bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Heavy Oil Recovery by Unconventional Thermal Methods
Authors: Alomair O.. , Alarouj M.. , Althenayyan A.. , Alsaleh A.. , Mohammad H.. , Altahoo Y.. , Alhaidar Y.. , Alansari S.. , Alshammari Y..
Published: December 2012

Thermal recovery methods have the objective of accelerating hydrocarbon recovery by raising the temperature of the formation and reducing hydrocarbon viscosities. Thermal recovery involves several well-known processes such as steam injection, in situ combustion, steam assisted gravity drainage (SAGD), and a more recent technique that consists of heating the reservoir with electrical energy. The most common thermal method is steam injection. However, some difficulties occurs with steam injection includes; water availability, the cost of water vaporization process, and how to keep steam temperature above the condensation temperature at reservoir conditions. Also it is limited to relatively shallow, thick, permeable, and homogenous sand reservoirs that are located onshore.

In this project three unconventional thermal approaches were developed in laboratory scale to improve the recovery of heavy oil. Those methods are; electrical resistant electrodes, electromagnetic inductors, and microwaves. Designing and experimenting were prepared using low cost material to achieve the success of the new approaches. In the electrical resistance approach, a potential difference was applied between two electrodes; one act as anode and the other one as a cathode. A sufficient heat has been introduced between the electrodes, which improved the oil recovery by adding a maximum of 21% additional recovery to the primary recovery. For the electromagnetic induction, a coil has been wrapped around a core through which the introduced heat was transmitted to the fluid inside and hence increasing the oil recovery by a maximum of 34%. As for the microwave method, microwaves were applied on the core to vibrate water molecules. These microwaves were created and applied by using normal microwave oven, where the waves were transmitted from the source, and reflected inside an isolating body to prevent any wave leakage. The molecules movement resulted in heat generation and thus a reduction in the oil viscosity. The conducted test revealed an increase of 30% in the oil recovery which varies according to the operating power. Finally, economical comparison between the proposed methods was conducted. The three methods were compared by combining recovery and power consumption. Average power consumption per unit production for electromagnetic induction, Electrical Resistance, and microwave were 39, 2570, and 3.775 watt.hr/cc, respectively. The comparison revealed that the Microwave Heating is the most economical choice followed by electromagnetic induction and finally the electrical resistance heating.
Salinity Effect on the Rheological Properties of Water Based Mud under High Pressures and High Temperatures of Deep Wells
Authors: Hassiba Khaled J. , Amani Mahmoud
Published: December 2012

The significance of exploring deep and ultra-deep wells is increasing rapidly to meet the increased global demands on oil and gas. Drilling at such depth introduces a wide range of difficult challenges and issues. One of the challenges is the negative impact on the drilling fluids rheological properties when exposed to high pressure high temperature (HPHT) conditions and/or becoming contaminated with salts, which are common in deep drilling or in offshore operations.

The drilling engineer must have a good estimate for the values of rheological characteristics of a drilling fluid, such as viscosity, yield point and gel strength, and that is extremely important for a successful drilling operation. In this research work, experiments were conducted on water-based muds with different salinity contents, from ambient conditions up to very elevated pressures and temperatures.

In these experiments, water based drilling fluids containing different types of salt (NaCl and KCl) and at different concentrations were tested by a state-of-the-art high pressure high temperature viscometer. In this paper, the effect of different electrolysis (NaCl and KCl) at elevated pressures (up to 35,000 psi) and elevated temperatures (up to 450 °F) on the viscosity of water based mud has been presented.
Continuous Solvent Flush Approach for Asphaltene Precipitations in a Kuwaiti Reservoir: Phase I - An Experimental Solvent Screening
Authors: Rashed Abeer M. , Ghloum Ebtisam F. , Al-Matrook Mohammad F. , Oskui Gh. Reza , Mali P.. , Telang M.. , Al-Jasmi Ahmad
Published: December 2012

Asphaltene deposition problems in Kuwait have become a serious issue in a number of reservoirs during primary production in different fields, resulting in a severe detrimental effect on the economics of oil recovery. Hence, one of the mitigation approaches in the field is using remedial solvent treatments, such as Xylene or Toluene, which is very costly and harmful to the environment.

Kuwait Oil Company (KOC) is planning to produce from asphaltinic Marrat wells that have been shut down due to low bottom-hole pressure (BHP), by artificial lifting technique using an Electric Submersible Pump (ESP) supported with continuous chemical injection, as a pilot. The main objective of this study was to investigate in the lab the effectiveness of various concentrations of toluene/diesel (T/D) mixtures on Marrat reservoir fluid in order to mitigate asphaltene deposition problem during the actual pilot implementation.

Preliminary screening tests were conducted on the surface oil sample using Solid Detection System (SDS) "laser technique" to determine the optimum dose of the T/D mixture ratio. The results showed that pure diesel accelerated the asphaltene precipitation; however, mixing T/D inhibited the precipitation process. Series of pressure depletion tests was then conducted on live oil, single phase samples, to determine the Asphaltene Onset Pressure (AOP) with and without adding various ration of T/D solvents at different temperatures from reservoir to surface conditions.

