challenges of oil exploration in florida of florida: challenges and risks of unconventional oil...

Geology of Florida: Challenges and Risks of Unconventional Oil Exploration

Presenter: Noah B. Kugler, M.S.,P.G.

Geology of Florida: Challenges and Risks of Unconventional Oil Exploration

Geologic History of Florida

Hydrogeology of Florida

History of Oil and Gas Exploration in Florida

Conventional Oil and Gas Recovery and the Development of Unconventional Extraction Techniques

Geologic Challenges of Unconventional Oil and Gas Exploration in Florida

Potential Risks of Unconventional Oil and Gas Exploration in Florida

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Source: Emporia State University

When the Florida plateau was part of the supercontinent Pangaea about 255 million years ago, it was sandwiched between what were to become North and South America and Africa.

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Source: www.dailymotion.com


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From about 145 to 66 million years ago (Cretaceous) a period of relatively warm climate existed, resulting in high eustatic sea levels and creating numerous shallow inland seas. Oil deposits are within these layers

Beginning about 66 million years ago (Paleocene) The Florida peninsula remained a shallow sea. As marine creatures lived and died over millions of years their calcium carbonate rich shells dissolved and precipitated on the ocean floor as the building blocks of the massive limestone forming the Floridan aquifer system.

Beginning about 28 million years ago (Oligocene) periods of tectonic uplift, erosion and deposition of portions of the southern Appalachian mountains occurred. These sediments form the confined aquifers in southwest Florida

Geologic Evolution of North America


As the last ice age ended, sea levels rose, Florida shrank in size, the climate became much wetter, and habitats changed.

A notable example of these climatic changes is formation of the Everglades, which occurred sometime around 4,000-6,000 years ago. Many of Florida's modern topographic features and surficial sediments were created or deposited during periods when sea levels were high.

Waves and currents in these ancient seas eroded the exposed formations of previous epochs, reshaping earlier landforms and redistributing eroded sediments over a wide area.

Florida's geological history has been principally affected by changing sea levels, which influenced the formation of bedrock and its surface topography.

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Source: Emporia State University

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCLXGzfuH0sgCFQPZHgoduUgDeg&url=http://academic.emporia.edu/aberjame/student/barr1/report.htm&bvm=bv.105454873,d.dmo&psig=AFQjCNG92bKb3k3CJ4gg4hN2AvrEBslgIw&ust=1445465261408099


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South of Tampa Bay, sedimentary layers overlying the thick limestones of the Floridan aquifer system begin to thicken. The top of the Floridan aquifer system occurs increasingly deeper reaching a depth

of approximately 1,000 feet in southern Florida.

Source: Florida Geological Survey


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In Florida, sedimentary rocks are the most common type of rock made up of cemented mineral particles formed by marine organisms.

Shell fragments (the mineral aragonite) that are cemented together loosely by calcite form coquina.

Limestone forms when aragonite shell completely dissolves and re-precipitates as, or is replaced by calcite.

Limestone, shell and sand are heavily mined for road building and other construction applications.

Source: Aubrey Jaffer 2007

Fossiliferous Limestone

Coquina


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Source: Aubrey Jaffer 2007

As coral, shellfish, and fish skeletons piled up, this created layers of limestone hundreds or thousands of feet thick.

As the Appalachian Mountains eroded, sand and clay were deposited over Florida’s massive limestone layers.

Fossiliferous Limestone


Source : Emporia State University

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Exposed Limestone Deposits in Central Florida

Neutral pH or acidic water gradually dissolves the rock creating interconnected pore space and permeability


Source: Northwest Florida Outdoor Adventures

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Exposed Limestone beds with developed secondary porosity due to dissolution in northern Florida

The porous limestone layers of Florida hold vast amounts of water


Groundwater is Florida’s most valuable natural resources.

Usable quantities of potable groundwater can be obtained throughout the state, with the exception of a few places, most of which are near the coasts.

About 93 percent of Florida’s population depends on groundwater for drinking water. Florida is among the highest users of fresh groundwater in the country.

Because of its abundance and availability, groundwater is the principal source of freshwater for public supply and domestic (rural) and industrial uses. About 60 percent of all freshwater uses are from groundwater

Florida is covered nearly everywhere by sands that overlie a thick sequence of limestone and dolomite. Together, the surficial sands and the limestone and dolomite form an enormous groundwater reservoir that provides more available groundwater than any other state.

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Information source: FDEP


Thick unconfined limestone of the Floridan Aquifer occurs near the surface across the northern and central portions of the state. Thin layers of recent sedimentary deposits generally overlay the limestone.

