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OilfieldTechnology
February
2014
Challengeofemergingdrillingtechnologies
Worldwide, there havebeen several attempts todevelop
breakthrough, cost‑effectivedeepdrilling concepts. Their
common aimhas been to significantly decrease the overall cost
of thedrillingprocess, whilstmaintaining ahigh constant speed,
good energy efficiency and reduceddrilling time. The advantages
of technologies thatmeet these criteria should increasewith
increasingdrillingdepths.
A joint industry approach to thedevelopment of technologies
that tackle this kindof shared industry challenge canbe
extremely beneficial for the technology developer, the endusers
and the industry as awhole. It not only has benefitswith respect
to cost and risk sharing, but also increases communication,
knowledge andunderstandingbetween the technology
developer and the technology users throughout theprocess, thus
helping todeliver better solutions.
ITF is anoil and gas industry owned technology facilitator
with the key objectives of identifying the technology needs
of itsmember companies and facilitating thedevelopment
and implementationof technologies thatmeet those needs,
primarily through the establishment of joint industry projects.
The not‑for‑profit organisation, has launchedmore than
200projects since itwas established in 1999, was recently
involved in securing funding from three of itsmembers for a
feasibility project to investigate thepotential of a continuous
casing‑while‑drilling technology, which is beingdevelopedby
GADrilling.
Thedrillingtechnology
ThePLASMABIT technology aims todeliver drillingwith a
constant higher speed, without the need to change thedrill bit
on regular basis andwith increasedwell stability. Thedrilling
system, which is currently
at thedemonstration
prototype stage, is based
on a set of patented
technologies comprising
complementary subsystems,
each tackling a specific part
of thedrillingprocess. They
are thePLASMABIT rock
disintegration system,
which is anon‑contact
drillingprocess; the
ContiCase additive
metal for enhancement
of well stability;
Real TimeDataAcquisition,
which is an advanced
cabling solution for energy
andmaterial supply to thePLASMABIT system that enables real
timemeasuringwhiledrilling; and thePLASMABITmovement
and anchoring subsystemwhich is an autonomousmovement
and anchoring subsystem thatworks inhigh temperature, high
pressure subsurface conditions, securing synchronisationof
thedrillingprocesswith surfacematerial supply channels – a
downhole inclinometer secures thepossibility of directional and
horizontal drilling.
Rockdisintegrationsystem
In the last 40 years there havebeenmore than 20 research
attempts, of differingmaturity, toprove novel drilling
approaches anddeliver a step change in technology. These
have involved an array of different technologies including: laser
spallation, plasma, electronbeam, shootingpellets, enhanced
rotary, electric spark anddischarge, electric arc, water jet
erosion, ultrasonic, chemical, heating/cooling stress and electric
current aswell as several other approaches. However, to the
authors’ knowledge, none of the abovementioned technologies
are currently proven tobe effective in real conditions or have
delivered a completepackage that tackles issues such as energy
delivery and transport of fluids. In addition, previous attempts
have oftenbeenunable to control the quality of the thermal
process andparameterswithin thedrillingprocess, andwith
respect to the category of thermal drillingby penetrators,
systems developedhave generally not achieved the required
competitivedrilling speed.
ThePLASMABITprocess takes adifferent approach
toprevious attempts andutilises an efficient conversion
from electrical energy to in‑situheat on the rock. The rock
disintegration is basedon:
Ì
Ì
An electric arcwith a temperature of tens of thousands
of degrees Kelvin, which heats the rock directly, without
heating the intermediate gas (as is the case in conventional
plasma torches, which reduces the efficiency of heat transfer
into the rock).
Ì
Ì
An area‑wide, relatively homogeneous heat flow from
a spiral form long arc on to thewhole surface for a
high‑intensity disintegration process.
Ì
Ì
The rotating arc performs the additional function of moving
the disintegrated rock from the centre of the targeted area to
itsmargins bymeans of a centrifugal effect. The rock is then
carried away by fluid.
Ì
Ì
Compared to conventional plasma torch technology, direct
electric arc plasma technology exploits the electrohydraulic
Figure1.
PLASMABITfieldtestprototype inadeepdrillingcentre inBratislava,Slovakia.
Figure2.
ThePLASMABITdrillingsystem.