The results revealed that using 15% (by volume of oil) from the (50T:50D) mixture reduced the AOP close to the bubble point pressure. Furthermore, the amount of the precipitated asphaltene was physically quantified using a bulk filtration technique. It was observed that, based on blank sample, the wt% of the precipitated asphaltene was minimized at the AOP and maximized at the bubble point. However, using the recommended mixture of 50T/50D, the amount of asphaltene that precipitated was almost negligible. Therefore, from a health, safety, and economic point of view, this study recommends using a low dose of 7.5% (by volume of oil) from toluene mixture with diesel (50%:50%) rather than using pure toluene to prevent the precipitation.
A Study of Transversely vs Longitudinally Fractured Horizontal Wells in a Moderate-Permeability Gas Reservoir
Authors: Liu Tianyiu , Marongiu-Porcu Matteo , Ehlig-Economides Christine , Economides Michael J.
Published: December 2012

Transverse fractures created from horizontal wells are a common choice in tight and shale gas reservoirs. Previous work has shown that proppant pack permeability reduction due to non-Darcy flow in a transverse fracture from a horizontal well causes significant reduction in the fracture performance when the gas formation permeability exceeds 0.5 md. There are other configurations and architectures such as aligning the well trajectory with the fracture, either by drilling horizontal wells in the direction that results in longitudinal fractures or by just sticking with drilling vertical wells. However, when drilling and fracturing costs are considered, productivity is not the only optimization consideration.

The field example illustrates a case when the apparent choice to use transverse fractures from horizontal wells proved to be suboptimal from the productivity perspective, but fundamental considering economics. Parametric studies for permeability ranging from 0.01 to 5 md illustrate the importance of economics in addition to physical performance. For similar reservoir characteristics, the optimum fractured well architecture varies considerably, and therefore an extensive reservoir engineering approach may be necessary beyond the well completions and/or current prejudices and inadequate understanding.
Dynamic Filtration Properties of Clay Based Drilling Muds under Elevated Temperatures
Authors: Osgouei A. E. , Ozyurtkan M. H. , Altun G.. , Dilsiz E. A.
Published: December 2012

Static filtration of drilling fluids has long been recognized as an important parameter for drilling operations. Since the standard laboratory testing procedures only consider static conditions, the filtration and cake properties under continuous circulation and dynamic borehole conditions are not usually well determined. Therefore, the measurement of dynamic filtration is particularly important in order to mimic actual downhole conditions.

An experimental study has been carried out by the ITU/PNGE research group to characterize the dynamic filtration properties of clay based drilling fluids. This study is an impressive attempt to figure out the dynamic filtration phenomena of clay based muds. The experimental results obtained from a dynamic filtration apparatus (Fann Model 90) are reported in this study.

Bentonite and sepiolite clays based muds formulated with commercial additives have been investigated throughout the study. Numerous dynamic filtration histories with test duration of 45 to 60 minutes at temperature conditions ranging from 150 to 400 °F, and a differential pressure of 100 psi have been applied to muds. Three key parameters namely spurt loss volume, dynamic filtration rate (DFR), and cake deposition index (CDI) have been determined to characterize the dynamic filtration properties of mud samples.

Results have revealed that bentonite based muds have better dynamic filtration properties than those of sepiolite muds at temperatures up to 250 °F. However, they have lost their stability over 250 °F. Furthermore, formulated sepiolite based muds have remarkable dynamic filtration rates and cake depositions above 300 °F. To sum up, the experimental results of this study point out that sepiolite based muds might be a good alternative to drill wells experiencing high temperatures, particularly in deep oil, gas and geothermal wells.
Evaluation of the Effect of Asphaltene Deposition in the Reservoir for the Development of the Magwa Marrat Reservoir
Authors: Al-Qattan A.. , Blunt M. J. , Gharbi O.. , Badamchizadeh A.. , Al-Kanderi J. M. , Al-Jadi M.. , Dashti H. H. , Chimmalgi V.. , Bond D. J. , Skoreyko F..
Published: December 2012

The Magwa Marrat reservoir was discovered in the mid-1980s and has been produced to date under primary depletion. Reservoir pressure has declined and is approaching the asphaltene onset pressure (AOP). A water flood is being planned and a decision needs to be taken as to the appropriate reservoir operating pressure. In particular the merits of operating the reservoir at pressures above and below the AOP need to be assessed.

Some of the issues related to this decision relate to the effects of asphaltene deposition in the reservoir. Two effects have been evaluated. Firstly the effect of in-situ deposition of asphaltene on wettability and the influence that this may have on water-flood recovery has been investigated using pore scale network modes. Models were constructed and calibrated to available high pressure mercury capillary pressure data and to relative permeability data from reservoir condition core floods. The changes to relative permeability characteristics that would result from the reservoir becoming substantially more oil-wet have been evaluated. Based on this there seems to be a very limited scope for poorer water flood performance at pressures below AOP.

