Oil and natural gas wells have traditionally been drilled vertically, at depths ranging from a few thousand feet to as deep as five miles. Today, advances in drilling technology allow oil and natural gas companies to reach more reserves while reducing environmental impact by:

• reducing the surface “footprint” of drilling operations
• drilling smaller holes and generating less waste
• creating less noise,
• avoiding sensitive ecosystems
• completing operations more quickly.

Here are some technologies used:

Horizontal Drilling - Horizontal drilling starts with a vertical well that turns horizontal within the reservoir rock in order to expose more open hole to the oil. These horizontal “legs” can be over a mile long; the longer the exposure length, the more oil and natural gas is drained and the faster it can flow. More oil and natural gas can be produced with fewer wells and less surface disturbance. However, the technology only can be employed in certain locations.

Multilateral Drilling - Sometimes oil and natural gas reserves are located in separate layers underground. Multilateral drilling allows producers to branch out from the main well to tap reserves at different depths. This dramatically increases production from a single well and reduces the number of wells drilled on the surface

Extended Reach Drilling - Extended Reach Drilling - Extended reach drills allow producers to reach deposits that are great distances away from the drilling rig. This can help producers tap oil and natural gas deposits under surface areas where a vertical well cannot be drilled, such as under developed or environmentally sensitive areas. Wells can now reach out over 5 miles from the surface location. Offshore, the use of extended reach drilling allows producers to reach accumulations far from offshore platforms, minimizing the number of platforms needed to produce all the oil and gas. Onshore, dozens of wells can be drilled from a single location, reducing surface impacts.

Complex Path Drilling - Complex well paths can have multiple twists and turns to try to hit multiple accumulations from a single well location. Using this technology can be more cost effective and produce less waste and surface impacts than drilling multiple wells.

Rock and fluid properties will determine how much oil and natural gas can be recovered from a reservoir. After an exploratory well has been drilled, it is evaluated to determine if there is enough oil and natural gas in the reservoir to make it economically feasible to initiate recovery operations.

Drill Cuttings and Core Samples - As the drilling mud is brought to the surface, it is run through a sieve to removed the drill cuttings (pulverized rock) before the mud is recycled down into the well. Small pieces of rock are selected for microscopic analysis to determine the type of rock being drilled, how porous it is, and whether oil is present. The drilling mud also is analyzed with sensors to see if trace amounts of oil or natural gas are present — an indication of a possible accumulation at depth. In the past, rock cuttings were the principal source of well information.

Well Logging - A special bit can be used to cut a cylindrical piece of rock that can be brought to the surface for analysis. The core is sent to a laboratory where the exact porosity and permeability can be determined. This gives a good indication of how well oil or natural gas would flow through the rock. Fluid samples can be taken and analyzed to determine the amount and type of hydrocarbon present in the rock.

Wells are completed for production if the value of the recoverable oil and/or natural gas is greater than the cost of drilling and producing them and delivering them to market. If not, the well is plugged In accordance with industry standards and federal or state requirements (depending on the location) and the site is restored.

Laversab’s latest Atex computers - the Zone-1 and Zone-2 rig-floor computers are designed to overcome challenges presented by drill rig environments.

Onshore Drilling (Part 3)

As of result of advances in horizontal drilling natural gas resources in shale basins has been more accessible leading to more diversified sources of natural gas. Combining this with other technologies such as seismic imaging has contributed to lower marginal operating and capital costs, which in turn allow natural gas producers to more economically extract natural gas from resources.

Horizontal drilling also permits the development of natural resources with minimal above-ground disturbance, reducing the environmental footprint of natural gas operations and the cost and potential disturbance of existing roads or other infrastructure. Directional drilling and horizontal drilling terms are often used interchangeably. Directional drilling refers to drilling at a slant or angle to increase contact with the resource. Horizontal drilling is a type of directional drilling. Horizontal drilling uses a technique known as hydraulic fracturing in order to extract natural gas from geologic formations. For more information please visit our hydraulic fracturing section. Measurement while drilling is something that is carefully done during this process. To fail to do so can be financially crippling - leaving plenty of money on the table.

Most wells drilled for water, oil, natural gas, information or other subsurface objectives are vertical wells - drilled straight down into the earth. However, drilling at an angle other than vertical can obtain information, hit targets and stimulate reservoirs in ways that can not be achieved with a vertical well. In these cases, an ability to accurately steer the well in directions and angles that depart from the vertical is a valuable ability.

