bluuebunny/crossref_metadata_2025_split huggingface dataset:
Best Practices and Lessons Learned from more than 1,000 Treatments: Revival of Mature Fields by Hydraulic Fracturing in Khalda Ridge, Egypt's Western Desert
Authors: Salah Mohamed , El-Sebaee Mohamed , Batmaz Taner 
Published: September 2016

Abstract
Most of Egypt's Western Desert reservoirs are characterized to have low permeability and heterogeneous, poor rock quality. In the early development stages only layers with high permeability were produced, while the low-permeability, low-porosity layers were not considered economic.
As these high-permeability layers became more mature and declined in production, tight layers became the operator's alternative choice to unlock the enormous amounts of hydrocarbons still present in these rocks and achieve economical production targets from these marginal fields. Hydraulic fracturing technology enabled us to unlock the potential of these challenging layers that were previously considered uneconomical.
Hydraulic fracturing is now a common practice, even pushing extremes such as deeper, high-temperature and high-pressure wells in the Western Desert. The incremental production gains from these challenging layers have encouraged operators to invest. Currently, hydraulic fracturing is routinely conducted for all new production and injection wells and is reconsidered for the old wells.
Completion practices, candidate selection criteria, perforation and design strategies, and workflows were revised to address these new challenging conditions and reservoir complexities with hydraulic fracturing technology. For example, vertical completions were replaced by horizontal multistage fracturing completions to increase the reservoir contact. State-of-the-art software was used to simplify decisions on fracture initiation points across heterogeneous reservoirs. Different technologies, alternative to conventional perforating, were introduced to enhance the proppant placement, post-fracturing production, and operational efficiency. This paper provides a review of hydraulic fracturing in Egypt's Western Desert. The hydraulic fracturing technique has been used to develop mature fields and challenging formations of Egypt since the early 1990s. More than 1,000 treatments targeting low- to medium- permeability rocks were pumped in Khalda Ridge. Correlation between mechanical properties, reservoir properties, essential fracturing design, completions, and operational parameters were established over time to help other operators that intend to apply hydraulic fracturing to their assets. Case histories are also provided, demonstrating different fracturing techniques for extreme conditions. In this paper we detail the progress related to completion practices and technologies to revive the mature fields of Egypt.
Proper Planning Supported by Latest Technology Leads to Drilling the Longest 8.5-in. Section in an Extended-Reach Well: Case Study
Authors: Al Dabyah A. A. , Zubairi B. A. , Al Umairin I. S. , Chima J. I. , Kunhiveetil D. , Otaif H. W. 
Published: September 2016

Abstract
Over the last few years, extended-reach drilling (ERD) field development has significantly increased globally, and its benefits are well recognized. ERD techniques are increasingly used to intersect hydrocarbon targets that are difficult to access due to logistic issues. While these wells are challenging to drill, complete, and service, the benefits can be significant. These benefits drive the development of technology and techniques to continuously expand the ERD envelope and increase the complexity of profiles to reach more challenging targets. The directional drilling and evaluation service supplier plays an important role.
Each ERD well has a unique set of challenges. Common to all ERD projects is that many aspects of drilling engineering principles are not only pushed to the limit, but become highly interrelated and sensitive to smaller changes than conventional wells. For this reason, a team approach to planning and executing ERD activities should be considered critical. Each team member should bring to the project relevant experience, knowledge, a range of field-proven technology, and a solid global support structure.
Drilling successful ERD wells in challenging conditions depends on various factors, which include careful planning and use of the latest technology. Planning involves understanding the geological structure, not only within the reservoir section, but also in the overburden where typically most of the time efficiency gains can be achieved. The last step in planning is designing an efficient bottomhole assembly (BHA) based on previous experiences, lessons learned and inputs from various teams. Good planning is supported by use of new technologies, especially tools that give real-time information, enabling quick and informed decisions to ensure safe and efficient drilling in a challenging environment. This paper discusses the planning and decision-making process to drill ERD wells by using latest real-time technologies in drilling challenging wells. This paper describes the experiences and huge success of drilling the longest 8.5-in. hole section in an ERD well, drilled and cased smoothly through challenging formations.
Multiscale Change Characteristics of Chinese Wufeng Shale Under Supercritical Carbon Dioxide
Authors: Zhu Hai-Yan , Tao Lei , Liu Qing-You , Lei Zheng-Dong 
Published: September 2016

