bluuebunny/crossref_metadata_2025 huggingface dataset:
Paradigm Shift in the Development of the North Kuwait Fields
Authors: Al-Rasheedi Saleh , Yannimaras Demetrios V
Published: May 2016

This paper discusses the reasons and results of the paradigm shift in NK reservoir management that was necessary in order to increase oil production and safeguard reserves. The new best practices implemented included: field development via horizontal & slant wells, significantly increased water injection with peripheral horizontal wells, Produce High-Inject Low (PHIL) strategy to enable gravity-stable oil production, horizontal re-entries and sidetracks, and the wide adoption of the advanced completion technology of passive inflow control devices (ICDs). Implementation results are provided for those implementation steps where enough time has passed, sufficient to form meaningful conclusions.

In order to promote dependable production forecasting and accurate operations results reporting, the QRI-KOC AVAILS+Ô (from "available production") package was developed. It is a powerful tool for the management and developmental planning of NK's set of oilfield assets and its two aspects, production forecasting and operations monitoring, are described below.

Introduction

The North Kuwait (NK) production area is made up primarily of the Raudhatain (RA), Sabriyah (SA), and Border fields.

The major productive horizons are the Mauddud (MA), Upper Burgan (UB), & Lower Burgan (LB) formations. Production for the last 4 years has ranged from 600–700 KBOPD.

The operator, KOC (Kuwait Oil Company), faced an overall production challenge, in that the options to sustain and increase production were limited by: (a) lack of new proven acreage, or behind-pipe resources, for development, (b) continuous drop in Pres, approaching Pb, for the reservoirs under depletion or under waterflooding (due to VRR<<1), and (c) gradually diminishing oil rate and rising watercut for the reservoirs with aquifer support, due to oil column invasion by water.

Discussion

In view of the serious challenges discussed in the Introduction, a paradigm shift, a fundamental change in approach or underlying assumptions, was necessary in order to increase production and reserves.

Drilling & Completions.

In the Drilling & Completions area, the need to quickly implement advanced well technology required the NK assets to implement best practices in all phases of their well planning and drilling operations. The organization quickly moved away from vertical wells and conventional completions to deviated wells (horizontal and slanted) with ICDs, in order to maximize reservoir contact and well productivity, while controlling water production. This paradigm shift impacted all partners and vendors, who had to shift their work emphasis to better support KOC in both the new horizontal drilling paradigm and the higher oil rate targets.

The Drilling & Completions improvements have been gratifying. Figure 1 shows the drilling improvements for the last three years. Figure 2 shows the resulting production improvement (20+ MMBO benefit) in one large reservoir, due to the adoption of horizontal wells and improved drilling and completion practices.
Challenges in Data Integration, Design and Modeling of the Coreflood for FWAG EOR
Authors: Jalan Shlok , Karkooti Hooman , Masoudi Rahim , Baruah Bikram Mojinder , Salmi Norbashinatun
Published: May 2016

Most of the Malaysian oil fields are mature and the need for IOR/EOR driven development planning is vital to maintain the national production. The most common EOR methods employed in Malaysia are immiscible WAG and CEOR. However, one of the main problems in WAG is how to control gas mobility to minimize the conformance issue and maximize the 3-phase region in the reservoir. Using Foam is a relatively cost effective way of controlling gas mobility by means of low concentration of surfactant. However, the practical implementation has been hindered due to the lack of general understanding of the complex process of foam phase behavior and flow dynamics in porous media, the absence of reliable predictive models of multi-phase foam flow, and also the challenges in upscaling the lab results to the field application.

The data integration, fundamental understanding, input evaluation and predictive modeling of WAG and Foam Assisted WAG (FAWAG) have been reviewed in this work using two extensive core flooding data of one of the Malaysian oil field in two different simulators. Review of the laboratory procedure showed the importance of taking proper pre-design measures to be able to achieve conclusive results. The modeling practice shows that output parameters from coreflood experiments might be affected by forced history matching and consequently unrealistic simulation input parameters as well as the shortcomings of the predictive capability of different simulators.

The study showed that in the core flood experiments and simulations, various aspects need to be carefully considered including:Reliable data integration and understanding of the physics/dynamics involved in the process are important for proper evaluation of the foam effect.Simulation studies to be used for the pre-design and optimization of the coreflood experiment and parameters (i.e., rate, cycles, pore volume, etc.).The measured rates and pressures must be of consistent resolution to be able to capture the exact phase breakthroughs and precise fractional flows of the experiment.The SCAL endpoints and WAG parameters must be measured and fixed prior to FAWAG experiment and simulation.Capillary end effect, formation water salinity effect on contact angle and capillary pressure impact on coreflood results needs to be carefully considered in both laboratory and modeling stages.Different commercial simulators may results in different prediction on foam output and the effect, hence proper evaluation, de-risking and sensitivity analysis should be performed to capture the foam EOR window of opportunity.
Experimental and CFD Erosion Modelling of Large Radius Pipe Elbows in Liquid
Authors: Johar Zurita , Bin Jadid Maharon , A. Shaffee Siti Nur , A. Zamberi M Shahrul , Wong Chong Y , Solnordal Christopher B. , Boulanger Joan
Published: May 2016

Numerical erosion modelling of elbows at various elbow curvatures (ratio of elbow radius to elbow inner diameter) in gas only flows has been well validated with extensive experimental data available in the literature. Surprisingly, this is not the case for liquid only flows.