Secondly the scope for impaired well performance has been evaluated. This has been done using a field trial where a well was produced at pressures above and substantially below AOP and pressure transient data were used to estimate near wellbore damage "skin". Also compositional simulation has been used to estimate near wellbore deposition effects. This has involved developing an equation of state model and identifying, using computer assisted history matching, a range of parameters that could be consistent with core flood experiments of asphaltene deposition. Results of simulation using these parameters are compared with field observation and used to predict the range of possible future well productivity decline.

Overall this work allows an evaluation of the preferred operating pressure, which can drop below the AOP, resulting in lower operating costs and higher final recovery without substantial impairment to either water-flood efficiency or well productivity.
Field Treatment to Stimulate a Deep, Sour, Tight Gas Well using a New, Low Corrosive and Environmentally Friendly Fluid
Authors: Nasr-El-Din H. A. , de Wolf C. A. , Stanitzek T.. , Alex A.. , Gerdes S.. , Lummer N. R.
Published: December 2012

Matrix acidizing of high temperature gas wells is a difficult task, especially if these wells are sour or if they are completed with high chrome content tubulars. These harsh conditions require high loadings of corrosion inhibitors and intensifiers in addition to hydrogen sulfide scavengers and iron control agents. Selection of these chemicals to meet the strict environmental regulations adds to the difficulty in dealing with such wells. Recently, a new environmentally friendly chelating agent, glutamic acid -diacetic acid (GLDA), has been developed and extensively tested for carbonate and sandstone formations. Significant permeability improvements have been shown in previous papers over a wide range of conditions. In this paper we evaluate the results of the first field application of this chelating agent to acidize a sour, high temperature, tight gas well completed with high chrome content tubulars.

Extensive laboratory studies were conducted before the treatment, including: corrosion tests, core flood experiments, compatibility tests with reservoir fluids, and reaction rate measurements using a rotating disk apparatus. The treatment started by pumping a preflush of mutual solvent and water wetting surfactant, followed by the main stage consisting of 20 wt% GLDA with a low concentration of a proper corrosion inhibitor. Following the treatment, the well was put on production, and samples of flow back fluids were collected. The concentrations of various ions were determined using ICP. Various analytical techniques were used to determine the concentration of GLDA and other organic compounds in the flow back samples.

The treatment was applied in the field without encountering any operational problems. A significant increase in gas production that exceeded operator expectations was achieved. Unlike previous treatments where HCl or other chelates were used, the concentrations of iron, chrome, nickel, and molybdenum in the flow back samples were negligible, confirming low corrosion of well tubulars. Improved productivity and longer term performance results confirm the effectiveness of the new chelate as a versatile stimulation fluid.
Reservoir Characterization Using Wellbore Storage Dominated Flow
Authors: Al Rbeawi Salam , Tiab D..
Published: December 2012

The reliability of the estimated parameters in well test analysis depends on the accuracy of measured data. Early time data are usually controlled by the wellbore storage effect. However, this effect may last for the pseudo-radial flow or the boundary dominated flow. Eliminating this effect is an option for restoring the real data. Using the data with this effect is another option that can be used successfully for reservoir characterization.

This paper introduces a new technique for interpreting the pressure behavior of horizontal wells and fractured formations with wellbore storage. A new analytical model describes the early time data has been derived for both horizontal wells and horizontal wells intersecting multiple hydraulic fractures. Several models for the relationships of the peak points with the pressure, pressure derivative and time have been proposed in this study for different wellbore storage coefficients. A complete set of type curves has been included for different wellbore lengths, skin factors and wellbore storage coefficients. The study has shown that early radial flow for short to moderate horizontal wells is the most affected flow regime by the wellbore storage. For long horizontal wells, the early linear flow is the most affected flow regime by the wellbore storage effect.

The most important finding in this study is the ability to run a short test and use the early time data only for characterizing the formation. This means there is no need to run a long time test to reach the pseudo-steady state. Therefore, from the wellbore storage dominated flow, the early radial and pseudo-radial flow can be established for horizontal wells and hydraulic fractured formations. A step-by-step procedure for analyzing pressure tests using the analytical models (TDS) and the type curves is also included in this paper for several numerical examples.
A High Angle and Horizontal Well Interpretation Toolkit for Quantitative Formation Evaluation and Reservoir Characterization
Authors: Zhou JinJuan , Guo Pingjun , Mardon Duncan , Passey Quinn , Mendoza Alberto , Gaillot Philippe , Wertanen Scott , Yin Hezhu , Fitz Dale , Nicosia Wayne
Published: December 2012

Over last several years, the ability to perform accurate, quantitative formation evaluation in high-angle and horizontal (HA/HZ) wells has been increasingly recognized as a high priority, unsatisfied need within the formation evaluation (FE) community. The industry has realized that the ability to drill extended reach wells has surpassed the ability to evaluate them. Well logs are often underutilized for geologic modeling and assessment applications due to lack of confidence in petrophysical analysis results.