Many of Florida’s prominent features have resulted from karst, a landscape with a base layer of limestone. The limestone layer of the state is honeycombed with underground rivers. Where the rivers break through to the surface, springs and sinkholes occur. Source: FDEP Florida Aquifer Vulnerability Assessment (FAVA)

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Dynamics of Florida’s Coastal Water Cycle and Hydrogeology

Source: USGS


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Source: Florida Springs Institute

Cave divers in a spring-fed limestone karst system in Central Florida


The Floridan aquifer system is one of the most productive aquifers in the world providing water to Savannah and Brunswick, Georgia; Jacksonville, Tallahassee, Orlando, and St. Petersburg, Florida. The aquifer system also provides water for hundreds of thousands of people in smaller communities and rural areas.

In the Lower East Coast the prolific Biscayne Aquifer occurs at surface as a sand unit up to 200 feet thick overlying the Floridan aquifer system.

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Source – University of South Florida


Source: USGS

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The Floridan is a multiple-use aquifer system intensively pumped for industrial and irrigation supplies. Where it contains freshwater, it is the principal source of potable water supply.


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The Lower West Coast area is hydro-geologically unique in Florida.

A thickening sequence of terrestrial sedimentary layers of sand and clay with intermittent layers of limestone create numerous confined aquifers that provide water for potable and irrigation purposes.

Source: SWFWMD


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Source: SFWMD

Confined aquifers in southwest Florida and the transition to the east coast


The Boulder Zone is a deeply buried zone of cavernous permeability developed in fractured dolomite in the Lower Floridan aquifer in southern Florida.

The permeability of the Boulder Zone is extremely high because of its cavernous nature. This anomalous permeability, which prevents pressure buildup in injection wells, coupled with the fact that the Boulder Zone contains saltwater, makes it the chosen zone for receiving treated injected wastes.

The Boulder Zone has been used for many years to store vast quantities of treated sewage injected into it by Miami, Fort Lauderdale, West Palm Beach, and Stuart.

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Source: GROUND WATER ATLAS of the UNITED STATES - USGS


The salinity, chemistry and temperature of the water in the Boulder Zone are similar to those of modern seawater. Therefore the zone is thought to be connected to the Atlantic Ocean off south Florida where the sea floor is at about the same depth.

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Source: FGS Special Publication No. 21


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Source: USGS

Complexity of Groundwater Flow within the Floridan aquifer system


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Natural Flow of Boulder Zone water through a wellbore near North Port, Florida

Source: FGS Special Publication No. 21


The Collier County News: Sunniland No. 1 oil drilling rig and site.

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The first Florida producing oil well was drilled in 1943 by Humble Oil Company after expending about $1 million and reaching a depth of 11,626. The well’s site is about 12-miles south of Immokalee, by present day Big Cypress Preserve. The state paid the $50,000 bonus for the discovery.

Initial daily production was 140 barrels of oil and 425 gallons of salt water, which eventually settled down to 20 barrels per day. Though the productivity of the well was not great it proved Barron Collier’s belief of the existence of oil.

Source: Florida Oil and Gas Museum website


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Source: FDEP Oil and Gas Permit Database

Number of Oil and Gas Well Completions in Florida by Year

*Based upon wells with completion dates in the database


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Source: Florida BEBR/Bureau of Mining and Minerals Regulation

Volume of oil and gas produced from Florida Wellfields since 1970


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In the last 20 years techniques were developed that allowed for the extraction of oil and gas from previously unrecoverable low-permeability shale formations.

These shale formations are deeper than conventional reservoirs, which are generally found in porous sandstone.

Source: Coloraro.edu

Source: Offshore Technology.com – Galoc Oil Field


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Two key advancements in extraction techniques over that last 20 years have lead to the development of what we think of today as hydraulic fracturing or “Fracking”.

One was the ability to drill directionally from a vertical borehole using advanced GPS which gives the ability to drill long distances along low-permeability reservoirs horizontally deep below the earth.

The second was the use of sand or proppant to create and maintain (prop open) fractures in the low-permeability reservoirs.

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Source: FDEP - Expert Evaluation of the DA Hughes Collier-Hogan 20-3H Well Drilling and Workover


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Source: Making it Magazine


Hydraulic Fracturing with Proppant (Fracking):

Performed in horizontal wells using high pressure and volume of water with sand proppant and fracking-related additives.

Requires the pumping of a mixture of water and sand with corrosion and bacterial inhibitors and other additives used to change the properties of the injected fluid.

