Reservoir Engineering

Carbon dioxide capture, use, and storage (CCUS) issues are currently gaining more attention due to climate change. One of the CCUS methods may be the use of CO2 as cushion gas in underground gas storage (UGS). Typically, high-permeability structures are preferable for gas storage purposes. High permeability ensures good flow in reservoirs and well bottom-hole pressure maintenance. However, in the case of the use of CO2 as a part of the cushion gas, it mixes with natural gas within the reservoir pore space, and high permeability, with the resulting “ease of flow”, can accelerate the migration of CO2 to the near-well zone. For this reason, the analysis of the effect of permeability on CO2 content in withdrawal gas and the overall performance of UGS seems to be of high importance. In this study, we used a compositional numerical simulator to evaluate the effects of not only permeability but also pore structure on gas storage of this type. The simulations covered depletion of the reserv...

This paper presents the effect of liquid droplet injection on separation efficiency in a cyclone separator using a numerical procedure. As common cyclone separators (dry cyclone separators) unable to collect fine particles efficiently, the liquid droplets are injected into cyclone chamber, to improve separation efficiently of cyclone separators. The major focus is the study of the effect of liquid droplet injection, on the collection of particles with diameter smaller than 10 microns. The problem of isothermal flow-field in cyclone separators is formulated in terms of the Eulerian partial differential equations of the gas phase conservation of mass and momentum An algebraic Reynolds stress model (ASM), is also used to involve turbulence efefcts. A Lagrangian approach is employed to predict the trajectories of discrete phase (particles and droplets) in cyclone chamber. The effect of velocity fluctuations on separation efficiency is studied by use of instantaneous fluctuating velociti...

As so ci ate Ed i tor: Pawe³ Aleksandrowski Sys tem atic joints play an im por tant role in ef fec tive fluid con duc tiv ity and in the me chan i cal re sponse of shale res er voirs to hy drau lic frac tur ing. Spe cific fea tures of joints, such as their strata-bound as pect, and their at ti tude, com monly nor mal to bed ding, make it nec es sary to mod ify stan dard meth ods of their anal y sis from bore hole data. Our study, based on bore hole core and microresistivity im age logs, is ad justed to typ i cal ex plo ra tion pro ce dure, with ver ti cal bore holes pen e trat ing subhorizontal beds. This sim ple con fig u ra tion makes it pos si ble to mea sure the true height of most joints. We have used joint height as the weight ing pa ram e ter for the con struc tion of ori en ta tion di a grams and for com pu ta tion of frac ture in ten sity profiles. We also pro pose here a method for eval u a tion of frac ture ori en ta tion er ror on di rectly ori ented core, show how to dis tinguish joints pres ent in the scan ner re cord but ab sent from the core, and how to ap ply this kind of data fil ter ing to core/log cor re la tion. We also pro pose to ex tend the anal y sis of min er al ized joints by us ing the type and de gree of vein crack ing in order to better char ac ter ize their sus cep ti bil ity to hy drau lic stim u la tion. Ap pli ca tion of the mod i fied meth ods re vealed a strat i fica tion of joint dis tri bu tion which, in some cases, may not be ob served due to the scar city of joint data from bore holes.

Deepwater exploration and drilling pose many challenges and uncertainties to both explorationists and drillers. The entire cycle from prospect delineation to drilling management needs special attention, technology and expertise. Seismic data, integrated with well information is capable of deriving comprehensive and unified model consisting of structural framework, stratigraphic understanding, reservoir model, fractures, pore pressure, fracture gradients etc. that can be utilized not only for the exploration but also pre-drill and while drilling decision making. However, the major bottleneck in utilizing the full capability of seismic till now has been the integration of suitable technologies and feasibility in terms of turnaround times so that drilling time predictions could be made. Seismic Guided Drilling (SGD*), the technology of predicting ahead of bit uncertainties by integration of rock physics guided high definition seismic, suites of well logs and high -end checkshot technol...

As fracturing materials, fracturing fluid and proppant are two very important parameters in doing hydraulic fracturing design. The combination of fractuirng fluid and proppant selection is the main focus and determinant of success in the hydraulic fracturing process. The high viscosity of the fracturing fluid will make it easier for the proppant to enter to fill the fractured parts, so that the conductivity of the fractured well will be better and can increase the folds of increase (FOI) compared to fracturing fluid with lower viscosity (Economides, 2000). This research was conducted by using the sensitivity test method on the selection of fracturing fluid combinations carried out at the TX-01 well with various sizes of proppants (namely; 12/18, 16/20, and 20/40 mesh) with the proppant selected being ceramic proppant type carbolite performed using the FracCADE simulator. Fracturing fluid was selected based on its viscosity, namely YF240OD and PrimeFRAC20 fluids with viscosity value ...

