Hydraulic Fracturing as Game Changer to Maximize Waterflooding Efficiency in a Brownfield

Primary production mechanism of a clean sandstone reservoir in a brownfield for oil production has been recently changed from natural depletion to waterflooding. Despite the apparently moderate petro-physical properties of the formation, injector wells performances were observed to be extremely poor, mainly due to: high drilling-induced formation damage and Fluids interaction within the reservoir (injection across the oil rim section). Several stimulation technologies have been applied to improve wells injection capability for pressure support optimization. Re-perforation via abrasive jetting, perforations wash through coiled tubing and various acid formulations via bullheading were attempted without achieving any significant increase in injectivity. Considering the modest rock permeability, the need to access a wider formation area to improve oil sweep efficiency and the crucial requirement to re-pressurize the reservoir, an additional card was played as last resort: hydraulic fracturing. This technique was not new to the area and already experimented by different operators. Several producer wells in different layers were hydraulic fracturing stimulated with proppant and/or acid in the past with a good rate of success. Why not to try then? Given the past experience on the same field with hydraulic fracturing in oil producers and accounting for well integrity and potential injectivity, one was chosen as suitable candidate. Offset wells hystorical data were used to build a hydraulic fracturing reservoir model and plan for the activity in details; operator and service providers engaged in a Frac Well On Paper activity in order to reduce any margin of error during field operations. An approach that proved successful. From there, the first trial well was planned and performed successfully. 4 other hydraulic fracturing jobs on 4 wells followed at close distance in time with different, but steadily comforting, results. Injection was improved from negligible initial values up to 2000 mc/day for the post-stimulation condition, exceeding the preliminary expectations. This paper introduces the steps taken to start the hydraulic fracturing campaign, the decision process that led to the design of the treatment, an overview of the execution phases, results well by well and lessons learned to optimize future campaigns.

Additive manufacturing a powerful tool for the aerospace industry

Purpose Additive manufacturing (AM) offers potential solutions when conventional manufacturing reaches its technological limits. These include a high degree of design freedom, lightweight design, functional integration and rapid prototyping. In this paper, the authors show how AM can be implemented not only for prototyping but also production using different optimization approaches in design including topology optimization, support optimization and selection of part orientation and part consolidation. This paper aims to present how AM can reduce the production cost of complex components such as jet engine air manifold by optimizing the design. This case study also identifies a detailed feasibility analysis of the cost model for an air manifold of an Airbus jet engine using various strategies, such as computer numerical control machining, printing with standard support structures and support optimization. Design/methodology/approach Parameters that affect the production price of the air manifold such as machining, printing (process), feedstock, labor and post-processing costs were calculated and compared to find the best manufacturing strategy. Findings Results showed that AM can solve a range of problems and improve production by customization, rapid prototyping and geometrical freedom. This case study showed that 49%–58% of the cost is related to pre- and post-processing when using laser-based powder bed fusion to produce the air manifold. However, the cost of pre- and post-processing when using machining is 32%–35% of the total production costs. The results of this research can assist successful enterprises, such as aerospace, automotive and medical, in successfully turning toward AM technology. Originality/value Important factors such as validity, feasibility and limitations, pre-processing and monitoring, are discussed to show how a process chain can be controlled and run efficiently. Reproducibility of the process chain is debated to ensure the quality of mass production lines. Post-processing and qualification of the AM parts are also discussed to show how to satisfy the demands on standards (for surface quality and dimensional accuracy), safety, quality and certification. The original contribution of this paper is identifying the main production costs of complex components using both conventional and AM.

Mechanism of Support Optimization and Confined Blasting of Thick and Hard Rock with a Wedge-Structure Immediate Roof: A Case Study

Based on the occurrence conditions of a thick and hard main roof and wedge-structure immediate roof in the Zhuxianzhuang Coal Mine, the fracture characteristics and instability migration law of a thick and hard roof (THR) were examined via physical simulations. Mining zones were divided with respect to the strata behaviors and roof control difficulty levels, and the principles and methods of zonal control under THR were put forward. This study proposed a coordinated control strategy of using confined blasting in water-filled deep holes, and reasonable support optimization, which could effectively reduce the roof fracture size, increases the supporting intensity and eliminate roof-control disasters. The length of confined blasting blocks and supporting intensity were calculated using a mechanical model for roof control in the strong strata behavior zone and less-strong strata behavior zone. These key parameters were determined as 20–25 m and 1.15–1.28 MPa, respectively, and the mining strategy was successfully applied in working face 880, performing high security and reasonable economical efficiency.

