WELL-BORE INSTABILITY IN THE NORTH WEST SHELF OF AUSTRALIA

1994 ◽  
Vol 34 (1) ◽  
pp. 1
Author(s):  
C.P. Tan ◽  
D.R. Willoughby ◽  
R.R. Hillis ◽  
S. Zhou ◽  
H-B Mühlhaus ◽  
...  
Keyword(s):  
Research Centre ◽  
Well Bore ◽  
Cooperative Research ◽  
Stress Regime ◽  
North West ◽  
The North ◽  
In Situ Stresses ◽  
Stress Changes ◽  
Contour Plots

Well-bore instability, experienced mainly in shales, has resulted in significant drilling delays and abandonment of wells in the North West Shelf of Australia. Although these problems may be induced by physico-chemical interactions, there is an increasing awareness that instability in this region is principally associated with in situ stresses that are high relative to the strength of the materials.This paper describes the research undertaken by the Australian Petroleum Cooperative Research Centre to assist industry in understanding and managing stress-induced well-bore instability in this region. To conduct such stability analyses the basic information required includes knowledge of the orientation and magnitude of the principal in situ stresses and the strength and deformation response of the materials to stress changes imposed by drilling. The required data can be determined using welllogging, analytical and laboratory techniques.Analytical methods can be used to examine the relationship between well-bore stability and changes introduced through drilling. Spreadsheets based on the analytical methods have been produced and applied to the assessment of drilling alternatives and/or design of some well-bores in the North West Shelf.The application of the critical mud weight contour plots and mud weight stability profiles produced by the spreadsheets in assessing drilling alternatives, selection of optimum well-bore alignment and mud weight design are demonstrated through examples. The analyses showed that counter to intuitive expectations, an inclined well may be more stable than a vertical well depending on the well-bore direction, deviation angle and stress regime.

IMPROVING THE OPERABILITY OF REMOTELY OPERATED VEHICLES

1998 ◽  
Vol 38 (1) ◽  
pp. 849
Author(s):  
A.J. Woods ◽  
J.D. Penrose ◽  
A.J. Duncan ◽  
R. Koch ◽  
D. Clark
Keyword(s):  
Visual Information ◽  
Vision System ◽  
Control Process ◽  
Inertial System ◽  
Research Centre ◽  
Stereoscopic Display ◽  
Remotely Operated Vehicles ◽  
Cooperative Research ◽  
North West ◽  
The North

Underwater Remotely Operated Vehicles (ROV's) have a significant support role to play in offshore petroleum production facilities. The extent to which ROVs can replace diver-based operations depends significantly on ROV capacity and the relative costs of mobilising and implementing the two modes of underwater operation. This paper presents work directed at two aspects of ROV operability: the quality of visual information presented to the ROV pilots and the degree of station keeping control exhibited by the vehicle.Significant improvement in pilot performance of selected maintenance-type tasks has been achieved by the use of a purpose built underwater stereoscopic video camera and associated ship-based stereoscopic display unit. Two generations of cameras have now been built and used on a Perry Triton vehicle in use at the North Rankin A platform on the North West Shelf.In a related program, stereoscopic images of the platform structure are processed to determine the relative position of the ROV. Changes in position are used as inputs to thruster control algorithms, with a view to enabling the vehicle to hold position in fluctuating current fields. The position data from the processed 3D images are linked to output from an on-board inertial system to enable position to be maintained despite periodic loss of visual information.First trials of the combined vision-inertial system indicated some success, notably using the vision system, but indicated difficulties with the inertial package and its integration into the control process. An extension of this project is now being supported by the Australian Maritime Engineering Cooperative Research Centre (AMECRC).

scholarly journals Effect of Temperature on Stiffness of Sandstones from the Deep North Sea Basin