In this paper, we introduce a state-of-art formation evaluation toolkit specifically developed for quantitative interpretation of high angle and horizontal well logs. Starting with wellbore images and standard triple-combo field logs, the workflow consists of: 1) three-dimensional (3D) and two-dimensional (2D) display modules for well path, wellbore images logs, scalar logs and dips to quality control (QC) the data; 2) a comprehensive image analysis module combined with log analysis to build a 3D geometrical earth model; 3) a depth coherence processing (DCP) module to effectively correct recorded borehole images of different logging tool sensors with different depths of investigation (DOI) back to borehole size (BS); 4) a 3D joint inversion module to accurately model and interpret gamma ray (GR), neutron, density, and resistivity logs, to build a common petrophysical earth model; and 5) an output module in which the common earth model is populated with bedding geometries and petrophysical property distributions.

The advanced formation evaluation toolkit described in this paper enables geoscientists to realize much more value than ever before from high-angle and horizontal well data, especially in thinly bedded reservoirs. The detailed description of the internal architecture and lateral petrophysical characterization of the reservoirs are essential for understanding stratigraphy and conditioning geological models. The improved estimations of the petrophysical properties yield more accurate estimates of reserves in place.
Heavy Oil Viscosity and Density Prediction at Normal and Elevated Temperatures
Authors: Alomair Osamah , Ali Mohammad A.J. , Alkoriem Abullhaq , Hamed Mohamed
Published: December 2012

Viscosity and Density are important physical parameter of crude oil, closely related with the whole processes of production and transportation, and are very essential properties to the process design and petroleum industries simulation. As viscosity increases, a conventional measurement becomes progressively less accurate and more difficult to obtain. According to the literature survey, most published correlations that are used to predict density and viscosity of heavy crude oil are limited to certain temperatures, API values, and viscosity ranges. The objective of present work is to propose accurate models that can successfully predict two important fluid properties, viscosity and density covering a wide range of temperatures, API, and viscosities. Viscosity and density of more than 30 heavy oil samples of different API gravities collected from different oilfield were measured at temperature range 15°C to 160°C (60°F to 320°F), and the results were used to ensure the capability of proposed and published correlations to predict the experimental viscosity and density data. The proposed correlation can be summarized in two stages. The first step was to predict the heavy oil density from API and temperature for different crudes. The predicted values of the densities were used in the second step to develop the viscosity correlation model. A comparison of the predicted and actual viscosities data, concluded that the proposed model has successfully predict all data with average relative errors of less than 12% and with the correlation coefficient R2 of 0.97, and 0.92 at normal and high temperatures respectively. Meanwhile, the results of most of the available models has an average relative error above 40%, with R2 values between 0.19 to 0.95. These comparisons were made as a quality control to confirm the reliability of the proposed model to predict density and viscosity values of heavy crudes when compared with other models.
Unconventional Use of Production Logging Technology
Authors: Chaudhary S.. , Murty M. S. , Bora S.. , Chandra Y.. , Singh P. P. , Pandey R. K. , Bhatt U. C. , Verma V.. , Ogra K.. , Pandey A.. , Gupta S.. , Sinha R..
Published: December 2012

Production logging has been traditionally used for zonal quantification of layers for identification of most obvious workover for water shut off, acid wash or reperforation candidate identification. The basic sensors help in making some of the critical decisions for immediate gain in oil production or reduction in water cut. However, this technology can be used in a non standard format for various purposes including multilayer testing to obtain layer wise permeability and skin factor using pressure and flow rate transient data acquired with production logging tools. This is very crucial and complements the present wellbore flow phenomenon to better understand relative zonal performance of well at any stage of its production. In addition, production logging along with the pulsed neutron technique is very crucial to evaluate the complete wellbore phenomenon, understand some of the behind the production string fluid flow behaviors. Another major concern in low flow rate wells is recirculation, causing fall back of heavier water phase while lighter phase like oil and gas move upwards. This well bore phenomenon renders the quantification from production logging string, and this in extension also prevents any comprehensive workover decisions on the well because of the risk involved. Oil rate computation from hydrocarbon bubble rates becomes very critical in such scenarios to bring out the most optimal results and enhance confidence in workover decisions. Another key concern in any reservoir is to evaluate the productivity Index; this is even more critical once the field is on production. It is essential to determine the performance of various commingled layers and reform the Injector producer strategy for pressure support or immediate workover. Selective Inflow performance is a technique used to identify the Productivity index of various layers in a commingled situation. This paper elaborates on various non conventional uses of production logging from the western offshore India.
Wettability Alteration of Carbonates by Optimizing the Brine and Surfactant Composition
Authors: Martavaltzi Christina , Dakik Ahmad , Agrawal Shubham , Gupta Anuj
Published: December 2012

It is well known that the majority of carbonate reservoirs are neutral to oil-wet. This leads to much lower oil recovery during waterflooding since there is no spontaneous imbibition of water in heterogeneous reservoir displacement. It has been verified by a number of researchers that Adjustment of ion concentration in brine solutions, or adding surfactant solutions can enhance the oil recovery by altering the wettability. In the published literature, contact angle studies usually refer to measurement on calcite crystals and there are no results for the contact angle of carbonate porous media representative of reservoir rocks. Moreover, there are few studies on the effect of non-ionic surfactants, compared to those for ionic surfactants. Understanding the effect of various ions and their concentration in the injection brine on the wettability of the Limestone outcrop core samples is the first step for tailoring of the optimum injection brine. This will be followed by a study of the effect of surfactant on the wettability of calcite crystal samples. The evaluation of the results may provide guidelines for the design of injection brines for efficient enhanced oil recovery from carbonate reservoirs.