When directional drilling is combined with hydraulic fracturing some rock units which were unproductive when drilled vertically can become fantastic producers of oil or natural gas. Examples are the Marcellus Shale of the Appalachian Basin and the Bakken Formation of North Dakota.

Why Drill Wells That Are Non-Vertical?

Directional and horizontal drilling have been used to reach targets beneath adjacent lands, reduce the footprint of gas field development, increase the length of the "pay zone" in a well, deliberately intersect fractures, construct relief wells and install utility service beneath lands where excavation is impossible or extremely expensive.

Sometimes a reservoir is located under a city or a park where drilling is impossible or forbidden. This reservoir might still be tapped if the drilling pad is located on the edge of the city or park and the well is drilled at an angle that will intersect the reservoir.

If a rock unit is fifty feet thick, a vertical well drilled through it would have a pay zone that is fifty feet in length. However if the well is turned and drilled horizontally through the rock unit for five thousand feet then that single well will have a pay zone that is five thousand feet long - this will usually result in a significant productivity increase for the well. When combined with hydraulic fracturing, horizontal drilling can convert unproductive shales into fantastic reservoir rocks.

This is done by drilling in a direction that intersects a maximum number of fractures. The drilling direction will normally be at right angles to the dominant fracture direction. Geothermal fields in granite bedrock usually get nearly all of their water exchange from fractures. Drilling at right angles to the dominant fracture direction will drive the well through a maximum number of fractures.

Onshore Drilling (Part 2)

Cable tool drilling has historically taken many forms. These tools have now become so sophisticated, and so complex, that it takes a company like Laversab oilfield systems to generate said tools. Laversab oilfield systems has created highly advanced surface system equipment. In the early days of percussion drilling, equipment was very crude compared to today’s technology. The ‘springpole’ technique, used in the early 1800s, consisted of a flexible pole (usually a tree trunk) anchored at one end, and laying across a fulcrum, much like a diving board. The flexible pole, or springpole, would have a heavy bit attached at the loose end. In order to get the bit to strike the ground, workers would use their own body weight to bend the pole toward the ground, allowing the bit to strike rock. The tension in the pole would spring the bit free, in case it became stuck in the ground.

Many improvements have been made since these early percussion rigs. In fact, it was from cable tool drilling that one of the most important drilling advancements was made. In 1806, David and Joseph Ruffner were using the springpole technique to drill a well in West Virginia. In order to prevent their well from collapsing, they used hollow tree trunks to reinforce the sides of the well, and to keep water and mud from entering the well as they dug. They are credited as the first drillers to use a casing in their well – an advancement that made drilling much more efficient and easily accomplished. It is believed by many that ‘Colonel’ Drake’s 1856 well achieved success due to the use of steel casing to reinforce the well. Drake’s well was drilled using steam powered cable tool drilling methods.

Innovations, such as the use of steam power in cable tool drilling, greatly increased the efficiency and range of percussion drilling. Conventional man-powered cable tool rigs were generally used to drill wells 200 feet or less, while steam powered cable tool rigs, consisting of the familiar derrick design, had an average drilling depth of 400 to 500 feet. The deepest known well dug with cable tool drilling was completed in 1953, when the New York Natural Gas Corporation drilled a well to a depth of 11,145 feet. Despite the historical significance of cable tool drilling, modern drilling activity has shifted mainly toward rotary drilling methods. However, the foundation of knowledge laid by years of cable tool drilling is, in many cases, directly transferable to the practice of rotary drilling.

Horizontal Drilling

Horizontal drilling is flexible in that it allows for the extraction of natural gas that had previously not been feasible. Although on the surface it resembles a vertical well, beneath the surface, the well inclines so that it runs parallel to the natural gas formation. These legs can go in different directions at different depths and can be more than one mile long horizontally, in addition to the vertical well that can be thousands of feet below the surface. Horizontal drilling allows one surface well to branch out underground and tap many different natural gas resources. It also allows the well to make contact with larger areas within productive formations.

Onshore Drilling (Part 1)

Drilling into the Earth in the hopes of uncovering valuable resources is nothing new. In fact, the digging of water and irrigation wells dates back to the beginning of recorded history. At first, these wells were primarily dug by hand, then by crude stone or wood tools. Metallurgy brought about the use of iron and bronze tools to delve beneath the Earth’s surface, and innovations led to more efficient ways of removing debris from the newly dug hole. The first recorded instance of the practice of ‘drilling’ holes in the ground came about around 600 B.C., when the Chinese developed a technique of repeatedly pounding bamboo shoots capped with metal bits into the ground. This crude technology was the first appearance of what is known today as ‘percussion drilling,’ a method of drilling that is still in use. Much advancement has been made since these first bamboo drilling implements. This section will cover the basics of modern onshore natural gas drilling practices. Laversab oilfield systems equips its clients with the technology and tools to expedite the drilling process.

