bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field-Scale Deformation Analysis of Cyclic Solvent Stimulation in Thin Unconsolidated Heavy-Oil Reservoirs With Developed Wormhole Network
Authors: Rangriz Shokri Alireza , Babadagli Tayfun 
Published: October 2015

Summary
With the current interest in exploiting thin unconsolidated heavy-oil reservoirs, cold heavy-oil production with sand (CHOPS) can be considered to be a promising primary-recovery technique. However, it offers low recovery factors (~5-15%) and creates a complex network of high-permeability channels known as workholes, while simultaneously changing formation compressibility and in-situ stress conditions. Eventually, development of such a network would lead to a softer layer within the shallow unconsolidated reservoir, which can carry less of the overburden stress. Further development of such reservoirs is usually achieved through enhanced-oil-recovery (EOR) applications in the form of cyclic solvent stimulation within an economic framework. Cyclic loading and unloading of this EOR technique make it even more difficult to predict the recovery performance.
In this study, a 3D geomechanical model was used to calculate the stress distribution in a history-matched field in Alberta with 15 producers. The fractal patterns generated from the diffusion-limited-aggregation (DLA) algorithm were used to represent the wormhole network with different strength properties. Foamy behaviour of heavy oil was modelled with the help of a set of kinetic reactions. The hydro-geomechanical model was then used for field-development planning, reservoir management, and assessment of near-wellbore regions during cyclic injection and production. The fieldwide deformation and stress changes were analyzed in deep overburden, caprock, and reservoir to show the influence of local stress orientations in soft and stiff layers.
Next, we considered a sector model with a single well. The model introduced was used to assess EOR processes with different solvent streams. While light hydrocarbon components help to repressurize the formation, the heavier components seem more effective in heavy-oil dilution. This occurred while stress arching redistributed the cyclic injection/production-induced stresses to flow around soft inclusions. Although it is difficult to obtain data to calibrate the 3D hydro-geomechanical model, it allows for reliable investigation of reservoir performance and provides deeper insight than does the use of flow simulation alone. The assessment of the potential of geomechanics can ascertain whether a more-detailed modelling is necessary.
Investigating the Effect of Improved Fracture Conductivity on Production Performance of Hydraulically Fractured Wells: Field-Case Studies and Numerical Simulations
Authors: Sun Jianlei , Schechter David 
Published: October 2015

Summary
Unconventional reservoirs require extensive hydraulic-fracturing treatments to produce fluids economically and efficiently. The main purpose of such treatments is to create complex fracture networks with high-conductivity paths deeper into the nonstimulated reservoir regions. Proppants play an important role in maintaining good-quality fracture conductivities, which then greatly affect long-term production performance. In addition, research on proppants has shown a reduction in conductivities under downhole stresses and multiphase-flow behaviours. Therefore, it is important to study the effect different proppants and conductivities have on production performance through actual field cases.
To evaluate the production performance of wells completed with different proppants, the authors proposed an integrated work flow for characterization and simulation of unconventional reservoirs. This work flow is unique because of the stochastic fracture-network-generation algorithms and improved unstructured-grid-generation techniques. Both analysis of field-production data and numerical simulations were performed on eight wells in the CAPA field of North Dakota. For the field-data analysis, three public-data resources were reviewed to prepare a summary of reservoir properties, fracture properties, proppant properties, and production history. For the numerical simulations, all the wells were modelled and simulated with the proposed work flow. Finally, sensitivity analyses were carried out to investigate the effects of fracture conductivities and natural fractures.
After completing the field-case studies and reservoir simulations, it was concluded that with the same fracture design, higher fracture conductivity improves production performance. Pumping a smaller volume of upgraded proppants with higher conductivity not only improves long-term production performance, but also justifies the additional costs and reduces the overall operation time of the entire hydraulic-fracturing job. The stimulated reservoir volume was greatly increased, as was the production performance, where natural fractures exist.
In this paper, field-data analysis was applied in the Bakken to demonstrate the integrated unconventional work flow. The proposed unstructured-gridding algorithms can be incorporated into any preprocessor to handle complex networks. Reservoir, fracture, and proppant characterization and reservoir simulation of the field cases can help engineers prepare and interpret simulation input and output.
Optimum Fracture Conductivity for Naturally Fractured Shale and Tight Reservoirs
Authors: Gu Ming , Kulkarni Pandurang , Rafiee Mehdi , Ivarrud Endre , Mohanty Kishore 
Published: October 2015