Reservoir monitoring and intelligent completions require permanent downhole equipment to monitor and control wells with flow-control devices. Reliability qualification testing (RQT) is essential for these systems that are installed in a severe downhole environment. Reliability testing identifies weak links, measures progress, and builds confidence to avoid risks and surprises. Ten years of experience with downhole safety valves and permanent gauge installations show surprisingly similar reliability and testing problems to those experienced in automotive and aerospace applications. RQT provides an objective set of techniques to develop and deploy reliable long-life systems.

In this work, we have investigated the well pressure distribution in a bounded circular reservoir under the condition of constant pressure outer boundaries. The diffusivity equation was used in the analysis. The finite element technique, using Lagrange quadratic shape elements was employed to carry out the analysis over the cross-section of the reservoir which involves discretizing the domain into finite element, analysing these finite element, assembling the results from the analysis of the analysed finite element, imposing the boundary conditions and finally, getting the results that represent the entire domain. The results obtained where shown in a log log plot (dimensionless pressure against dimensionless time) for dimensionless radii of 1 to 1,000,000 in log cycles. It was shown that the relationship between dimensionless pressure and dimensionless time was linear whose slope was zero. The result obtained at the wellbore was compared with the results obtained by Van Everdigen and Hurst. It was shown that there was a strong positive correlation between the results. The result obtained from the analysis also shows the pressure variation outside wellbore of the same reservoir. It is important to note that solutions from existing literature only state the pressure at the wellbore at a particular time but this work predicts the pressure variation in the entire reservoir from the wellbore to the external boundary at the same time.

Plan of Development (POD) is an essential component of the long-term strategy aimed at ensuring the efficient operation of a hydrocarbon field. This is primarily because hydrocarbon production must meet the targets set in POD while management often desires to extract even more from the field. Therefore, the withdrawal strategy needs to be improved in order to enhance cumulative production and recovery factors. This led to the mapping of characteristics as well as the screening of the location of infill wells to determine the most functional areas in this research. The characteristic potential mapping was developed by combining saturation, pressure, and permeability. Meanwhile, appropriate locations were required to be selected to efficiently drain oil from the reservoir and this was achieved by designing the sector model to represent the real circumstances in the full-field of a particular region. Several scenarios were applied based on history to determine the best forecast for incremental production of hydrocarbon. Furthermore, a model was developed for both gas and oil fields and the simulation conducted showed its ability to determine the performance of the fields under several specific scenarios. The results showed that the optimum incremental production of gas was recorded in scenario 4 to be 353.2 MSCF at a recovery factor of 49.23% followed by scenario 5 with 353.2 MSCF and 49.22% respectively. Furthermore, the optimum increment production of oil was found in scenario 2b for infill drilling (production) to be 2.14 MMSTB at a recovery factor of 22.63% while the injection location was scenario 2bii as showed by 3.01 MMSTB and 25.64% respectively. It was also discovered that characteristic potential mapping was able to determine the optimum hydrocarbon cumulative and highest recovery factors in both reservoirs.

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This research presents an improved procedure for generating pseudo relative permeability curves for stratified waterflooding using either constant pressure or constant flux at the reservoir boundaries. Pseudo relative permeability reflects the generation of a relative permeability curve that can be used to represent the entire reservoir thickness, rather than a specific layer during reservoir simulation, thus saving computational time. In this project, Fractional Flow Theory is applied to the generation of pseudo relative permeability curves for i) constant flow rate condition, and ii) constant pressure boundary condition. Previously pseudo relative permeability curves were generated for the constant flow rate condition only. The method differs from previous methodologies and studies, which are all based on a piston-like displacement for water flooding. Instead, this new model uses fractional flow theory to generate a pseudo relative permeability curve that is physically more realis...

Planning for injection operation and determination of optimum time for acidizing an injection well require knowing the reservoir properties in the near wellbore. Conventional method to determine these properties is using two observation and one injection well, which is require ceasing the injection operation and spending more money and time. Based on performed studies, using daily production and injection data could be a proper solution to reduce expenses. In this paper, it has been tried to determine essential near wellbore properties such as formation skin, radius of damage and permeability of damage area using daily injection data including: pressure, injection rate and injection time. A new method to determine reservoir properties around the wellbore was devised by the application of injection process modeling. Finally, the developed method was applied to a real data of a water injection well in one of southern Iranian oil fields. In addition, the estimated data were validated c...

