bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pre-Drilled Geomechanical Modeling Reduces Risks in Drilling a Wildcat High-Pressure/High-Temperature Exploratory Well - A Case Study from Asia Pacific
Authors: Ghosh Amitava , Chatterjee Avirup , Ong See Hong 
Published: March 2018

Abstract
Pore pressure prediction and geomechanical modelling play a very important role in well planning. The exploration focus worldwide is moving more and more into the challenging environments. Well planning and design in high pressure high temperature (HPHT) environments comprise numerous challenges such as play identification and prospect de-risking to drillability and development to production. Overpressure prediction is one of the principal challenges facing the oil industry today, as exploration focus worldwide moves further into the HPHT environments. Pressure related problems in HPHT wells include well control incidents, lost circulation, formation breathing, differential sticking, reduced rates of penetration, and reservoir damage, many which can potentially lead to expensive sidetracks, well abandonments and underground blowouts. A better understanding of the prevalent pore pressure regimes including generating mechanisms, pressure maintenance and dissipation through geologic time enables invaluable insight into these challenges and the ability to mitigate or minimize them. It is important to analyse the challenges prior to drilling so that various plans and systems can be established. Once the pore pressure regime is well understood, the next step is to understand the stress regime. Thus building a geomechanical model is the next key element for well design. The stress model can be used for wellbore stability analysis to understand wellbore failures and help in thedesignof optimum mud weights. Additionally in HPHT environments, thermal-induced stresses and their impacts on stability must also be considered. This understanding helps in modelling wellbore failures due to heating and cooling arising from mud circulation. Other considerations including drilling through faults can set another aspect of wellbore failure which could further complicate the already difficult drilling situation.
This paper presents a case study on using geomechanical evaluations to reduce drilling risks and costs in a high-pressure/high-temperature (HP/HT) well located in offshore Asia Pacific. The major risk anticipated for this well, which was drilled to explore a deep-play (&gt;3.5 Km), was high-pressure (&gt;10,000 psi) and high-temperature (&gt;2000C) with narrow margin drilling conditions. The geomechanical study provided inputs for an effective well design.
Comparing Results of Time Domain Fatigue Design of Steel Catenary Risers Using Linear and Nonlinear Riser Soil Interaction Models Under Random Waves
Authors: Muraleedharan Atmaram , Kimiae Mehrdad 
Published: March 2018

AbstractSteel Catenary Risers (SCRs) are still among the most popular types of riser systems and are widely adopted across deep water oil and gas projects globally. Fatigue design of SCRs are associated with high nonlinearity and it remains a challenge for riser engineers and researchers. In the Touch Down Zone (TDZ), the soil structure interaction model plays a vital role in the fatigue design and it becomes more complex when dealing with irregular waves and a nonlinear soil structure interaction model.In this paper the effect of nonlinear and linear soil structure interaction models under randomly generated waves for a wide range of seastates are analyzed in time domain. Fatigue damage results under randomly generated waves are calculated in time-domain analysis. Sensitivity of the results to various parameters like the soil type model, the severity of seastates and the duration of dynamic simulations are discussed in detail. Results of this study give a better insight into the fatigue design of SCRs in TDZ.
OCTG Standardization and Surplus Reutilization Bring Cost Reduction Efforts to Fruition
Authors: Ong Gary S. H. , Abdullah Malik Faisal , Razak M. Zahin A. , Ghani Athiyatul Shakirah Abdul , Bong David , Thanaraju Andrew , Low Jun Leon 
Published: March 2018

Abstract
The ongoing low oil price environment underscores the need to be constantly prudent. Long term sustainable changes implementation are necessary in all areas to preserve profitability including that of effective drilling materials and surplus management with OCTG (Oil Country Tubular Goods) being the prime issue from both quantity and price perspectives. Drilling operators especially those with large scale and diversely complex well programs have to manage excessive surplus mess uncontrollably amassed when oil prices were high. Some opted to dispose while others chose surplus reutilization. Disposal seems to be an easier way out as it frees up yard space and reduces preservation cost but it incurs value leakages as it often fetches unreasonably low scrap prices. PETRONAS took on a bold strategy to overcome the issue by channeling efforts on producing a robust OCTG standardization program as well as enhancing reutilization through reverse engineering which involves meticulously designing wells casing programs based on available surplus. These initiatives aim to take materials management to a higher level of efficiency and avoid future excessive surplus accumulations.
This paper will walk through the various hurdles and solutions in the course of delineating Fit-For-Purpose (FFP) configurations and minimum technical criteria for OCTG material and connections specifications to satisfy PETRONAS’ application requirements for all well types ranging from conventional to High Pressure High Temperature (HPHT) and Deepwater. It also describes various operational challenges from onshore machine shop support to offshore tubular running equipment and services which were critical pieces in putting together the standardization puzzle. It will further provide a lowdown on the misperception of having the lowermost specifications and lowest prices as the primary drivers in realizing the greatest value for money for OCTG applications especially for operators with wide ranging application needs.
Improved Understanding of Reservoir Performance Behaviors from 4D Seismic Data – A Case Study from Malaysian Basin
Authors: Pathak Ravi , Ranjan Rakesh , Masoudi Rahim 
Published: March 2018

