bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Scenario for the Creation of H2S Heterogeneities in Acid Gas Reservoirs in Contact with an Active Aquifer: a Simulation Study
Authors: Bonnaud E. , Dessort D. , Lagneau V. , Chiquet P. 
Published: November 2012

Abstract
Compositional heterogeneities of H2S have been noticed in many sour gas reservoirs. Its occurrence is an important factor of economic depreciation. Thus, the knowledge of its content and distribution is a critical parameter when planning field development. The paper aims at exploring the role of an active aquifer in the creation of H2S heterogeneities in high H2S-bearing gas reservoir. Indeed, under conditions of pressure and temperature of typical reservoirs, H2S is far more soluble than hydrocarbons and other gases. A preferential leaching of H2S (e.g. versus CH4) over time is thus possible.
This mechanism is controlled by: (1) Differential solubility of gases, which change the relative amounts of each gas near the gas-water contact (GWC); (2) Contact with an active aquifer, which can export the dissolved gases thus enhancing dissolution on the long-term; (3) Diffusional transport in the gas phase, which transfers the compositional anomalies farther from the gas-water contact; (4) Geological parameters (type of aquifer, permeability heterogeneities) which can modify the transport scenario.
To illustrate and quantify this process, we show the results of numerical simulations, performed with the two-phase transport and geochemical software Hytec. First, a very schematic reservoir with a composition considered uniformly distributed within the reservoir, has been simulated to quantify the leaching of H2S. The results highlight the potential role of the active aquifer, which can leach the gases and export them outside the reservoir. In a second phase, the effect of geological parameters on the H2S heterogeneity development was studied: additional simulations were performed on geometries closer to natural cases. The amount of leached H2S depends strongly on the geometry: the larger the GWC area, the larger the amounts leached.
Four-Fluid-Phase, Fully Implicit Simulation of Surfactant Flooding
Authors: Patacchini Leonardo , Loubens Romain de , Moncorgé Arthur 
Published: November 2012

Abstract
The Microemulsion phase behavior model based on oleic-aqueous-surfactant pseudo-phase equilibrium, commonly used in chemical flooding simulators, is coupled to Gas-Oil-Water phase equilibrium in our new four-fluid-phase, fully implicit InHouse Research Reservoir Simulator (IHRRS). The method consists in splitting the equilibrium in two stages, where all the components other than surfactant are equilibrated first (e.g. using a black-oil, K-value or equation of state model), and the resulting Gas, Oil and Water phases are then lumped into pseudo-phases to be equilibrated using the Microemulsion model. This subdivision in stages is conceptual, and at each converged time-step the four phases (Gas, Oil, Water and Microemulsion, when simultaneously present) will be in equilibrium with each other.
The fluid properties (such as densities, viscosities and interfacial tensions) and rock-fluid properties (such as relative permeabilities), required in the transport equations, are evaluated with models from well-known industrial or academic simulators. Surfactant flooding being usually implemented as a tertiary recovery mechanism, on fields for which complete models that we do not wish to modify already exist, particular care is devoted to ensuring continuity of the physics at the onset of surfactant injection.
Our code is validated against a reference academic chemical flooding simulator, on 1D corefloods where the original hydrocarbons in place form a dead-Oil phase, possibly with free dry-Gas. Some numerical aspects of our implementation such as numerical dispersion versus time-step size and nonlinear convergence performance are also discussed. As an application example of our code where it is necessary to account for four phases in equilibrium, we consider a scenario where the chemical flood is preceded by a vaporizing Gas drive.
Improving Waterflood Recovery Efficiency in Carbonate Reservoirs through Salinity Variations and Ionic Exchanges: A Promising Low-Cost "Smart-Waterflood" Approach
Authors: Zhang Yi , Sarma Hemanta 
Published: November 2012