Abstract
Objectives/Scope. Waterless fracturing for shale gas exploitation with supercritical carbon dioxide (scCO2) is effective and environment-friendly, which has become an international fascinating research topic. The formers mainly focus on the chemical and physical properties, and microstructure of sandstone, carbonate and shale caprock, rather than the properties of shale gas formation. And the macroscale mechanical properties and nanoscale fracture characteristics of Wufeng shale under scCO2 conditions (above 31.8 °C and 7.29 MPa) is still not clear.
Methods, Procedures, Process. To study multiscale change characteristics of shale under scCO2 condition, the Chinese Wufeng shale crops (upper Ordovician formation) is obtained from Yibin, Sichuan Basin, China. Firstly, SEM and XRD are taken to study the original microstructure and mineral content of shale. Then, triaxial tests with controlled coring angles and gas conditions (immersed scCO2 and N2 for 10 hours) have been carried out on shale φ25 × 50 mm cylindrical specimens for the objective of studying macro mechanical change of Wufeng shale. In addition, SEM and XRD are also conducted after the triaxial tests.
Results, Observations, Conclusions. Some results are concluded as follow. (1) In the SEM figures, the Group 2 (after testing) are similar to the original ones: the tight bedding planes and undamaged minerals (with sharp edges and smooth surfaces) are found in Group 1 (before testing) and Group 2 (before and after testing), which indicating that the triaxial test with N2 can't damage the microstructures of shale. (2) However, the microstructures in Group 1 SEM figures (after testing) are quite different than the others: the bedding planes are damaged, which lefts some connectivity micro-fractures and corrosion holes; the minerals are broken into lots of small debris and left some uneven mineral surfaces. That demonstrates the scCO2 can change the microstructures and make some minerals (e.g. calcite) fracture more easily. (3) A relative content reduction of calcite, dolomite and pyrite have been found in Group 1, significantly. (4) The scCO2 reduce the triaxial compressive strength of shale with a decline of 3.82% to 19.38%. (5) huger fractures in macroscale have been found in the specimens of Group 1, scCO2 and bedding plane lead to the diversities of failure modes.
Novel/Additive Information. The multiscale physical and chemical changes of shale under scCO2 are essential for scCO2 fracturing, scCO2 jet breaking rock and the geological storage of CO2. The complex microscale fractures, the macro decrease of strength in shale are helpful to the seepage and gathering of shale gas, and finally enhance the shale gas recovery.
Nested Optimization - A Practical Approach Delivering Increased Production Opportunities
Authors: Hadjipieris Pieris , Bishop Simon 
Published: September 2016

Abstract
This paper describes the solution formulation that was put in place in order to maximize oil production on fields with complex optimization spaces. The fields considered presented an infinite combination of control settings that could be used to regulate production. As such, the process by which each problem is broken down into elements that can be easily understood and combined, shows the potential of a technique referred to as "Nested Optimization" in the improvement of production in virtually any field around the world.
The process by which optimization is applied in practice is obviously important, as different approaches to the maximization of production may lead to solutions with various levels of robustness, efficiency and practical application in the field. The workflow presented achieves the need from any operator to distinguish between these approaches and select the one that offers maximum production, while at the same time being able to cope with the ever changing nature of field reality from a flow assurance perspective. The fields considered have multiple constraints that operators have to adhere to, such as erosional velocity limits, integrity limits and others. Controls typically relate to chokes on every well along with such parameters as the speed of compressors that feed export pipelines with associated gas. Routing of wells, risers and other systems at surface is yet another control that often needs to be considered. As such, a variety of optimizers were applied, each dealing with a subset of the complete problem. The boundary conditions of each optimization problem in the nested approach were dynamically controlled by higher level optimizers, so that the overall solution is fully consistent.
Formulating the solution in a way that allowed multiple optimizers to work together in a nested fashion meant that a number of very significant optimisation opportunities could be identified. Generally, the implementation of these opportunities would not require significant additional capital expenditure.
The paper discusses the application of Nested Optimization as well as how this can be automatically coupled to an automated quality control process. Workflows that transform the results of the optimizers into settings that operators can easily follow have been implemented. The solution also shows how steady state and transient models can be linked to the quality control of the pipeline stability results. The linking of optimization results to their application in the field means that operators can be confident of a safe implementation of the recommendations made.
3D Downhole Drilling Automation Based on Minimum Well Profile Energy
Authors: Mittal Manish , Samuel Robello 
Published: September 2016

