Reservoir Simulation Of Unconventional Gas Reservoirs

The extraction of natural gas requires a borehole which is dug down to the deep shale formation. After the hole is dug, a steel pipe is inserted into the borehole where it is encased with cement on the outer perimeter of the pipe. A perforation gun is lowered into the cement-encased piping. Using an explosive, the perforation gun perforates the casing and puts initial fractures into the shale at targeted locations. The shale is fractured further by inserting fracking fluids, which consists of 98% water and sand, plus 2% proprietary fluids. The fracking fluids are pushed down into the wellbore and pressurized to 3000 psi causing the initial fracture to spread in the shale, along the shale natural fracture lines. The sand in the fracking fluids keeps the created fractures open which allows the gas from the shale pores to flow into the casing and then to the surface, where it is collected.

Hydraulic fracturing is a process of collecting natural gas by pressurizing shale beds. Fracking consists of two components: a drill and fracturing fluids [4]. Well shafts are drilled into a bed of shale less than two thousand feet deep to form a horizontal fracture because less force is required to make the rock strata buckle perpendicularly to the drill [2]. After the primary shaft has been drilled, cement is poured into the surrounding area to keep the fracturing fluids from backtracking up the shaft [2]. Once the drill is placed into the pay zone, where the reservoir of oil is located, fracturing fluids are forced into the surrounding

This report illustrates a geological review of a play within the South Brae oilfield and determines the potential of reservoirs within this area. It is hard to predict and provide ability for oil companies to license an oilfield before drilling therefore it is dependent upon several core sections available to investigate petrographically the northern North Sea. Cores and petrophysical data extracted from blocks 16/7a-A9, 16/7a-A17 and 16/7a-A21 related to licenses in block 16/07a found in the South Viking Graben area are provided and analysed in order to resolve whether exploration licenses should be purchased and the possible drilling of an exploration well.

For more than sixty years, oil and gas companies have been fracturing shale rock far below the earth’s surface in order to release pockets of natural gas. The extraction of shale gas from wells dates back to 1821; but the revolutionary procedure of hydraulic fracturing—injecting pressurized fluid into shale rock to create fissures—was commercialized in the 1950s. New drilling techniques, created in the 1970s, reach previously inaccessible shale gas by allowing the use of horizontal piping within the wells. While the United States is currently dependent on foreign countries for natural resources, a hope for independence has led companies to further explore hydraulic fracturing, redefining the way that natural resources are

With shale natural gas now on the horizon in the United States of America, many supporters of the horizontal hydraulic fracturing industry are looking at the economic benefits of fracking shale. The current horizontal drilling abilities provided “23.608 quadrillion Btu [of just shale natural gas alone] in 2011” (Hassett and Mathur 2014). This number in terms of energy production marked the “USA [as] the second largest natural gas producer” (Hassett and Mathur 2014) as of the year 2011. Since 2011, the production of natural gas in the United States has been raised even higher as more and more states lift their moratoriums on fracking and new natural gas hotspots are discovered.

The process of the collection of an underground fluid would not be possible without the use of hydraulic fracturing. In the Shale reserves, located about 5,000 feet underground, suffer an extremely low permeability rate. Permeability is the measure of how well a fluid flows through an absorbent material at the depth, and within such nonporous rock, the ability of fluids to travel to the well is greatly limited. Fracturing increases the area of the fluid that is exposed to porous materials and thus greatly increases production. The method of fracturing utilizes a few key components which allow for an economical extraction of resources.

Fissures created by high pressure fracking fluid to increase gas flow to the well also create pathways for leakage and consequent contamination of groundwater (Yu et al. 2014). Boreholes drilled for well access must pass through shallower strata, which may contain groundwater aquifers, before reaching target natural gas reservoirs (Davies et al. 2014). Passing through shallow layers of strata introduces a potential source of contamination to groundwater resources (Davies et al. 2014). Leakage into groundwater wells can occur due to poor well completion practices, the corrosion of steel casing, and the deterioration of cement during production of shale gas (Davies et al. 2014). Therefore, shale gas well integrity is important in reducing contamination events.

One of the most highly debated topics in the gas industry is hydraulic fracking. News about it is on the radio, tv and all over the internet. The truth about hydraulic fracking can be hard to find but is imperative to know the truth. The U.S Energy Information Administration estimates that the United States has 2,119 trillion cubic feet of recoverable gas. They predict that 60% of this gas is “unconventional gas” that is stored in low permeability formations such as shale, coalbeds, and tight sands (Jackson, 2011).