The sand slurry is pumped under pressures in the range of 8 to 10 thousand PSI which exceeds the strength of the formation producing fractures that are held open by the sand.

The propped open fractures provide and excellent pathway to deliver additives deeper into the reservoir to react chemically and physically to increase oil and gas flow potential.

Many of the chemicals utilized fall under the exclusion the “Halliburton clause” which does not require the industry to divulge the safety data sheets for the chemicals used in the fracking process as trade secret.

There is a poor understanding of the various chemicals that are used in the blends, particularly from site to site as decisions to use different additives may change depending upon the geology of the reservoir and each companies methods.

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Types of Additives used in Fracking

Acid - Helps dissolve minerals and initiate cracks in the rock

Biocide - Eliminates bacteria in the water that produces corrosive by-products

Breaker - Product Stabilizer; Allows a delayed break down of the gel

Clay Stabilizer - Prevents clays from swelling or shifting

Corrosion Inhibitor - Prevents the corrosion of the pipe

Crosslinker - Maintains fluid viscosity as temperature increases

Friction Reducer - “Slicks” the water to minimize friction

Gelling Agent - Thickens the water in order to suspend the sand

Iron Control - Prevents precipitation of metal oxides

Non-Emulsifier - Used to prevent the formation of emulsions in the fracture fluid

pH Adjusting Agent - Adjusts the pH of fluid to maintains the effectiveness of other components, such as crosslinkers

Scale Inhibitor - Prevents scale deposits in the pipe

Surfactant - Used to increase the viscosity of the fracture fluid

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Source: Earthworksaction.org


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Pumps and mixers used to deliver fracking mixture of water, sand and additives

Source: KeepTapWatersSafe.org


Acidizing refers to the stimulation of a reservoir formation by pumping a solution containing reactive acid to improve the permeability and enhance production of a well. In sandstone formations, the acids help enlarge the pores, while in carbonate formations, the acids dissolve the entire matrix. Acidizing can be divided into two categories:

Matrix acidizing – mostly used in sandstone formations, acid is pumped into a well at low pressures, dissolving sediments and mud solids, increasing the permeability of the rock, enlarging the natural pores, and stimulating the flow of oil and gas.

Fracture acidizing – mostly used in carbonate formations, involves pumping acid at higher pressures without a proppant. The acids fracture the rock allowing for the flow of oil and gas.

Hydrochloric (HCl), Sulfuric (H2SO4), Phosphoric (H3PO4) and Hydrofluoric (HF) acids are used typically.

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Source: Earthworksaction.org


Acid Fracking – same process as Fracking with addition of acid in the additives

Shale is a very fine-grained, layered sedimentary rock made up of varying amounts of silica, carbonate and clay minerals. If a target rock has a high carbonate component, typically Hydrochloric acid (HCl) is used to help create greater permeability and flow to the well by dissolving the rock in concert with fracturing.

In Florida source beds for Unconventional Extraction that are carbonate-rich mudstones readily dissolve with HCl.

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Source: Oil & Gas Journal, 2012


Necessary and reasonable water well rehabilitation using acidization in Florida

Typically hydrochloric acid (HCl) also known as muratic acid is used to remove scale and biological build up from the wellbore face without other additives. Acid is added under a very small amount of pressure (several psi) until the targeted area has been treated. Most treatments target up to several inches into the formation.

Larger volumes may be used to treat up to approximately 30 feet into the formation. The acid reacts with carbonate minerals that have grown around the well due to use over time (mineral phase change due to pressure and pH).

Once the acid has reacted with the limestone in the aquifer, the volume of acid that was pumped in is pumped out as reacted water and stored in a holding tank until the salinity of the water approaches the initial concentration.

The reacted water is elevated in salinity and typically pH neutral. Depending on the acidity of the reacted water, it is held in the storage tank and potash or other pH basic material is added to neutralize the water.

This neutralized water is disposed of at a wastewater treatment plant. Once the salinity of the water approaches the initial concentration it can generally be discharged to the ground.

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Between Christmas of 2013 and New Years the Dan A. Hughes company out of Texas initiated a “Simulation” process which included pumping a water, acid and silica sand-slurry to create and prop-open fractures in the “Rubble Zone” of the Lower Sunniland Formation in Collier County.

Although debate over what to call this technique went on for some time the consultant hired by the Florida DEP, ALL Consulting, concluded that it was indeed a multi-stage, high-volume, high-pressure fracturing event using acid aka “Acid Fracking”.

Although a number of producing horizontal wells in Florida may have been stimulated using water pressure (hydraulic fracturing), this was the first known well to utilize a sand proppant which changes the process to the commonly used term “Fracking”.