Abstract
Improved understanding of reservoir performance and behavior are critical for developing sound reservoir management strategy for optimized field development. The reservoir surveillance information gathered over different stages of depletion provide hard data for validating the predicted reservoir performance and trigger suitable course correction in development strategy. Majority of surveillance information gathered is at the well level and flow inside the reservoir is interpreted using reservoir simulation models and/or other analytical methods. Non-uniqueness of these models create uncertainty in understanding of flow patterns inside the reservoir driving the observed reservoir performance.
The paper illustrates an example from Malaysian basin where 4D seismic information was used for optimizing reservoir management and future development strategies.
Optimal Sand Control Design & Technique Selection: A Simplified Practical Guidance Tool
Authors: Reyes Raymond , Sipi Aluyah 
Published: March 2018

Abstract

Objectives
The primary aim of this study was to design a guideline in the form of a flow chart that can potentially be used in practice when optimal sand control methods and implementation of completion techniques are considered in sand producing wells. The flow chart could also serve as a tool during the decision-making process where sand control is deemed necessary. Distinct reservoir data and key parameters were incorporated into the designing of the flow chart. This paper predominantly focused on two of the most common techniques used currently in practice; sand screens and gravel pack.

Methodology
A retrospective analytical review was carried out. A systematic search was undertaken to analyze sand control methodologies used in recent studies to ascertain key considerations undertaken when choosing gravel pack and/or sand screen. Studies selected were based on a predetermined set of inclusion and exclusion criteria. Recurrent pattern that existed when choice of a specific technique was identified; a list of criteria that was considered when selecting gravel pack and/or sand screen techniques was developed. Information and data obtained were then eventually integrated in stages into designing a concise flowchart.

Results, Discussion, Conclusion
List of criteria developed when contemplating sand control and completion methods were as follows, 1. Determine rock mechanics, 2. Study individual reservoir conditions, 3. Note lithological changes, 4. Obtain well data, 5. Characterize formation sand, 6. Select gravel size, 7. Select screen and size, 8. Select completion method and 9. Evaluate the potential cost and economical outcome. The development of flow chart then began with the categorisation of key information into four significant stages as follows, sand prediction, sand analysis, sand control and completion method. Looking at the step 1 to 9 of the list of criteria and the four phases of the flow chart together, a more structured and integrated thought process took place. When the sand analysis stage was referred to, criteria 1 to 5 were determined simultaneously. Then, the sand prediction stage was referred to in the flow chart where upon obtaining the sand production rate it could be determined if the sand produced was low/manageable. A choice to live with the sand produced is made if so. If the rate was high, then the rest of criteria 6 to 9 as per the list above were determined and advancement is made to the next stage flow chart according to the sections. Both, the criteria list and flow chart can be used in parallel as guidance when implementing respective techniques in an individual sand-producing well.
Application of Integrated Compositional Gas Ratio Analysis to Understand Reservoir Hydrocarbon Potential and Enhance Confidence of Testing and Reservoir Lateral Drilling: With Examples from Krishna Godavari Basin, India
Authors: Sahu Arijit 
Published: March 2018

Abstract
The subsurface geological complexities in Krishna Godavari Basin, India often result into discrete and challenging reservoirs. Limited geological correlation plus HP-HT regime down-hole further add up to the challenge to understand reservoir HC potential. In this context, application and meaningful interpretation of gas ratio analyses are discussed in reservoir sections of two exploratory wells (A & B of L. Cretaceous and L. Eocene) from KG Basin.
Formation Gas data obtained during drilling are commonly analyzed as well-known ratios of ‘Dryness’, ‘Wetness’, ‘Balance’, ‘Character’ & ‘Pixler ratios’ which are simple, quick and field based. It is a proxy that can save time and resource; by aiding in identification of reservoir fluids, fluid contacts & choosing testing intervals, thus enhancing confidence about reservoir. It can be practiced especially where log quality is poor and in cases where logging scope is limited due to complications or high thermal regime.
It is found that gas ratio studies indicate gas-condensate in Well-A while gas with light crude oil in Well-B reservoirs. Moreover it is capable of picking up top of reservoir facies, gas-water & gas-oil contacts and variation in reservoir tightness across reservoir sections as found in Well-A & B. The comparative approach of ratios also interprets about presence of several discrete yet closely spaced HC pools across the reservoir section of Well-B. These findings simply enhance understanding of otherwise complex reservoirs. Along with petrophysical analysis it adds confidence to propose precise testing intervals against HC fluid of interest.
Since gas-ratios are proxy of fluid contacts, their utility can be extended to drilling reservoir lateral wells, if compositional gas data can be obtained fast- in which case gas-ratio analysis can guide drilling effectively to avoid deviation to unwanted fluid zone although reservoir litho-facies variation is less. Gas ratios and electrologs are integrated to introduce to a practical concept of Oil Potential Parameter (OPP) to evaluate effective extent of arenaceous reservoir and reduce qualitative geological risk while planning wells to develop an oil field, as shown with a KG basin example.
Gas Centrifugal Compressor: Pushing its Capacity Limit via Surge Control & Polytrophic Efficiency Operating Point Optimization, Driven Gas Turbine Fuel Savings
Authors: Ir. Siva Kumaran C. 
Published: March 2018

