bluuebunny/crossref_metadata_2025 huggingface dataset:
Contaminants of emerging concern in reverse osmosis brine concentrate from indirect/direct water reuse applications
Authors: Romeyn Travis R. , Harijanto Wesley , Sandoval Sofia , Delagah Saied , Sharbatmaleki Mohamadali
Published: February 2016

Water shortage is becoming more common due to droughts and global population increases resulting in the increasing popularity of water reuse to create new water sources. Reverse osmosis (RO) membrane systems are popular in these applications since they can produce drinking water quality effluent. Unfortunately, RO systems have the drawback of generating concentrate streams that contain contaminants rejected by the membrane including chemicals of emerging concern (CECs). CECs are chemicals such as hormones, steroids, pesticides, pharmaceuticals, and personal care products that are used for their intended purpose and then released into wastewater. CECs are believed to be detrimental to aquatic wildlife health and pose an unknown human health risk. This research gathered the existing knowledge on CEC presence in concentrate, available proven concentrate treatment methods, their CEC removal abilities, and current CEC regulations. It was found that 127 CECs have been measured in RO concentrate with 100 being detected at least once. The most potent treatment process available is UV/H2O2 as it offers the highest removal rates for the widest range of chemicals. The less expensive process of ozone/biologically activated carbon offers slightly lower removal abilities. This comprehensive report will provide the groundwork for better understanding, regulating and treating concentrate stream CECs.
Prioritizing sewer rehabilitation projects using AHP-PROMETHEE II ranking method
Authors: Kessili Abdelhak , Benmamar Saadia
Published: February 2016

The aim of this paper is to develop a methodology for the prioritization of sewer rehabilitation projects for Algiers (Algeria) sewer networks to support the National Sanitation Office in its challenge to make decisions on prioritization of sewer rehabilitation projects. The methodology applies multiple-criteria decision making. The study includes 47 projects (collectors) and 12 criteria to evaluate them. These criteria represent the different issues considered in the prioritization of the projects, which are structural, hydraulic, environmental, financial, social and technical. The analytic hierarchy process (AHP) is used to determine weights of the criteria and the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE II) method is used to obtain the final ranking of the projects. The model was verified using the sewer data of Algiers. The results have shown that the method can be used for prioritizing sewer rehabilitation projects.
Kinetic model of water disinfection using peracetic acid including synergistic effects
Authors: Flores Marina J. , Brandi Rodolfo J. , Cassano Alberto E. , Labas Marisol D.
Published: February 2016

The disinfection efficiencies of a commercial mixture of peracetic acid against Escherichia coli were studied in laboratory scale experiments. The joint and separate action of two disinfectant agents, hydrogen peroxide and peracetic acid, were evaluated in order to observe synergistic effects. A kinetic model for each component of the mixture and for the commercial mixture was proposed. Through simple mathematical equations, the model describes different stages of attack by disinfectants during the inactivation process. Based on the experiments and the kinetic parameters obtained, it could be established that the efficiency of hydrogen peroxide was much lower than that of peracetic acid alone. However, the contribution of hydrogen peroxide was very important in the commercial mixture. It should be noted that this improvement occurred only after peracetic acid had initiated the attack on the cell. This synergistic effect was successfully explained by the proposed scheme and was verified by experimental results. Besides providing a clearer mechanistic understanding of water disinfection, such models may improve our ability to design reactors.
Mass balance and mass loading of polybrominated diphenyl ethers (PBDEs) in a tertiary wastewater treatment plant using SBSE-TD-GC/MS
Authors: Rocha-Gutiérrez Beatriz A. , Lee Wen-Yee , Shane Walker W.
Published: February 2016

A mass loading and mass balance analysis was performed on selected polybromodiphenyl ethers (PBDEs) in the first full-scale indirect potable reuse treatment plant in the United States. Chemical analysis of PBDEs was performed using an environmentally friendly sample preparation technique, called stir-bar sorptive extraction (SBSE), coupled with thermal desorption and gas chromatography/mass spectrometry (GC/MS). The three most dominant PBDEs found in all the samples were: BDE-47, BDE-99 and BDE-100. In the wastewater influent, the concentrations of studied PBDEs ranged from 94 to 775 ng/L, and in the effluent, the levels were below the detection limit. Concentrations in sludge ranged from 50 to 182 ng/g. In general, a removal efficiency of 92–96% of the PBDEs in the plant was accomplished through primary and secondary processes. The tertiary treatment process was able to effectively reduce the aforementioned PBDEs to less than 10 ng/L (>96% removal efficiency) in the effluent. If PBDEs remain in the treated wastewater effluent, they may pose environmental and health impacts through aquifer recharge, irrigation, and sludge final disposal.
Boron nitride nanoplates supported zero-valent iron nanocomposites for enhanced decolorization of methyl orange with the assistance of ultrasonic irradiation
Authors: Zha Yiming , Wang Tianlin
Published: February 2016