Rather, the available literature data presents conflicting results of the erosion ratio trend for elbows of various curvature ratios in liquid only flows. The present work seeks to address and clarify these ambiguities through physical erosion experiments using a Coordinate Measurement Machine (CMM) to measure the net eroded surfaces of a standard elbow with a curvature ratio of 1.5 and an elbow with curvature ratio of 4.

Both elbows are tested in water-sand slurry at ambient conditions. Numerical modelling using Computational Fluid Dynamics (CFD) complements the physical understanding of the erosion results. The validated CFD model is then used to conduct parametric studies for the development of a revised correlation to predict erosion ratio, defined in this work as maximum erosion of elbows of given curvature with respect to erosion of a standard radius elbow (elbow curvature of 1.5) in liquid-solid flow.

CFD is able to predict qualitative erosion trends and erosion patterns, and provide quantitative match of relative erosion ratio of elbow with curvature ratio 4 to standard elbow in experimental specimen to within 10% accuracy.

Introduction

Management of erosion is one of the challenges in an oil and gas system with sand production. Severe erosion caused by impingement of sand particles on a metal wall may cause damage to facilities such as piping, pipe fittings, choke valves and crude oil transfer pumps as sand is being transported along the flow path. Erosion on pipe fittings such as standard and long radius elbows and plugged tees has been studied by various researchers over the years both through experiments and Computational Fluid Dynamics (CFD) modelling [1–8].
The Use of Fluorescent Tracers for Inhibitor Concentration Monitoring Useful for Scale Inhibitor Squeeze Evaluation
Authors: Brichart Thomas , Moussaron Albert , Marais Arthur , Martini Matteo , Tillement Olivier , Hurtevent Christian , Baraka-Lokmane Salima
Published: May 2016

A common problem, in oilfield reservoirs is mineral scale deposition. The build-up of scale inside well bores and the surrounding reservoir causes millions of dollar in damage every year. The most common remedy is to treat the formation of such minerals with scale inhibitor chemicals in a "squeeze" treatment; which is performed periodically. One of the big challenges remains the real-time and on-site control of inhibitor concentration during production. A simple and accurate method to determine the concentration of inhibitors has been developed; this method is based on the use of luminescent tracers. The multiple lifetimes as well as the differences shown in the emission and excitation spectra of the tracers appear to be suitable for the luminescence detection. The increased signal to noise ration due to the suppression of the background resulting from the organic oil residues is used to measure the concentration of residual inhibitors in production waters. Furthermore, the use of a technique as versatile and simple as luminescence spectroscopy allows the online and/or on-site monitoring with very limited drawbacks. This paper describes the use of novel real-time scale inhibitor monitoring; this new technique will help to optimize the treatment rates of the scale inhibitor squeeze treatment.

Introduction

Limescale (calcium carbonate) that deposits on the surface of well bore will, if untreated, reduce the efficiency of the exploitation, inducing corrosion of the production chain and ultimately leading to appliance failure. Indeed, pipework scale reduces the available cross-section area, and fluids are affected by increased pipe wall friction. A larger, more power-consuming pump will be required to maintain throughput volumes, but this can only be a temporary solution to the problem. A plant that needs to be shut down for cleaning costs millions of dollar in damage every year (Moghadasi, J. et al. 2004-A).

The formation of a thin uniform layer of scale or wax temporarily gathers the steel corrosivity, but at long-term the stagnant conditions of deposit and electrochemical reactions will corrode the steel surfaces. The fluid leaks as well as the equipment failure have been expected with potentially dangerous consequences.

Performed periodically, "squeeze" treatment is one of the most common remedies to treat the formation of such minerals. Treatment options include inhibitor chemicals, descalers, ion exchange, physical cleaning such as pipeline pigging (Collins, I.R. et al. 2001).
Integrating Broadband Seismic and CSEM to De-risk Exploration Targets
Authors: Kiyashchenko Denis , Fan Yuanzhong , Blades Dina , Geisslinger Axel , Hindriks Folkert , See Mark , Hazewinkel Jeroen
Published: May 2016

CSEM can be used as a tool for regional exploration. However, CSEM-based prospect screening may be often mis-lead by anomalies caused by tight sediments. Integration of acoustic impedance derived from broadband seismic and CSEM helps us to identify those false anomalies and highlight the ones being potentially related to hydrocarbons. We also develop the methodology of inversion-based quantitative interpretation for CSEM and Broadband seismic data in order to quantify hydrocarbon potential and Earth resistivity uncertainty.

Introduction

CSEM has been used extensively for de-risking prospects and is now rapidly emerging as a regional exploration tool that supports the detection of hydrocarbon formations. A key challenge with using CSEM for prospect identification is to differentiate HC related resistors from the non-HC related resistors and separate the "true positives" from the "false positives". Integration with other subsurface data, such as well logs, geochemistry and the seismic underpins joined interpretation, appropriate inversion for rock properties and, finally, PoS polarization. We build upon both regional CSEM and the latest broadband seismic data to achieve this goal.

