+ All Categories
Home > Documents > QEMSCAN WellSite Papau New Guinea

QEMSCAN WellSite Papau New Guinea

Date post: 28-Apr-2015
Category:
Upload: haberlah
View: 50 times
Download: 7 times
Share this document with a friend
Description:
FEI Natural Resources application note on QEMSCAN® WellSite™ : on-shore field test in Papua New Guinea
16
Application Note QEMSCAN® WellSite : on-shore field test in Papua New Guinea Introduction FEI, in collaboration with Halliburton and Oil Search Limited, field-tested the prototype of QEMSCAN® WellSite on oil rigs in the remote highlands of Papua New Guinea (PNG). QEMSCAN WellSite is an automated petrography solution applied at the well site as an advanced mudlogging service. The outcome demonstrates a mobile, ruggedized workflow solution, providing unprecedented near real-time data from drill cuttings used to support time-critical onsite decisions and the interpretation of downhole data. Background This application note provides a detailed account of the Joint Development Project between FEI Company (Hillsboro, Oregon), Halliburton (Houston, Texas), and Oil Search Limited (Sydney, Australia), testing the QEMSCAN WellSite automated petrography solution on drilling platforms in the highlands of Papua New Guinea (Figure 1). The remote site was chosen for the on-shore field test as a logistical and geological challenge, being located in the inaccessible southern highlands within the complex, tectonically disturbed siliciclastic stratigraphy of the Papuan foldbelt. The field test involved six months of on-site sample preparations, measurements, and daily reporting for >1,000 sample intervals collected from three separate wells, including: a gas injection well; a production well; and an exploration well. FEI’s objectives for the field test were to assess the robustness and initial readiness of the newly developed advanced mudlogging solution, and to understand how the system comprising a scanning electron microscope (SEM) equipped with energy-dispersive spectrometers (EDS) operates in a challenging on-shore environment. The field tests also provided FEI with experience for integrating QEMSCAN WellSite into an existing surface logging workflow. Daily feedback and reports by a range of professional operators and all stakeholders provided a solid foundation to optimize every step in the workflow; from sample preparation, measurements, data processing, to data analysis and reporting.
Transcript

Application Note

QEMSCAN® WellSite™ : on-shore field test in Papua New Guinea

Introduction

FEI, in collaboration with Halliburton and Oil Search Limited, field-tested the prototype of QEMSCAN® WellSite™ on oil rigs in the remote highlands of Papua New Guinea (PNG). QEMSCAN WellSite is an automated petrography solution applied at the well site as an advanced mudlogging service. The outcome demonstrates a mobile, ruggedized workflow solution, providing unprecedented near real-time data from drill cuttings used to support time-critical onsite decisions and the interpretation of downhole data.

BackgroundThis application note provides a detailed account of the Joint Development Project between FEI Company

(Hillsboro, Oregon), Halliburton (Houston, Texas), and Oil Search Limited (Sydney, Australia), testing the

QEMSCAN WellSite automated petrography solution on drilling platforms in the highlands of Papua New

Guinea (Figure 1). The remote site was chosen for the on-shore field test as a logistical and geological

challenge, being located in the inaccessible southern highlands within the complex, tectonically disturbed

siliciclastic stratigraphy of the Papuan foldbelt. The field test involved six months of on-site sample

preparations, measurements, and daily reporting for >1,000 sample intervals collected from three separate

wells, including: a gas injection well; a production well; and an exploration well.

FEI’s objectives for the field test were to assess the robustness and initial readiness of the newly developed

advanced mudlogging solution, and to understand how the system comprising a scanning electron

microscope (SEM) equipped with energy-dispersive spectrometers (EDS) operates in a challenging on-shore

environment. The field tests also provided FEI with experience for integrating QEMSCAN WellSite into an

existing surface logging workflow. Daily feedback and reports by a range of professional operators and all

stakeholders provided a solid foundation to optimize every step in the workflow; from sample preparation,

measurements, data processing, to data analysis and reporting.

Application Note QEMSCAN® WellSite™ on-shore

Page 2

Halliburton’s objectives were to better understand the operational

requirements involved in running QEMSCAN WellSite by their

staff, and to assess the practical workflow in a 12-hour work shift

environment. Operation and basic servicing of the system in the field

was first performed by two, and subsequently by a single, Halliburton

Data Engineer.