Abstract
With increased well complexity, difficulty matching the actual well profile with the planned well profile increases. This study discusses building a workflow for automating the bottomhole assembly (BHA) to take corrective actions upon detection of a deviation from the planned well path in a 3D coordinate space, and constructing and programming a prototype demonstrating the proposed theory. The corrective paths would be conventional constant curvature curve and unconventional curves, such as catenary and spline, which are proven to be smooth, thereby reducing torque and drag in the well. The main constraint governing the unknown parameters of the corrective path is the minimum well profile energy criterion, which is excellent in terms of producing smooth curves because it minimizes the curvature and torsion of the curve together. Balanced tangential and minimum curvature methods are used for building the corrective trajectory.
Previous work on downhole drilling automation showed that the minimum energy method, compared to proportional, integral, and derivative (PID) control and fuzzy control, where the model was built for 2D and 3D coordinate space by considering conventional constant curvature curves for correction, yields much smoother wellbore trajectories. The work was continued for unconventional well profiles in 2D wells, where spline, catenary, and clothoid curves were used to return the deviated well to the original planned path. This work focuses on building the model to determine the corrective paths based on unconventional curves for wells in a 3D coordinate space. The model first determines the point on the planned path where the bit needs to join and then estimates the best possible path to do so. The whole corrective workflow is demonstrated with a small scale working prototype. Finally, the results of various optimization models obtained by combining different unconventional curves and trajectory calculation methods are compared.
Low Salinity Flooding (LSF) in Sandstones at Pore Scale: Micro-Model Development and Investigation
Authors: Bartels W.-B. , Mahani H. , Berg S. , Menezes R. , van der Hoeven J. A. , Fadili A. 
Published: September 2016

Abstract
Low salinity waterflooding (LSF) is receiving increased interest as a promising method to improve oil recovery efficiency. Most of the literature agrees that on the Darcy scale, LSF can be regarded as a wettability modification process leading to a more water-wet state, although no general consensus on the microscopic mechanisms has been reached. While wettability alteration may be a valid causal mechanism also on the pore scale, it is currently unclear how oil that detaches from mineral surfaces within individual pores connects to an oil bank or finds its way to a producer. In order to establish a link between the pore scale and the Darcy scale description, the flow dynamic at the scale of (networks of) multiple pores should be investigated. One of the main challenges in addressing phenomena on this intermediate "pore network" scale is to design a model system representative for natural rock. The model system should allow for a systematic investigation of influencing parameters with pore-scale resolution whilst simultaneously being large enough to capture larger length scale effects like saturation changes and the mobilization and connection of oil ganglia.
In this paper, we use micro-models functionalized with active clay minerals as model system to study the low salinity effect (LSE) on the pore scale. A new method was devised to deposit clays in the micro-model. Clay suspensions were made by mixing natural clays (Montmorillonite) with isopropyl alcohol (IPA) and injected into optically transparent 2D glass micro-models. By drying the micro-model, the clay particles are deposited and stick naturally to the glass surfaces and remain attached even under flow of high salinity (HS) and low salinity (LS) brines. In a parametric study the dependence of the LSE on the type of oil (crude oil versus n-decane), the presence of clay particles and ageing was investigated.
Our results show that the system is responsive to LS brine as the effective contact angle of crude oil shifts towards a more water-wetting state when brine salinity is reduced. When using n-decane as a reference case of inert oil, no change in contact angle occurred after a reduction in brine salinity.
This responsiveness in terms of contact angle does not necessarily mean that more oil is recovered. Only in the cases where the contact angle change (due to low salinity exposure) led to release of oil and re-connection with oil of adjacent pore bodies, the oil became mobile and oil saturation was effectively reduced. This makes contact angle changes a necessary but not sufficient requirement for incremental recovery by LSF. Interestingly, the wettability modification was observed in absence of clay. Osmosis and IFT were found to be not the primary driving mechanisms of the low salinity response.
Approach towards Establishing Unified Petroleum Data Analytics Environment to Enable Data Driven Operations Decisions
Authors: David Richard Mohan 
Published: September 2016