2020 ◽  
Author(s):  
Tobias Orlander ◽  
Katrine Alling Andreassen ◽  
Ida Lykke Fabricius
Keyword(s):  
North Sea ◽  
Temperature Effects ◽  
Mass Density ◽  
Thermal Strain ◽  
High Stress ◽  
Testing Temperature ◽  
Effect Of Temperature ◽  
Stress Regime ◽  
The North

Abstract Development of high-pressure, high-temperature (HPHT) petroleum reservoirs situated at depths exceeding 5 km and in situ temperature of 170 °C increases the demand for theories and supporting experimental data capable of describing temperature effects on rock stiffness. With the intention of experimentally investigating temperature effects on stiffness properties, we investigated three sandstones from the deep North Sea Basin. As the North Sea Basin is presently undergoing substantial subsidence, we assumed that studied reservoir sandstones have never experienced higher temperature than in situ. We measured ultrasonic velocities in a low- and high-stress regime, and used mass density and stress–strain curves to derive, respectively, dynamic and static elastic moduli. We found that in both regimes, the dry sandstones stiffens with increasing testing temperature and assign expansion of minerals as a controlling mechanism. In the low-stress regime with only partial microcrack closure, we propose closure of microcracks as the stiffening mechanism. In the high-stress regime, we propose that thermal expansion of constituting minerals increases stress in grain contacts when the applied stress is high enough for conversion of thermal strain to thermal stress, thus leading to higher stiffness at in situ temperature. We then applied an extension of Biot’s effective stress equation including a non-isothermal term from thermoelastic theory and explain test results by adding boundary conditions to the equations.

scholarly journals ANALYSING POST-SEISMIC DEFORMATION OF IZMIT EARTHQUAKE WITH INSAR, GNSS AND COULOMB STRESS MODELLING

2016 ◽  
Vol XLI-B1 ◽  
pp. 417-421 ◽  
Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos
Keyword(s):  
Measurement Techniques ◽  
Satellite System ◽  
Northern Region ◽  
Strike Slip ◽  
Coulomb Stress ◽  
North West ◽  
Coulomb Stress Changes ◽  
Izmit Earthquake ◽  
The North ◽  
Stress Changes

On August 17<sup>th</sup> 1999, a M<sub>w</sub> 7.4 earthquake struck the city of Izmit in the north-west of Turkey. This event was one of the most devastating earthquakes of the twentieth century. The epicentre of the Izmit earthquake was on the North Anatolian Fault (NAF) which is one of the most active right-lateral strike-slip faults on earth. However, this earthquake offers an opportunity to study how strain is accommodated in an inter-segment region of a large strike slip fault. In order to determine the Izmit earthquake post-seismic effects, the authors modelled Coulomb stress changes of the aftershocks, as well as using the deformation measurement techniques of Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS). The authors have shown that InSAR and GNSS observations over a time period of three months after the earthquake combined with Coulomb Stress Change Modelling can explain the fault zone expansion, as well as the deformation of the northern region of the NAF. It was also found that there is a strong agreement between the InSAR and GNSS results for the post-seismic phases of investigation, with differences less than 2mm, and the standard deviation of the differences is less than 1mm.

Rock properties and in-situ stress state of the Egilabria Prospect, Lawn Hill Platform, Queensland

2019 ◽  
Vol 59 (1) ◽  
pp. 383 ◽  
Author(s):  
Adam H. E. Bailey ◽  
Liuqi Wang ◽  
Lisa Hall ◽  
Paul Henson
Keyword(s):  
In Situ Stress ◽  
Rock Properties ◽  
Resource Potential ◽  
North West ◽  
Reservoir Volume ◽  
Geological Surveys ◽  
In Situ Stresses ◽  
Petroleum Resource ◽  
Gas Potential