Joint CSEM and Acoustic Impedance interpretation

High resistivity foremost indicates an absence of saline formation water and can be caused by tight formations, certain lithologies, low salinity aquifers or hydrocarbon presence. Seismic data provides information on the acoustic properties of the sediments, which can be related to burial, uplift, fluid fill and overpressures for typical lithologies in Brunei acreage. For brine-saturated sands, Archie law can be used to relate electrical resistivity and acoustic impedance to porosity (see Figure 1).
Multiscale Simulations of Fluid Flow in Nanopores for Shale Gas
Authors: Umeda Kazuki , Li Rongjuan , Sawa Yunosuke , Yamabe Hirotatsu , Liang Yunfeng , Honda Hiromi , Murata Sumihiko , Matsuoka Toshifumi , Akai Takashi , Takagi Sunao
Published: May 2016

Advanced microscopy and image analysis techniques revealed that massive nanpores exist in shale gas formations. The process of the microscopic gas transportation from nanpore systems (of shale) and the macroscopic produciton from shale gas reservoirs needs to be better understood. Here, we developed a multiscale simulation scheme for studying gas flow in nanpore systems using molecular dynamics (MD) and lattice Boltzmann method (LBM). MD is a powerful technique by which we can get thermodynamic properties of the simulation system at desired temperature and pressure, and simulate the gas flow in molecular scale. By this computational method, we will investigate transportation characteristics of methane molecule in molecular scale and estimate the slip velocities fordifferent solids at different temperatures and pressures. LBM, on the other hand, is a computational method for continuous fluid dynamics. In enables us to upscale MD simulation results from molecular scale to pore-scale with complicated geometries, and estimates the permeability to taking consideration of the slip velocities.

First, we calculated the mean free path and slip velocity, and evaluated the slip velocity as a function of Knudsen number using MD simulations. The MD simulations were conducted for three different constituents of shale nanpore surfaces; quartz, clay and kerogen at around 12 MPa and temperatore from300 K to 400 K. The fully hydroxlated α-quartz (001) surface, which contains vicinal silanol, was employed as a model of quartz system. The uncharged pyrophyllite surface was employed to represent a model of clay. The shinn model (Type III) kerogen slab was employed as a model of organic rich shale.

Second, we implemented the slip velocity obtained from MD simulations in LBM simulations. As for the fluid-solid boundary, we adopted counter slip boundary condition, which enables us to configure the slip velocity at the wall so as to satisfy that obtained from MD simulations. Then, we simulated the gas flow in nanpores with different pore geometries. For a simple slit geometry, it was found that the slip flow induced high permeability, which is about 0.1–1.8 times of that for non-slip flow. For systems with complicated geometries, we demonstrated that permeability of slip flow can be estimated from the pore profile. The application of multiscale simulation scheme to a more realistic system is straightforward.
Enhancing Business Performance through Collaboration and Fast Decision Making
Authors: van den Berg Frans
Published: May 2016

Collaborative Work Environments (CWEs) have provided significant benefits to Shell in production, field management and maintenance. The CWEs enable faster and better decision making by improved communication and easier sharing of relevant information and data. Business benefits include increased production, higher equipment reliability, lower operating cost and improved HSE. Considerable learning was derived that helps future implementations and ensures sustainability.

A Global CWE Programme

Around 2005, Shell began the journey to enhance collaborative working within its producing assets (Knoppe 2008). Today the advantages of working in a collaborative environment are well understood and the concept is widely embraced throughout the petroleum industry (e.g. Gilman 2012).

Shell embarked on a large-scale implementation in all its major assets around the world since 2011, under drive from the global production leadership. This forms part of the global Smart Fields programme (De Best 2012, Van den Berg 2010). Many CWEs are now in place (Fig. 1), by 2015 more than 60 Shell assets will have over 400 live CWE rooms. The global implementation programme has enabled achieving these benefits faster, by creating a common methodology, standardising technical solutions, capturing lessons learnt and transferring the knowledge and best practices to new assets. In addition, it has provided the business leadership a vehicle for standardising business processes in the many assets around the world.
New Inversion Method to Determine In-Situ Stress From Borehole Induced Fractures
Authors: Huang Jinsong , Wong Sau-Wai
Published: May 2016

The drilling induced tensile fractures can be observed from borehole image logs but they must be differentiated from natural fractures. This paper focuses on the understanding of hydraulically or artificially induced tensile fractures while drilling. We present an inversion method using rigorous principles of mechanics, to determine the in-situ formation stress state from observed induced tensile fractures. Contrary to common practices where only vertical or near vertical wells can be analysed, the present method is applicable to wellbores of all orientations. For a geological rock formation and area where the in-situ stress regime can be assumed to be similar, all the relevant borehole image logs can be included to provide information to yield the most probable subsurface in-situ stress state. The proposed inversion method directly solves for the in-situ stress states given any single set of observed tensile fracture location and orientation. It provides not only an estimate for the minimum horizontal stress magnitude and direction, but also the maximum horizontal stress magnitude which is usually very difficult to pin down. The resultant equations are non-linear and a simple numerical scheme is adopted for the solution. Although published data on borehole images of fractures with corresponding in-situ stress information are scarce, two observed field data from published papers are chosen for comparison.

