Heartland Energy Colorado

Tuesday, June 16, 2009

Oil Exploration

In the early years of oil, drillers imagined that they were drilling for a pool or an underground river of oil using seeps as a guide for where to drill. Such exploration was successful if the surface oil came from an oil reservoir directly beneath the seep. Many seeps offered little reward to the driller as they merely marked the spot where the migratory rock breeched the earth’s surface. Drilling straight down missed oil embedded in a layer of migratory rock slanted at an angle to the surface. Since the first oil was found near a creek, early oil drillers followed creek beds, thinking that oil flowed beneath running water. Once oil was discovered, production wells were placed as close as possible to one another to ensure commercial success. Spacing wells increased the chance of drilling a dry hole beyond the perimeter of an oil reservoir. This practice, having the greatest possible concentration of wells furiously pumping oil, rapidly exhausted an oil reservoir and another search for seep oil began.

Once sites marked by seep oil were exhausted, and the creek theory debunked, oil drillers turned to geologists for advice on prospective sites. Geologists examined the land for hints of the presence of three necessary conditions for oil: (1) source rock to generate petroleum, (2) migratory rock through which petroleum moves toward the earth’s surface and (3) reservoir rock where there is an impediment preventing further migration. Whether sedimentary rock is source, migratory or reservoir rock is a matter of circumstance.

Early geologists became geophysicists when they started using gravity meters and magnetometers to search for oil. A gravity meter is sensitive to the density of rocks below the surface. A mile of sedimentary rocks on top of basement rock is dense compared to a salt dome or a layer of porous reef or lighter rocks, which are detectable as anomalies or variations in gravity.

Magnetometers, because they are sensitive to anomalies or variations in the earth’s magnetic field generated by magnetite in basement rock, are useful for estimating the thickness of overlying sedimentary rock. Both gravity and magnetic anomalies may indicate an anticline or fault that holds an oil reservoir.

One of the top hydrocarbon-based energy providers in the USA is Heartland Energy Colorado, based in Englewood, CO. They have many drilling locations throughout the country and remain one of the top producers of US oil & gas companies. For more information on Heartland Energy Colorado, see Heartland Energy Development Corporation online.

(Source: "Energy for the 21st Century," Nersesian)

Sunday, June 14, 2009

Moving the Oil to the Well

The primary force that causes oil and gas to flow through pores in the reservoir rock toward the bottom of the well is the pressure differential between the oil and gas within the reservoir rock and the pressure at the bottom of the well. The driving force in the reservoir can be provided by dissolved natural gas in the oil or by a natural gas cap on top of the oil that expands as oil is removed from a reservoir.

Natural gas cannot maintain the same initial reservoir pressure as it expands, which causes oil production to decline with time. Subsurface water entering an oil reservoir from its bottom or sides as a primary driving force can maintain nearly constant reservoir pressure and oil production.

An oil well goes “dry” when natural gas or water reaches the bottom of the well. Gravity can also be an effective drive mechanism for wells drilled into the bottom of steeply inclined reservoirs. Most oil reservoirs have more than one of these four primary driving forces.

Directional Drilling

One would think that a drill string made up of thirty-foot lengths of steel pipe would be rigid, but this not at all true when the drill string is measured in miles. It is rather flexible, and actually twists several times when being rotated before the bit begins to turn. This characterizes the type of drill string used for directional drilling.

A directional well is first drilled vertically and then cased. A hole or window is cut into the casing and an installed whipstock bends the drill string at a preset angle. A pilot hole of 10-15 feet in length is drilled, and when it is certified to be at the right direction and angle, which can be as great as 60 degrees, a turbo drill can be used. With a turbo drill, the drill pipe no longer rotates to drive a fixed drill bit.

Mud driven down the center of a stationary drill pipe turns a rotary bit attached to the end of the drill string where it exits the drill pipe and enters the annulus. A magnetic compass and a gyroscope control the orientation and the degree of deviation of the well. The degree of deviation can be changed at various points along the way until the well is horizontal.