The Energy component of Geoscience Australia’s Exploring for the Future (EFTF) program is aimed at improving our understanding of the petroleum resource potential of northern Australia, in partnership with the state and territory geological surveys. The sediments of the Mesoproterozoic South Nicholson Basin and the underlying Paleoproterozoic Isa Superbasin in the Northern Territory and Queensland are amongst the primary targets of the EFTF Energy program, as they are known to contain organic-rich sedimentary units with the potential to host unconventional gas plays, although their subsurface extent under the cover of the Georgina Basin is presently unknown. In order to economically produce from unconventional reservoirs, the petrophysical rock properties and in-situ stresses must be conducive to the creation of secondary permeability networks that connect a wellbore to as large a reservoir volume as possible. This study utilises data from the recently drilled Armour Energy wells Egilabria 2, Egilabria 2-DW1, and Egilabria 4 to constrain rock properties and in-situ stresses for the Isa Superbasin sequence where intersected on the Lawn Hill Platform of north-west Queensland. These results have implications for petroleum prospectivity in an area with proven gas potential, which are discussed here in the context of the rock properties and in-situ stresses desired for a viable shale gas play. In addition, these results are relevant to potential future exploration across the broader Isa Superbasin sequence.

Building a world-class Australian decommissioning industry

2018 ◽  
Vol 58 (2) ◽  
pp. 690 ◽  
Author(s):  
Kym Bills
Keyword(s):  
Science Research ◽  
Asia Pacific ◽  
Research Centre ◽  
Marine Science ◽  
Australian Government ◽  
Cooperative Research ◽  
North West ◽  
Effective Manner ◽  
World Class ◽  
The University

Collaboration in decommissioning offshore infrastructure could save both industry and taxpayers billions of dollars and facilitate new industries and exports for Australia, especially in the Asia-Pacific region. At the end of the liquefied natural gas (LNG) plant construction boom, Australia must not miss out on this major new opportunity. The 2017 bid for Commonwealth funding to establish a Decommissioning Offshore Infrastructure Cooperative Research Centre (DOI-CRC) involved more than 30 participants and many other collaborators. High-level commitments were made by Chevron, Woodside, Shell, BHP, ExxonMobil, Quadrant, The University of Western Australia, Curtin University, the University of New South Wales, Deakin University, Australian Maritime College, CSIRO and Australian Institute of Marine Science. A Perth-based DOI-CRC was supported by National Energy Resources Australia, National Offshore Petroleum Safety and Environmental Management Authority and other Australian Government bodies and by the Western Australian Government and its Chief Scientist and agencies but did not receive sufficient support from the CRC Advisory Committee. Meeting decommissioning challenges in the North West Shelf, Bass Strait and the Northern Territory in a timely, robust, scientific, efficient and cost-effective manner that contributes to a sustainable marine environment should draw upon and augment international best practice with local capability and expertise. Good science and innovative engineering are needed to support regulatory approval of options such as ‘rigs to reefs’ and commercial opportunities such as in waste management and expanded fishing and tourism. APPEA and operators wish to maintain DOI-CRC’s momentum and learn from UK research arrangements through funding marine science projects. But we must be much broader if we are to build a sustainable world-class Australian decommissioning industry. In particular, we need to work more closely with state and federal regulators and policymakers and undertake more engineering science research and innovation.

scholarly journals ANALYSING POST-SEISMIC DEFORMATION OF IZMIT EARTHQUAKE WITH INSAR, GNSS AND COULOMB STRESS MODELLING

2016 ◽  
Vol XLI-B1 ◽  
pp. 417-421
Author(s):  
R. Alac Barut ◽  
J. Trinder ◽  
C. Rizos
Keyword(s):  
Measurement Techniques ◽  
Satellite System ◽  
Northern Region ◽  
Strike Slip ◽  
Coulomb Stress ◽  
North West ◽  
Coulomb Stress Changes ◽  
Izmit Earthquake ◽  
The North ◽  
Stress Changes