Introduction

In-situ stresses in deep rock formations reached equilibrium over geologic time; but drilling, production and injection processes cause deformation in the rock mass and change these stresses, and often negatively impact the operator's development plan. If they are not well anticipated, the challenges and costs of managing a prospect can far exceed the initial field development expectation. Therefore, it is vital to characterize the undisturbed in-situ stress and evaluate potential impact of field development induced rock stress changes. Two examples that come to mind are 1) enhanced oil recovery field development where injection scheme takes place under hydraulic fracturing condition and 2), the development of unconventional resources such as shale gas, where the effectiveness of hydraulic fracturing to access hydrocarbon is impacted by the in-situ stress regime. The latter, for instance, is encountered in China's Sichuan basin where operators are striving to determine whether hydraulic fractures in certain areas of the basin are developed under thrust-faulting or reverse-faulting stress regime (Yuan et al, 2013). A reverse-faulting stress regime implies that the hydraulic fractures would grow in a horizontal 'pancake' fashion, diminishing its effectiveness in draining the reservoir.
Reviving Brown Field Oil Potential: Case Study of Multilayer Reservoir
Authors: Antariksa Zona Nuansa , Ultra Dian , Malau Aldani , Sukotrihadiyono Tejo
Published: May 2016

High demand and a significant increase in the price of crude oil have triggered the oil and gas industry to produce more oil and gas from their assets. Optimizing mature fields is one of the efforts that can be applied to increase production.

"RBT" field is located in South Sumatera, Indonesia, and was discovered in October 1972. It has produced from multilayer "PLB" sand reservoir since 1974. Originally this field was produced as an oil field, with a peak rate of up to 1630 BOPD, declining to 300 BOPD 9 years later. Thereafter the field was converted into a gas field producer with small condensate and is still producing now. Based on the above, it is very challenging to look for by-passed oil in "PLB" sands reservoir, since the production test data and history of this field are very limited, so the field can produce more oil and maximize the recovery factor.

This paper explains the steps that need to be taken to analyze by-passed oil in a multilayer reservoir, including: production data test review, surveillance data analysis, historical completion review, sand layer re-correlation, estimating update reservoir contact and updating geological map. After all of these steps have been completed, work over and well service jobs will be used to validate the analysis and evaluation, allowing further development strategy to be prepared.

This method has been proven in "RBT" field, which is currently producing oil at around 200 BOPD, 2.5 MMSCFD and also found by-passed gas potential in "PLB" sand, in addition to by-passed oil. This production will increase gradually later through the addition of more work over or well service jobs.

Introduction

"RBT" field is one of mature field that is operated by PT Medco E&P Indonesia. It is located in South Sumatera, Indonesia, and was discovered in October 1972. This field was originaly developed as oil field since 1974 and has produced from a multilayer reservoir named "PLB" sand, which has 6 (six) main productive layer zones and several other thin layers. The peak oil production was 1630 BOPD and then was declining to 300 BOPD in 9 years production time. In 1990 this field was converted into a gas field producer with small condensate and is still producing now.

As mature field reactivation and optimization is becoming an important aspect for increasing oil production at this time, effort to find bypassed oil in "RBT" Field was started in mid of 2011, started with initial field review, data rebuild and update, workover candidate selection and then followed by re-activation and workover campaign in 2012.

Field review, rebuild & update data

The initial effort to find by-passed oil potency in "RBT" Field were examining cumulative production allocation and analyzing historical production data from each zone and sand layer. These steps also became the main challenge as there were lack of detailed historical oil production and allocation especially in commingle zone.
Why is it Possible to Produce Oil from the Ekofisk Field for Another 40 Years?
Authors: Puntervold Tina , Strand Skule , Ellouz Raed , Austad Tor
Published: May 2016

The Ekofisk field, which is a naturally fractured chalk field, was the first offshore oilfield that was put on production in Norway in 1972. The field was produced by pressure depletion the first 10 years, and the initial recovery was estimated to only 17%. Due to the high porosity, up to 40%, significant compaction of the reservoir rock was observed. Injection of seawater was approved in 1983 and it was a great success. The expected oil recovery was adjusted to 46%. The Ekofisk formation is characterized as: low permeability in the matrix blocks (1–2 mD), high reservoir temperature (130 °C), low initial water saturation (5 -10%), and the rock appeared to be preferential oil-wet. Under such conditions, water-based EOR can only be successful if the fluid is able to change wetting properties of the rock in such a way as to increase the capillary forces. Intensive research during the last decade has proven that seawater at high temperatures acts as a "Smart Water" being able to improve the water wetness of carbonates. Even though the reservoir pressure was increased to the initial pressure, seawater had a weakening effect on the rock, and compaction is still taking place (about 10–12 cm/year) thus being a drive mechanism for oil recovery. The estimated oil recovery has now been increased to about 55%. Research show that seawater can even be modified to improve the oil recovery from the Ekofisk field, in a spontaneous imbibition process, by an additional 10% compared to ordinary seawater.