(Source: "Energy for the 21st Century," Nersesian, Roy L.)

Friday, June 12, 2009

Drilling Rigs: Ratholes vs. Mouseholes vs. Conductor Holes

Some rigs use a special pipe called the "kelly," which is part of the drill string. The kelly is part of the system that rotates the bit. Rigs with kellys require a rathole - a shallow hole drilled off to the side of the main borehole. On land, the operator sometimes hires a special truck-mounted, light-duty unit called a "rathole rig" to drill the rathole. During drilling, the crew uses the rathole to store the kelly temporarily.

The rathole rig or the main rig itself may also drill a mousehole on land sites. A mousehole, like a rathole, is also a shallow hole lined with pipe that extends to the rig floor. The mousehole is a lined hole into which the crew puts a length of drill pipe during drilling operations. When crew members are ready to add the joint to the drill string as the hole deepens, they add it from the mousehole.

The rathole crew may also drill the first, or top, part of the main borehole. This is called a conductor hole. The operator can, in some cases, save time and money by using this technique.

(Source: "A Primer of Oilwell Drilling, Sixth Edition")

Crude Oil: Sour vs. Sweet

Crude oil is a hydrocarbon mixture that often occurs as a liquid, though some crude oils are very thick and dense and do not flow easily. Crude oil varies considerably in weight, viscosity and color. It may also contain non-hydrocarbon impurities such as hydrogen sulfide.

Generally, oil companies classify crude oil as light, intermediate or heavy. If it contains hydrogen sulfide, they call it "sour crude." Crude oil that does not contain hydrogen sulfide is classified as "sweet crude." Oil refineries put crude oil through several chemical and physical processes to render it into many useful products such as gasoline, kerosene and diesel fuel.

(Source: "A Primer of Oilwell Drilling, Sixth Edition")

Wednesday, June 10, 2009

Heartland Energy Development Corporation Expands Drilling

ENGLEWOOD, CO--(Marketwire - February 12, 2009) - Heartland Energy Development Corporation (HEDC) -- a leader in domestic oil and gas exploration and production -- has expanded its drilling operations to include a 100 percent interest in the Cerda #1 natural gas well in Jim Hogg County, Texas.

Heartland Energy Colorado is looking to expand on a well that is located adjacent to the Northeast Thompsonville Field, which is the largest Wilcox gas field in the state. According to a survey performed by the Texas Economic Geology Commission, the field produces more than 650 CBF of gas with a total 850 EUR. HEDC currently has 860 acres under lease, with an option to lease an additional 800 acres directly from the property owner. The company is collecting 3D seismic data to determine the field's long term potential.

HEDC also has a working interest position in the Margo Heirs Field in Starr County, Texas. The company has participated in drilling Margo Heirs wells 1-4, and plans to participate in the drilling of two more wells during the first half of 2009. The field's primary output comes from the Vicksburg series sands at 6,500 to 8,000 feet in depth. For the past six months, the average output of gas for the first four wells has remained steady at 10 MMcfd (Millions of cubic feet per day). Well #2 is especially productive, yielding more than 10 MMcfd with 200 BCPD (billion cubic feet per day).

In Fall 2008, HEDC participated as a non-operating working interest holder in the Xtreme Oil Creek well 1-19s in McClain County, Oklahoma. The well was drilled to 8,500 feet and completed in the 1st Bromide sand target with an initial production rate exceeding 80 BOPD (Barrels of Oil Per Day).

About HEDC

Established in 2006, Heartland Energy Development Corporation (HEDC) is dedicated to environmentally sensitive exploration and development of domestic gas and oil fields that reduce U.S. dependence on foreign energy. It employs advanced drilling/extraction technologies and stratigraphic surveys to maximize yield and protect the environment. While HEDC focuses on fields in Texas and Oklahoma, it boasts a national presence with hundreds of wells and thousands of acres in development. More information is available at www.heartlandenergydevelopment.com.

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