In this work, boron nitride nanoplates (BNNPs) supported nanoscale zero-valent iron (nZVI) was prepared through facile liquid-phase chemical reduction of ferric ion by borohydride under ambient conditions in the presence of BNNPs. The nZVI@BNNPs hybrids were characterized by scanning electron microscopy, X-ray diffraction and magnetic properties measurement. The hybrid material was evaluated for decolorization of a common azo dye, methyl orange (MO), with the assistance of ultrasonic irradiation. Results exhibited that a complete decolorization of 100 mg/L MO was achieved within 6 min using nZVI@BNNPs as the active material. Compared with bare nZVI and BNNPs, nZVI@BNNPs provided a faster reaction process for MO decolorization. The kinetic rate constants of MO decolorization reached 0.8175 min−1 under ultrasound-assisted condition due to the synergistic effect of ultrasonic irradiation. Fluorescence spectrum experiment confirmed that hydroxyl radicals could be generated in the system combined nZVI with ultrasonic irradiation, and as a result, hydroxyl radicals would contribute to the decolorization process of MO.
Relationships between sources of acid mine drainage and the hydrochemistry of acid effluents during rainy season in the Iberian Pyrite Belt
Authors: Pérez-Ostalé E. , Grande J. A. , Valente T. , de la Torre M. L. , Santisteban M. , Fernández P. , Diaz-Curiel J.
Published: February 2016

In the Iberian Pyrite Belt (IPB), southwest Spain, a prolonged and intense mining activity of more than 4,500 years has resulted in almost a hundred mines scattered through the region. After years of inactivity, these mines are still causing high levels of hydrochemical degradation in the fluvial network. This situation represents a unique scenario in the world, taking into consideration its magnitude and intensity of the contamination processes. In order to obtain a benchmark regarding the degree of acid mine drainage (AMD) pollution in the aquatic environment, the relationship between the areas occupied by the sulfide mines and the characteristics of the respective effluents after rainfall was analysed. The methodology developed, which includes the design of a sampling network, analytical treatment and cluster analysis, is a useful tool for diagnosing the contamination level by AMD in an entire metallogenic province, at the scale of each mining group. The results presented the relationship between sulfate, total dissolved solids and electrical conductivity, as well as other parameters that are typically associated with AMD and the major elements that compose the polymetallic sulfides of IPB. This analysis also indicates the low level of proximity between the affectation area and the other variables.
Industrial safety of pressure vessels - structural integrity point of view
Authors: Sedmak Aleksandar , Algool Mahdi , Kirin Snezana , Rakicevic Branislav , Bakic Ramo
Published: February 2016

This paper presents different aspects of pressure vessel safety in the scope
of industrial safety, focused to the chemical industry. Quality assurance,
including application of PED97/23 has been analysed first, followed shortly
by the risk assessment and in details by the structural integrity approach,
which has been illustrated with three case studies. One important conclusion,
following such an approach, is that so-called water proof testing can
actually jeopardize integrity of a pressure vessel instead of proving it.
Factors associated with recovery from paraplegia in dogs with loss of pain perception in the pelvic limbs following intervertebral disk herniation
Authors: Jeffery Nick D. , Barker Andrew K. , Hu Hilary Z. , Alcott Cody J. , Kraus Karl H. , Scanlin Elizabeth M. , Granger Nicolas , Levine Jonathan M.
Published: February 2016

OBJECTIVE To investigate associations between recovery of locomotion and putative prognostic factors in dogs with loss of deep pain perception in the pelvic limbs caused by intervertebral disk herniation (IVDH).

DESIGN Prospective cohort study.

ANIMALS 78 client-owned dogs evaluated for IVDH that underwent spinal decompression surgery.

PROCEDURES Dogs with complete loss of deep pain perception in the pelvic limbs and tail underwent routine examinations, advanced imaging, and spinal decompression surgery in accordance with standards of practice and owner consent. For each dog, information was prospectively collected on duration of clinical signs prior to onset of paraplegia; delay between onset of paraplegia and initial referral evaluation; date of recovery of locomotion, death, or euthanasia (3-month follow-up period); and whether dogs had received corticosteroid drugs before surgery. Severity of spinal cord compression at the lesion epicenter was measured via CT or MRI.

RESULTS 45 of 78 (58%) of dogs recovered the ability to ambulate independently within 3 months after spinal decompression surgery. No evidence of prognostic value was identified for any of the investigated factors; importantly, a greater delay between onset of paraplegia and referral evaluation was not associated with a poorer prognosis.