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Acid Fracking in Florida


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Source: Energy Information Administration


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Bakken – North Dakota Eagle Ford – Texas Barnett –Texas Niobrara – Colorado , Nebraska, Kansas Monterey – California


The number of dry holes (wells drilled without finding oil) shown in the FDEP Oil and Gas Well database indicates the challenges in locating economically viable oil reservoirs in Florida.

The Boulder Zone provides a further unique and daunting challenge for all aspects of oil and gas well construction.

Upwelling/flow of water while drilling the upper portions of the Floridan Aquifer can create challenges in controlling flow from the well during well construction which can lead to contamination of shallow ground water with salt.

Upwelling/flow of water while drilling can also cause poor drilling mud conditions resulting in unsound cementing of casings.

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Drilling of wells through the cavernous and fractured nature of the Boulder Zone commonly leads to breaking and loss of drill strings in the wellbore.

Strong upward flow within the wellbore causes drilling muds to break down and loss of circulation ability leading to drilling challenges removing rock cuttings.

Once penetrated large pieces of fractured rock can fall into the wellbore each time the drillstring is removed necessitating re-drilling.

Constant collapse of small pieces of fractured dolomite material may occur clogging drill bits.

It is not possible to set and cure cement around the casing within the interval of the Boulder Zone.

Loss of drilling mud conditioning due to mixing with large volumes of saline formation water leads to unfavorable wellbore conditions and cementing outcomes.

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Source: NGWA


Typically only the bottom 500 feet or less of each casing string below the Underground Source of Drinking Water (USDW) is cemented in place.

Only heavy drilling muds are left behind major portions of casings leading to lack of overall integrity.

Well casing strings can get hung-up on fracture ledges or;

Be impeded by rock material that has fallen into the well between the time when the drillstring is removed and the casing is lowered into the wellbore.

If the casing gets hung-up on ledges or collapsed rock it may necessitate removing 1000’s of feet of welded casing from the borehole and re-drilling the area that caused the hang-up.

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Source: Cave Diver Forum


In the case of horizontal wells inflatable rubber packers may be used as the only method of sealing of the production string.

The rubber packers are susceptible to damage during installation of the final production casing if metal Junk is left in the borehole during construction; particularly along the region of the well that curves from vertical to horizontal.

The final production casing is under intense pressure during hydraulic fracturing operations leading to a root pathway for leaking and possible contamination.

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Source: FDEP


The well and associated flowback disposal well were permitted by the Florida Depart met of Environmental Protection within one mile of two 1940’s abandoned boreholes that were not plugged to current standards and laws.

The FDEP’s consultant concluded that potential junk left in the hole very possibly damaged open-hole packers and the final production casing during installation and that every casing string installation and cementing was problematic.

Numerous lost circulation zones and the need for excessive drilling likely led to enlarged boreholes which cause cementing issues and poor or marginal resultant cementing of casings.

Poor installation and cementing of the production, intermediate and surface casings could have provided conduits to the USDWs (plural).

While rigging down, wastes could have traveled down to where there was no liner, outside of the mouse hole, outside of the conductor pipe or out of an apparent pad discharge pipe any which could've impact the shallow USDW.

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Source: FDEP - Expert Evaluation of the DA Hughes Collier-Hogan 20-3H Well Drilling and Workover

Challenges, permitting and questionable construction of the Collier-Hogan Well


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Source: EA

Generalized diagram showing sources of environmental risk associated with “Fracking “


A short-list of documented potential risks

Depleting potable and irrigation water supply for use in “Fracking” make-up water that leaves the useable water cycle

Lack of regulatory well construction oversight Drilling a well near an abandoned oil well exploration borehole Construction issues leading to well casing failure/leak and groundwater

contamination Pipeline breaks or leaks Damage to sensitive habitat On-site spills of chemicals or product entering surface or shallow groundwater Disposal of large volumes of flowback water, treated to undetermined degrees,

to injection wells or ocean outfall Chemical and flow back disposal truck accidents Air quality and vegetation degradation due to leaking methane or off-gassing

from on-site retention pits and chemicals Contamination of residential wells tapping shallow aquifers Contamination of commercial or agriculture wells tapping deeper aquifers

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Complexities and interconnection of groundwater in Florida

Fracking accident: Reportedly pumping at 8500 psig caused the 7-inch diameter steel production casing to split. The surface casing parted above that causing the Fracking Head and Blow-Out-Preventers to be blown out of the hole landing in the middle of a truck cab.

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Source: KeepTapWatersSafe.org


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