Computer support for the shape formation of helical surfaces with a disk tool

An analytical description of the process of making helical surfaces with a disk tool with a substantiated definition of the objective function is proposed. By analogy with coordinate metrology, it is proposed to adopt a minimum tolerance zone as an objective function. This allows to specify the required solution error and eliminates the need to use normal lines or tangents to the profiles. An example of calculating the profile of a helical groove of a twotoothed end mill, performed with an error of 0.05 mm is presented. Keywords: helical surface, disk tool, computer support, optimization, minimum tolerance. [email protected]

Exploring Factors that May Influence Ontario Nurse Practitioners’ Patient Panel Size in Primary Healthcare Settings

Limited knowledge exists about the factors that may influence nurse practitioner (NP) patient panel size. Patient panel size refers to the number of patients for whom a NP is their usual care provider. Increased knowledge of these factors may improve patient care, NP practice, and primary health care (PHC) workforce planning. Two hundred and eighty-three NPs working in Ontario PHC were surveyed to explore patient, NP, and organizational factors that may influence NP patient panel size. Three factors were associated with NP panel size. Higher percentages of certain health conditions and/or longer appointment time for multi-morbid and palliative care were associated with smaller NP patient panel size. NPs who worked more hours per week had larger patient panels. Also, the PHC practice model was related to NP patient panel size, which was largest in NP-led clinics. Decision makers can use these findings to support optimization of NP patient panel size.

Exploring Factors that May Influence Ontario Nurse Practitioners’ Patient Panel Size in Primary Healthcare Settings

Limited knowledge exists about the factors that may influence nurse practitioner (NP) patient panel size. Patient panel size refers to the number of patients for whom a NP is their usual care provider. Increased knowledge of these factors may improve patient care, NP practice, and primary health care (PHC) workforce planning. Two hundred and eighty-three NPs working in Ontario PHC were surveyed to explore patient, NP, and organizational factors that may influence NP patient panel size. Three factors were associated with NP panel size. Higher percentages of certain health conditions and/or longer appointment time for multi-morbid and palliative care were associated with smaller NP patient panel size. NPs who worked more hours per week had larger patient panels. Also, the PHC practice model was related to NP patient panel size, which was largest in NP-led clinics. Decision makers can use these findings to support optimization of NP patient panel size.

A Case Study of Socially-Accepted Potentials for the Use of End User Flexibility by Home Energy Management Systems

Due to the increase of volatile renewable energy resources, additional flexibility will be necessary in the electricity system in the future to ensure a technically and economically efficient network operation. Although home energy management systems hold potential for a supply of flexibility to the grid, private end users often neglect or even ignore recommendations regarding beneficial behavior. In this work, the social acceptance and requirements of a participatively developed home energy management system with focus on (i) system support optimization, (ii) self-consumption and self-sufficiency optimization, and (iii) additional comfort functions are determined. Subsequently, the socially-accepted flexibility potential of the home energy management system is estimated. Using methods of online household survey, cluster analysis, and energy-economic optimization, the socially-accepted techno-economic potential of households in a three-community cluster sample area is computed. Results show about a third of the participants accept the developed system. This yields a shiftable load of nearly 1.8 MW within the small sample area. Furthermore, the system yields the considerably larger monetary surplus on the supplier-side due to its focus on system support optimization. New electricity market opportunities are necessary to adequately reward a systemically useful load behavior of households.

Transport of Au(III) from HCl Medium across a Liquid Membrane Using R3NH+Cl−/Toluene Immobilized on a Microporous Hydrophobic Support: Optimization and Modelling

By the use of the tertiary amine A327 and 1 M HCl solution as precursors, the ionic liquid A327H+Cl− was generated and used to investigate its performance in the transport of Au(III) from hydrochloric acid medium. The influence of the stirring speed (600–1800 min−1), ionic liquid concentration (1.25–50% v/v) in the membrane phase, and gold concentration (0.01–0.15 g/L) in the feed phase on metal transport have been investigated. An equation which included both equilibrium and kinetics parameters was derived, and the membrane diffusional resistance (Δm) and feed phase diffusional resistance (Δf) was estimated as 9.5 × 106 s/cm and 307 s/cm, respectively. At carrier concentrations in the 5–50% v/v range and gold concentrations in the 0.01–0.15 g/L range, metal transport is controlled by diffusion of metal species through the feed boundary layer, whereas at the lowest carrier concentrations, membrane diffusion is predominant. From the receiving solutions, gold can be recovered as gold nanoparticles.