Abstract
Exploration and Production companies are increasingly instrumenting their fields with the objective to proactively monitor and surveillance of its wells, reservoir, and facilities for safe and better operations. With this scenario, there is ever increase in the volume and variety of data being generated to support workflows such as real time drilling operations, production surveillance and reservoir monitoring. Data Analytics enables to get most value out of the vast volume of data being generated. In order to extend the present limits of digital oil field envelope from operations monitoring, companies need to harness data analytics to identify patterns, trends, correlation, forecasting out of its vast petroleum data. This includes exception based surveillance, case based reasoning, and condition based monitoring in order to facilitate advanced monitoring, and to support tactical and strategic decision-making process.
To establish data analytics environment it requires systematic way of capturing, storing and managing data, integrating and embedding data analytics into the mainstream sub-surface, drilling, production and operations workflows which includes integrated reservoir monitoring, drilling and production optimization. Data analytics technology blends traditional data analysis with sophisticated algorithms and business rules for processing large volumes of diverse types through an Integrated Data Analytics Environment (IDE). Data governance is a vital part of IDE to ensure there is clear ownership and responsibilities as the accuracy of the results are as good as the quality of the data. IDE environment enables systematic harvesting of operational event, lessons learnt and best practices to enable knowledge based operations decisions.
The integrated data analytics platform enables integrating E&P workflows and data analytics to enhance operations monitoring, predict well productivity, identify performance patterns and KPI, improve reservoir recovery factor, and predict equipment failure, towards achieving the objective of continuous optimization of oilfield performance.
Enhanced Oil Recovery by Combined Nanofluid and Low Salinity Water Flooding in Multi-Layer Heterogeneous Reservoirs
Authors: Yuan Bin , Moghanloo Rouzbeh Ghanbarnezhad , Zheng Da 
Published: September 2016

Abstract
The aim of this paper is to investigate an application of nanofluid-slug preflush to enhance well injectivity while improving the sweep efficiency by fines migration-assisted mobility control in multi-layer heterogeneous reservoirs during low salinity water flooding. An axisymmetric radial flow model and fraction flow analysis are applied to interpret the performance of nanofluid-slug and the following low salinity water injection in a layered heterogeneous flow system. The interplay among nanoparticles, fines and rocks is described by a physical-chemical reaction model. The improvement of mobility control is characterized as the ratio of displacement fronts' advancing velocity along each layer. The improved well injectivity by nanofluid preflush is presented as an explicit formulation of injectivity index. This paper also introduces a graphic workflow to optimize nanofluid treatment and injected water salinity for nanofluid-fines-assisted low salinity water flooding under arbitrary initial and injection conditions.
The results indicate: 1) Compared with conventional water flooding, the alteration of water salinity can help to achieve uniform water flooding profile within each heterogeneous layer and then improve sweep efficiency before water breakthrough; 2) The nanofluid preflush prior to water injection can effectively control fines migration in the vicinity of injection wells to improve well injectivity, but it cannot control fines migration in reservoirs that realizes mobility control by decreasing water-phase permeability in the higher permeable layers; and 3) there does exist an optimal nanofluid concentration and slug size to offset decline of permeability near wells and then improve water injectivity.
The outcomes of analytical model are validated by both numerical simulations. This paper has the following novel points: 1) the model provides physical insights to examine nanofluid utilization to improve well injectivity and enhance oil recovery; 2) The induced mobility-control by fines migration during low salinity water flooding is confirmed as an effective method to improve sweep efficiency in heterogeneous reservoirs.
Engineering Gravel Packs for Reliability
Authors: Wassouf Philip , Jain Samyak , Kranenburg Aart van 
Published: September 2016

Abstract
Sand production is a global problem which causes millions of dollars in equipment damage, deferred or lost production and non-productive time (NPT) every year. Consequently, the accurate selection, modeling and evaluation of sand control techniques is crucial for completion and production optimization as well as risk minimization. This has traditionally been done using spreadsheets, industry rules of thumb and previous experience but, as completions become more complex with longer intervals and smaller fracture pressure windows, error margins are tightening and the cost of failure increasing so a more robust approach is required.
This paper details the application of a novel commercially available gravel pack software in the prediction of circulating pressures and gravel placement during the wellbore displacement, step rate test and gravel pack stages of completions operations for two horizontal open hole wells completed with alpha/beta gravel packs. Each well is first simulated to predict expected packing and pressure trends, then evaluated using measured surface and downhole gauge data to identify actual packing mechanisms and better understand downhole events, and finally optimized by directly comparing predicted and measured data to validate model accuracy and reliability. This detailed approach enables the early identification and mitigation of potential risks as well as the ability to better investigate any failures for continuous improvements in both design and operations.
Overall, the model is found to match closely with measured data, providing a robust engineering tool for the simulation, evaluation and optimization of horizontal open hole gravel pack (OHGP) completions. The methodology presented facilitates the more accurate design of increasingly complex treatments and helps identify deviations from expected pressure and packing trends to reduce risk, improve reliability and maximize the likelihood of success.