismic mapping plays an important part. When sound waves are passed through the earth, P and S waves can recode the slippage of shearing of the rock surfaces. Sensors that are placed in a bore hole can pick up the echoes of the sound waves which then can be interpreted into a map of the rock layer.

The purpose of this type of mapping in relation to natural gas drilling is to determine how the rock formation is responding to the pressure that is being applied to it, with the fluid volume being pumped into the wells.

The use of microseismic mapping has grown over the past 5 years and is starting to play a significant role in determining the effectiveness of the hydro fracturing on a specific well and its gas extraction potential.

This type of preliminary exploration is done in advance of moving in the necessary drilling equipment and fracking sand, and that is where Transloding comes in to the system.

For a well that contains natural gas, fracking the shale rock has become a common practice. There are two different mediums that are currently being used in this process. Immaterial of which medium is used, the principle is the same – to force a cracking or fracturing of the rock bed so the natural gas and oil deposits can be recovered.

In the early days, this procedure was done on vertical wells. With the advancement in boring well technology, horizontal wells have shown to have a better reaction to the fracking process. This is due to the fact that more of the shale rock layer that has the trapped energy reserves is exposed.

The most common is the use of a mixture of water, hydrocarbons, and sand in a slurry mixture. This slurry is forced down into the well bore under tremendous pressure. Once there are cracks, this exposed rock layer. Through these cracks, the trapped oil and gas is released. Once the pressure is released at the top, the sand that is in place in the newly formed fractures keeps it open.  This process is called hydro fracturing.

Once the pressure is released, the medium needs to be extracted from the wellbore. This is where the main different between the two are evident. The traditional medium is water. This extraction can take up to 7 days before oil or gas recovery can resume at the well.

When liquid propane or LPG is used as the medium, the recovery process is reduced and is easier. The liquid propane is extracted as a gas, and in most cases, the gas is funneled in the same lines as the natural gas is during normal recovery. The recovery period is generally between 24 and 48 hours.

With oil and natural gas fracking is a proven method for extracting 30% to 50% more energy reserves than those wells that are not fracked.

Transloading.org is a blog that is sponsored by TranZ a company that provides freight transportation and material handling for the Marcellus Shale gas fracking industry.

The term gas fracking is the slang used in the oil and gas industry when referring to hydro fracturing of the rock deposits. When first used at the turn of the last century, the injecting of water into a well was used to bring more of the oil deposit to the surface.

Horizontal drilling began to be used over 60 years ago. This helped drillers tap into a larger cross section of a deposit. Natural gas explorers soon noticed there were advantages of injecting sand with the water under high pressure to break the rock formations and cause micro fractures in the rock.

The water and sand mixture is called slurry. When this is injected into a well at pressures up to 15,000 psi, it causes the cracking of the rock. This releases the trapped gas that is in the shale rock formations. The sand is used to help keep these micro fractures open so the gas can escape to the surface and be collected.

The horizontal drilling techniques make it possible for the fractures to develop in the rock layer more evenly and in greater numbers. There is no need to fracture rock layers that contain no oil or gas, which this type of drilling helps to reduce.

From an environmental standpoint, this hydro fracturing to recover more trapped natural gas could be beneficial to reducing the buildup of greenhouse gases especially CO2. This is possible if more coal burning electrical plants convert their energy source to the cleaner burning natural gas that is becoming more abundant. This in part can be contributed to advances in the gas fracking techniques now being deployed in the Marcellus shale deposit in the Appalachian mountain region of our country.