Abstract
Our recent study demonstrates significant improvement in waterflood recovery efficiency could be possible in carbonate reservoirs through adjusting the salinity and/or ionic composition of injecting brine, and hence, this approach holds a huge potential to enhance oil recovery from the carbonate reservoirs in the UAE and elsewhere at a much lower cost while freeing up cleaner and greener hydrocarbon gases for other use.
A set of comprehensive tests using carbonate rock have been completed to estimate displacement efficiency, assess wettability variation through wettability monitoring, optimize brine composition vis-à-vis the oil recovered and to explore and better understand the possible mechanisms that are at play. Tests were conducted at temperature ranging from 70°C to 120°C to mimic the UAE reservoir conditions to the extent possible. For both coreflood and wettability monitoring tests, salinity and composition variations were tested on the injection brines, seawater and formation water. In addition, certain mechanisms at play have been identified. Although the research on this approach is still in progress, the following key findings have been noted to date and they appear to have a direct relevance towards improving oil recovery from several UAE carbonate reservoirs:
Reducing water salinity and increasing sulfate concentration of the injection brine could mobilize a significant amount of extra oil beyond the conventional seawater and formation water injection at both 70 ° C and 120 °C. At 70 °C, lowering the water salinity was more effective than raising the sulfate concentration in injection water in terms of incremental oil recovery after secondary conventional waterflood, whereas they exhibited similar potential at 120 °C. And at 70 °C, wettability alteration towards less oil-wetness could be triggered by low salinity water. The process was sensitive to temperature. Lowering water salinity and raising sulfate concentration of the injection water at 120 °C led to a much higher incremental oil recovery than that at 70 °C. At 90 °C, water-wetness of our carbonates could be enhanced by either reducing water salinity or increasing sulfate concentration of the surrounding water. However, the divalent cations in the surrounding water had limited effect on rock wettability. During low salinity water injection process, oil production was usually accompanied with pressure difference increase.
Successful Case Histories of Smart Multilateral Well with Inflow Control Device and Inflow Control Valve for Life-cycle Proactive Reservoir Management in High Mobility Reservoir, Minagish Field West Kuwait
Authors: Al-Enezi Khalaf , Das Om Prakash , Aslam Muhammad , Ziyab Khaled , El-Gezeeri Taher 
Published: November 2012

Abstract
Advanced smart multilateral wells with extended reservoir contact from a single well location have accelerated sustained oil production and increases hydrocarbon recovery from ultra-high water mobility oil-wet Burgan reservoir in Minagish Field West Kuwait. Further the smart multilateral wells have proven to be a great tool for adequate proactive reservoir management and production management without well interventions. The Burgan reservoir has active aquifer, very high permeability sands associated with active faults and contain highly viscous reservoir fluid with downhole viscosity of more than 40cp, enhance water mobility and resulted in premature water breakthrough with increasing water cut trend within few months of production in existing horizontal wells. This has resulted into non-uniform reservoir depletion, by-passed oil regions and low oil recovery. The smart level-4 multilateral wells were successfully designed and implemented in Burgan reservoir by combining the reliable Level-4 junction along with stacked dual lateral completion having customized viscosity independent Inflow Control Device (ICD), customized two Inflow-Control Valves as well as down hole gauges, wide operating range Electrical Submersible Pump (ESP), suitable wellheads, X-MAS tree and Integrated surface panel for real time data monitoring first time in Kuwait. The improved production performance of smart multilateral wells in Burgan reservoir of Minagish Field, West Kuwait have achieved appropriate production management through flow regulations across laterals and adequate reservoir management with the combination of inflow control device as well as inflow control valves along with downhole pressure temperature gauges. Moreover the smart multilateral wells have enhanced sustained oil production, maximizes hydrocarbon recovery at lowered capital and operational expenditure resulted in improved economic performance of reservoir with significant increase in net present value (NPV). The paper covers the successful implementation of smart multilateral wells and its effectiveness in achieving the life-cycle production management as well as proactive reservoir management supported with actual well performance results. Further the paper details about the economic benefits of smart multilateral wells and its contribution in improving the economic performance of Burgan reservoir of Minagish Field, West Kuwait.
Design Challenges of Chemical EOR in High-Temperature, High Salinity Carbonates
Authors: Levitt D. , Klimenko A. , Jouenne S. , Chamerois M. , Bourrel M. 
Published: November 2012

Abstract
The optimization of chemical floods for a low-permeability, high-salinity, high-temperature carbonate formation presents several unique design challenges, which may be overlooked in short coreflood experiments. Low permeability formations require the optimization of polymer molecular weight distribution such that both mobility reduction and injectivity are maximized. Mitigation of emulsion issues - possibly related to high surfactant adsorption - requires the optimization of surfactant concentration and slug size. The effects of high core-scale heterogeneity must be understood and mitigated, for example, by increasing core length. These subjects are explored in the context of an ongoing flood design project. Additionally, an attempt is made to shed light on the discrepancy between available carbonate capillary desaturation curves for carbonates and the near-complete recovery reported in surfactant-polymer corefloods.
Derivation of Kinetic Rate Constant of Enzyme-Buffer Mud Cake Clean Up Systems - Laboratory Investigation and Verification in High Temperature Fractured Carbonate Reservoir
Authors: Mehtar M. A. , Kasam Y. , Al-Aleeli A. , Ghosh B. , Ghosh D. , Chaudhuri B. 
Published: November 2012

