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24-047
Geosensing for Exploration—New Technology for Underground
Directional Drilling
Scott Thomson
CoalBed Innovations, Lake Macquarie, NSW
Australia
Duncan Thomson
CoalBed Innovations, Lake Macquarie, NSW
Australia
Dan Brunner
REI Drilling, Inc, Salt Lake City, UT
Ben Lyddall
REI Drilling, Inc, Salt Lake City, UT
ABSTRACT
Geosensing is used in oilfield drilling in conjunction with
geophysical tools to support characterization of rock prop-
erties, geology, and reservoir conditions. This technology is
now available to the mining industry and has been success-
fully applied to underground in-seam directional drilling in
Australian coal mines for geologic exploration and meth-
ane drainage. The system utilizes a range of drill rig and
wellhead mounted sensors which, combined with analyti-
cal software, produce real-time data from which 3D spatial
features can be accurately modelled significantly in advance
of mining. This innovation greatly expands on the infor-
mation obtained from current in-seam directional drilling
practices and provides for improved characterization of coal
seams, including soft and weak zones, locations of geologic
discontinuities, and analysis of formation flow.
This paper provides a description of the geosensing sys-
tem and the interpretation of actual data from long in-seam
directionally drilled methane drainage boreholes at mines
in Australia, and discusses how this system increases the
value of directional drilling as an exploration tool for the
coal mining sector, and the evaporite and hard-rock mining
sectors where directional drilling is also applied.
INTRODUCTION
Background
Underground in-seam directional drilling is performed
extensively in Australian coal mines as the primary tool for
methane drainage in gassy mines. Although effective for
methane drainage, in-seam directional drilling also creates
an opportunity to record valuable geological data, which
has not been effectively realized due to limitations in exist-
ing underground in-seam directional drilling technology.
Historically, underground in-seam directional drilling
has been performed with methane drainage in mind, and
not subsurface exploration. Geological uncertainty remains
the bane of many high-capacity underground coal opera-
tions. There are many examples in which large geological
structures (such as faults, intrusions, etc.) or smaller out-
burst-prone features have been missed by in-seam drilling
programs, only to be subsequently intercepted by continu-
ous miners or longwalls. This has serious safety and produc-
tivity implications and severely limits the development of
mining automation technologies without greater certainty
in geological interpretation in advance of the face.
Currently, these issues exist at many operations due
to ambiguous interpretations of surface-based geophysical
data and the lack of certainty in data generated by surface
exploration drilling and underground in-seam directional
drilling programs, the latter of which are entirely reliant on
the driller’s logs of “hard, soft, grey returns, coal/shale mix”
or similar. Standards of reporting vary, and misinterpreta-
tion is common.
New developments in geosensing technology involve
placing a series of real-time sensors onto existing under-
ground directional drilling rigs, which integrate this data
flow into the drilling process via interpretative software.
24-047
Geosensing for Exploration—New Technology for Underground
Directional Drilling
Scott Thomson
CoalBed Innovations, Lake Macquarie, NSW
Australia
Duncan Thomson
CoalBed Innovations, Lake Macquarie, NSW
Australia
Dan Brunner
REI Drilling, Inc, Salt Lake City, UT
Ben Lyddall
REI Drilling, Inc, Salt Lake City, UT
ABSTRACT
Geosensing is used in oilfield drilling in conjunction with
geophysical tools to support characterization of rock prop-
erties, geology, and reservoir conditions. This technology is
now available to the mining industry and has been success-
fully applied to underground in-seam directional drilling in
Australian coal mines for geologic exploration and meth-
ane drainage. The system utilizes a range of drill rig and
wellhead mounted sensors which, combined with analyti-
cal software, produce real-time data from which 3D spatial
features can be accurately modelled significantly in advance
of mining. This innovation greatly expands on the infor-
mation obtained from current in-seam directional drilling
practices and provides for improved characterization of coal
seams, including soft and weak zones, locations of geologic
discontinuities, and analysis of formation flow.
This paper provides a description of the geosensing sys-
tem and the interpretation of actual data from long in-seam
directionally drilled methane drainage boreholes at mines
in Australia, and discusses how this system increases the
value of directional drilling as an exploration tool for the
coal mining sector, and the evaporite and hard-rock mining
sectors where directional drilling is also applied.
INTRODUCTION
Background
Underground in-seam directional drilling is performed
extensively in Australian coal mines as the primary tool for
methane drainage in gassy mines. Although effective for
methane drainage, in-seam directional drilling also creates
an opportunity to record valuable geological data, which
has not been effectively realized due to limitations in exist-
ing underground in-seam directional drilling technology.
Historically, underground in-seam directional drilling
has been performed with methane drainage in mind, and
not subsurface exploration. Geological uncertainty remains
the bane of many high-capacity underground coal opera-
tions. There are many examples in which large geological
structures (such as faults, intrusions, etc.) or smaller out-
burst-prone features have been missed by in-seam drilling
programs, only to be subsequently intercepted by continu-
ous miners or longwalls. This has serious safety and produc-
tivity implications and severely limits the development of
mining automation technologies without greater certainty
in geological interpretation in advance of the face.
Currently, these issues exist at many operations due
to ambiguous interpretations of surface-based geophysical
data and the lack of certainty in data generated by surface
exploration drilling and underground in-seam directional
drilling programs, the latter of which are entirely reliant on
the driller’s logs of “hard, soft, grey returns, coal/shale mix”
or similar. Standards of reporting vary, and misinterpreta-
tion is common.
New developments in geosensing technology involve
placing a series of real-time sensors onto existing under-
ground directional drilling rigs, which integrate this data
flow into the drilling process via interpretative software.