Oil Search Limited wanted to improve their knowledge about the

intersected subsurface geology and potentially support time-critical

operational decisions.

Figure 1. Kutubu Oil Project located in the Papuan foldbelt of the Southern Highlands Province (indicated), ~550 km NW of the sealed roads of Port Moresby, Papua New Guinea. (Source: maps.google.com)

Logistics and EnvironmentBy any account, field testing the prototype of a QEMSCAN-powered

petrography solution in the remote jungle of PNG can be described

as a bold move. Petroleum wells in the Papuan foldbelt are among

the world’s most expensive land-based wells to drill because of the

logistical difficulties and costs involved in transporting equipment to

site. The remoteness of the location, and the lengthy custom clearance

procedures effectively limited FEI’s ability to send spare parts past

the initial shipment. The QEMSCAN WellSite solution was thoroughly

tested for ruggedness even before it arrived at site. The long transport

involved shipping by sea, land and air, and lasted for nearly two

months. Relocation between rig pads was achieved with the help of

a Bell helicopter and 4WD pickup trucks over steep, pot-hole ridden

tracks which could only be navigated in low gear (Figure 2).

Application Note QEMSCAN® WellSite™ on-shore

Page 3

Figure 2. QEMSCAN® WellSite™ system transported to rig locations by Bell helicopter and 4WD pickup trucks.

In addition to the logistical challenges, the tropical mountain climate

characterized by high humidity, heat, and daily torrential rains,

comprised another important operational test.

QEMSCAN WellSite was successfully set up in a range of existing

containers, none of which were equipped with air locks to keep out

moisture. Different setup configurations of the sample preparation

and system were tested, to better understand how the solution can

be fitted into an existing limited space (Figure 3). The daily working

environment was characterized by fluctuations in power, harsh climate,

intermittent air-conditioning, and alternatively dusty and muddy

ground surface.

WorkflowQEMSCAN WellSite is an integrated solution covering sample

preparation, measurement, data processing, data analysis, reporting,

and archiving. An important focus during the development and

field test was on providing a largely automated and easy to operate

workflow experience; from creating representative samples to

providing consistent, reliable cuttings data of unprecedented

detail. The workflow was extensively tested with the single longest

continuous run by Halliburton staff lasting for 34 days.

Figure 3. QEMSCAN® WellSite™ integration into existing container.

Application Note QEMSCAN® WellSite™ on-shore

Page 4

thin layer of electro-conductive carbon, in order to prevent charging

under the electron beam (e-beam). In order to minimize time-to-data

in time-critical operations, the sample preparation process has been

designed to be applied to individual samples in the sequence they are

collected from the shakers. However, the most time-consuming step of

carbon coating can be performed in batches of up to six samples.

From cuttings collection to a measurement-ready sample block took

on average ~25 minutes (Figure 5). This provided enough time for the

operators to prepare, and in parallel set up, run, process, and report

measurements. During the 12-hour single operator shifts, Halliburton

staff prepared on average 25 samples per day. However, the Data

Engineers demonstrated that twice the number of sample blocks can

be prepared when processing a backlog of cutting samples from a

previous well during drilling downtime. Consumables per 100 prepared

samples include: <1 set of 500 ml bottles of epoxy; <10 re-usable plastic

sample moulds; and ~25 cm of carbon rod.

A number of challenges not present in the original laboratory

environment were faced and resolved successfully in the field. Instead

of dealing with oven-dried samples, the wet and clay-rich cuttings

had to be thoroughly dried within the existing time requirements in

order to be carbon-coated and loaded into the vacuum chamber of

the system. Rapid drying was achieved by placing the wet-screened

aliquots for ~2 min into a standard microwave. Further, the sectioning

of some sample blocks resulted in the dispersion of clay-rich particles

and significant plucking from the 2-D surfaces. By exchanging the

original water-based coolant for the cutting saw with diesel, this

problem could successfully be resolved. In some samples, size and

density segregation were observed as an artifact of the sample

preparation. Any impact of horizontal segregation on measurement

results was counted in the measurement setup by defining measured

surface segments equally covering the area from the center to the

perimeter of the block (Figure 6).