This paper reviews the applications of reservoir geochemistry from a reservoir engineering point of view. Some of the main tasks of reservoir engineering are discussed with an emphasis on the importance of appraising reservoirs in the pre-development stage. A brief review of the principal methods and applications of reservoir geochemistry are given, in the context of applications to reservoir engineering problems. The importance of compositional differences in fluid samples from different depths or spatial locations is discussed in connection with the identification of internal flow barriers. The importance of understanding the magnitude and origin of vertical compositional gradients is emphasised because of possible confusion with purely lateral changes. The geochemical origin and rate of dissipation of compositional differences over geological time is discussed. Geochemical techniques suitable for bulk petroleum fluid samples include GC fingerprinting, GCMS, isotopic and PVT measurements. Core sample petroleum extracts may also be studied by standard geochemical methods but with the added complication of possible contamination by drilling mud. Aqueous phase residual salt extracts can be studied by strontium isotope analysis from core samples. Petroleum fluid inclusions allow the possibility of establishing the composition of paleoaccumulations. The problems in predicting flow barriers from geochemical measurements are discussed in terms of "false positives" and "false negatives". Suggestions are made for areas that need further development in order to encourage the wider acceptance and application of reservoir geochemistry by the reservoir engineering community. The importance of integrating all available data is emphasised. Reservoir geochemistry may be applied to a range of practical engineering problems including production allocation, reservoir compartmentalisation, and the prediction of gravitational gradients. In this review applications where reservoir geochemistry is being used successfully are contrasted with those where applications are less well established.

This paper reviews the applications of reservoir geochemistry from a reservoir engineering point of view. Some of the main tasks of reservoir engineering are discussed with an emphasis on the importance of appraising reservoirs in the pre-development stage. A brief review of the principal methods and applications of reservoir geochemistry are given, in the context of applications to reservoir engineering problems. The importance of compositional differences in fluid samples from different depths or spatial locations is discussed in connection with the identification of internal flow barriers. The importance of understanding the magnitude and origin of vertical compositional gradients is emphasised because of possible confusion with purely lateral changes. The geochemical origin and rate of dissipation of compositional differences over geological time is discussed. Geochemical techniques suitable for bulk petroleum fluid samples include GC fingerprinting, GCMS, isotopic and PVT measurements. Core sample petroleum extracts may also be studied by standard geochemical methods but with the added complication of possible contamination by drilling mud. Aqueous phase residual salt extracts can be studied by strontium isotope analysis from core samples. Petroleum fluid inclusions allow the possibility of establishing the composition of paleoaccumulations. The problems in predicting flow barriers from geochemical measurements are discussed in terms of "false positives" and "false negatives". Suggestions are made for areas that need further development in order to encourage the wider acceptance and application of reservoir geochemistry by the reservoir engineering community. The importance of integrating all available data is emphasised. Reservoir geochemistry may be applied to a range of practical engineering problems including production allocation, reservoir compartmentalisation, and the prediction of gravitational gradients. In this review applications where reservoir geochemistry is being used successfully are contrasted with those where applications are less well established.

Maximum oil production can be obtained with more oil wells, but few optimal numbers of wells in good location reduces economic costs and increase recovery. In this work, The Norne field C-segment reservoir model in Eclipse software is used to study the effect of well placement. Six producers (while the four injectors remain the same as those of the base case) for two different well placement scenarios, 1 and 2, are located manually after identifying grid blocks with high oil saturation from an updated geological model. Insignificant variation in oil recovery factors, 1.3%, is obtained for the base case and the two scenarios. However, after taking into account the well costs, gas and water injection costs under reasonable economic assumption, the NPV results shows that scenario 2 with the highest NPV is considered to be more favourable.

India is a world agricultural power, the share of agriculture in GDP is 17.8%, agricultural employment represents 54.87% of total employment and the country is considered the second largest producer wheat and rice. But this advantage is facing several obstacles because India is likely to be severely affected by climate change. India is one of the FRXQWU\ ¶V most vulnerable to disasters around the world and many of its 1.2 billion people live in areas vulnerable to hazards such as floods, cyclones and droughts. In this work, we propose a model that highlights the impacts of climate changes (changes in temperatures and precipitations) on the production of wheat and rice. The results confirm the hypothesis according which the impact of climate changes in India are Important.

Az utobbi evtizedekben a sz ennyvizkezelesben keletkez ő iszap mennyisege folyamatosan novekszik. Az iszapkezel esi eljarasok kozo tt egyre inkabb el ő terbe kerulnek az energetikai es egyeb hasznositast lehet ő ve tev ő modszerek. A termikus iszapkezelesi eljarasokhoz kapcsolodo kutatas ok egyik legujabb terulete a mikrohullamu energiakozlesen alapulo modszerek fejlesztese es hatekonysag-vizsgalata. A munkank soran az elelmiszer ipari iszap alapanyag eseteb en vizsgaltuk a mikrohullamu energiakozles hatasat a biologi ai hasznositasi eljarasok el ő kezelesekent. A kutatasunk soran az iszapok szerkezeti valto zasainak es a biologiai lebontha tosaganak jellemzesere szolgalo mutatoknak a dielektromos jellemz ő kkel valo osszefuggeseit vizsgaltuk.