In this work, a procedure is established for the measurement of the contact angle on limestone outcrop core samples. Results showed that, at atmospheric conditions, low salinity CaCl2 solution induced the most significant improvement on the wettability of the outcrop sample. Moreover, among all the non-ionic surfactants studied, only the presence of the two first members of the 15S analogous series might lead to a slight decrease of the contact angle.
History Matching Saturation and Temperature Fronts with Adjustments of Petro-Physical Properties; SAGD Case Study
Authors: Mirzabozorg Arash , Nghiem Long , Chen Zhangxing , Yang Chaodong , Hajizadeh Yasin
Published: December 2012

History matching of reservoir flow models based only on production data may not reveal deficiencies that affect future predictions. Incorporating saturation and temperature profile data that come from 4D seismic surveys in the history matching process can reduce the uncertainty of reservoir models for the prediction stage. We constructed a field reservoir model from which production history, saturation and temperature profile history were obtained. We started the history matching process with a base reservoir model, the petro-physical properties of which were substantially different than those of the field reservoir model. We propose a new methodology for matching the fluid and temperature profiles by adjusting reservoir petro-physical properties. In this methodology, some grid blocks in a reservoir model were selected judiciously to capture the overall saturation and temperature distribution profiles. In addition to well production data, we included the saturation and temperature profiles at these grid blocks as extra objective functions during the history matching process. The DECE optimization is used to reduce the objective function. We applied this method in a Steam Assisted Gravity Drainage (SAGD) process and matched the saturation and temperature profiles with an average error of less than 2%.
An Integrated Approach to Designing an Offshore Heavy Oil Well Test - North Sea Example
Authors: Akuanyionwu Obinna , Shumakov Yakov
Published: December 2012

Offshore production of heavy oil can be challenging due largely to adverse fluid properties, sand production and flow assurance concerns. Recent technology advancements effectively driving management of these challenges and government support through tax relief have significantly contributed to the increased appraisal activity over the last several years in the North Sea heavy oil fields. Application of appropriate technologies and techniques has always been of paramount importance for acquiring high quality information throughout welltest for reservoir characterization at appraisal stage of the fields. It also provides high level of confidence in technology and"proof of concept" prior to further application in a full field development at investment intensive offshore operating environment.

This paper describes an integrated approach in analytical modeling and design developed and applied in the planning of flow test in a number of North Sea heavy oil fields. This includes a comprehensive pre-evaluation of well productivity, PVT properties modeling as well as design and selection of appropriate artificial lift method. A series of technical solutions considered relevant in relation to enhancing the low flowing well head temperature conditions, typically observed during the cold heavy oil production offshore and often leading to operational constraints on fluid handling capabilities is also discussed. Additionally, a probablistic approach considering base case, low and high case scenarios has been developed and implemented as part of the evaluation process, given the limited amount of available information and high level of uncertainties.

The study demonstrates the benefits of applying analytical techniques for uncertainties handling during flow test planning and thereby enabling accentuation of potential issues, properly planning for mitigation actions and predicting the entire flow test sequence. Finally the study underlines some important guidelines pertaining to planning for further appraisal and development of new heavy oil fields.
Innovative In-house Geosteering Utilizes Gas-While-Drilling Data for Deep Jurassic High Angle Well Placement
Authors: Al-Shamali Adnan , Verma Naveen K. , Jha Bhawesh Chandra , Estarabadi Javad , Al-Khamees Waleed
Published: December 2012

The directional drilling companies in oil industry usually provide well placement services using proprietary geosteering software that utilize conventional Logging-While-Drilling (LWD) data. Usually online access to the recorded logs is available to end users, but often very limited capability exists within the oil companies to test geosteering interpretations and advise. Present paper shares the case studies of some wells in which Gas-While-Drilling (GWD) data was used in conjunction with the LWD data for well placement. Furthermore, the Geosteering Module of a third party 3D Geological modeling software was used independently within the West Kuwait Fields Development group of KOC for well placement.