There are two main types of onshore drilling. Percussion, or ‘cable tool’ drilling, consists of raising and dropping a heavy metal bit into the ground, effectively punching a hole down through the earth. Cable tool drilling is usually used for shallow, low pressure formations. The second drilling method is known as rotary drilling, and consists of a sharp, rotating metal bit used to drill through the Earth’s crust. This type of drilling is used primarily for deeper wells, which may be under high pressure.

Cable Tool Drilling

Cable tool, or percussion drilling, is recognized by many as the first drilling method employed to dig wells into the earth for the purpose of reaching petroleum deposits and water. This method is still in use in some of the shallow wells in the Appalachian Basin, although rotary drilling has taken over the bulk of modern drilling activities.

The basic concept for cable tool drilling consists of repeatedly dropping a heavy metal bit into the ground, eventually breaking through rock and punching a hole through to the desired depth. The bit, usually a blunt, chisel shaped instrument, can vary with the type of rock that is being drilled. Water is used in the well hole to combine with all of the drill cuttings, and is periodically bailed out of the well when this ‘mud’ interferes with the effectiveness of the drill bit.

Offshore Drilling

Offshore oil drilling is an oil extraction technique which allows oil companies to access deposits of oil buried under the ocean floor. Most typically, offshore drilling sites are situated over the continental shelf, although advancements in drilling technology have made platforms even further out to sea economically and physically feasible. Many people are opposed to offshore oil drilling, due to concerns about its impact on the environment, and the unaesthetic appearance of oil rigs off the coastline.

Many sections of the Earth's oceans have massive deposits of oil buried deep beneath their surface, and these oil deposits are extremely appealing to many oil companies. The first offshore oil drilling operation was established in 1938 in the Gulf of Mexico, and other producers quickly started to follow suit in other regions of the world. By the 1970s, many communities had enacted specific bans against offshore drilling, and the issue became a bone of contention in some areas.

There are several ways in which an offshore oil drilling operation can be run, and the type of oil rig used is usually dependent on the depth at the location, the type of oil, and prevailing conditions. Classically, fixed rigs are built into place on the ocean floor, with multiple well heads and adjustable parts to allow engineers to extract oil from the surrounding area. Floating rigs are also used, in some regions, and in some areas offshore oil drilling is conducted on ships for even more mobility.

Working on an offshore drilling rig can be extremely dangerous. Although hazardous area computers help obviate some danger, the risks of something going wrong still are much higher in the drilling industry than in most others. Several accidents have caused rigs to explode, capsize, or become badly damaged, with accompanying loss of life, and many crews today are housed offsite, so that if something happens to the rig, the loss of life will be less severe. Workers on oil rigs still have to contend with severe weather conditions, problems with the rig, and geological conditions which could become dangerous, and they are typically highly paid in recognition of the risks of the industry.

The environmental effects of offshore drilling are primarily caused by pollution related to poorly maintained and operated rigs. Oil spills around rigs are common, especially at the seafloor, where drilling may stimulate seepage, and heavy metal pollution can also occur. Some people also feel that offshore oil drilling disrupts and confuses marine life, although ironically rigs can also provide shelter to seabirds and fish.

How Have We Improved Oil Rig Technology?

When the technology in consumer goods like cell phones improves, we all know about it instantly, because we all use these gadgets. But truthfully, technological improvements in specialized equipment like oil rigs, is probably just as important, if not as reported.

For instance, in the wake of the 2010 oil spill in the Gulf of Mexico, GE Oil & Gas created more advanced blowout preventers that use the water pressure surrounding the well to seal it in case of an emergency. The company also developed a black-box system similar to those used in airplanes. This black box will record data if something goes wrong on the rig or with the well so the problem can be quickly analyzed and corrected. Its function serves a purpose similar to that of an ATEX computer or Zone 1 Computer

Intel, the same company that likely made the memory for your computer, has invented sensors that are housed inside heavy-duty cases meant to be strapped directly to the oil rig. Several of these sensors could be fitted to any oil rig and would feed information to a central computer set up to collect the data. This warning system could tell well workers when it was time to start emergency procedures, which could save lives, oil and the environment, too.