The overall onsite sample preparation workflow has been described by

surface loggers involved in the field test as a convenient and elegant

solution to sample handling and archiving. The measured blocks can

easily be stored and take up less space than conventional bags of dry

cuttings. If required, the resin-mounted cuttings can be re-measured

at a later time. The described onsite sample preparation presents a

major leap from the existing lab-based preparation procedure, which

typically takes up to two days and is optimized for the preparation of

large batches of samples.

Figure 4. 2-D surface of drill cuttings mounted in a resin block compared with the original sample collected from the shale shakers.

Sample Preparation

QEMSCAN WellSite sample preparation is different from conventional

and other advanced mudlogging sample preparation requirements.

Drill cuttings are measured in 2-D section in their original size and

shape as produced by the drill bit. As a result, there is no bias being

introduced by physical size fractionation or by reducing cuttings

to powder, as required for example by x-ray diffraction (XRD), x-ray

fluorescence (XRF), or laser-induced breakdown spectroscopy (LIBS).

In the field test, cutting samples generated by a PDC drill bit were

collected from the shale shakers at regular drilling intervals ranging

from 3 to 10 m predefined by the drilling program. The samples were

wet-screened using 2 mm and 63 micron sieves, complying with the

sample preparation protocol of the conventional surface logging team

on site. A representative scoop of ~5 ml (~5 g of dry cuttings) was

collected from the ~200 g washed sample material spread over the

63 micron screen, placed onto a watch glass, and dried in a microwave.

The dry sample was added to fast-curing epoxy into a re-usable 30 mm

plastic mould, and placed into a planetary mixer. The solid resin block

was removed, labeled, and subsequently sectioned by a diamond saw.

As a result, sample aliquots are presented in the form of representative

2-D surfaces of randomly distributed cuttings mounted in resin

(Figure 4). In a final step, the surfaces were coated with a 25 nanometer

Application Note QEMSCAN® WellSite™ on-shore

Page 5

Figure 5. Schematic of sample preparation procedure indicating the individual steps and approximate times.

Measurement

Sample blocks can be loaded into the vacuum chamber and measured,

either one-by-one in the sequence of sample collection, or as batches

of up to six blocks. The QEMSCAN WellSite measurement parameters

and workflow have been optimized to minimize measurement times

without compromising mineral and textural identification, and the

overall measurement statistics. The following setup was consistently

applied to all measurements in the field test, targeting average

measurement times of ~30 min in order to provide time-critical data

within an hour from sample collection (Table 1).

Parameter Value Comment

frame size 2,000 µm equivalent to maximum cuttings size

number of frames 61 half a block (semi-circle)

e-beam voltage 20 keV optimal for heavy and clay mineral identification

e-beam current 7 nA providing maximum EDX count rate

total x-ray count 1,000 providing reliable mineral identification

e-beam stepping interval 20 µm providing sufficient textural resolution

mineral identification O&G v3.3 new QEMSCAN® Spectral Analysis Engine

Table 1: Summary of instrument setup and measurement parametersFigure 6. Image of half a block measurement.

Application Note QEMSCAN® WellSite™ on-shore

Page 6

Figure 7. Schematic of automated QEMSCAN® measurement.

Figure 8. Primary Mineral List of phases identified in drill cuttings from siliciclastic reservoirs.

The e-beam stepping interval defines the spatial resolution and

thereby pixel size of the image. Sample surfaces were measured

as semi-circles of 61 frames, each 2 mm wide and mapped at a 20

microns stepping interval, providing both sufficient textural detail

(Figure 6) and overall robust measurement statistics. The total

x-ray count defines the number of x-ray photons collected at each

measurement point to build up the energy-dispersive x-ray (EDX)

spectrum used to determine the chemical composition (Figure 7).

QEMSCAN automatically discriminates between resin (background)

and sample, and skips the analysis of areas identified as background.

QEMSCAN WellSite mineral identification is based on an x-ray count

of 1,000 photons, which has been demonstrated to provide ultra-fast

(~200 points/sec) and reliable mineral identification.

The mineral identification protocol for QEMSCAN WellSite is based

on the latest QEMSCAN Spectral Analysis Engine (SAE) element

concentration approach. A custom Species Identification Protocol

(SIP) was developed for the application of drill cuttings in siliciclastic

sequences. The O&G _v3.3 SIP is capable of accurately discriminating

>30 mineral groups, including: clay minerals and micas such as

kaolinite, smectites, chlorite, illite and glauconite; solid solution series

of feldspars; and trace minerals such as pyrite, rutile and zircon.