Summary
With the development of unconventional shale and tight reservoirs, stimulation treatments that place multiple transverse fractures have received greater attention in recent years. The post-fracture productivity of such low-permeability reservoirs is largely determined by the matrix/fracture contact area with appropriate fracture conductivity. Although it is often anticipated that the fractures are infinitely conductive, the general belief is that production increases with the proppant amount injected.
This paper presents an approach to assess the proppant amount injected by determining the optimum post-fracture conductivity. First, through use of 3D finite-difference reservoir simulations in a naturally fractured reservoir, which has both the hydraulic fracture and natural fractures modeled explicitly as discrete gridblocks, we find cumulative production as a function of fracture conductivity. For a fixed propped length and production time, we observe a critical conductivity beyond which the production is insensitive to the conductivity. The critical conductivity is then obtained as a function of the propped length and production time. The numerical results show that the critical conductivity increases with propped length and decreases with production time. The effect of stimulated natural-fracture properties (spacing and permeability) on the critical conductivity is then investigated. For reservoirs with matrix permeability in the range of 20 to 1,000 nd, natural fractures increase the short-term critical conductivity, but decrease the medium- to long-term conductivity. The paper also evaluates the influence of water production, cluster spacing, and flowing bottomhole pressure (BHP) on the critical conductivity.
This study demonstrates that fracture designs that are based on pseudosteady-state solutions are not appropriate for naturally fractured shale reservoirs and can lead to significantly lower initial production. Considering conductivity degradation over time, fracture designs that target achieving 1-year critical conductivity are recommended. A simple, yet robust workflow that is based on knowledge of 1-year critical conductivity is also presented for systematically selecting the type and amount of proppant for stimulation treatment. Such a workflow can mitigate trial-and-error-based and data-driven approaches in the industry. An example is demonstrated for the Marcellus play.
Re-Assessing Surveillance Data to Unlock Significant Recoverable Oil Volume in a Highly Complex Area in the Chirag Field
Authors: Ismayilov Aydin , Rzayev Elshan , Hajinskaya Farana , Lokke Paul , Kin Maria Lum 
Published: October 2015

Abstract
The decision to drill a development well in a structurally complex area can be a difficult one. This paper shows an example of how the critical analysis of previous interpretations was done to re-assess reservoir quality. Core data and log-derived petrophysical properties suggested an infill well will likely have low productivity index. However, classical analysis of pressure and dynamic data showed that these previous reservoir assumptions were pessimistic, and subsequently led to the successful drilling and completion of a development oil well in the Nose area of the Chirag field in Azerbaijan.
Regional Integrated Near Surface Geological Study
Authors: Contet Julien , Unterseh Stephan 
Published: October 2015

Abstract
During the preliminary stage of a field development project, a regional multiscale near-surface geological study is carried out in order to assess geohazard processes with regards to their potential impacts for subsea installation (flowlines, wellhead, templates…) and drilling activities. This integrated approach, essential to assess a new subsea field development project, especially in a very challenging province, needs several types of geophysical and geotechnical surveys, from large to small scale extent. Each survey brings particular informations associated with a specific uncertainty and resolution.
This typical process has been implemented to assess the geohazards potentially affecting an offshore subsea development of the South Caspian Basin (SCB-Azerbaijan). The site investigated is located on the continental slope of the Caspian Sea in water depths ranging from 50m to 600m.
A preliminary regional study, based on a 3D seismic dataset, revealed large scale geological features, including a giant mud volcano, regional scale Mass Transport Complexes (MTC) and a large slope failure scar at seabed. Nevertheless, the resolution of the dataset was of insufficient quality to address the drilling hazards with enough confidence and series of hydrographical and geophysical site investigations have been recommended. They include a dense 2D high resolution seismic survey and a high resolution Autonomous Underwater Vehicle (AUV) survey, aimed at characterizing the drilling hazards, the seabed and near-seabed hazards. These geophysical site investigations have been complemented by a dedicated geotechnical survey in order to provide preliminary geo-mechanical parameters and a proper geological modeling.
This integrated study revealed an unsuspected complexity in the recent geological history of the site, resulting from the close interaction of tectonics, mud volcanism, high sedimentation rates, mass transported deposits and gaseous fluid upward migration.
The gaseous fluid migration is currently active and is at the origin of many geohazards, with shallow gas accumulation at shallow depth, seepages at seabed along faults, mud volcano and pockmarks, and occurrence of methane derived authigenic carbonates (MDAC). They may also be related to the occurrence of slope failure and collapse depressions observed at shallow depth within the soil.
The Application of the Accelerative Learning Cycle to the Design and Delivery of Safety Leadership Programs for Personnel of Onshore and Offshore Upstream Oil Assets
Authors: Kucherov Valery , McDonald Amy , Ivanov Ivan , Rose Janet 
Published: October 2015