This paper describes a new method, the fluid properties estimation (FPE sM), that can be used at the wellsite to provide realistic predictions of PVT and physical properties of the reservoir fluid during testing. Simple and rapid measurements of key fluid properties and onsite compositional analysis of the produced fluid are input data for an equation-of-state (EOS)-based thermodynamic model. The simulator is tuned primarily by regression to match the measured data and is subsequently used to predict the phase behavior and PVT properties of fluids produced at reservoir, well, and surface conditions. The method, which is currently applicable only to oil reservoirs, has been successfully tested in several areas of the world. Examples given compare on-site FPE predictions with full PVT studies performed in the laboratory.

Elmqc7. S CHAPTER 3.-SPECIAL _CHARACTERISTICS OF C02 FLOODXNG 20 EMMRCES CHAPTER 4t MECHANI: SMS AND REPRESENTATION OF THE GlkS MISCIBLE MOODING PM)CZSS 4.1 Intrcduction 24 4.2 Ternary Representation of Phase Equilibrium 25 4.3 Quaternary Representation for Hydrocarbon-InJection Gas Mixture 30 REFE3UNCES PART I DEVEMPMENT OF A THEORETICAL MODEL TO PREDICT PHASE BEHAWOUR OF MULTICOt-WONENT GAS/OIL Ml:. V. IVMS Paqe C2DU? TER 5-. PMMICTION OF PHYSICAL PROPERTIES OF NMTICOMPONENT SYSTEMS 5.1 Methods of calculating Physical Propert, les 33 5.2 Methods Based on the Principle of Corresponding States 34 5.3 Methods Based on Molecular Thermodynamics 35 5.4 Methods Based on Equations of State 35 5.4.1 Thermodynamic Concepts of the EOS 35 5.4.2 The Van der Waals EOS 41 5.4.3 EOS Used in This Study 42 5.4.4 The Peng-Robinson EOS 43 5.4.5 The Modified Soave Redlich Kwang EOS 44 5.4.6 The Modified Redlich Kwong BOS 45 CHAPTER 6.-5.5 ApplIcation of the EOS to Mixtures 47 REFERENCES

Узагальнено результати польових інженерно-геологічних, топографо-геодезичних, гідрологічних, еколого-гідробіологічних, санітарно-гігієнічних і гідрохімічних досліджень Щирецького водосховища. Розглянуто особливості природних умов району дослідження із особливою увагою на вивчення гідрологічних умов водозбору р. Щирка. Проаналізовано гідрохімічний і санітарно-гігієнічний стан Щирецького водосховища. Виявлено джерела забруднення та оцінено сучасний гідроекологічний стан водойми та прилеглої до неї території. Досліджено різноманіття і структуру угруповань безхребетних гідробіонтів, водяних і повітряно-водяних мактофітів. Оцінено ступінь антропогенного навантаження на водосховище та його околиці. Обґрунтовано пропозиції й рекомендації першочергових заходів із ліквідації та зменшення негативного впливу на водойму в умовах рекреаційного використання.

Для екологів, географів, гідрологів, науковців природничого профілю, краєзнавців, працівників органів виконавчої влади, представників органів місцевого самоврядування, викладачів і студентів природничих спеціальностей і всіх, хто небайдужий до стану довкілля.

Геоекологія Щирецького водосховища / Андрейчук Ю., Біланюк В., Бота О. та ін. / за заг. ред.. Є. Іванова та О. Пилипович. Львів: Львівський національний університет імені Івана Франка, 2024. 116 с.

Автори: АНДРЕЙЧУК Юрій, БІЛАНЮК Володимир, БОТА Олег, ГОЛУБЄВ Юрій, ДАНИЛИК Іван, ДУМИЧ Оксана, ЖОВТЯНСЬКИЙ Олександр, ІВАНОВ Євген, КРУТА Наталія, КУЗЯРІН Олександр, МИКІТЧАК Тарас, ПИЛИПОВИЧ Ольга, САХНЮК Ірина, ЧОРНИЙ Володимир.

The Ekofisk reservoir is a high porosity, low matrix permeability naturally fractured chalk. Fluid flow is largely governed by the distribution, orientation, and interconnectivity of the natural fracture system associated with complex structure and reservoir distribution. Because of the impact heterogeneity has on preferential fluid-flow direction, significant attention was given to capturing as much of the intrinsic heterogeneity as possible, both laterally and vertically, in the new three-dimensionally geological model. A non-uniform simulation mesh was defined for the fluid-flow model with a grid size of 450 ftϫ450 ft in the crestal area of the field and increasing towards the flanks. A flow-based upscaling technique was then applied to preserve the heterogeneity from the geological to the fluid-flow model. Because of the complexity of the Ekofisk field, with its numerous faults and fracture networks, anisotropy was one of the primary attributes calibrated to achieve an individual well and field history match. However, faults and fault sealing factors, vertical permeability, pseudorelative permeability curves, bubblepoint pressure correlations, local permeability, and rock compressibility were also key parameters in the history match, and are presented in this paper. A brief discussion on the preliminary implementation of water-induced compaction is included.