The fundamental knowledge of the effect of seawater on oil recovery from the Ekofisk formation has been important when the decision recently was made to invest in extending the oil production from the field for another 40 years.

Introduction

Ekofisk was the first oil field that was put on production in Norway in 1972. It is a naturally fractured chalk reservoir consisting of three formations:Tor formation - preferentially water-wet,Lower Ekofisk - neutral to low water wetness,Upper Ekofisk - neutral to preferentially oil-wet. Important reservoir parameters are: matrix permeability 0.1–10 mD, porosity 30–33%, reservoir temperature about 130 °C, initial water saturation about 15–20%. The reservoir has an oil column of more than 300 m and lies 2900–3250m below sea level.1 The field was initially developed for oil recovery by pressure depletion with an estimated oil recovery factor of 17%. After producing the reservoir below the bubble point, the operator and authorities in 1987 agreed upon a water injection program for three reasons: (1) Pressure support; (2) Oil displacement; (3) Decrease or prevent compaction of the reservoir rock. The following experience showed that the displacement of oil by seawater was a great success, and it actually appeared to be more effective than expected from laboratory experiments. The expected recovery factor for Ekofisk has gradually been adjusted to slightly above 50%.
A Novel Approach of H2S Corrosion Modeling in Oil/Gas Production Pipeline
Authors: R. Siagian Utjok W. , Siregar Hasian P. Septoratno , Santoso Ryan Kurniawan , Salam Damian Dion , Sumarli Shieren
Published: May 2016

Corrosion is a critical problem during Oil/Gas production, especially in sour field, Hydrogen Sulfide is the biggest contributor in the corrosion of production facilities. During the production period, pipeline will be corroded with reaction between H2S and Fe. This reaction will be occured differently in various temperature which determines the rate of your pipeline becoming thinner and thinner then will be unsafe. This paper presents a study about corrosion phenomena in production pipeline in sour field by analyzing the heat transfer to determine the corrosion rate in every part of the pipeline. An analytical model for heat transfer is coupled with fluid flow model, frictional heat and considering the Joule Thomsoneffect for steady-state condition. Then, from the analysis of the heat transfer, the corrosion rate in every section of the pipeline, 300 ft, will be obtained. This corrosion rate is determined from the analytical model. This model is applicable to be used in onshore and deepwater cases, depending on the surrounding condition. Thus, the position in which corrosion happened worst can be located. Coating or doing material selection for the several part of the pipeline could be a solution to prolong the age of the pipeline. Effectiveness is about how long the coating or the material selecting would be placed. Then, it could finally contribute in economical analysis about how much would be invested to reduce the impact of corrosion to assure the better production.

1. Introduction

It is a fact that corrosion is always happened during oil/gas production and there is nothing to do to eliminate it. The only way to do is to make the process occur more slowly. Corrosion will damage production facilities which are exposed by the fluid and surrounding environment containing corroding agents such as H2S, CO2, etc. In this paper, the main concern is H2S as the agent which can trigger the corrosion process happens. The existence of corrosion on the production facilities will disturb the flow assurance and make the production cost increase. Corrosion will make the pipe wall become thinner, then reduce the diameter of the pipe. Corrosion will also change the pipe roughness. Thus, these two occuring phenomena will significantly change the flow characteristic, then damage the flow assurance. In order to ensure the flow assurance, preventive actions such as pipe coating, injecting inhibitor, etc are always done. In the other hand, all of those actions also have to be considered from the economic view. Thus, a right action has to be chosen to ensure the flow assurance and also be economically done. In this paper, authors develop mathematical model to choose and predict the right action to be executed. Authors also suggest pipe coating and material selection as a right solution to answer the flow assurance problems in that condition.
Computation of Relative Permeability Curves in Middle Eastern Carbonates Using Digital Rock Physics
Authors: Dakshinamurthy Natarajan , Verma Naveen Kumar , Abdul Salam Tareq , Al-Sammak Ibrahim , Koronfol Safouh , Dernaika Moustafa , Teh W J
Published: May 2016

Digital Rock Physics (DRP) has significantly evolved in the last few years and added invaluable contributions in improving core characterization and in providing high quality advanced SCAL measurements, emphasized through various studies (Al Mansoori et al., 2014 and Kalam et al., 2011).

This paper represents a unique DRP relative permeability SCAL study done on two plug samples from a carbonate reservoir in the Middle East. It outlines the DRP method used to determine the relative permeability curves including sub-sample selection, high resolution CT scanning (down to nano level), generation of the 3D rock models, and simulation of fluid flow displacements.

The paper will also discuss the power of pore scale imaging and how it helps in understanding macro property variations. The DRP results are comparable to the SCAL results of same formation of nearby fields and are currently being used for the Full Field simulation. The conclusions will be supported by a comparison with physical lab measurements that were done independently on samples of the same formation from the same well's core.