Abstract
This paper will summarize an approach for developing and rolling out high-impact safety leadership training programs to managers and employees of onshore and offshore upstream oil assets. The main objective of the paper is to illustrate how to integrate the Accelerative Learning (AL) methodology in the design of safety leadership trainings in order to enable people throughout the organization to understand and act upon HSE priorities for their company with the ultimate goal to improve safety performance, achieve cost savings, reduce risk and raise employee safety awareness and motivation.
The approach to design and delivery of safety leadership trainings uses the AL Methodology, which is considered to be one of the state-of-the-art learning approaches that are in use today, and which is based on the latest research on reconciliation between the brain physiology and the learning process. The method is based on addressing the Auditory (A), Visionary (V) and Kinaesthetic (K) learning modalities through the AL Cycle. The incorporation of this methodology in the safety training programs design and delivery effectively seeks to de-mechanize and re-humanize the learning process and make it mind and body experience, achieving maximum level of information retention and enhancing a transition from safety management approach to safety leadership mindset.
Incorporation of both active (practice by doing, discussion groups, immediate use of learning) and passive (lecture, reading, audio visual and demonstration) methods of engagement under the AL philosophy into the design and delivery of safety leadership programs helps to achieve up to 95% retention of information, leading to higher competency outcomes and immediate linkage of the concepts back to everyday realities in the field. The following results were achieved with the application of this concept to safety leadership development of personnel in onshore and offshore upstream assets: ▪Developing ability to understand motivational and behavioural profiles of personnel and apply relevant tools to influence, engage and create positive change in the safety performance of organizations (achieving an up to 70% improvement);▪Developing ability to demonstrate visible and felt safety leadership from front-line level-personnel up to the management teams;▪Enhancing personal leadership capability to build safety into newly established teams, and prepare them for new responsibilities to pave the road for operational success.
Bioremediation Plan on Contaminated Soil Shiraz Oil Refinery Site: Identification of Heavy Hydrocarbon Degrading Micro-organisms
Authors: Koohestani M. , Koohestani N. , Sadeghi S. 
Published: October 2015

Abstract

Background and Purpose
Heavy hydrocarbons such as toluene are one of the main petrochemical and oil products that due to high toxicity and carcinogenic properties, are now considered as a widespread contaminant. Meantime, the capabilities of some micro-organisms to change or degrade oil products are proven. The purpose of this study as the first step of our Bioremediation plan is the identification of hydrocarbon degrading bacteria from the contaminated soil Shiraz oil refinery site.

Materials and Methods
After sampling the refinery contaminated soil at three points from three stations in spring and summer, determining the distribution of toluene-degrading bacteria was performed through microbial count test by variable plate count method as an indicator of microbial activity. Toluene-degrading bacteria in MSM saline medium with toluene as a carbon source were isolated. After screening and identification of superior strains through biochemical and molecular detection method (16SrRNA), the growth curve of various concentrations of toluene was studied during 8 days.

Results
The numbers of bacteria per cfu / ml per gram of soil were 6.4 ×106, 3.4× 106, 3.2×106 in spring and 3.3×108, 5.4×108, 6.4×109 in summer, respectively. Identified strains belonged to the Klebsiella, Kluyvera, Staphylococcus and Pseudomonas genus. Klebsiella had the highest growth in concentrations of 1, 2, 3, 4 mol per liter over 8 days. Statistical analysis between strains by ANOVA and DUNCAN tests indicated a meaningful difference at the 0.05 level.

Conclusions
The results of this study indicated the capability of the local mentioned strains as the first aim in degrading heavy hydrocarbons. In addition Identification of diversity and efficiency of the local micro-organism for the next stage of bioremediation plan was considered.
Subsea Technology Enabling Cost Effective Developments – Subsea History and Perspective of the Subsea Future
Authors: Nilsen Per Arne 
Published: October 2015