All mineral definitions are based on elemental ranges and ratios,

backscatter electron brightness (BSE) thresholds, and take into account

the challenging sampling environment characterized by contamination

from oil and drilling fluid additives, i.e. potassium chloride and barite

(Figure 8).

The average measurement time in the field test was ~35 minutes,

ranging from ~25–45 min depending on the packing density of the

sample. Measurements could keep up with the general drilling speed,

resulting in an average of 23 measurements per day. The average

raw data generated per single sample interval is based on >300,000

spectra, collected on >2,000 genuine drill cuttings.

Application Note QEMSCAN® WellSite™ on-shore

Page 7

During the field test, the application team faced some operational

challenges which could all be resolved onsite without requiring

additional tools or spares. On arrival, the unit was dropped off from

a helicopter, resulting in the shearing of the heavy penning gauge

from the vacuum chamber. As a workaround, the broken pipe was

plugged with a plastic cone. The automated measurement start had

to be set to a fixed 2 min pump-down period. While this increased

the overhead on measurement times slightly, measurement results

remained unaffected. Fluctuations in the power supply in one of

the workshops areas caused intermittent carbon coating interlocks

and e-beam instability. On the rig sites, power supply proved stable

enough for trouble-free 24/7 operation. The initially targeted average

measurement time of ~30 min was slightly exceeded, mainly due

to the unexpected large presence of fines in some intervals which

translated in an increase in measurement points.

In contrast to existing lab-based QEMSCAN systems, setup and

calibration of QEMSCAN WellSite is fully automated. Measurements

are started via a software interface developed to provide a single-click

solution to system calibration; including e-beam alignment, BSE, EDS

and SAE calibration. In the field test, all measurements and routine

maintenance were successfully performed by Halliburton staff without

advanced SEM training. Maintenance included changing the tungsten

filament, which took <5 minutes.

Data Processing

The measurement raw data are subsequently processed by offline

software. The data processing can be separated into: 1) image-based

operations performed on the stitched image of the measurement

area; and 2) particle-based operations classifying individual particles

into similar categories. Both processing capabilities are unique to

QEMSCAN data and are here demonstrated to increase the significance

and value of the generated cuttings data.

Despite wet-screening, most drilling intervals showed considerable

contamination with drilling mud. Contamination by fines attached to

cuttings was effectively removed by applying a set of “digital screens”

to the raw data, including: image-based field stitching; touching

particle separation; size filter; and a boundary phase processor.

Some sample intervals were characterized by significant contributions

of BARACARB®, an engineered ground marble added to the drilling

mud as a borehole strengthening treatment to prevent fluid loss,

and by swarf generation from the drill string. QEMSCAN’s ability to

perform particle-by-particle classification was used to apply a set of

“contextual screens”, separating additives from cuttings (Figure 9). As

a result, data could be generated from genuine cuttings originating

from the drilled rock formation (Figure 10). Each data processing step,

including digital and contextual screening, is documented in the

metadata and fully reversible.

Figure 9. Classification rules applied to resolve similar particles such as: swarf (contaminants) from iron-oxide/siderite cemented clasts (cuttings) in top row; BARACARB® crushed marble (additives) from calcite-cemented clasts (cuttings) in bottom row.

Application Note QEMSCAN® WellSite™ on-shore

Page 8

Figure 11. Image of drill cuttings sorted into 10 lithology classes.

Figure 10. Contaminated sample demonstrating the impact of digital and contextual screening improving the relevancy of the reported data: wet-screened sample as measured (left); digitally screened sample (center); contextually screened sample (right).

QEMSCAN particle classification was then applied to sort the genuine

drill cuttings into lithology classes defined by shared mineral

composition and textural attributes. Cuttings classification is an

interactive, data-driven approach, by developing a protocol that sorts

the present mix of cuttings encountered within the sample interval

into discrete, meaningful lithology categories. Cuttings classes provide

a snapshot of the subsurface lithology, and take full account of the

regional basin geology, drilling practice, and any other information

requirement defined by the well-site geologist (Figure 11). Lithology

classes were identified by Oil Search Limited as carriers of potentially

valuable information, which has not been previously applied to the

onsite interpretation of changes in the subsurface geology, and the

calibration of downhole data.

calc-cmt-crs-qtz ark-crs-qtz cl-crs-qtz crs-qtz calc-cmt-si cl-si si calc-cl cl cmt uclass

Application Note QEMSCAN® WellSite™ on-shore

Page 9

In terms of time-to-data, the full set of detailed reports on mineral and

lithology composition, including percentage cuttings return, average

cuttings and grain size trends, the presence of tracer minerals, clay

typing, and calculated matrix density, were all made available within

~1 hour from sample collection at the shakers, if not run in batches of

six samples. QEMSCAN log data could be updated every 40 mins, once

a sample has been measured and the data fully processed.