Abstract
In many offshore oil and gas installations, the gas compressors are directly driven by the gas turbines which uses fuel gas that can be monetized if the gas turbines fuel gas consumption is reduced; both from operating the compressors at higher efficiency and optimized compressor operating envelope to operate as close to surge region, thus avoiding gas recycling at the compressor. This paper shows every molecule savings on the fuel gas consumption can derive substantial commercial value for the end users.
The presenter list prerequisites for the gas compressor operating points optimization and surge control optimization. The methods used will guide end users to operate multiple gas compressors by taking advantage of their best efficiency operating points based on either polytrophic or isentrophic efficiency calculated. Simple algorithm and easy to measure parameters from the field to derive the monetized values of the fuel savings to see if it is worth to adjust the operating points can be determined. The incipient surge test can be conducted to determine the surge region to ensure we operate the compressors without gas recycling which is waste of energy during capacity turndown for the compressor, thus this also yields return on investment.
By operating the compressor at better efficiency points, the compressor absorbs lesser brake horsepower (bhp) or shaft power, in turn, the gas turbines fuel is consumed at optimized flowrate, resulting in reduction of fuel gas that can be monetized instead of being burned in combustion chamber of the gas turbine and emitted as Green House Gas (GHG) from the gas turbine exhaust stacks. Operating the gas turbine efficiently means we are truly embarking on GREENER environment, not just by words but this is also a practical way to embrace Paris climate change initiatives. The Paris Agreement, Paris climate accord or Paris climate agreement is an agreement within the United Nations Framework Convention on Climate Change dealing with greenhouse gas emissions mitigation.
It is also common that we recycle gas to avoid surging the compressors for low flowrate scenarios in our compression operations which is an inefficient way of compression as recycling gas means energy is wasted by compressing gas then its pressure is killed via capacity recycle or anti surge control valve which in turn dissipates as heat and noise during gas recycling. Therefore, one of the desired solution is to push compressors closest to the surge region by conducting incipient surge test at site conditions to define the actual surge boundary, allowing the compressor to operate without recycling at lower flowrates, thus recycling is minimized or/and some cases avoided. This paper presents the incipient surge test done offshore with risk mitigated whilst some OEM's do not recommend this test. The author has personally conducted such test offshore, and presents risks and values proposition for end users.
Measures to Overcome Subsea Installation Challenges from High Currents Offshore East Coast of India
Authors: Gupta Ashish , Paul Eldho 
Published: March 2018

Abstract
Subsea installation across the globe comes with associated challenges and offshore East Coast of India is no exception considering the limited installation window available due to the annual monsoon season. The months of December to March are normally considered as the most suitable period for offshore installation. However, McDermott International, Inc as a contractor, faced a number of challenges due to persistent high currents during one of its recent offshore installation campaigns. The surface currents were recorded as high as 3.0 knots during the campaign which persisted for several days.
This paper details novel ideas adopted by McDermott to improve operability and mitigate the risks involved with working in high currents.
Lessons Learned from Using a Drilling Connection in Extreme Conditions
Authors: Marta Lafuente , Fabien Carrois 
Published: March 2018

Abstract

Objectives/Scope
This paper presents a comprehensive summary of the different techniques for increasing the available torque of existing drilling products, the limitations of these techniques and the best practices that can be implemented to reduce risks when using drilling tubulars beyond the API recommended make-up torques.

Methods, Procedures, Process
The torsional strength and make-up torque of a threaded connection are traditionally calculated by only using inherent attributes of the connection, such as the thread design, the yield strength of the connector's material, and the cross critical section of the connector. However, the design of a connector is not the only option to increase its operational torque. Stress balancing considerations and the thread compound friction factor can also help increase operational torque. The recommended make-up torque for rotary shouldered connections is typically defined by stressing those connections to 60% of their torsional strength, thus leaving a margin for using a higher make-up torque‒and hence reaching a higher operational torque. Another option to increase the available operational torque is to use a thread compound with an increased friction factor. API thread compounds are designed with a friction factor of 1. Because of this, when using a thread compound with a higher friction factor, the applicable make-up torque has to be corrected.