Such comparison will demonstrate the added value in using DRP, and will show the effectiveness of the technology in generating advanced SCAL data in a significantly shorter timeframe compared to conventional laboratory measurements.

Introduction

Relative permeability (Kr) curves provide macroscopic description of the way in which two (or three) phases flow together locally in a porous medium (Honarpour et al., 1986 and 1995; Heaviside, 1991). Imbibition water-oil Kr data are critical in the evaluation and management of fields having natural water influx or having planned or actual water-flooding. However, high percentage of such laboratory measurements yields unrepresentative data that cannot be used in reservoir simulation models or as input for history matching of production profiles. In addition, the traditional laboratory evaluation methods may not be applicable to every testing condition or every type of reservoir rock and hence the continued development of laboratory methods is required to help characterize and understand challenging reservoir behaviors (Dernaika, 2010 and Serag et al., 2010).

Digital imaging technology has been extensively used in the petroleum industry to obtain fast and reliable core data from reservoir rock samples. The technology (Digital Rock Physics) has contributed reliably to reservoir core characterization through the application of Dual Energy X-ray CT Scanning (Walls and Armbruster, 2012 and Al-Owihan et al., 2014) and to the prediction of reservoir engineering quantities like capillary pressure and relative permeability through direct simulation into high resolution 3D images (Amabeoku et al., 2013, De Prisco et al., 2012, Mu et al., 2012 and Grader et al., 2010)
Subsea Emergency Response System (SERS): Optimised Response for Subsea Production Well Incidents in the Gulf of Guinea
Authors: Bourguignon Jean Claude , Ryan Michael , Bretenou Michel
Published: May 2016

As a major operator of subsea wells, the technological risks associated with the production phase of deepwater wells was a focus of efforts in the post-Macondo era. Shortly after this catastrophic incident, Total launched a number of in-house initiatives and in parallel joined several industry projects. Among its own, in-house initiatives, Total created the Subsea Emergency Response System Project (SERS), in order to develop and supply tools for use if an intervention was required in response to an uncontrolled hydrocarbon leak on a Total production subsea well. The SERS Project has now progressed significantly and is about to deliver its first set of tools to its operating affiliates in the Gulf of Guinea. This set of tools can be split into two systems:A Dynamic Killing System, capable of injecting fluids through the subsea Xmas tree choke interface,A Diverter System, which can be connected on top of each subsea Xmas tree for capping or diverting a leak.

The SERS Project is considered to be a significant advancement of the response capability for Totals affiliates. The design, fabrication and placement of a capping and diversion response in the Gulf of Guinea region, where Total has its greatest concentration of subsea wells, is a major improvement of Total's capability to intervene should a subsea problem arise. The new concept of a capping and diversion system adapted directly to the constraints of a blowout on a subsea production well is an industry first. The flexibility inherent in the design provides a solution that is adaptable to various types of well kill, horizontal or vertical Xmas trees, compatible with numerous installation workover control systems and is even adaptable to a well control incident on a drilling BOP.

This paper describes these two systems and the deployment strategy developed by Total to minimize the consequences of a subsea hydrocarbon leak during the production phase.

Introduction

Total is a major operator of deepwater subsea wells worldwide and particularly in the Gulf of Guinea region. Total operates around 250 subsea wells in 2014, a number which will rise to around 1000 in 10 years time with the arrival of numerous deepwater projects. In this respect, Total has an exposure to well control events not only linked to the drilling of these subsea wells, a period which lasts just a few weeks, but also to the production phase which clearly lasts for many years.
Triple cereal system with fertilizer and planting management for improving productivity in coastal saline soils of Bangladesh
Authors: Rahman M Ataur , Rahman M Atikur , Barma NCD , Tiwari TP
Published: May 2016

A field experiment was conducted on a saline environment of Shatkhira to assess the feasibility of an intensive wheat-maize-rice cropping system with crop residue used as mulch, bed planting and fertilizer management to improve productivity. Three levels of fertilizers (Recommended dose of NPKS fertilizers, recommended fertilizers plus 50% additional K and S and recommended fertilizers with 2 t/ha ash) were assigned in main plots and four combinations of soil management and mulching (Conventional flat, Conventional with straw mulching @ 3 t/ha, Bed planting, and Bed with straw mulching @ 3 t/ha) were kept in subplots with three replications. Rice straw mulch was used after wheat sowing, wheat straw mulch was applied after maize sowing. Rice was puddle transplanted without mulch. Crop varieties like BARI GOM 25, BARI Hybrid Maize 7, and BRRI Dhan 39 were used for wheat, maize and rice, respectively. Chemical analysis of soils after two years of experimentation and the response of component crops for the two cropping cycles indicated that straw mulching either on bed or flat soil was equally effective in preventing rapid development of soil salinity in the dryer periods and thereby resulted in better stand establishment contributing to higher spikes/m2 of wheat and ears/m2 of maize. Available nutrient contents in soil, especially P (Olsen), B and K were improved when straw much was applied in bed or flat plantings. Application of ash with recommended fertilizer was effective in improving grain yields of component crops as compared to other fertilizer treatments without ash. The highest grain yield of wheat and maize was achieved when recommended dose of fertilizers plus ash with straw mulching were applied either in bed or flat soil condition for both the years. Treatment effect was not noted on rice yield in the first year, however the residual effect of treatments and its combinations became significant in the second year. Like wheat and maize, rice yield positively increased by fertilizer+ ash and mulching. Straw mulch and ash application contributed to soil salinity mitigation, favoured crop establishment and improved the yields of component crops.Bangladesh J. Agril. Res. 41(1): 1-15, March 2016
Productivity of garlic under different tillage methods and mulches in organic condition
Authors: Kabir MA , Rahim MA , Majumder DAN
Published: May 2016