CONCLUSIONS AND CLINICAL RELEVANCE In this group of dogs with IVDH, immediacy of surgical treatment had no apparent association with outcome. The prognosis for recovery may instead be strongly influenced by the precise nature of the initiating injury.
Ultrasonographic findings and outcomes of dogs with suspected migrating intrathoracic grass awns: 43 cases (2010–2013)
Authors: Caivano Domenico , Birettoni Francesco , Rishniw Mark , Bufalari Antonello , De Monte Valentina , Proni Alessia , Giorgi Maria Elena , Porciello Francesco
Published: February 2016

OBJECTIVE To describe ultrasonographic findings and outcomes for dogs with suspected migrating intrathoracic grass awns.

DESIGN Retrospective case series.

ANIMALS 43 client-owned dogs.

PROCEDURES Records for dogs with suspected migrating intrathoracic grass awns examined between 2010 and 2013 were reviewed. Ultrasonographic images and additional information such as signalment and pleural fluid analysis, radiographic, bronchoscopic, and CT findings were collected. Surgical treatments and outcomes were also reviewed.

RESULTS Transthoracic or transesophageal ultrasonography revealed grass awns in the pleural space (n = 13) or pulmonary parenchyma (10) of 23 dogs. Surgical removal of grass awns was successful on the first attempt in 21 of these 23 dogs (including 11/23 that had intraoperative ultrasonography performed to aid localization and removal of the awn). In the remaining 2 dogs, a second surgery was required. Twenty dogs with evidence of migrating intrathoracic grass awns had no foreign body identified on initial ultrasonographic evaluation and were treated medically; 16 developed draining fistulas, and awns identified ultrasonographically at follow-up visits were subsequently removed from the sublumbar region (n = 10) or thoracic wall (6). The remaining 4 dogs had no grass awn visualized. Clinical signs resolved in all dogs.

CONCLUSIONS AND CLINICAL RELEVANCE Transthoracic, transesophageal, and intraoperative ultrasonography were useful for localization and removal of migrating intrathoracic grass awns. Ultrasonography may be considered a valuable and readily available diagnostic tool for monitoring dogs with suspected migrating intrathoracic grass awns.
Underbalanced Coiled Tubing Drilling Practices in a Deep, Low-Pressure Gas Reservoir (Russian)
Authors: Kavanagh T. , Pruitt R. , Reynolds M. , Ortiz R. , Shotenski M. , Coe R. , Davis P. , Bergum R.
Published: February 2016

The pdf file of this paper is in Russian. To purchase the paper in English, order IPTC-10308-MS.

The Sajaa field in Sharjah, United Arab Emirates, is a deep, low-pressure gas field that has been a prolific producer since the first wells were drilled in the 1980s. Initial field development was through a series of vertical wells drilled overbalanced with conventional drilling rigs. As field pressure and production declined, it became necessary to access additional reserves not being drained efficiently by these older wells. As a result of this need, a campaign to drill horizontal, multilateral sidetracks from the existing wellbores was started in March 2003 using coiled tubing. From a standpoint of production, cost, health, safety, and environment, the results of the program thus far have been excellent.

This paper examines the surface and downhole equipment and operational best practices used in the Sajaa coiled tubing (CT) underbalanced drilling (UBD) campaign. It also reviews some of the key details that make a safer, more efficient day-to-day operation and created a highly successful project that has drilled 27 wells, comprising more than 90 laterals and more than 212,000 ft drilled.

Introduction

The Sajaa field was discovered in 1980 by Amoco Sharjah Oil Company; since that time a total of 41 wells have been drilled in the Sajaa field. Initial reservoir pressures were 7,500 psi or greater; these pressures have since declined substantially, with most wells now being drilled with equivalent circulating densities of 1.5 to 2.0 lb/gal. Initial completions were polished bore receptacle tubing completions, but with corrosion and packer leaks, these were changed to packerless 5-in. tubing completions with wells that have 7 -in. liners tied back and cemented to surface in most cases. Production trees are, for the most part, 5-1/8-in., 10,000-psi sour-service trees.

The initial drive to perform CT UBD in this field came about because data on the Sajaa field showed that valuable reserves were not being added or produced, and that additional technology needed to be brought to this field to exploit these reserves. A peer-assist team composed of personnel from Alaska's North Slope, Houston Engineering Technical Practices (ETP), Sunbury, UK ETP, and Sharjah worked through the various options and found coiled tubing to be the best option.

Downhole data transmission in underbalanced conditions can be done with pulse telemetry (previous UBD campaigns in Sharjah) or electromagnetic (EM) signals, but by 2003 the bottomhole pressure would not support a fluid column and the formations above the reservoir blocked EM transmission.
An Integrated Approach For Evaluating and Characterising Horizontal Well Inflow and Productivity in Heterogeneous Carbonate Reservoirs
Authors: Farran Herve , Harris Jeremy , Al Jabri Saleh H. , Jackson Richard Robert , Alkhayari Saif Rashid , Thomas Tony
Published: February 2016