In this first Chapter, the terminology used in well testing and interpretation is presented, and different testing procedures are explained. In the second part, characteristic well pressure behavior is illustrated, and the corresponding analysis methods are introduced. It is shown that well test responses follow chronological characteristic behavior at different times, depending upon the well and reservoir configuration. The interpretation techniques are presented in detail in the following Chapter 2. 1.1 Principles of transient testing When the well is shut-in, the build-up pressure change Ap is estimated from the last flowing pressure p(At=O):

SUMMARY Traditional reservoir simulation and modeling is a bottom-up approach. It starts with building a geological model of the reservoir followed by adding engineering fluid flow principles to arrive at a dynamic reservoir model. The dynamic reservoir model is calibrated using the production history of multiple wells and the history matched model is used to strategize field development in order to improve recovery. Top-Down Intelligent Reservoir Modeling approaches the reservoir simulation and modeling from an opposite angle by attempting to build a realization of the reservoir starting with well production behavior (history). The production history is augmented by core, log, well test and seismic data in order to increase the accuracy and fine tune the Top-Down model. The model is then calibrated (history matched) using the most recent wells as blind dataset. Although not intended as a substitute for the traditional reservoir simulation of large, complex fields, this novel approa...

Reservoir characterization plays a critical role in appraising the economic success of reservoir management and development methods. This study identifies the different rock types that comprise reservoirs, marginal reservoirs and non-reservoirs. Porosity and permeability are the key parameters for identifying the rock types and reservoir characterization. The qualification of these parameters is usually measured directly from cores using conventional core analysis methods, and indirectly using geophysical well logs, well tests, and artificial neural network methods. However, for determination of rock types and reservoir evaluation, in addition to quantity of porosity and permeability we need to determine pore geometry and pore aperture size which are related to grain size, sorting and packing as well as to factors such as the mineralogy and diagenetic history of the reservoir. This paper presents the results of a combination of conventional core analysis, capillary pressure curve ch...

Dalam proses pendistribusian minyak mentah, sering dijumpai adanya masalah yang dapat mengganggu aliran fluida yang melewati pipa. Salah satu problematika yang sering terjadi pada proses pendistribusian crude oil adalah terbentuknya endapan yang disebut scale. Scale adalah hasil pengendapan mineral yang berasal dari air formasi yang terproduksi bersama minyak dan gas. Scale didefinisikan sebagai suatu deposit dari senyawa-senyawa anorganik yang terendapkan dan membentuk timbunan kristal pada permukaan suatu substansi. Penyebab langsung terbentuknya scale adalah penurunan tekanan, perubahan temperatur, dan bercampurnya dua macam mineral yang susunan mineral yang dikandungnya tidak saling cocok. Adanya scale menimbulkan banyak masalah dalam proses produksi minyak dan gas karena dapat mengganggu proses pendistribusian fluida, disamping itu biaya yang harus dikeluarkan untuk keperluan pembersihan dan pencegahannya juga tinggi. Pencegahan terbentuknya scale di lapangan minyak khususnya d...

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In the complex field of carbonate reservoir evaluation, the intricate structural features present significant obstacles. This study tackles the essential task of structural delineation, with a particular focus on fractured reservoirs, and highlights the crucial influence of permeability on the performance of wells and reservoirs. The Oil Based Mud Micro-Imager - resistivity of invading zone (OBMI-Rxo) offers a high-resolution curve that is sensitive to fluid mobility near the borehole wall, although it is often underexploited by oil companies. Maintaining borehole stability after drilling is critical for ensuring the longevity of wells. This research introduces a holistic workflow that combines borehole imagery, petrophysical logs, the Modular Formation Dynamics Tester (MDT), Xpress Pressure Tool (XPT), and core samples for sophisticated formation evaluation in both carbonate fractured and clastic reservoirs. The study reveals new insights into reservoir structure, fracture detection, visualization of rock texture, and permeability distribution, thereby improving our understanding of well conditions in these challenging geological environments.

Production data analysis has extensively been applied to predicting the future production performance and field recovery. These applications are mostly on a single well basis. This paper presents a new approach to production data analysis using Artificial Intelligence (AI) techniques where production history is used to build a field-wide performance prediction models. In this work AI techniques and data driven modeling are utilized to predict future production of both synthetic (for validation purposes) and real field cases. In the approach presented in this article production history is paired with geological information from the field to build datasets containing the spatio-temporal dependencies amongst different wells. These dependencies are addressed by compiling information from Closest Offset Wells (COWs) that includes their geological and reservoir characteristics (spatial data) as well as their production history (temporal data). Once the dataset is assembled, a series of ne...