On August 17<sup>th</sup> 1999, a M<sub>w</sub> 7.4 earthquake struck the city of Izmit in the north-west of Turkey. This event was one of the most devastating earthquakes of the twentieth century. The epicentre of the Izmit earthquake was on the North Anatolian Fault (NAF) which is one of the most active right-lateral strike-slip faults on earth. However, this earthquake offers an opportunity to study how strain is accommodated in an inter-segment region of a large strike slip fault. In order to determine the Izmit earthquake post-seismic effects, the authors modelled Coulomb stress changes of the aftershocks, as well as using the deformation measurement techniques of Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS). The authors have shown that InSAR and GNSS observations over a time period of three months after the earthquake combined with Coulomb Stress Change Modelling can explain the fault zone expansion, as well as the deformation of the northern region of the NAF. It was also found that there is a strong agreement between the InSAR and GNSS results for the post-seismic phases of investigation, with differences less than 2mm, and the standard deviation of the differences is less than 1mm.

Stockholm Agreement—Past, Present, Future (Part 1)

2002 ◽  
Vol 39 (03) ◽  
pp. 137-158
Author(s):  
Dracos Vassalos ◽  
Apostolos Papanikolaou
Keyword(s):  
Status Quo ◽  
Research Centre ◽  
New Developments ◽  
North West ◽  
The North ◽  
The Status ◽  
Potential Impact ◽  
The University ◽  
North And South ◽  
South Of Europe

April 1, 2001 marked the fourth anniversary of the Stockholm Agreement (SA), a period during which almost 80% of the roll-on/roll-off (Ro-Ro) fleet in North West Europe have been subjected to calculations, model testing and numerical simulations in the struggle to meet these demanding new requirements. The experience gained has been invaluable in understanding better the problem at hand and is being utilized to shape new developments likely to lead to more meaningful requirements. The North-South divide, however, continues to cause unrest, particularly at the European level. Efforts to assess the status quo in North West Europe, and to use the information amassed so far as a means to predict the potential impact of introducing the SA in the South, led to a dedicated call by the Commission and to a contract being awarded to two closely collaborating teams, one at the Ship Stability Research Centre of the University of Strathclyde under the leadership of Professor Vassalos and one at the Ship Design Laboratory of the National Technical University of Athens, under the leadership of Professor Papanikolaou, representing the North and South of Europe, respectively. This background provided the incentive for an introspective look at the SA, with a view to ascertaining its status before embarking into future projections. This forms Part 1 of the SA related research with Part 2 aiming to cover the results of the Commission study itself.

scholarly journals On the Late Pliocene stone tools of the Quranwala Zone, north-west sub-Himalayas, India

Antiquity ◽  
2017 ◽  
Vol 91 (357) ◽  
Author(s):  
Vidwan Singh Soni ◽  
Anujot Singh Soni
Keyword(s):  
Stone Tools ◽  
Fossil Bone ◽  
Question Mark ◽  
North West ◽  
Cut Marks ◽  
The North ◽  
Geological Processes ◽  
Animal Bones ◽  
Fossil Bones

A recent study of the Quranwala Zone (QZ) of the north-west sub-Himalayas, India, presents evidence for anthropic activity during the Pliocene that includes a number of stone tools found in association with fossil animal bones with cut marks. Based on the date of the Pliocene rock outcrop, the tools and bones are suggested to date from 2.6 Ma (Gaillard et al. 2016). There is, however, a question mark over the context of these tools within an outcrop of Pliocene rocks and, hence, over the date of these tools and the fossil bones. The trench from which they were excavated at Masol 2 (Gaillard et al.2016: fig. 3) lies in a depression at the bottom of a slope; the description provided in section 2 of the paper by Gaillard et al. (2016) suggests that the stone tools may not have been in situ within the Pliocene levels, but had accumulated there and were mixed with the fragments of fossil bone due to geological processes. Moreover, many of the stone tools, such as the ‘simple choppers’ found in association with the fossil animal bones (Gaillard et al.2016: figs 6, 8, 9), are usually found on much more recent sites and are therefore unlikely to date from 2.6 Ma.

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