Carbonate reservoirs are generally highly heterogeneous and complex because many phenomena, such as diagenesis and tectonism have modified primary depositional structure and texture. Many carbonate reservoirs in the Shuaiba Formation of north Oman are characteristically heterogeneous with complex reservoir architecture. It is common to observe dual-media and natural fracture system behaviors with large variations in reservoir properties. Many of these reservoirs have been developed with horizontal wells, so they require application of advanced reservoir evaluation and management practices. Many of the horizontal wells produce at high water cuts, despite apparent initial high oil saturations. The need for data is paramount for effective management of these reservoirs, and to understand factors affecting the productivity of horizontal wells - both at the wellbore and within the reservoir itself. The first stage of this process is to define an accurate structural model incorporating all available reservoir, wellbore (2D modeling) and seismic data. The second stage, involves integrating this model with the inflow profile derived from advanced production logging measurements. We describe several field examples from a complex and heterogeneous carbonate reservoir in Oman, and discuss how they may be used to identify a range of important needs relating to horizontal well placement, improving completion strategy, and optimizing water shut-off activities.

Introduction

Short to long radius horizontal wells have been drilled in many types of oil and gas reservoirs, in both carbonate and siliclastic formations. A variety of technical advances in drilling, including logging while drilling and formation evaluation have meant that the application of horizontal wells for reservoir development in both primary recovery and enhanced oil recovery (EOR) applications is now a common practice. There are many options available for completion of horizontal wells, such as open hole (barefoot), cased hole (e.g. cemented, expandable and perforated liner), slotted liners and gravel-pack completions. In the Middle East and North America a large proportion of horizontal wells have openhole completions. Since horizontal wells have a much greater reservoir contact area than vertical wells, for reservoirs with lateral heterogeneity, fault and fracture networks or structural compartmentalisation, this can result in well performances that range from the spectacular to the very mediocre.
CRS Seismic Processing: A New Approach To Obtain High-Resolution Images From Sparse 3D-Exploration Surveys
Authors: Coman Radu , Gierse Guido , Trappe Henning , Robinson Simon , Owens Michael , Moller Nielsen Esben
Published: February 2016

The CRS method assumes subsurface reflector elements with dip and curvature. The corresponding CRS stacking operator is not limited to a single CMP gather, but collects the reflection energy of a subsurface element from all contributing traces, including neighbour CMPs of the imaging location. CRS imaging of the sparse 3D data provided a strong increase in subsurface resolution, and signal-to-noise ratio. It also resolve the faulting which was largely buried in noise in conventional images. The combination of sparse 3D aquisition with CRS processing prove to be a suitable strategy for achieving good subsurface resolution at limited costs.

Introduction

Seismic acquisition in frontier areas faces a high risk when dealing with remote areas with difficult access, limited operation times due to seasonal influences and governmental restrictions, and a large uncertainty in the design of optimum acquisition parameters. Under such circumstances, high-fold 3D seismic surveying is not feasable, but 2D surveying may also not be appropriate to describe the areal extent of potential targets.

Sparse 3D surveys are frequently used as a compromise. A land data example from North Africa is presented here where large bin sizes (50x50m), and low data fold kept the acquisition turnaround in an acceptable time range. Seismic investigations focussed on flat target horizons, and low-throw faulting in the target regions. As expected, the results of standard time processing could not compete with results from nearby high-fold surveys. A much lower signal-to-noise ratio provided a very restricted resolution of the subsurface.

In an attempt to increase resolution, a CRS time processing was applied to these data. The CRS, or Common Reflection Surface method, is well suited to tackle noise problems in low-fold data, since it uses a much higher stacking fold than conventional time domain imaging. CRS obtains this high fold by assuming subsurface reflector elements with dip and curvature. In addition to the desired increase of signal-to-noise ratio and reflector continuity, the CRS processing aimed at resolving the faulting which was almost completely buried in noise in conventional images.

CRS Method

In time domain seismic imaging, the NMO/DMO stacking technique has been dominant for many decades. However, the simple subsurface model of the NMO stack, the loss in resolution by the DMO process, and the dependence on a user-derived velocity model has motivated the search for alternative time domain imaging methods.
Assessing Horizontal Stress Direction Using Seismic and Borehole Geometry Data: Study from Balam South Field
Authors: Umam Syafiul
Published: February 2016

This study demonstrated the utilization of seismic data and borehole geometry to determine the horizontal stress direction in Telisa Formation, Balam South Field Central Sumatra Basin, Indonesia. Telisa Formation is one of the oil reservoirs in the Balam South Field, where enhanced oil recovery project has been initiated in this shally-sand reservoir. In the reservoir of interest, seismic attributes gave strong indication of the presence of natural fractures. Acoustic impedance data showed relatively lower magnitude in the suspected natural fractures zone. The decrease of the acoustic impedance magnitude was interpreted as corresponding to the decrease of the acoustic seismic velocity in the suspected fractured zone.