Fossil fuel drilling is even using green energy. GlassPoint Solar has created a system of mirrors inside a glasshouse that generates the steam required to force oil to the surface of the Earth. Normally, this steam is heated by natural gas, but using the sun’s power is cheaper and cleaner. Plus, this glasshouse system produces five times more steam than other solar facilities used for the same purpose.

It will be years before fossil fuels are phased out of our daily lives, but in the meantime, technology is improving to keep workers and the environment safer as oil drilling and exploration expands.

Oilfield Systems - Fracking

The natural gas boom in the US due to hydraulic fracturing (fracking) has provided the country with a cleaner burning, inexpensive fuel source that has lowered energy bills for industrial facilities and homeowners alike. The fracking process is still a hot topic of controversy wherever it is used to extract fuel. Environmentalists claim it will ruin watersheds and leave scars on the earth, and other concerns range from flammable tap water to carcinogenic soil.

Fracking won’t set your faucet on fire.

The 2010 documentary GasLand famously illustrates the potential hazards of methane polluted water. In the film, a homeowner holds a lit match up to his running tap water and a burst of flame results. This homeowner’s water is contaminated with flammable methane. The film asserts the pollution is the result of a nearby fracking operation, but actually methane pollution can occur in wells which are drilled into natural methane pockets. This was the situation with the homeowner in the film, but by the time this was established the connection between flammable tap water and hydrofracking had already been made. The fact is, the phenomenon of flammable water depicted in the film is not restricted to areas where hydraulic fracturing is taking place, but occurs wherever water wells encounter methane pockets underground. This could happen literally anywhere, and it is a result of poorly explored and drilled wells, not fracking.

This is not to say that fracking has never caused such an episode. Isolated incidents of pollution to freshwater wells have been caused when drilling is done too close to the surface, and natural gas companies have settled several cases where damage is attributed to the gas wells. This is the case, even with the use of measurement while drilling techniques.

The point is, however, that the horror story of the flammable faucet is extremely uncommon. For one thing, the drilling components used to trap the natural gas are encased in steel and cement to prevent it from escaping. If the casing is done properly, it is nearly impossible for methane gas to escape. Also, fracking is done so far underground, that escaped methane would have to travel through solid rock in order to contaminate aquifers. There are reports that this has happened due to problems like improperly cemented boreholes. 16 families in Beaver County PA were affected by such an incident. As a result, the drilling company was fined over $1 million. Problems like this are rare, and can be completely avoided by constructing and sealing equipment properly.

Fracking won’t cause earthquakes.

There are several claims around the country, and even around the world, that fracking activity has spurred a number of low-registering seismic disturbances. A recent study released April 16, 2013 by Durham University found fracking to be “not significant” in causing earthquake activity. The study explains that seismic disturbances caused by hydraulic fracturing are minimal. So small, in fact, that they would only be detectable by the sensitive instruments used by geoscientists.

It would be nearly impossible for hydraulic fracturing to cause any major earthquakes unless drilling equipment were to come into contact with a major fault line and somehow cause the fault to release any built up energy it has stored. A recent British study concluded exactly this. “The fact is that court case after court case and study after study have shown plainly that fears over earth tremors . . . have no basis in fracking facts,” summarizes Peter Glover of The Commentator.

Fracking fluid isn’t going to give you cancer.

What is that mysterious concoction being shot underground into the shale rock, and how can it not be dangerous? Fears over pollution and contamination of drinking water and the environment from fracking fluid seem to stem from a lack of information about what this rock-shattering mixture actually is. The secret to fracking fluid is water and sand. Those two components make up about 98% of the fluid mix. The remaining 2% is composed of ingredients that are familiar to many of us, such as citric acid, guar gum (a common food additive, used to suspend the sand in the fluid), and even common table salt. Currently, fracking is regulated at the state level, and as such is exempt from the federal Clean Water act, which would require all companies to disclose the chemicals they use. Even so, some states have implemented regulations requiring disclosure, and some companies list their chemicals voluntarily. The information can be found here.

Certainly not all of these chemicals are harmless to the environment or to drinking water. But, the fracking industry has a habit of recovering most of its fluid and recycling it. This does not prevent every drop of fluid from being spilled, but it certainly means that most of the material is recovered. This saves the company doing the drilling money as well as improving its environmental impact.

Like any method of recovering fossil fuels, hydraulic fracturing does do damage to the environment. But, even accounting for methane leakage during extraction, the total carbon cost of natural gas is less than that of coal or oil. The transition to natural gas for power generation in many places has led to a drop in carbon emissions for the United States. Since the world is not yet ready for 100% renewable energy, natural gas could be a suitable energy source to “bridge the gap” in the transition to truly renewable fuel.