JPT | 7 May 2015
Beyond the Headlines: Are Well Construction Practices Safe for the Environment?
Editor’s note: Professionals in the oil and gas industry often receive questions about how industry operations affect public health, the environment, and the communities in which they operate. Of particular concern today is the impact of hydraulic fracturing on the environment. In this new column, JPT is inviting energy experts to put those questions and concerns about industry operations into perspective. Additional information about the oil and gas industry, how it affects society, and how to explain industry operations and practices to the general public is available on SPE’s Energy4me website at www.energy4me.org.
There are headlines every day that discuss the ethics and safety behind oil and gas operations, particularly hydraulic fracturing. According to the media, hydraulic fracturing can cause earthquakes, contaminated water, and even deformity in animals (if you believe the movie Promise Land). The truth behind the headlines is that hydraulic fracturing is a safe way to get natural gas out of the ground. What makes it a safe practice is solid well construction.
The evolution of oil and gas well construction has passed through many frontiers with each new foray into the next “unconventional” hydrocarbon resource generating the needed technology to keep pace with the immediate needs. In light of more than 4 million wells drilled in North America over the past 194 years, it is somewhat surprising that the industry has been successful so many times, and what we have done with lessons learned from the relatively few failures.
Wells are designed from the bottom to the top and from the inside outward, but they are drilled and constructed in exactly the opposite manner—often by practitioners with metrics different from the initial design principles. The fundamental objective that must shape every action along the way is that the final product of well construction must be a highly durable pressure vessel, albeit one that is composed of hundreds of threaded connections with a variety of seals and with a long coat of cement. Few other engineering disciplines operate in this highly cloaked area, in which the final engineering product, the downhole section of the well, cannot be conventionally seen, heard, or touched and produces a product that no one really wants to smell or taste.
The birth of the US gas industry was ushered in by William Hart’s shale gas well in Fredonia, New York, in 1821. He encountered flowing gas at 28 ft and, consistent with the technology of the time, cased it with wood and flowed shale gas through wood and early steel pipes to light the streets and buildings previously illuminated with lamps filled with whale oil.
Both Hart and Edwin Drake, with his 1859-era oil well, made use of one of the earliest hydrocarbon prospecting tools by locating their wells in areas of natural gas and oil surface seepage. Both wells hit natural flows of hydrocarbons in the same depth range as freshwater wells; it is a small wonder that fresh water, gas, and oil cohabitate the same strata today. Present on every continent, in every ocean, and above virtually every oil and gas producing area, natural seeps of oil and gas are indications of overfilling of some conventional reservoirs or natural geologic structure interruptions such as faults and natural fractures. The appearance of oil and gas seeps is evidence of oil generation potential below.
The early oil industry was undeniably a highly polluted place in time. Although well construction moved forward to steel casing, artificial lift pumps, and the first steel pipeline for oil transport in 1879, the first use of cement to seal and reinforce a well’s steel pipe was not seen until 1903. This fledgling cementing technology took a significant jump in 1915 with Almond Perkins’ two plug cement system, which Earl P. Halliburton purchased and pushed into worldwide use. Although the first widespread use of cement was undoubtedly a significant pollution control step, it is difficult to say whether that accomplishment was its main intent.
As other forms of technology moved forward, related advances quickly followed. Rotary drilling made possible dynamic pressure control feasible and blowout preventer technology gave rise to kick control; a technology combination that gradually replaced the gushers that came after oil strikes by cable tool drilling. The advances in cementing, drilling muds, pumps, corrosion control, and various stimulation mechanisms in the 1920s to 1940s ensured that the protection of hydrocarbon resources and the environment were not mutually exclusive. Significant regulation and enforcement on all phases of well construction in the oil and gas industry varied for years in different regions of the country, particularly in the early boom areas drilled in 1859 to the 1890s.
The first unified approach to effective resource conservation rules and practical enforcement came in 1935 with the establishment of the Interstate Oil and Gas Compact Commission, the oldest and largest interstate compact in the US that now represents governors of 30 member and eight associated states. The goal of the group is not only to conserve resources, but also to protect the public. Their survey work on idle and orphaned wells has been the driver for most of the well construction and abandonment rules that states have adapted to fit the needs of local geology.
Fig. 1—Pollution potential changes with time—US O&G Industry.
The advances and some of the problems that drove the technology development are shown in Fig. 1.
The fact that disastrous failures have driven the development and evolution of every field of technology, from medicine to space trips, should not be forgotten, although much of the public seems blissfully unaware of the trial and error journey that all technical disciples have taken.
Read the full column here.