Analysis of borehole shape from multi-arm caliper data in this field also supported the interpretation. The borehole shape is slightly elongated perpendicular to the interpreted maximum stress direction, giving indication of the presence of excess horizontal stress applied to the borehole from the maximum horizontal stress direction. Several other multi-arm caliper data were then acquired to confirm and calibrate the stress map for better interpretation result.

This study inferred the natural fractures orientation from seismic attributes to represent maximum horizontal stress direction. The interpreted map from the seismic data was then calibrated with the maximum horizontal stress orientation determined from the reconstructed borehole geometry. The final interpreted map of maximum horizontal stress direction was then used as a guideline for optimum hydraulic fracturing in the wells drilled in the waterflood project.

Introduction

Balam South Field is located in Central Sumatra, Indonesia (Fig. 1). Telisa Formation in Balam South Field is one of the major oil reservoirs in this field with the original oil in place is in the order of 650 MMBO. Telisa Formation is characterized by sand-shale laminations over approximately 100 feet (33 meter) thick interval in Balam South (Fig. 2). The trapping mechanism of this reservoir is anticlines controlled by northwest and North-South faults as shown in (Fig. 3).
Gas Field Integrated Modeling: A Practical Example of How To Optimize Production in a Mature Asset
Authors: El-Khawas K.M. , El-Ashry M.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

This paper discusses the value of integrating subsurface and surface elements for gas fields located in Egypt's Western Desert concession. The Hydrocarbon accumulations in the operating company consist of oil and gasfields; first gas was discovered in 1982. Currently gas is produced from three fields that share the same plant and facilities. Each field is producing from two to five reservoirs with different productivity, pressure, Temperature, and PVT.

To optimize production and thereby maximize the remaining value of the asset, the use of an integrated forecast tool is beneficial. As the gas fields become a more mature asset, the allocation of well production to different production trains (High, medium, low pressure) in the future needs to be evaluated. Also the benefit of further optimisation on surface facility (e.g., decreasing the inlet pressure) in the tail-end production period could be addressed.

The integrated model was built with the aim to address the coupling of several reservoirs with the surface network to allow predicting the interactions between different fields/reservoir/pressure regimes, wells and facilities. The following key issues were addressed:–Pressure interaction between surface and subsurface–Pressure interference between different reservoirs and wells connected to a shared surface facility.–Influence of facility constraints, e.g., separator limits, commingled flowlines, etc. on a set of reservoirs connected to a shared facility.–Production optimization in the overall system against a set of common criteria or the current constrains.

The model's results allowed the operating company to improve its understanding of the interaction between the subsurface and surface activity and constraints. It serves as a tool to optimize the production of remaining reserves within a common timeframe.
State-of-the-Art of Heavy-Oil Development in China and Its Technology Challenges
Authors: Haiyan Hu , Shuhong Wu , Yitang Zhang , Dingmin Wei , zhong Guan
Published: February 2016

The commercial heavy oil development in China was initial in 1982 when the first cyclic steam stimulation (also known as steam huff and puff) pilot well test was successful in Liaohe Oil Field, northeast of China. In 1993, the annual heavy oil production had reached 70 million barrels and kept the level for more than 10 years.

The major development manner of heavy oil reservoir is steam injection, including cyclic steam (CSS) and steam flooding. CSS annual production is beyond 5.5 million barrels, more than 80% of heavy oil production. Steam flooding, successful in developing shallow heavy oil reservoir such as Kalamy oil reservoir, northwest of China, accounts for 8% heavy oil production with the highest annual production nearly 7 million barrels. For more than 20 years development, great progress has been made in several technologies as followed. (1) Integrated steam huff and puff technology with recovery factor higher than 20% of OOIP (2) Steam flooding technology, including high-temperature profile conformance technology, survey technology and steam measurement technology. The recovery factor of shallow heavy oil reservoir is beyond 40% of OOIP. (3) Super-heavy oil development technology, including integrated heat technology, high-efficiency steam injection technology, playing an important role in maintaining heavy oil production level with the highest annual oil production beyond 16 million barrels.

Although lots of progresses have been made, several problems as followed exist in heavy oil reservoir development. (1) CSS enters into later stage, with low pressure, low oil production and so, poor recovery results. (2) No mature development manner following CSS has come into being. (3) Steam flooding in deep heavy oil reservoirs is still in pilot test. It will take a long time to make it commercial application. (4) Steam Assisted Gravity Drainage (SAGD), is also in pilot test being carried out in Liaohe oil field.
Evaluating Gas-Injection Performance in Fractured Reservoirs Using Discrete Fracture Network Models
Authors: Sahni A. , Bakenov R. , Kaveh D. , Narr W. , Dull D.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

This paper presents an alternative approach to modeling gas injection performance in naturally fractured reservoirs. The two conventional methods of modeling fractures have been to either use a single porosity medium with enhanced tensor permeability or a dual porosity system, where the matrix feeds the higher permeability fracture network. The former approach captures variability in well productivity, which is important during primary production but may not be suitable for modeling displacement mechanisms at the large simulation grid block scale. The dual porosity approach may provide some more flexibility in accounting for displacement mechanisms (imbibition, drainage, gravity effects etc.), however, calibrating dual porosity models (using an appropriate matrix to fracture transfer coefficient) may again be difficult.