Results, Observations, Conclusions
Although stress balancing and the thread compound friction factor considerations can easily and economically increase the available torque of a connector during drilling and allow having more versatile products on the rig, these practices can also carry some risks.

Novel/Additive Information
Compilation of lessons learned from torque-increasing techniques for rotary shouldered connections and compatibility considerations with rig equipment when using them.
Impact of Real-Time Optimisation and Geomechanics to Enhance Performance and Optimise Cost
Authors: Dabyah Ali A. Al , Elsherbeny W. I. , Taylor R. H. 
Published: March 2018

Abstract
Poor drilling performance can lead to increased costs when enhanced drilling performance and extended reach are the main goals for oil operators. Service companies and operators can use the latest technology and several pre-well planning processes and methods to enhance drilling operations effectively and attain these goals. These processes include developing a thorough understanding and application of the geological structure and conducting a formal planning process that incorporates all aspects of drilling, well design, formation evaluation, bit selection and bottomhole assembly.
In this dynamic market where companies are trying to minimize the cost and attain the objective, basic planning and execution using the latest advanced technology are not enough to provide significant performance improvements.
Extensive job planning, including sensitivity analysis, is essential. During the execution phase, close monitoring of drilling parameters and continual testing against modeled data help identify hazards early.
Enabling quick and informed decisions to ensure safe and efficient drilling in a challenging environment will be one of the main factors to improve performance.
Using the right downhole optimization tool with highly experienced engineers enable the interaction with real-time parameters. That's the key factor to overcome extended-reach challenges such as Steering in different environmentsVibrationsTransfer of usable energyHole cleaning and quality indications
Supporting downhole optimization with real-time geomechanics will influence the success rate to deliver the expected performance. The involvement of geomechanics in the planning stage and during execution enables faster and safer drilling and resolves many challenges in extend-reach wells such as Wellbore stabilityHole qualityHole cleaningPressure managementTorque and dragMud system and properties
This paper highlights the importance of utilizing a downhole optimization tool and real-time geomechanics by describing a case study from the Middle East.
Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency
Authors: Guérette Elise-Andrée , Paton-Walsh Clare , Desservettaz Maximilien , Smith Thomas E. L. , Volkova Liubov , Weston Christopher J. , Meyer Carl P. 
Published: March 2018

Abstract. We characterised trace gas emissions from Australian temperate forest fires
through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube
mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We
report emission factors for a total of 25 trace gas species measured in smoke
from nine prescribed fires. We find significant dependence on modified
combustion efficiency (MCE) for some species, although regional differences
indicate that the use of MCE as a proxy may be limited. We also find that the
fire-integrated MCE values derived from our in situ on-the-ground open-path
measurements are not significantly different from those reported for airborne
measurements of smoke from fires in the same ecosystem. We then compare our
average emission factors to those measured for temperate forest fires
elsewhere (North America) and for fires in another dominant Australian
ecosystem (savanna) and find significant differences in both cases. Indeed,
we find that although the emission factors of some species agree within
20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde
and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes,
ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This
indicates that the use of ecosystem-specific emission factors is warranted
for applications involving emissions from Australian forest fires.
Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece
Authors: Perrone Loredana , De Santis Angelo , Abbattista Cristoforo , Alfonsi Lucilla , Amoruso Leonardo , Carbone Marianna , Cesaroni Claudio , Cianchini Gianfranco , De Franceschi Giorgiana , De Santis Anna , Di Giovambattista Rita , Marchetti Dedalo , Pavòn-Carrasco Francisco J. , Piscini Alessandro , Spogli Luca , Santoro Francesca 
Published: March 2018

Abstract. Ionosonde data and crustal earthquakes with magnitude M≥6.0 observed in Greece during the 2003–2015 period were examined to check if the relationships obtained earlier between precursory ionospheric anomalies and earthquakes in Japan and central Italy are also valid for Greek earthquakes. The ionospheric anomalies are identified on the observed variations of the sporadic E-layer parameters (h′Es, foEs) and foF2 at the ionospheric station of Athens. The corresponding empirical relationships between the seismo-ionospheric disturbances and the earthquake magnitude and the epicentral distance are obtained and found to be similar to those previously published for other case studies. The large lead times found for the ionospheric anomalies occurrence may confirm a rather long earthquake preparation period. The possibility of using the relationships obtained for earthquake prediction is finally discussed. Keywords. Ionosphere (Ionospheric disturbances)