Well D-08 was drilled as vertical producer in a West Kuwait Marrat carbonate reservoir, produced economic quantities of oil during initial testing, but it started cutting high amount of water due to the effect of a fault. Therefore, the well was re-entered and sidetracked at a high angle, away from the fault. Similarly, the U-73 vertical well which encountered poor reservoir facies on flank of the field, was re-entered for productivity enhancement into a thin porous reservoir layer as horizontal sidetrack towards the crest. Both these wells were monitored and geosteered in near real-time using a geosteering software module which combines the overall structural framework provided by 3D geological model, along with the well log responses characteristics from offset wells, to produce a detailed pre-drill model for Geosteering. This is achieved by forward modeling to predict changes in log characters along the planned wellbore profile. The results are displayed both in vertical and measured depth domains along a 2D curtain section with formation tops parallel to the planned well azimuth.

In addition to the conventional LWD logs, the GWD logs generated from advanced gas analysis of the drilling mud were used for geosteering during drilling well D-08 and U-73 re-entry sidetrack wells. The LWD and GWD based geosteering were done independent of each other to test the efficacy of GWD method. Geosteering software and advanced mud gas data have been paired for high angle and horizontal well placement for the first time in Kuwait which successfully guided the well trajectory while drilling.
Dynamic Penalty Function Evolution Algorithms for History Matching of Oil and Gas Reservoir Models
Authors: Abdelkhalik Ossama , Daoud Ahmed , Goh Shu Ting
Published: December 2012

This paper presents a novel implementation for evolutionary algorithms in oil and gas reservoirs history matching problems. The reservoir history is divided into time segments. In each time segment, a penalty function is constructed that quantifies the mismatch between the measurements and the simulated measurements, using only the measurements available up to the current time segment. An evolutionary optimization algorithm is used, in each time segment, to search for the optimal reservoir permeability and porosity parameters. The penalty function varies between segments; yet the optimal reservoir characterization is common among all the constructed penalty functions. A population of the reservoir characterizations evolves among subsequent time segments through minimizing different penalty functions. The advantage of this implementation is two fold. First, the computational cost of the history matching process is significantly reduced. Second, problem constraints can be included in the penalty function to produce more realistic solutions. The proposed concept of dynamic penalty function is applicable to any evolutionary algorithm. In this paper, the implementation is carried out using genetic algorithms. Two case studies are presented in this paper: a synthetic case study and the PUNQ-S3 field case study. A computational cost analysis that demonstrates the computational advantage of the proposed method is presented.
HPHT 101 - What Every Engineer or Geoscientist Should Know about High Pressure High Temperature Wells
Authors: Shadravan Arash , Amani Mahmood
Published: December 2012

The high-profile blowout at Macondo well in the US Gulf of Mexico, brought the challenges and the risks of drilling into high-pressure, high-temperature (HPHT) fields increasingly into focus. Technology, HSE, new standards, such as new API procedures, and educating the crew seem to be vital in developing HPHT resources. High-pressure high-temperature fields broadly exist in Gulf of Mexico, North Sea, South East Asia, Africa, China and Middle East. Almost a quarter of HPHT operations worldwide is expected to happen in American continent and the majority of that solely in North America. Oil major companies have identified key challenges in HPHT development and production, and service providers have offered insights regarding current or planned technologies to meet these challenges. Drilling into some shale plays such as Haynesville or deep formations and producing oil and gas at HPHT condition, have been crucially challenging. Therefore, companies are compelled to meet or exceed a vast array of environmental, health and safety standards.

This paper, as a simplified summary of the current status of HPHT global market, clarifies the existing technological gaps in the field of HPHT drilling, cementing and completion. It also contains the necessary knowledge that every engineer or geoscientist might need to know about high pressure high temperature wells. This study, not only reviews the reports from the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) and important case studies of HPHT operations around the globe but also compiles the technical solutions to better maneuver in the HPHT market. Finally, the HPHT related priorities of National Energy Technology Laboratories (NETL), operated by the US Department of Energy (DOE), and DeepStar, as a strong mix of large and mid-size operators are investigated.
A New Approach Optimizing Mature Waterfloods with Electrokinetics-Assisted Surfactant Flooding in Abu Dhabi Carbonate Reservoirs
Authors: Ansari Arsalan , Haroun Mohammed , Sayed Nada Abou , Kindy Nabeela AI , Ali Basma , Shrestha Reena Amatya , Sarma Hemanta
Published: December 2012

EOR technologies such as CO2 flooding and chemical floods have been on the forefront of oil and gas R&D for the past 4 decades. While most of them are demonstrating very promising results in both lab scale and field pilots, the thrive for exploring additional EOR technologies while achieving full field application has yet to be achieved. Among the emerging EOR technologies is the surfactant EOR along with the application of electrically enhanced oil recovery (EEOR) which is gaining increased popularity due to a number of reservoir-related advantages such as reduction in fluid viscosity, water-cut and increased reservoir permeability.