An experiment was conducted at the field of USDA-Alliums project, Bangladesh Agricultural University, Mymensingh to study the effect of tillage and mulches on the growth and yield of garlic. The experiment consisted of three tillage conditions (conventional, puddling and zero tillage) and four mulches (control, rice straw, water hyacinth and Curcuma amada leaf). The results revealed that different mulches had remarkable contributions on the growth and yield of garlic. The highest values of growth parameters as well as bulb yield were obtained from rice straw mulch identical with that of water hyacinth mulch. Different tillage also had significant influence on yield and yield contributing traits of garlic. Garlic cultivated under zero tillage showed remarkable variation in terms of percent emergence. Puddling and zero tillage practices resulted in higher yield compared to the conventional tillage. It was also noticed that both the tillage conditions as well as mulches showed profound effects on the yield and yield contributing parameters. Moreover, the highest net return (196647Tk. /ha) and the highest BCR of 2.90 was obtained from zero tillage with rice straw.Bangladesh J. Agril. Res. 41(1): 53-66, March 2016
Effect of weed extracts against pulse beetle, Callosobruchus chinensis L. (Coleoptera: Bruchidae) of mung bean
Authors: Ahad MA , Nahar MK , Amin MR , Suh SJ , Kwon YJ
Published: May 2016

The n-hexane extracts of the weeds bhatpata Clerodendrum viscosum, kashiature Cassia tora, dhakishak Dryoptris filix-max, bonmorich Croton bonpalandianum and ghagra Xanthium strumarium were used to evaluate their effectiveness for suppressing pulse beetle, Callosobruchus chinensis reared on mung bean Vigna radiata grains. The investigations were done with 1, 2 and 4% n-hexane extracts of the weeds and an untreated control. The weed extracts exhibited considerable effectiveness which varied with weed species, concentrations and exposure durations. The higher concentrations showed the higher rate of insect mortality, fecundity, adult emergence inhibition, and grain protection. The LC50 values of the extracts ranged from 5.3 to 7.8, 4.7 to 6.5 and 4.1 to 6.0 g/100 ml at 24, 48 and 72 hours after treatment, respectively. The fecundity inhibition varied from 31.7 to 78.7%, adult emergence inhibition from 33.8 to 81.1%, and grain damage inhibition from 10.3 to 60.1% when bhatpata with concentration of 1 g/100 ml and ghagra with concentration of 4g/100 ml were applied, respectively. Among the tested weeds, ghagra (4g/100 ml) showed better efficacy against C. chinensis compared to other tested extracts and may be suggested to control pulse beetle and protection of mung bean grains.Bangladesh J. Agril. Res. 41(1): 75-84, March 2016
Responses of garlic to zinc, copper, boron and molybdenum Application in grey terrace soil of amnura soil series
Authors: Yousuf MN , Hasan MM , Brahma S , Sultana Deeder , Kabir AHM Fazlul
Published: May 2016

A field experiment was conducted at the Spices Research Centre, Shibgonj, Bogra, Bangladesh during rabi (winter) seasons of 2008-09 and 2009-10 to determine the requirement of Zn, Cu, B and Mo of garlic (BARI Garlic 2) along with a blanket dose of cowdung 5 t, 100 kg N, 40 kg P, 100 kg K and 30 kg S/ha for achieving satisfactory bulb yield of this crop. Different levels of zinc (0, 1.0, 1.5, 3.0 and 4.5 kg/ha), copper (0, 0.5, 1.0 and 1.5 kg/ha), boron (0, 1.0, 2.0 and 3.0 kg/ha) and molybdenum (0, 0.5 and 1.0 kg/ha) were distributed in the plot. The experiment was tested in randomized complete block design with three replications. The positive impact of application of those nutrients plant height, number of leaves per plant, cloves per bulb, diameter and weight of bulb and yield of garlic up to a moderate level of Zn3.0Cu1.0B3.0Mo1.0 kg/ha. The highest bulb yield (4.87 t/ha in 2008-09 and 6.6 t/ha in 2009-10) was obtained from Zn3.0Cu1.0B3.0Mo1.0 kg/ha and yield was declined with higher dose of these elements except Mo. The fertilizer treatment Zn3.0Cu1.0B3.0Mo1.0 kg/ha was observed to be the best suitable dose for garlic production on Grey Terrace Soil of Amnura Soil Series under AEZ-25 (Level Barind Tract) of Bangladesh.Bangladesh J. Agril. Res. 41(1): 85-90, March 2016
Genetic variability, character association and path analysis in maize (Zea mays L.)
Authors: Begum S , Ahmed A , Omy SH , Rohman MM , Amiruzzaman M
Published: May 2016