Results and Data ApplicationsOver the duration of the field test, more than 1,000 samples were

collected, prepared and measured. The most continuous sampling

sequence comprises 728 samples collected in 34 days from a single

well. The following results are excerpts from this dataset, including

~200 million individual spectra from 1 million genuine cuttings.

QEMCAN data are unique in that images, more specifically individual

compositional maps of cuttings, form the basis for all numerical and

graphical reports. QEMSCAN reports can be generated for any selected

sample interval, lithology class, or even individual cuttings. For this

application note, drilling depth sections defined by the drill bit size

were selected as the basis for reporting results.

From particles to genuine cuttings

The first level of information provided by QEMCAN WellSite includes

reports on the overall composition of particles within a sample

sequence. In addition to drill cuttings, these can include cavings, swarf,

additives, and casing cement. Reports include the percentage return

of cuttings and their average size and shape, identified by Oil Search

Limited as an independent measure of the drill bit performance, in-situ

stress fields, and borehole condition. In the given example, a well

section is presented in which BARACARB additives make a significant

contribution to overall sample composition (Figure 12).

From cuttings to lithology classes

The second level of information includes reports on the composition

of representative drill cuttings within a sample sequence. In the given

example, the removal of contaminants by digital and contextual

screening is shown to have a significant impact on the modal

mineralogy. The reported mineral stratigraphy on genuine cuttings

is demonstrated to be more relevant and sensitive to changes in the

subsurface lithology than the whole sample composition (Figure 13).

Oil Search Limited was particularly interested in reports quantifying

the mineralogy of clays; discriminating swelling (e.g. smectites) from

non-swelling (e.g. chlorite), and radioactive (e.g. illite) from non-

radioactive (kaolinite) clay minerals. In addition, the presence of trace

phases such as pyrite, apatite, heavy minerals and tracer minerals

were monitored for downhole data calibration and well correlation

Figure 12. Percentage return of cuttings and particles of swarf and solid drilling fluid additives, showing a significant but varying contribution of BARACARB® additives.

Application Note QEMSCAN® WellSite™ on-shore

Page 10

Figure 13. Comparison of modal mineralogy results for: wet-screened raw data (left); digitally screened data (center); and, final contextually screened data reporting on genuine cuttings (right). Independently determined geological formation tops are indicated by horizontal red lines.

purposes. In addition to the mineralogy, average mineral grain sizes

were reported as equivalent sphere diameters. In the field test, quartz

grain sizes were plotted as an independent means to highlight fining

and coarsening trends in the siliciclastic sequence. The cuttings matrix

density calculated from mineral reference data was reported and

compared to downhole bulk density values. As discussed in the data

processing paragraph, drill cuttings were sorted into discrete lithology

classes based on similar mineral composition and textural attributes.

In the given example, the modal mineralogy log for a well section

is compared with the lithology log for the same sample interval,

highlighting the additional contextual detail provided by the lithology

classes (Figure 14).

Application Note QEMSCAN® WellSite™ on-shore

Page 11

Figure 14. Comparison between fully processed modal mineralogy log (left) and lithology log (right). Geological formation tops for the selected sequence of sample intervals are indicated by horizontal red lines.

Application Note QEMSCAN® WellSite™ on-shore

Page 12

Figure 15. Property sheet for lithology class ‘cl’ (clay) based on combined well cuttings. This cuttings class comprises illite-rich claystone cuttings.