Abstract
Horizontal wells enable drainage from a longer wellbore which helps to allow lower drawdown rate compared to vertical wells, minimizing gas or water coning. However productivity can be seriously affected unless mud cake damage is efficiently removed from all producing intervals along the horizontal wellbore. In recent years eco-friendly and non-corrosive bioenzymes (α/β-amylase) have shown great potential in cleaning wellbores uniformly and achieving higher well productivity. However in a low pressure fractured reservoir, there is always a possibility of localized reaction and loss of the clean-up fluid, unless the reactivity of the fluid is engineered based on the given well parameters.
In this study α-amylase enzyme is modified to withstand higher thermal shock by structurally reinforcing the β-Helix layer to strengthen the catalytic centre by preferential protein hydration technique. Buffering was done to maintain different system pH and kinetic rate constant is derived through reducing sugar release measurement by DNS method using starch-xanthan gum-CaCO3 based drill-in-fluid as substrate. Though the overall reaction is extremely complex, a good correlation could be drawn between system pH and the rate of breaking mud cake into simple sugar. The kinetic rate constant index is used in final formulation of enzymatic clean up fluid for application in high temperature (110 °C) long horizontal wells drilled in carbonate formation, which allowed different soaking time due to operational constraints. The results show that there is excellent correlation between laboratory prediction and clean up efficiency in terms of well productivity.The study showed that each individual well demands a specific formula for clean-up fluid and higher than prognosed production could be achieved through custom formulation, based on well condition and operational requirement.
Production Optimization and Zonal Allocation for Auto Gas Lift Wells: A Case Study from Oman
Authors: Al-Ruheili Sharifa , Angelatos Mathew , Nair Sujith , Peringod Chandran , Sonti Kartik , Karacali Ozgur 
Published: November 2012

Abstract
In Auto gas-lifted wells, gas from either a gas zone or gas cap is used to lift oil in a commingled way. Balancing gas zone energy depletion to the benefit of oil production requires an accurate understanding of zonal contribution and an ability to adjust and control inflow from both zones.
A project was undertaken for accurate zonal allocation and optimization of lift gas rates by designing an appropriate zonal contribution measurement procedure for five Auto gas-lifted wells on two fields. This approach utilized both production logging and production testing to obtain both zonal down hole and commingled surface flow measurements. As a result of the exercise, lift gas flow into the tubing was optimized, thus maximizing the oil production rate while conserving reservoir energy through efficient gas usage.
Measurement of zonal contributions in multi-zone intelligent well completions are often challenging due to the complex nature of fluid flow under varying dynamic conditions of multiple reservoirs. This paper will explain the zonal contribution measurement program design, implementation, interpretation of data and lessons learnt from the project.
Trial of Multiphase Flow Meters for Remote Well Head Towers
Authors: Challa Raj Sekhar , Ismail Jawed , Karim Amin Alaa Abdel 
Published: November 2012

Abstract
Well testing on remote unmanned wellhead platforms (WHPTs), especially those with marginal wells is a challenge. On some of these remote WHPTs, currently well testing is done using a test separator installed on a supply boat. This method of testing the wells involves lot of manual intervention and is a time consuming activity with various activities which are sometime quite hazardous. In view of new field developments plans to increase production and to have more frequent and longer duration testing, an initiative was taken to look at the option of installing multiphase flow meters (MPFMs) on such well head towers which do not have well testing facilities. Accordingly, one MPFM each was installed on separate WHPTs.
By installing the MPFMs, ZADCO is now able to test these wells more frequently and for longer durations.These trial installations have been very successful as verified by the comparison of test results of the MPFM vs. Test Boat vs. Reservoir simulations. The success is not only in terms of testing but also proved beneficial in terms of saved man-hours and increased safety. Safety is increased and man-hours spent are reduced by avoiding all theconection / disconnection oftemporary manual piping from the boat to the well head tower.
This has encouraged ZADCO to embark on an exercise to install MPFMs on all those WHPTs which do not have a test separator and also to install MPFMs on those WHPTs where the existing test separators have become undersized due to the increase in production profile.
This trial use of MPFM in addition to providing very satisfactory test results in line with ZADCO testing requirements also has benefitted in various other ways as follows:
The need for frequent visit of test boat to the WHPTs is reduced. Carry testing more often thereby eliminating various factors related to weather, safety, unstable operation, etc. Longer duration of testing is facilitated for the wells; Increased safe operations by avoiding all the temporary piping from the boat to the well head tower which involves lot of lifting activities. There is also a huge saving in the man-hours spent in testing activities utilizing the boat. Thesesaved man-hours have also helped in effective utilisation of manpower.
SUBSEA PEC: The NDT Diverless Robotic System for the Pipeline Corrosion Inspection
Authors: Slomp E. , Bertelli M. , Milijanovic D. 
Published: November 2012