One of the key factors that analysts consider when calculating the economics of oil field development is the amount of oil in place (OIP). Conventional methods used for its estimation have some features affecting their predictive capabilities and applications. In addition, Oil bidders have limited time to evaluate and rank reservoirs from complex and large reservoir data packages - which sometimes fees are paid for their access. In this study, data-driven machine learning models - artificial neural network (ANN), support vector regression (SVR) and multiple linear regression (MLR) were developed for quick estimation of OIP for oil rim reservoirs in the Niger Delta. The models were evaluated using statistical error tools, and the results showed reasonable predictions. The sensitivity analysis performed on the selected input parameters showed that areal extent has the greatest impact on the estimation of the OIP with 29.94 %, oil formation volume factor has 22.74 % impact, oil column ...

Summary Under currently known reservoir drive mechanisms, initial exploitation of a new field usually leads to drilling in several regions of the field for optimum production. As the field matures, it often is necessary to drill new wells to recover oil reserves trapped because of undetermined reservoir heterogeneity and not acknowledged during initial field development. Targeting new wells in a mature field is challenging because it calls for consensus among interdisciplinary groups (reservoir and production engineers, geoscientists, and drilling and facility engineers). The challenges usually involve estimating the cost and production of the new wells and finding convincing arguments that the existing wells will not drain the trapped reserves adequately. This paper provides a team approach to confront these challenges to target new wells in the mature Prudhoe Bay field. The field example shows that additional oil recovery was obtained with infill drilling. Introduction The large, ...

To analyze the economic viability of Pelican Lake field, located in Canada, some scenarios using enhanced oil recovery methods were simulated by request of the field operator, Canadian Natural Resources Limited. Surfactant concentrations influence essential characteristics responsible for promoting good recovery, lowering interfacial tension of fluids and aiding oil bank mobility. Considering different polymer and surfactant concentrations in the injection water and using the PumaFlow software, 5 (five) scenarios of fluid injection were simulated. Results show that the oil recovery factor is directly proportional to the concentration of chemical agents. Among the injection tests carried out, the one with the best performance was the case presenting a concentration of 1400 ppm of polymer and 3000 ppm of surfactant in the injected water, allowing a larger oil production from the field. The case presenting the best outcomes had a 50% higher net present value if compared to the water injection case, as well as an increase of 4.85 percent points in the recovery factor. In addition, for each barrel of additional oil produced, only USD 8.18 is spent on chemical agents, which makes it a cost-effective solution to oil production.

The minimum miscibility pressure (MMP) is one of the critical parameters needed in the successful design of a miscible gas injection for enhanced oil recovery purposes. In this study, we explore the capability of using the Gaussian process machine learning (GPML) approach, for accurate prediction of this vital property in both pure and impure CO2-injection streams. We first performed a sensitivity analysis of different kernels and then a comparative analysis with other techniques. The new GPML model, when compared with previously published predictive models, including both correlations and other machine learning (ML)/intelligent models, showed superior performance with the highest correlation coefficient and the lowest error metrics.

Simple correlations have been developed for evaluating the primary recovery factor for thin oil rims with large gas caps prior to detailed reservoir simulation. The correlations are based on oil recovery factor estimates obtained from three dimensional, three-phase black oil reservoir simulation models for saturated reservoirs with overlying gas caps at their initial state, which capture spatial effects and the dynamics of oil rim and gas cap production. Dominant factors (oil rim thickness, horizontal permeability, gas cap size, oil viscosity, gas cap offtake, aquifer strength and reservoir dip) that affect oil rim and gas cap production were obtained using foldover Plackett-Burman screening designs. Response Surface Models (correlations) were then developed using BoxBehnken experimental design to obtain oil recovery estimates under conventional development and concurrent development at gas cap production up to 15% of the free gas initially in Place per annum. The oil recovery facto...

One of the major problems associated with history matching is the non-uniqueness of the solutions. A major flaw in this traditional history matching is that it lacks robustness as it shows a bias to the production data being matched while neglecting the mechanics governing other production data and such solutions generated are erroneous and gives a poor representation of the reservoir being matched.In this study, data driven and numerical modeling of a synthetic PUNQS3 reservoir were carried out. Single objective function, aggregated and multi-objective functions were adopted for the reservoir history matching. A proxy model was developed with data generated from a reservoir simulator using Artificial Neural Network (ANN) and the Response Surface Methodology (RSM). Firefly Optimization (FFO), Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) algorithms were used for the history matching process.The results showed that the history matching process was strongly influenced b...