MapView petrographic image for each sample

MinLog modal mineralogy (volume or mass %) for selected sample sequence, including clay mineral, feldspars, heavy and trace mineral quantification

LithoView cuttings images for defined lithology classes

LithoLog lithology classes contributions (volume or mass %) for selected sample sequence

DensityLog calculated matrix density for selected sample sequence

SizeLog average quartz grain size (or cuttings size) for selected sample sequence

LithoMin modal mineralogy (volume or mass %) for selected lithology classes

LithoProp lithology class properties for selected sample sequence

LithoQtzGSD average quartz grain-size distribution for selected lithology classes

Return percentage return (volume or mass %) of drill cuttings and contaminants/additives for selected sample sequence

Stats measurement statistics for selected sample sequence

From lithologies to rock properties

The third level of information provided by QEMSCAN WellSite includes

detailed reports on the composition and texture of cuttings within

individual lithology classes. Lithology-based reports in this field test

include the average modal mineralogy, quartz grain size distribution,

average cuttings and quartz grain sizes, matrix density, and the total

number and volume contribution of classified cuttings for selected

sample intervals. Here, one of ten basin-specific lithology class reports

corresponding to claystone is presented as an example (Figure 15).

As a result of discussions between FEI Application Scientists,

Halliburton Data Engineers, and Oil Search Limited Geologists and

Petrophysicists, a set of eleven report templates was developed in

order to provide consistency in data reporting in the field test.

This set of reports can easily be adapted and expanded to meet

individual reporting requirements:

Application Note QEMSCAN® WellSite™ on-shore

Page 13

From properties to integrated logs

Selected QEMSCAN WellSite data were exported as numerical log

data and imported into Oilfield Data Manager (ODM™), a third party

integration and interpretation software designed to store, manage,

and interpret geological well data. Within ODM, QEMSCAN data

were juxtaposed with data from selected downhole measurements,

including: rate of penetration; gamma radiation; caliper; bulk density;

resistivity (not displayed); and neutron porosity logs (Figure 16). The

example from the integrated log highlights aspects of the added

information obtained by QEMSCAN WellSite data.

Quantification of hydrous micas, such as glauconite, supports

the interpretation of the neutron porosity log, by calibrating the

inferred clay reading, and the interpretation of the resistivity

logs, by calibrating the inferred formation water content. Volume

contributions of alkali feldspars, as well as non-radioactive clays

(kaolinite), support the interpretation of the gamma-ray log response.

The interpretation of resistivity logs is supported by showing the

presence or absence of pyrite and clay grain coatings. Quantitative

QEMSCAN clay typing further assists in interpreting changes in the

rate of penetration of the drill bit and in the borehole diameter, by

discriminating swelling (smectites) from non-swelling clays (e.g. illite).

In the given example, the Alene Member is characterized by a sudden

increase in smectites and intervals with high glauconite content.

Identification of clays and clay types also assisted in the deterministic

petrophysical interpretation of the drilled intervals, particularly with

respect to the volume of clay parameter. It is anticipated that the

mineral identification information which has been extracted from

the QEMSCAN data will assist in the derivation of a more accurate

multi-mineral model for usage in an optimal solution petrophysical

interpretation.

The QEMSCAN lithology log corresponds well to the geological

formation tops. Intervals characterized by claystone, siltstone and

sandstone are clearly distinguished. In the given example, siltstone of

the Juha Member is identified and discriminated from the sandstone

reservoir intervals of the Toro Formation, despite overall similar

mineralogy. The lithology log also provides detailed information

on lithology associations with carbonate cementation. Here, calcite

cementation in claystone of the Bawia Member is contrasted with

calcite cementation in siltstone of the Basal Juha Sands. The individual

members of the Toro Formation are clearly identified as sandstone

intervals, separated by an increase in clay-rich siltstone. QEMSCAN

data integration with downhole data shows considerable potential, but

is still at an early stage. Using the ODM software, different logs can

be designed to highlight specific correlations, such as clay mineralogy

with gamma-ray log.

QEMSCAN WellSite log data were also compared with the original

Formation Evaluation Log provided by the onsite surface loggers

(Figure 16). Overall, the QEMSCAN lithology log compares well with the

conventional classification of cuttings into sand-, silt-, and claystone

based on optical microscopy observations. Discrepancies in the

amount of sand-, silt-, and claystone reported in the two logs can be

partly explained by the written remarks in the Formation Evaluation

Log, where inferences are made about contamination. The dominant

lithology reported in the Formation Evaluation Log generally has

a stronger presence than reported in the QEMSCAN lithology log.

This suggests differences between qualitative lithology descriptions

and consistent quantitative QEMSCAN lithology classification.