Abstract
Since the beginning of the global subsea history, TOTAL has been among the leaders in using Subsea technology in field developments. During this time, TOTAL has gained a significant track record of installing/operating ground breaking subsea systems – shallow water and deep water.
The start of the global subsea history is by many considered to be a subsea well installed by Shell in the Gulf of Mexico in 1961. Just a few years later, TOTAL installed their first subsea wells in Africa. In the 1980's the use of subsea technology as an enabling and enhancing technology, started to gain higher momentum globally. But it was maybe not until the early to mid to late 1990's that Subsea technology achieved a more significant global business volume. Since then (with some peaks and troughs) the global subsea business has steadily grown.
With the large variety of challenges encountered around the world, the experience to select the optimum subsea field architecture and associated technology is crucial. Parameters like water dept (shallow, deep and ultra deep), complicated and challenging reservoirs (HP, HT, sour services, CO2 etc), flow assurance issues, long distances, rough weather and/or remote regions, regions with undeveloped infrastructure etc – they are all challenges that may require technology innovations as well as requiring an experienced operator. There are many ground breaking developments that could be used to demonstrate this, and a few selected projects operated by TOTAl will be mentioned.
And today the industry is facing an additional challenge – escalating costs has resulted in significant challenges in creating developments that will be economical. More and more advanced technology may be required to conquer the increased challenges. With the current high cost levels in the industry (combined with lower commodity prices) it is critical to take actions that will enable a continued use and further development of subsea technology in new developments. Subsea Technology is considered to maintain being a key for future safe and cost effective development of offshore assets, whether this is shallow, deep or remote. In addition to improved and efficient technology, increased efficiencies in work methods and business processes are thought to be necessary to achieve a new lower and sustainable cost level.
Channel Fracturing Technique Increases Oil Production up to 30% from Jurassic Formations in Kogalym Area
Authors: Yudin A. V. , Klimenko V. N. , Golovanev A. S. , Potryasov A. A. , Makienko V. V. , Valiullin A. S. 
Published: October 2015

Abstract
Oil fields in Western Siberia, Russia are well-known for their diversity in size, formations, permeability and accessibility. Target of our research will be the set of oil fields around city of Kogalym. Paper will describe in details trial campaign with innovative stimulation technique and it's positive effect on operational reliability and wells productivity.
Main challenges of the Jurassic formations are low permeability and high heterogeneity. Hydraulic fracturing is required for economic wells exploitation. Historically, hydraulic fracturing in Kogalym oil fields was developing towards aggressive designs with cleaner fractures, although increased risk of premature screenouts is encountered with such approach. To further improve efficiency and economics of stimulation treatments, a logical step in conductivity enhancement was made implementing channel fracturing technique. Channel fracturing allows for heterogeneous proppant placement leaving open channels inside proppant pack. Thus, conductivity of the system increases significantly. Channels also help to better clean out fracture from fluids and polymers increasing an effective fracture half-length, which is important in low-permeability formations. Another important advantage of the new technique is minimized risk of screenouts.
First step in implementing channel fracturing to Kogalym fields was made in 7 newly drilled wells showing productivity increase of up to 30% when compared to conventional fracturing. Best production results were obtained from Jurassic formations of Vatieganskoe and Tavlinsko-Russkinskoe oil fields.
The paper contains detailed description of channel fracturing technique implementation to upper Jurassic formations of several oil fields. Comprehensive analysis of pilot campaign and wells productivity together with lessons learned description allow extending channel fracturing implementation to other oil fields with similar geological challenges.
Deployment of Downhole Fibre Optical Sensing Technology in the Karachaganak Field, Kazakhstan
Authors: Etuhoko Mike , Viti Massimo , Zmeyevskiy Sergey , Hutson Peter , Itisheva Zhanna , Hyland Connor 
Published: October 2015

Abstract
The electronic Permanent Downhole Gauges (PDHG) has traditionally been used in the Karachaganak field to monitor downhole pressures and temperatures, for reservoir management. The overall performance and quality of the data from some of the Permanent Downhole Gauges (PDHG) installed in the Karachaganak field was not satisfactory. Hence, fibre optics has been investigated as an alternative technology due to the reliability, calibration and cost concerns related directly to the Permanent Downhole Gauges (PDHG).
This paper will discuss the implementation and installation of the first fibre optic pressure and temperature monitoring system installed in the Karachaganak field.
A dual fibre optic pressure and temperature system (rated to 200°C and 20Kpsi) was installed to a depth of approximately 5000m with a maximum inclination of about 35°. The metallurgy for the fibre optics system was Inconel 718 due to the presence of H2S. The surface equipment comprised of a Zone 2 rated Wellhead Data Acquisition Unit which has direct connection to the operation base providing ‘real time’ pressure and temperature updates (up to one second update rate).
The paper will highlight some of the design and implementation considerations that were addressed to combat issues which had been experienced with more conventional monitoring systems such as reliability, accuracy and data communication issues. It will also describe the process that was undertaken to meet the stringent Kazakhstan Metrology requirements that are required to be obtained prior to the deployment of a subsurface measurement system. This process involved meeting the requirements for GOST-K for Safety and Quality and the Metrological Certificate which ensures that all measuring instruments are of stated accuracy and resolution and are acceptable to an accredited Institute of Metrology.
It will discuss the detailed Factory Acceptance Tests (FAT) and System Integration Tests (SIT), as part of the critical planning process prior to the field installation.
The paper will also cover the challenges during installation and subsequent use. The deployment data interface requirements and associated benefits during well stimulation, well testing and subsequent production will be described in full.