LIFE SAVING INVENTION WITHOUT PATENT COVERAGE
By: Jum’an
Drilling Fluid is an important part in Oil and Gas
drilling. In fact it is the only answer to the question: How to drill a small
diameter hole thousands of meters deep, and at the same time cleaning and keeping
it open without caving. Drilling
Fluid is basically a type of slurry pumped down the hole while drilling,
through the drill pipes to flush the drilled cuttings and some other duties,
and circulated back through the annulus to the surface. There are similarities
in the functions of the human blood and oil well drilling fluid. Blood eliminates
waste products of metabolism from the human body. Drilling fluid removes
drilling wastes, i.e. drilled cuttings from the hole. Blood helps to cool or
warm the human body as drilling fluid helps to cool the drill bit and pipes. Blood
circulates round the human body via an artery-vein system of connection and
drilling fluid circulates down hole and back to the surface via a
drill-string-annulus connection system. The mud pump resembles the heart in the
oil well drilling. Human blood as well as drilling fluid is re-useable, both work
continually. Blood contains white blood cells that defend the human body
against diseases. Drilling fluid contains additives that strengthen the borehole,
prevent formation damage and extend the life span of the drilling fluid. Testing
a blood sample can detect our health condition. Testing a drilling fluid sample
can tell us the safety condition of the well drilled.
Among the main functions of drilling fluid is to provide
hydrostatic pressure to prevent formation fluids (gases, salt water) from
entering into the well bore. Dissolved gases like Oxygen, Carbon Dioxide (CO2), and
Hydrogen
Sulfide (H2S) cause serious corrosion problems leading to metal
failures. H2S in particular is critical because of its high toxicity and is fatal
to workers when they breathe. H2S gas is ruthless and deadly hazards in the oil
and gas industry. It is highly toxic, colorless and has the specific odor of
rotten eggs. However the sense of smell is not a reliable warning because
exposure to H2S gas will quickly numbs the sense of smell. Loss of
consciousness can happen within seconds of exposure to a high concentration of
this gas. The presence of H2S gas in the drilling fluid indicates that the gas
from the formation enters into the well due to insufficient hydrostatic
pressure provided by the drilling fluid. This toxic gas can then escape into
the air, putting the personnel on the rig at risk. The only positive means of
determining the amount of H2S present is by testing with approved
detectors.
The Garrett Gas Train (GGT) is the most widely used
portable unit to determine H2S in drilling fluid. The GGT unit consists of a
transparent plastic block that contains three interconnected chambers. A
carrier gas is used to flow an inert gas through the chambers. The sample is
placed in the first chamber and is acidified to release the H2S gas.
A special Draeger tube is used to measure the effluent gas that is
evolved from the sample. The dark stain in the Draeger tube indicates that H2S
has evolved from the sample. Mud Engineers are familiar
to run this testing equipment. The device is named after Robert L. Garrett, who
invented it while working at Exxon Production Research in the early 1970.
Robert L. Garrett
Born in 1933, Bob earned his master's degree in
chemistry from Texas Tech University (TTU) in 1957. While working at Exxon
in the early 1970s, Bob invented this device that would help save lives out in
the oil fields – the Garrett Gas Train (GGT) – a reliable quantitative sulfide detector.
H2S gas is a problem on drilling rigs, he said. The poisonous vapors could
quickly kill employees and cause drill pipe to become brittle and break. An easy
test for it didn’t yet exist. "I saw a serious need for a rig-site
chemical test to clearly identify when an influx of sulfides came from the
formation down hole and into the circulating drilling mud," Garrett said.
"No reliable H2S test existed for rig use at that time – around
1970 – and lab tests available were too inconvenient for rig use." The
device quickly detects dangerous and poisonous H2S when drilling oil and gas
wells. This method is widely used on rigs and approved by the API and ISO. Garrett
said that neither he nor Exxon attempted to obtain patent coverage on the GGT
and neither he nor Exxon have ever obtained any royalty for use of the method.
"I looked on the GGT test device/method as a
life-saving benefit for our industry – useful to avoid serious situations and
hazards around the drilling rig," he said. "The whole industry
benefits from safe drilling practices."
Currently Robert L. Garrett runs his company “Garrett Fluid Technology” based
in Texas and served as chairman of several API committees.