Практикум составлен в соответствии с программой курса «География почв с основами почвоведения». Включает методические рекомендации к практическим и лабораторным занятиям, управляемой самостоятельной работе студентов. Адресован студентам географического факультета

Bendo dam is a multi-purpose dam which used as a flood control, irrigation, raw water, also tour place. Moreover, in this study intends to know the safety of initial dam planning and determine the effect of the spillway elevation on flood attenuation in the Bendo Dam with discharge planned. In this research is fully calculated the maximum flood discharge also the safe freeboard and compare the amount of inflow and outflow in different elevation. This analysis used unit hydrograph synthetic nakayasu as a design discharge calculation and newton raphson method as a flood routing calculation. The location in this analysis is taken at Bendo Dam Ponorogo. The data needed in this calculation was rainfall data from 1996 until 2016 in Ponorogo area also earth map in Ponorogo area from internet. In this analysis, will be calculated effect of flood attenuation with the increasing of spillway 2 m, starting from 214.6 m until peak dam are 224 m. The result of this analysis, spillway elevation ar...

In the oil province of southern Iran like other hydrocarbon zones, thorough understanding and risk management resulting from the rock mass deformation, can be of great help in executing operational processes such as the stabilization of the borehole wall, controlling the sand production in the borehole and hydraulic fracture. In oil well excavation operations, determining maximum and minimum horizontal stresses helps in designing the excavation route in the minimum stress direction so that collapsing of the borehole wall and drilling tube blockage against the rocks is avoided. The aim of this study was removing the main excavation problems especially of the diversion wells through exact geomechanical calculations in the Darian lime formation depth range in the understudy field. In order to develop the geomechanical model, first the bulk, the shear and the Young's modules, the Poisson coefficient and Vp/Vs ratio were calculated using the visual log data integrated with the geomec...

The cost of chemicals prohibits many technically feasible enhanced oil recovery methods to be applied in the oilfields. This research produced surfactants from phenols that were extracted from the pyrolysis oil of oil palm shells which are a byproduct of the palm oil industry. Xanthans which are imported can be produced from many available local sources such as starches and fruits. All of the additives produced were tested for enhanced oil recovery use and were found to have suitable properties. The recoveries for surfactant polymer flooding measured in the laboratory were comparable with the values reported in literature i.e. between 7 to 15 %. This work has proved that expensive chemicals can be produced locally using local sources and byproducts, consequently posing a potential savings in EOR processes. assistance during the course of the project completion. Last but not least to all the Research Management Centre staff who has laid their helping hands throughout the project. CHAPTER 1 INTRODUCTION 1.1 Overview 1.1.1 Introduction on enhanced oil recovery (EOR) Enhanced oil recovery (EOR) refers to reservoir processes that recover oil not produced from secondary processes. Primary recovery uses the natural energy of the reservoir to produce oil and gas. Secondary recovery uses injectants to re-pressurize the reservoir and to displace oil to producers. Enhanced oil recovery processes target what is left. The processes focus on the rock/oil/injectant system on the interplay of capillary and viscous forces (Stosur, 2003). There are many types of EOR processes. Thermal processes are the most common type of EOR, wherein a hot invading face, such as steam, hot water or a combustible gas, is injected in order to increase the temperature of oil and gas in the reservoir and facilitate their flow to the production wells. Another type of EOR process consists of injecting miscible phase with the oil and gas into the reservoir in order to eliminate the interfacial tension effects. The miscible phase can be miscible hydrocarbon, CO 2 or an inert gas. Another lesser used EOR technique is called chemical flooding, where chemicals are Flow direction Surfactant polymer flooding is shown in Figure 2.1. The various regions of immiscible flow during a typical displacement of oil by a surfactant solution are illustrated. The various zones are described as: Region 1: Water flooded residual oil saturation; only water is flowing. Region 2: An oil bank is formed; both oil and water are flowing. Region 3: Surfactant slug forming the low IFT region, two or three phase flow of oil, brine, and microemulsion depending on the actual phase behaviour. Region 4: Polymer solution for mobility control, single phase flow of water.