Hydraulic fracturing or “fracking” is a process that fractures rock formations in the earth’s surface in order to release hydrocarbons. When these hydrocarbons are released, they flow more freely through the rocks and up to the wellbore, were oil and gas are extracted to (Suchy, 2012). Not all rock formations require a hydraulic fracturing operation to be done because the fluids move freely through rocks that have been naturally fractured. Shale gas reservoirs on the other hand are not permeable and have very few natural fractures; therefore the trapped gas and oil must be extracted by fracking only.

The Eagle Ford shale formation in south Texas has recently become the focus of many oil industry operators searching for new sources of hydrocarbons by using the latest technology in previously unexplored areas. This exploration enhances the development of even more advanced techniques as issues are identified and problems solved to address the unique properties of the formation and the surrounding surface environment. Even though a formation may be comprised of a single sedimentary layer from a similar geological time frame it is not a homogeneous block and has many features and anomalies that effect the pressure, permeability, type of hydrocarbons trapped and methods required to extract them. To understand these properties one must understand that shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay placing it in the mudstone category of rocks [1]. Shale is different from other rocks in this category because it has a fissile structure and is laminated. The black shale in the Eagle Ford formation (Fig 1.) has a special property such that it contained organic material when it was deposited and during compaction over a millennium, the organic materials were converted into trapped oil and gas hydrocarbon deposits. This oil and gas are very difficult to remove because it is trapped within tiny pore spaces and or adsorbed onto clay mineral particles that makeup the shale.

It has long been known that large amounts of natural gas reside in deep layers of sedimentary rock such as shale. However, this gas could not be extracted until recent years due to previous limitations of technology making it economically unfeasible. This is now possible due to developments in drilling technology that now allow drillers to drill horizontally. Millions of gallons of water and chemicals are then injected at extremely high pressure that fractures the rock surrounding the drill hole, allowing trapped gas to escape. This process is called hydraulic fracturing, but is known colloquially as “fracking.”

The oil industry in the United States is booming. However, not all oil or natural gasses are available by drilling. There are some oils and gasses trapped inside shale rock. To access these gases, a process called Hydraulic Fracturing, informally known as fracking, was invented. Hydraulic Fracking “is a controversial oil and gas extraction technique developed in the late 1940s to gain access to fossil energy deposits previously inaccessible to drilling operations. The process…literally involves the smashing of rock with millions of gallons of water- along with sand and an undisclosed assortment of chemicals in order to bring gas to the surface. (serc-carelton.edu).” This process combines water, sand, and chemicals

The Haynesville shale in Louisiana is one of several unconventional gas plays that have been discovered in the U.S. in the past decade and promise to dramatically change the course of future energy development given its enormous resource potential. Unconventional gas resources are abundant, but their development is particularly sensitive to technologic risk, geologic uncertainty, and gas price. To produce at commercial rates, shale gas wells require horizontal drilling and hydraulic fracturing which significantly increases the capital cost. The purpose of this paper is to examine the price sensitivity of Haynesville wells and the economic viability of the play. We characterize the operating envelope under which Haynesville wells are economic

The purpose of this paper is to explain the depositional environment, petrology, mineralogy, structure, exploration, technology, methods of extraction and processing, as well as the applications and economics of oil in the Greater Green River Basin. This paper will mainly focus on the oil shale within the basin but will also touch on some of the more conventional oil and gas plays as well. According to Crawford and Killen (2010), Oil Shale is defined as being “a sedimentary rock embedded with organic material called kerogen… and has not been under the necessary heat, pressure, and/or depth for the right length of time to form crude oil”. Oil shale is typically found in silica and carbonate based rocks that are usually no greater than 900

Passey et al. (2010) claimed that there is a large variability in lithology between shale plays and even within a single shale formation (Passey et al. 2010). Britt and Smith (2009) emphasized the importance of geomechanics and the state of stress of a shale play for a successful hydraulic fracturing stimulation (Britt and Smith 2009). In addition, Rickman et al. (2008) stressed that the mechanical rock properties, such as brittleness and mineralogy, are fundamental in completion designs. While ductile shale tend to restore any fracture formed, brittle shale often have natural fractures which react to hydraulic fracturing (Rickman et al. 2008). In general, the Young’s Modulus of the shale measured parallel to the bedding plane is greater than that measured perpendicular to the bedding plane. Sone and Zoback (2013) explained the role of anisotropy on the