The comparison also highlights the limited ability of conventional

mud logging to describe the clay mineralogy, presence of genuine

carbonate cementation, and the type of feldspars, all of which are

combined in remarks.

Application Note QEMSCAN® WellSite™ on-shore

Page 14

Figure 16. Integrated ODM™ log juxtaposing QEMSCAN® data with selected downhole data and the original Formation Evaluation Log including written remarks by the mud loggers, the conventional cuttings log, as well as the final interpreted lithology log by the well-site geologist.

Application Note QEMSCAN® WellSite™ on-shore

Page 15

Figure 16. Continued from previous page.

ConclusionsSuccessful operation of QEMSCAN WellSite in the challenging on-shore

rig environment in the highlands of Papua New Guinea demonstrated

the ruggedness of the mobile system and the sample preparation

equipment. All operational challenges were resolved on site without

requiring shipment of additional consumables, tools or spare parts.

QEMSCAN WellSite was successfully integrated into 12-hour work shift

surface logging operations by Halliburton staff. Sample collection,

preparation and measurement could keep up with the drilling

speed. During rig relocation, QEMSCAN WellSite was moved to the

Halliburton workshop area and operated to measure selected samples

at higher resolution and cuttings samples from a previous well in batch

mode (Figure 17).

The field test demonstrated the ability to report near real-time data

which can be used to support time-critical on-site decisions and

downhole data interpretation. Single sample reports were on average

based on >2,000 genuine cuttings. The field test also demonstrated

that the digital removal of contaminants in addition to the wet-

screening routinely performed by surface loggers can provide

relevant data on the subsurface geology. QEMSCAN data processing

successfully separated genuine drill cuttings from contaminants and

drilling fluid additives. The drill cuttings were further sorted into

lithology classes.

A comparison of QEMSCAN lithology log data with downhole

instrument data and conventional cuttings descriptions shows good

alignment between geological formation tops. The detail provided on

clay mineralogy, feldspars, and lithology associations with carbonates

is unprecedented and was used to improve the interpretation of

the downhole data, in particular the gamma-ray and resistivity

log responses. All QEMSCAN data are linked to micron-scale color-

coded mineral maps of cuttings, making data interpretation readily

accessible to a range of well-site professionals, including geologists,

petrophysicists, drillers and engineers.

World HeadquartersPhone: +1.503.726.7500

FEI Europe Phone: +31.40.23.56000

FEI Japan Phone: +81.3.3740.0970

FEI Asia Phone: +65.6272.0050

FEI Australia Phone: +61.7.3512.9100

© 2011. We are constantly improving the performance of our products, so all specifications are subject to change without notice. QEMSCAN, WellSite and the FEI logo are trademarks of FEI Company, and FEI is a registered trademark of FEI Company. All other trademarks belong to their respective owners. AN0000 09-2011

fei-natural-resources.com

TÜV Certification for design, manufacture, installation and support of focused ion- and electron-beam microscopes for the Electronics, Life Sciences, Research and Natural Resources markets.

Application Note QEMSCAN® WellSite™ on-shore

David Haberlah is a Senior Applications Scientist

for automated petrography solutions at FEI Natural

Resources in Brisbane, Australia. He graduated

with an MSc in Physical Geography from the Free

University of Berlin in 2004 and obtained his PhD in

Geology in 2009 at the University of Adelaide. From 2009 to 2010, he

held a research fellow position within CO2CRC at the Australian School

of Petroleum. David joined FEI in late 2010, and supported application

development in the Papua New Guinea field test by helping to develop

the mineral identification and cuttings classification protocols, digital

and contextual screens, and adjustments to the sample preparation

workflow.

Mike Garrick is a Data Engineer with Halliburton in

the North Sea. He graduated with a BSc in Geology

from the University of Portsmouth in 2005, where

he specialized in Structural Geology. He started

working for Halliburton on various rigs as a Surface

Logger in late 2006, and was promoted to Unit Manager. Showing

a keen interesting in the development of advanced mudlogging

solutions, he was asked in November 2010 to assist in the field test of

the QEMSCAN WellSite solution in Papua New Guinea.

About the authors

Figure 17. PDC cuttings measured at 2 micron spatial resolution showing carbonate fossils (light blue) embedded within illite-rich claystone cuttings (green).


Recommended