This paper presents an application of uncertainty quantification to numerical reservoir simulation using the Sparse Probabilistic Collocation Method (SPCM). Reservoir simulation is used in several phases of the development and exploitation of a field, from the initial planning of the production strategy to sophisticated automated control schemes that schedule the operation of well controls on a daily basis in smart fields. It basically consists of solving numerically the complex nonlinear partial differential equations (PDEs) that models the fluid flow in porous media. The petrophysical properties of the rock matrix determine the coefficients in the PDEs and associated algebraic system of equations. Due to technological and economic constraints, the available data to determine these properties is scarce and subject to human interpretation. This problem becomes even more important for offshore fields, where wells are kilometers apart, the reservoirs several kilometers underground, there are very few wells and there is very little or no production history. The petrophysical properties are therefore very uncertain, and can be described only in a probabilistic manner. The simulation can no longer be considered deterministic, since uncertain inputs leads to uncertain results. Uncertainty propagation techniques become necessary tools for the robust and reliable application of numerical reservoir simulation. In the probabilistic collocation method, statistics of the uncertain output are computed directly through numerical integration, based on efficient quadrature rules like Gauss and Clenshaw-Curtis. However, this method is not suitable for dealing with high-dimensional models, because it suffers from the "curse of dimensionality". Sparse grid integration techniques can be used with the probabilistic collocation method to alleviate this problem, creating the sparse probabilistic collocation method. We present our implementation of the SPCM and apply it to estimate the statistics of uncertain variables such as the cumulative oil production and water breakthrough date, using a simple but realistic reservoir model. Comparisons of the efficiency of this technique against classical methods such as Monte Carlo are shown, as well as a discussion on the necessary computational resources for this kind of analysis and it's practical use.

Waduk Gondang mempunyai fungsi utama sebagai penyedia air untuk kebutuhan irigasi selain itu juga untuk pemenuhan kebutuhan air baku yang masyarakatnya sangat bergantung pada keberadaan Waduk Gondang ini terutama pada waktu musim kemarau. Waduk Gondang mempunyai kapasitas tampungan efektif 23,7 x 10 6 m 3. Tesis ini hanya menganalisi fungsi irigasi saja. Melalui tesis diharapkan dapat memperbaiki pola operasi waduk sehingga dapat meningkatkan intensitas irigasi dan keuntungan irigasi yang optimal. Daerah irigasi Gondang mempunyai 3 (tiga) musim tanam dengan 5 (lima) pola tata tanam antara lain Padi

Exploration of six decades in Bengal Basin resulted in a discovery of oil & gas in Mio-Pliocene sequence in a well in study area. Earlier findings were indication of hydrocarbons from different sequences viz. from basal Oligocene sand of Well-C and fractured Eocene limestone of wellK in the vicinity of Hinge zone area. The current study focuses on integration of G&G data, to analyze the spatial and temporal distribution of reservoir sand associated with current discovery. Pay zone (gas and oil pay tops equivalent to MioPliocene age) surfaces were mapped equivalent to hydrocarbon findings in well. Mixing of two channel systems has been established based on RMS amplitude, Sweetness and Amplitude Envelope attributes at gas pay level, indicator of stratigraphic entrapment for hydrocarbon. Impedance log/Impedance map shows lowering of impedance in Pay-zones. AVO analysis has also been carried out to characterize the gas sand which indicated class-IIP AVO anomaly. Post Stack Inversion sho...

The Upper Miocene lacustrine sandstones of the North Croatian Basin, located in the southwestern Pannonian Basin System, represent significant reservoirs for hydrocarbon exploration, yet their diagenetic evolution remains poorly understood. This study offers a comprehensive investigation into the diagenesis of these sandstones, analyzing samples from 14 exploration wells in the Sava and Drava depressions. Using petrographic analyses, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and petrophysical measurements, we aimed to explain the diagenetic processes affecting reservoir quality and hydrocarbon productivity. Our results reveal a consistent grain size distribution, modal composition, and diagenetic alterations across both depressions. Compaction, evidenced by evolving grain contacts and pressure dissolution, leads to a depth-dependent reduction in porosity. Carbonate cements, notably calcite and Fe-dolomite/ankerite, are primary contributors to reduction of primary intergranular porosity, alongside clay minerals, quartz, feldspar, etc. Secondary porosity resulting from dissolution and redistribution processes also significantly influences overall porosity evolution. Clay minerals, detrital and authigenic, exhibit a complex interplay with other diagenetic processes, further reducing porosity and permeability. Authigenic clay minerals, including illite, chlorite, and kaolinite, act as pore-filling cement or coatings, hindering fluid flow. Paragenetic processes delineate the intricate relationship between mineralogical transformations and petrophysical properties, defining reservoir quality. Understanding diagenetic dynamics is essential for predicting reservoir quality, fluid migration pathways, and hydrocarbon productivity. This study fills a crucial knowledge gap regarding the diagenesis of the Upper Miocene lacustrine sandstones in the southwestern part of the Pannonian Basin System, providing insights vital for the energy sector and supporting sustainable resource development in the region.

The aim of this paper is to present an integrated design procedure for plastic part development and manufacture. Reverse engineering (RE), reengineering (ReE) and mold design have been incorporated to infuse agile characteristics in the proposed design and development process. The integration of RE and ReE presented in this paper accelerate the design process and provide information necessary for complete injection molding process of plastic parts. The purpose is to create a new object geometrically similar to the existing object. The new object must have better mechanical properties and more favorable geometry from the standpoint of mold ability. This paper also, describes a methodology for quality geometry check of the manufactured part that is need for verified the used integrated CAD/CAE technologies.