Experiments were conducted on 1.5" carbonate reservoir cores extracted from Abu Dhabi producing oil fields, which were saturated with medium crude oil in a specially designed EK core flood setup. Electrokinetics (DC voltage of 2V/cm) was applied on these oil saturated cores along with waterflooding simultaneously until the ultimate recovery was reached. In the second stage, the recovery was further enhanced by injecting non-ionic surfactant (APG) along with sequential application of EK. This was compared with simultaneous application of EK-assisted surfactant flooding. A smart Surfactant-EOR process was done in this study that allowed shifting from sequential to simultaneous Surfactant-EOR alongside EEOR

The experimental results at ambient conditions show that the application of waterflooding on the carbonate cores yields recovery of approximately 46–72% and an additional 8–14% incremental recovery resulted upon application of EK, which could be promising for water swept reservoirs. However, there was an additional 6–11% recovery enhanced by the application of EK-assisted surfactant flooding. In addition, EK was shown to enhance the carbonate reservoir’s permeability by approximately 11–29%. Furthermore, this process can be engineered to be a greener approach as the water requirement can be reduced upto 20% in the presence of electrokinetics which is also economically feasible.
A New Approach in Modeling of Fracture Ballooning in Naturally Fractured Reservoirs
Authors: Shahri Mojtaba Pordel , Mehrabi Mehran
Published: December 2012

Fracture ballooning usually occurs in naturally fractured reservoirs and is often mistakenly regarded as an influx of formation fluid, which may lead to misdiagnosed results in costly operations. In order to treat this phenomenon and to distinguish it from conventional losses or kicks, several mechanisms and models have been developed. Among these mechanisms under which borehole ballooning in naturally fractured reservoirs take place, opening/closing of natural fractures plays a dominant role. In this study a mathematical model is developed for mud invasion through an arbitrarily inclined, deformable, rectangular fracture with a limited extension. A governing equation is derived based on equations of change and lubrication approximation theory (Reynolds's Equation). The equation is then solved numerically using finite difference method. Considering an exponential pressure-aperture deformation law and a yield-power-law fluid rheology has made this model more general and much closer to the reality than the previous ones. Describing fluid rheology with yield-power-law model makes the governing equation a versatile model because it includes various types of drilling mud rheology, i.e., Newtonian fluids, Bingham-plastic fluids, power-law, and yield-power-law rheological models. Sensitivity analysis on some parameters related to the physical properties of the fracture shows how fracture extension, aspect ratio and length, and location of wellbore can influence fracture ballooning. The proposed model can also be useful for minimizing the amount of mud loss by understanding the effect of fracture mechanical parameters on the ballooning, and for predicting rate of mud loss at different formation pressures.
Comparative evaluation of the essential oil terpenoids in the stem and leaf of Ziziphora clinopodioides in the regions of Almeh and Sojough of Golestan province, Iran
Authors: Ebrahimi Pouneh , Mirarab-Razi Akram , Biabani Abbas
Published: December 2012

Microwave-assisted hydrodistillation was used to isolate essential oil from
the leaf and stem of Ziziphora clinopodioides collected in the flowering
stage on two locations, Almeh and Sojogh, of the Golestan Province (Iran), in
June of 2009. The total contents of monoterpene and sesquiterpene fractions
(52.45% and 1.08%, respectively) in the leaf oil of Almeh plants were higher
than those of Sojogh (46.64% and 0.12%, respectively). The essential oil of
the stem of the plants from Sojogh was characterized by the presence of eight
oxygenated monoterpenes (22.17%), while four oxygenated monoterpenes
(11.15%), one monterpene hydrocarbon (2.71%), and one oxygenated
sesquiterpene (0.21%) were found in the plants from the region of Almeh. The
analysis of the essential oil of dried aerial parts showed the presence of
oxygenated monoterpenes pulegone and menthol (the region of Sojogh) and
pulegone, 1,8-cineol, D-neoisomenthol and chrysanthenone (the region of
Almeh), as the main constituents. Also, chrysanthenone (9.75%), found as the
second major component of the leaf of Z. clinopodioides of Almeh, was not
identified as the oil component of the other region. The results obtained on
the chemical composition of Z. clinopodioides oil of two regions from the
Golestan Province revealed that in general, that there are some differences
in the major components and their relative concentrations. This may be
probably due to the different environmental and genetic factors, different
chemotypes and the nutritional status of the plants, as well as other factors
that can influence the oil composition.
A new detection tube to detect hydrogen cyanide in the air
Authors: Pitschmann Vladimír , Kobliha Zbyněk , Tusarová Ivana , Bártová Lucie , Vetchý David , Bobál Pavel
Published: December 2012

A new simple and sensitive detection tube to detect hydrogen cyanide in the
air has been developed. The detection tube is based on the reaction of
hydrogen cyanide with 4-nitrobenzil to form a violet colored product. The
reaction takes place on the carrier made of a composite material which was
prepared by pelletization of a mixture of microcrystalline cellulose and
MgO. The detection tube can detect hydrogen cyanide in the air in the range
of concentrations 0.1-100 mg.m-3 based on visual evaluation (by naked eye)
of the change of indication layer coloring and comparison with etalon. The
detection limit is 0.05 mg.m-3. The detection tube is highly selective and
sufficiently stable during storage.
Structural and productive-developmental characteristics of white willow plantations of different density on humogley in Donji Srem
Authors: Andrasev Sinisa , Vuckovic Milivoj , Bobinac Martin , Ivanisevic Petar , Stajic Branko
Published: December 2012