Twenty-two maize hybrids were evaluated to find out their variability, character association and path coefficient of grain yield and its component characters. Significant differences were found among the genotypes for the characters studied. Ear length and grain yield (t/ha) had moderate genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV), but the had the low environmental co-efficient of variation (ECV). The heritability for all the characters was high. The characters viz. plant height, ear height and 1000-grain weight, showed high heritability along with high genetic advance. Ear length, ear diameter and kernel per row had highly significant positive correlation with grain yield. However, the deviations between genotypic and phenotypic correlation and magnitude of environmental correlation suggested considerable influence of growing environment in expressing almost all the characters. Path coefficient analysis revealed that plant height (0.659), ear length (0.934) and kernel-rows per ear (0.715) had highly significant positive direct effect on grain yield suggesting their importance during selection. Simultaneous restricted selection should be done for number of kernel rows per ear.Bangladesh J. Agril. Res. 41(1): 173-182, March 2016
Effect of various cereals on the development of Corcyra cephalonica (Stainton) and its egg parasitoid Trichogramma chilonis (Ishii)
Authors: Nasrin M , Alam MZ , Alam SN , Miah MRU , Hossain MM
Published: May 2016

Eight types of cereals viz., wheat grain, chopped wheat, paddy grain, rice grain, maize grain, chopped maize, rice bran, mixture of rice bran and chopped rice were fed to observe the development parameters like egg, larva, pupa and adult stages of Corcyra cephalonica (stainton) for three consecutive generations. The parasitism efficiency of Trichogramma chilonis (Ishii) was also evaluated on the resultant host eggs of C. cephalonica. The C. cephalonica revealed the highest number of eggs (115.6 female1), higher hatchability (92.9%), extented larval duration (45.9 days), increased larval weight (0.058 gm), survival rate (88.3%), adult emergence rate (93.5%), and male and female longevity (7.7, 7.2 days respectively) when they were reared on chopped wheat. On the other hand, the lowest number of egg was found on paddy husk (29.2 female-1). The lowest hatchability (45.6%), larval duration (45.9 days), larval weight (0.029gm), and survival rate (38.2%), pupal duration (17.9 days) adult emergence (42.0%), male and female longevity (4.8 and 4.7 days respectively) were found on paddy husk. The effect of food materials also reflected on the parasitism efficiency of the egg parasitoid T. chilonis. The highest percent egg parasitization was done by the T. chilonis on the host eggs, reared on chopped wheat (94.8±0.07%) followed by wheat grain (82.5±0.08%) and chopped maize (73.8±0.09%). On the other hand, the lowest parasitism was obtained when the larvae were reared on paddy husk (42.2±0.14 %) and paddy grain (48.8±0.05 %).Bangladesh J. Agril. Res. 41(1): 183-194, March 2016
Tracking a Driver’s Face against Extreme Head Poses and Inference of Drowsiness Using a Hidden Markov Model
Authors: Choi In-Ho , Jeong Chan-Hee , Kim Yong-Guk
Published: May 2016

This study presents a new method to track driver’s facial states, such as head pose and eye-blinking in the real-time basis. Since a driver in the natural driving condition moves his head in diverse ways and his face is often occluded by his hand or the wheel, it should be a great challenge for the standard face models. Among many, Active Appearance Model (AAM), and Active Shape Model (ASM) are two favored face models. We have extended Discriminative Bayesian ASM by incorporating the extreme pose cases, called it Pose Extended—Active Shape model (PE-ASM). Two face databases (DB) are used for the comparison purpose: one is the Boston University face DB and the other is our custom-made driving DB. Our evaluation indicates that PE-ASM outperforms ASM and AAM in terms of the face fitting against extreme poses. Using this model, we can estimate the driver’s head pose, as well as eye-blinking, by adding respective processes. Two HMMs are trained to model temporal behaviors of these two facial features, and consequently the system can make inference by enumerating these HMM states whether the driver is drowsy or not. Result suggests that it can be used as a driver drowsiness detector in the commercial car where the visual conditions are very diverse and often tough to deal with.
Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory
Authors: Casolari Andrea , Cardinali Alessandro
Published: May 2016

The Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the “time-averaged” parallel wave number at higher values (with respect to that launched by the antenna at the plasma edge) has been evaluated, in order to find an explanation of the filling of the spectral gap (Fisch, 1987) by “Hamiltonian chaos” in the Lower Hybrid Current Drive (LHCD) experiments (Fisch, 1978). The present work shows that the increase of the parallel wave number \(n_{\parallel}\) due to toroidal effects, in the case of the typical plasma parameters of the Frascati Tokamak Upgrade (FTU) experiment, is insufficient to explain the filling of the spectral gap, and the consequent current drive and another mechanism must come into play to justify the wave absorption by Landau damping. Analytical calculations have been supplemented by a numerical algorithm based on the symplectic integration of the ray equations implemented in a ray tracing code, in order to preserve exactly the symplectic character of a Hamiltonian flow.