We discuss an alternative methodology for generating, simulating and evaluating displacement performance using Discrete Fracture Network (DFN)models. While computationally expensive, the DFN models for smaller sectors could be used to calibrate displacement performance of full field dual or single porosity models. We generated stochastic realizations of fracture patterns conditioned to available data on fracture spacing and orientation using a multi-point statistics approach. These stochastic realizations were used to investigate the impact of fracture characteristics on displacement behavior. Fractures were explicitly treated as discrete entities having extremely low pore volume and high transmissibility. The rock-fabric permeability realizations were generated using sequential gaussian simulation, honoring well log data.

The models used to demonstrate the DFN approach were 1500m X 1500mspatially, with thickness varying from 200– 400m. They comprised of one up-dip gas injector and two down-dip producers. Simulations with the DFN approach show the injected gas moving rapidly through the fracture network, with significant bypassing of oil. The effective permeability and dual porosity models on the other hand, displayed more stable gravity drainage behavior. Displacement characteristics observed from the DFN sector models were then used to calibratefull field dual porosity models. Simulations showed that with higher rockfabric permeability, the displacement efficiency was significantly improved. Sensitivity studies were conducted to investigate the impact of fracture spacing, rock fabric permeability and well intervention techniques on recovery using the DFN approach.
The Supergiant Kashagan Field: Making a Sweet Development Out of Sour Crude
Authors: Malik Z. , Charfeddine M. , Moore S. , Francia L. , Denby P.
Published: February 2016

Introduction

The super Giant Kashagan field is located in a shallow-water (ice-locked during the winter), environmentally sensitive area of the Kazakh sector of the North Caspian Sea. The Kashagan field was discovered in 2000 by a consortium of oil companies. The current North Caspian PSA companies are affiliates of: ENI, ExxonMobil, Shell and TOTAL, each with 18.52% share, Conoco-Phillips (9.26%), Inpex and KazMunaiGaz (8.33%, each). Agip KCO (an ENI company) operates the field.

The Kashagan field is a deep, over pressured (initial reservoir pressure: 783 bar), isolated, carbonate build-up with a high-permeability, karstified and fractured rim and relatively low- permeability, stratified, platform interior. The field contains a 43-degree API light oil, with 15% H2S and 5% CO2, and contains more than 100 Tcf of associated gas.

One of the biggest challenges of the Kashagan field development is the management of huge volumes of highly sour associated gas. The consortium had essentially two options to address this challenge:A commercially unattractive, but technically not challenging, conventional choice of evacuating the sour gas to shore for treatment (H2S and CO2 removal) and sales; orA technically very challenging, but potentially economically beneficial, alternative of injecting the raw sour gas back into the reservoir.

This injection alternative, with its high discharge pressures and sour service, would extend the current capabilities of existing gas compression technologies. Nonetheless, it had the potential to significantly enhance oil recovery, as the Kashagan oil and injected gas are first contact miscible at pressures well below the initial reservoir pressure.

Before proceeding with such a decision (after all, miscible gas injection is usually a secondary, or even a tertiary, recovery technique), the consortium had to undertake extensive evaluations to ascertain the likelihood of subsurface and surface risks.

The paper describes the integrated approaches and the different technologies brought to bear to evaluate the likelihood of potential risks (such as breaching of cap rock integrity, early gas breakthrough or asphaltene precipitation), and to implement mitigating solutions. It presents the reservoir and gas management strategies to mitigate the risks of cap rock failure and premature gas breakthrough. It also mentions some of the technologies advocated to, notably, detect potential fracture growth, monitor gas front movement and shut-off high gas-oil ratio producing zones, efficiently and cost-effectively.
CO2 IOR Potential in Naturally Fractured Haft Kel Field, Iran
Authors: Alavian Sayyed Ahmad , Whitson Curtis Hays
Published: February 2016

We present results studying the IOR potential for CO2 injection in the naturally-fractured Haft Kel field, Iran, based on detailed compositional simulations of the matrix-fracture system. Oil recoveries from CO2 injection consistently range from 80–90% for reservoir pressures 1400 psia and higher (i.e. at and above current reservoir pressure of 1500–1800 psia). This compares with 15–25% recoveries reported for gas cap expansion and/or injection of hydrocarbon gas.

Fundamentally-different recovery mechanisms develop above and below 2000 psia, the pressure where CO2 density equals the reservoir oil density. At lower pressures, CO2 is less dense than reservoir oil and traditional gas-oil gravity segregation results, with a highly efficient process driven by gravity, compositional effects and IFT gradients that cause capillary-induced oil flow. At pressures greater than 2000 psia, CO2 density is greater than reservoir oil density, resulting in an unusual gravity drainage mechanism whereby CO2 enters the bottom of a matrix block and pushes oil out the sides and top of the matrix block.