Abstract
PEC (Pulsed Eddy Current) is an NDT system applied to many sectors, and nowadays it plays an increasingly significant role in the maintenance of the offshore structures. The operational principle is based on eddy currents created by a magnetic field induced in a metal structure.
Through the reverse principle it is possible to analyze their behavior: we obtain information related to the average wall thickness and therefore of the corrosion status. Salient feature of PEC system is that it operates without removing, modifying or pre-treating the protective coating of the steel structure to be inspected.
The physical human presence for the system utilization has been essential in the standard practice. In the offshore world this requirement is very expensive, risky to comply with and often even physically impossible to achieve. For these cases, the subsea technology has allowed developing systems aiming to replace the human presence if this is not achievable or economically not viable. The "Subsea PEC" technology has been strategically developed for deep offshore inspections; a completely diverless machine mounted on WROV is deployed on the pipeline. The machine operations are remotely controlled from the surface on board the vessel and underwater module is employed on the pipe. The system automatically performs all the placements along the pipe length in order to carry out sectional scanning and obtain corrosion status readings around entire pipe perimeter (360degree readings). A single placement of the system allows detailed scan around the targeted pipe section and includes inspection of one further meter in length along the pipe. This technology allows complete mapping of the pipeline corrosion status without production interruptions since no destruction or pre-treatment of the protective coatings is required. Subsea PEC has already achieved considerable success with encouraging results during inspections carried out in the Mediterranean Sea, Red Sea, the South China Sea and the North Sea.
Subsurface Uncertainty Assessment for a New Carbonate Field Development
Authors: Ouezzani Mohammed Ridha , Belery Paul , El-Kassawneh Reyad , Daify Hossam , Ishiyama Tomohide , Yoshida Koichi , Zidan Maher 
Published: November 2012

Abstract
The objective of this paper is to present an integrated approach to quantify subsurface uncertainties and to share the assessments that have been applied in the subsurface studies of a new offshore oil field development in United Arab Emirates.
A methodology was developed to review and rank the various subsurface uncertainties. Seismic and geological tools were used to assess uncertainties of static parameters, while integration of all uncertainties was made in the dynamic simulation model.
New approaches were implemented to address two important parameters: Critical Water Saturation and Permeability. Critical Water Saturation uncertainty was derived by history matching production test data using a Saturation-Versus-Height model coupled with a Fractional Flow equation. For estimating uncertainty on Permeability, correlations with core derived fracture densities were developed.
Uncertainty on the Critical Water Saturation was found to have the highest impact on oil recovery. This uncertainty is related to an observation already made for other carbonate reservoirs where perforated intervals are sometimes producing at very low water-cut in spite of high water saturations interpreted from the logs.
This uncertainty review allowed updating the Dynamic Model with more robust P50 estimates of its parameters. The updated model was used to define a new base case development well scheme and production profile.
The study was important in maturing the development studies further. It was used in particular not only for updating the Dynamic Model, but also for defining future studies, preparing a data acquisition plan, and identifying mitigation actions to reduce the subsurface risks.
Case Study: New Approach of Chemical Implementation to Improve Oil Recovery and Production for Tight Carbonate Reservoir in Sungai Lilin
Authors: Nugroho Wisnu , Saputro Gunawan , Mucharam Leksono 
Published: November 2012

Abstract
Sugai Lilin oil field, located on the northeast flank of the South Sumatra basin. In 1933, operated by BPM, a discovery well (SLL-1) encountered productive Upper Talang Akar Sandstone which yielded 1365 BOPD with 0.219 MMSCFD gas from DST-1 and 1975 BOPD with 0.375 MMSCFD gas from DST-4. This field consists of two formation rock i.e. Talang Akar (sandstone, TAF) and Batu Raja (Limestone, BRF), both formations contain oil deposit with relatively small gas.
Depth of the top reservoir sandstone is about -775 m, with original pressure and temperature were 1294 psia and 78 C, respectively. Since 1934, this field started to produce oil from both formations, TAF and BRF. However, significant oil production rate of this field started in 1984, where the peak oil production rate reached 1800 bopd. The oil production drop very sharply to about 100 bopd with high water cut, in 2007.
From recent laboratorium EOR study, it showed that oil reservoir system in Baturaja limestone reservoir is considered as a strong oil wetting, especially in low permeability layer. This penomenon was also shown by value of the SOR which is greater than 35 %. In this kind of reservoir system, displacement by water will not result in increasing RF significantly, even viscosity of the oil is considered low. To improve oil production and oil recovery factor in this reservoir requires chemical injection which is able to alter the oil wetting to become non oil wetting system where the oil phase will flow much easily to. the wellbore. Using chemical solution of SEMAR, Huff n Puff approach has been implemented in ten (10) production wells in this Sungai Lilin Field. In this case, 3000 bbls of SEMAR solution with 2 % concentration was injected to each well, with 7 days of soaking. Responds of these huff and puff implementation varied among those wells, ranging from 50% to 400% increase in production peak.