The study was conducted in two plantations of white willow (Salix alba L.) in
Donji Srem on the humogley soil type (hydromorphic black soil), which belongs
to a narrow-leaved ash forest with remote sedge (Carici remotae - Fraxinetum
angustifoliae Jov. et Tom., 1979). The plantations are located in the same
depression. The SP (sample plot)-1 plantation is 21 years old with a 6?6 m
planting spacing, and the SP-2 plantation is 27 years old with a 3?3m
planting spacing. Elements of stem growth in the SP-1 plantation showed that
with the white willow planting spacing of 6?6 m and a planned 25-year
production cycle it is possible to obtain about 250 m3?ha-1 of timber volume,
with an 80% net share of technical wood and a 20 % share of pulp wood. The
plantation in SP-2 is at the age, which is well above the optimum age in
terms of rational management, and the total volume at the age of 27 years is
about 300 m3?ha-1, with a 53.7% net share of technical wood and a 46.3% share
of pulpwood.
Critical analysis of the contemporary methods for estimating reference evapotranspiration
Authors: Djukic Vesna , Mihailovic Vladislava
Published: December 2012

Evapotranspiration is one of the most important processes within the
hydrological cycle whose reliable assessment is essential in the planning and
managing of land and water resources. Besides that, the water needs of plants
depend directly on the size of evapotranspiration. This paper presents a
comparison of reference evapotranspiration values calculated using the FAO
Blaney-Criddle method, the FAO Radiation methods, the FAO Penman and the FAO
56 Penman-Monteith method with the results of measurements of
evapotranspiration at the meteorological station in Kosutnjak during the
growing seasons of 2004, 2005 and 2006. It is shown that the application of
the FAO 56 Penman-Monteith equation provides the calculated values of
evapotranspiration that are closest to the results of measurement and it is
recommended to apply this method for the estimation of reference
evapotranspiration.
Modelling of base flows by analysing the streamflow hydrograph
Authors: Djukic Vesna , Mihailovic Vladislava
Published: December 2012

During dry periods, the flow of medium and small streams is significantly
reduced and equal to groundwater flow. Since the base flows provide
information about aquifer characteristics and retention characteristics of a
basin, the possibilities of analysis and simulation of base flows gain
importance under the conditions of intensive water use and the increasing
demand for adequate water quality protection. In this paper, a model was
established and used for the description of the principles governing the
changes of base runoff on the basis of a streamflow hydrograph registered at
the outlet of the basin on the example of the Kolubara basin up to the
?Valjevo? profile. Since the amount of base runoff from a basin cannot be
measured, the results of base flows obtained using the local minimum method
were adopted as the criterion for the comparison of the modelled values of
base runoffs. The created model was applied for making simulations of the
base runoff hydrograph during three characteristic years (rainy 1970, average
1985, and dry 1990). Deviations between the base flow values obtained using
the established model and by applying the local minimum method are acceptable
from the standpoint of general hydrological accuracy.
The impact of the top coating on the mechanical properties of lacquered wood surfaces
Authors: Jaic Milan , Palija Tanja
Published: December 2012

This paper investigates the impact of the top coating on the basic mechanical
properties of a lacquered surface, including indentation hardness, scratch
resistance and abrasion resistance. Three types of the top coating were used,
including a 2K polyurethane coating, a 2K acrylate-isocyanate coating and a
2K alkyd-urethane coating. Samples of two wood species, spruce (Picea abies
Karst.) and oak (Quercus robur L.), were used in this study, in order to
determine whether the wood species, which is not in direct contact with the
top coating, has an impact on the mechanical properties of a lacquered
surface. The samples coated with a 2K acrylate-isocyanate coating showed the
highest values of indentation hardness, in the samples of both wood species
(1.34 N for spruce; 1.4 N for oak). The samples coated with a 2K
alkyd-urethane coating showed the highest values of scratch resistance (20 N
for both wood species) and abrasion resistance (mass loss of 480 mg after 700
cycles for both wood species). The results have shown that the wood species
does not affect the value of indentation hardness, scratch resistance and
abrasion resistance of a lacquered surface.
Improvement of micropropagation protocol of Phalaenopsis sp. for the method of direct shoot regeneration from nodes of floral spikes
Authors: Markovic Marija , Tanasic Milos , Stojic Nevena , Bulatovic Radivoje , Jovic Marta , Vidojkovic Slobodan , Stankovic Dusan
Published: December 2012

This paper succesfully investigated the possibility of modification of the
micropropagation protocol of Phalaenopsis sp. with an aim to simplify the
procedure and reduce the costs. The obtained results show that some medium
components can be succesfully omitted (coconut water, glutamine,
2-morpholinoethanesulfonic acid) and some of them (peptone) can be replaced
with a cheaper constituent (soy flour) while preserving the quality of the
obtained microplants. The multiplication rate was 7,6 shoots per explant
after the period of 150 days of cultivation in vitro. On the same medium 60%
of explants were rooted and roots were mostly well developed.