The effect of several key parameters has been studied in detail – matrix permeability, matrix block size, matrix-matrix capillary continuity (stacked blocks), and the use of mixtures of CO2 and hydrocarbon gas. One of the key results is how the rate of recovery differs for HC and CO2 injection, and how it varies for CO2 injection for different model parameters.

IOR results are affected by grid sensitivity. Grid effects have been quantified and compared for different model parameters. Final IOR assessment is made using models where sufficient grid refinement is used to minimize grid sensitivity.

CO2 injection in fractured reservoirs in the Middle East appears to have great potential, even at relatively low pressures. Large sources of CO2 would need to be available from gas-driven power plants and reservoirs producing CO2 in significant quantities.

Introduction

When an oil-saturated matrix block is surrounded by gas in the fracture, oil will drain from the matrix as a result of density difference between the gas and the oil. However, drainage can occur only if the matrix block height is greater than the capillary entry height.
New Vision of the Shuaiba at a Regional Scale
Authors: Al-Mehsin K. , Pierson B. , Drysdale D. , Warrlich G. , Eberli G.P. , Droste H.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

The regional integration of well data, seismic observations and published information from the southern part of the Arabian Peninsula has led to a breakthrough in understanding the stratigraphy and depositional history of the Shuaiba and in extracting implications regarding hydrocarbon prospectivity.

The Shuaiba Formation is composed of system tracts from two supersequences, and the following subdivision is proposed: The Lower Shuaiba contains a TST and HST of a supersequence (Early Aptian, earliest late Aptian), while the Upper Shuaiba is a LST prograding package of the next supersequence (late Aptian).The TST of the older supersequence is distributed more or less equally over the entire Shuaiba province and the HST of the same supersequence is characterized by the development of the Bab Basin with a well-marked differentiation between basin and margins. An unconformity separates this supersequence from the LST of the next Supersequence during which new carbonate facies prograded into the BabBasin. On the basis of this subdivision, we propose a new, unified stratigraphic nomenclature for the Shuaiba.

Depositional facies associated with the 3 supersequence systems tracts are markedly different. Monotonous, widespread carbonate facies dominated the older supersequence. During the HST, organic-rich fine carbonates accumulated in the Bab Basin while rudist-rich facies lined and vertically enhanced the southern and western basin margin or developed as relatively large isolated platforms on the eastern slope of the Bab Basin. In the LST of the younger supersequence, new platforms prograded into the Bab Basin in a series of sub-linear, regular clinoforms that grew either parallel to the pre-existing southern and western margins of the Bab Basin or in a series of concentric rings, away from pre-existing isolated platforms.

Extracting the detailed sequence stratigraphy of the clinoforms and understanding reservoir quality, presence of intraformational seals and trap configuration has allowed us to identify and predict areas of higher HC prospectivity in the southern part of the Arabian Peninsula.
Accurate Corrosion Prediction Through an Integrated Approach
Authors: Reddy Ramani V. , Nelson Jocelyn L. , Pacheco Jorge Luis , Kroen Charles F.
Published: February 2016

The ability to optimize the use of carbon steel in corrosive service presents many economic advantages, including minimizing the use of expensive corrosion resistant alloys, reducing well count by enabling optimized large bore completions, and eliminating additional offshore pipelines and facilities. An integrated approach to corrosion modeling and testing is employed by ExxonMobil to reliably extend the application of carbon steel.

The integrated approach to predicting corrosion has five primary elements:Rigorously establish the environmental conditions by conducting thermodynamic and compositional hydraulic analyses, and characterize how these conditions are expected to change over time.Identify the local environmental conditions and the types of corrosion that are expected to occur (e.g., weight loss, pitting, environmental cracking), including sensitivity and upset cases.Conduct realistic corrosion tests under the identified field conditions by simulating brine chemistry, dissolved acid gas concentrations, hydrocarbon effects, fluid shear stresses, and flow regime in appropriate laboratory equipment. Specialized laboratory test apparati, such as a large-diameter sour, multiphase flow loop and large-volume high-pressure high temperature autoclave test cells, have been designed and constructed to ensure proper reproduction of field conditions.Mathematically extrapolate the results of the laboratory tests to the field, enabling calculation of expected tubular life.Conduct life cycle cost analysis.

This paper will describe how this integrated approach to predicting corrosion is used to evaluate the use of carbon steel in oil and gas production environments. Special emphasis will be placed on the prediction of pitting corrosion in H2S-containing environments.

Introduction

From the material selection perspective, the design decision is generally between CRAs and carbon steel, often with inhibition. The ability to optimize the use of carbon steel in corrosive service often presents economic advantages, primarily through a significant reduction in capital expenditures. The ability to run wet gas and full wellstream pipelines and flowlines can further reduce costs by eliminating offshore dehydration facilities.
Main Cryogenic Heat Exchanger Replacement at Brunei LNG
Authors: Omarali Adimasyaton , Groeneweg Peter , Kaart Sander , Pek Barend Johan Jan
Published: February 2016

Introduction

This paper addresses the economical and technical justification for the rejuvenation of the existing, 33 years old, Brunei LNG plant to extend its lifetime with a third 20-year contract period to 2033. After an introduction into the history of the development of the Brunei LNG plant, and its growth aspirations for the 21st century, the paper will further focus on the current Asset Reference Plan (ARP) and in particular the technical challenges of the replacement of the Main Cryogenic heat exchangers in four out of the five Brunei LNG production trains.

Brunei LNG History

The construction of Brunei LNG started in 1968, and first LNG was exported to Japan in 1972. The shareholders of the BLNG plant are the Brunei Government (50%), Mitsubishi Corporation (25%) and Shell (25%). Shell Global Solutions, has also been the technical advisor of the Brunei LNG plant since the initial phases of the project.

The BLNG project was the first to use the Propane Mixed refrigerant (C3/MR) process, with spool wound main cryogenic heat exchangers. In the original plant, eleven boilers generated the steam for the turbine driven refrigerant compressors. Treated river water is used as cooling medium in an open cooling cycle. Each liquefaction train has a separate gas treating section that consists of an acid gas removal unit, dehydration unit and mercury removal unit.

Originally, the BLNG project included four trains with a design capacity of 1.05 MTPA. During construction, the scope was increased with a fifth train of the same capacity. This fifth train started production in 1974. As the main cryogenic heat exchanger of the fifth train was produced later than the original four, an updated design was installed in train 5.

First Rejuvenation

Between 1992 and 1994, the first rejuvenation and debottlenecking project was carried out at BLNG. In subsequent years plant debottlenecking projects have been implemented and the production capacity reached a maximum of 7.3 MTPA or almost 140% of initial design capacity by 2003 (Fig. 1).
Deploying New Technology To Improve Canada's Underbalanced Operations
Authors: Pavel D.A. , Mitchell T.M.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

As global trendsetters in underbalanced operations, Canadian operators are taking a bold new approach to the drilling phase. Recently as a result of increased QHSE concerns around snubbing operations, operators are considering alternative methods to trip under live well conditions. This presents the opportunity to explore new alternatives in pressure control during underbalanced operations, as opposed to conventional methods such as snubbing and killing the well with an overbalanced fluid column. These methods createglaring problems such as rig non-productive time, environmental and safety hazards, and wellbore damage. One such alternative is the downhole isolation valve.

The downhole isolation valve is a casing deployed valve system that is set at a predetermined depth and used to shut-in the well to allow for deployment of the drill string and completion assemblies.

This paper will discuss the needs of operators and how they were met with the downhole isolation valve, the benefits realized by deploying this technology, and the results from wells where these tools were run.
An Innovative Geoscience and Reservoir Training Passport for New Recruited Engineers Worldwide as per Sustainable Development
Authors: Coste Jean-Francois Michel , Estival Jacques , Lecanu Hubert , Beauchamp Michel
Published: February 2016

The Oil industry has to face a significant aging of its E&P task force and its correlative retirements in a few years. In preparation for this crew change, a consistent hiring programme of hiring is being implemented within Total both at the Headquarters and in the affiliates worldwide. Giving these new engineers the required skills quickly poses a big challenge.

Once recruited, every new engineer in Geosciences and Reservoir disciplines is given a Training Passport. In other words, he will follow a personalised curriculum corresponding to about 6 months training distributed over a 2 to 4 year period.

This road book is designed to fill the gap between initial – on hiring - and expected skills.

For each discipline – i.e. Geophysics, Geology, Reservoir – the technical skills as well as the Personal and Management development objectives are exhaustively listed. An accurate training path comes from a skill list and the training proposal, both in-house and externally. For the Reservoir Engineering discipline, the list contains: HSE, Induction, G&G basics, Well Data acquisition and Interpretation, Well Performance, Reservoir geo-modelling and simulation, Uncertainties integration, Field Monitoring and Management, Economics, Project Management, etc…

During the Passport implementation, the new engineer is assigned to a Technical Department where he can apply what he has just learned through the specific training courses. The training effort represents on average up to 15% of the yearly working time. Launched in 2003, the Training Passport approach is being extended to all affiliates starting with Western Africa. The Young engineers Training Passport generates consistency in professional disciplines, and increases visibility and anticipation for all actors involved. It provides the young Headquarters engineers with required autonomy before being assigned in affiliates worldwide.

Because it is a skill driven and a long term process, the Training Passport represents a significant cultural change that efficiently allows us to meet the needs of the Company strategy.