Development and prospect of separated zone oil production technology

This article outlines the development of separated zone oil production in foreign countries,and details its development in China.According to the development process,production needs,technical characteristics and adaptability of oilfields in China,the development of separate zone oil production technology is divided into four stages:flowing well zonal oil production,mechanical recovery and water blocking,hydraulically adjustable zonal oil production,and intelligent zonal production.The principles,construction processes,adaptability,advantages and disadvantages of the technology are introduced in detail.Based on the actual production situation of the oilfields in China at present,three development directions of the technology are proposed.First,the real-time monitoring and adjustment level of separated zone oil production needs to be improved by developing downhole sensor technology and two-way communication technology between ground and downhole and enhancing full life cycle service capability and adaptability to horizontal wells.Second,an integrated platform of zonal oil production and management should be built using a digital artificial lifting system.Third,integration of injection and production should be implemented through large-scale application of zonal oil production and zonal water injection to improve matching and adjustment level between the injection and production parameters,thus making the development adjustment from"lag control"to"real-time optimization"and improving the development effect.

Layout design of a mixed-flow production line based on processing energy consumption and buffer configuration

Green manufacturing is a growing trend,and an effective layout design method for production lines can reduce resource wastage in processing.This study focuses on existing problems such as low equipment utilization,long standby time,and low logistics efficiency in a mixed-flow parallel production line.To reduce the energy consumption,a novel method considering an independent buffer configuration and idle energy consumption analysis is proposed for this production line’s layout design.A logistics intensity model and a machine tool availability model are established to investigate the influences of independent buffer area configuration on the logistics intensity and machine tool availability.To solve the coupling problem between machine tools in such production lines,a decoupling strategy for the relationship between machine tool processing rates is explored.An energy consumption model for the machine tools,based on an optimized configuration of independent buffers,is proposed.This model can effectively reduce the idle energy consumption of the machine tools while designing the workshop layout.Subsequently,considering the problems encountered in workshop production,a comprehensive optimization model for the mixed-flow production line is developed.To verify the effectiveness of the mathematical model,it is applied to an aviation cabin production line.The results indicate that it can effectively solve the layout problem of mixed-flow parallel production lines and reduce the idle energy consumption of machine tools during production.The proposed buffer configuration and layout design method can serve as a theoretical and practical reference for the layout design of mixed-flow parallel production lines.

Free cash flow productivity among Chinese listed companies:A comparative study of SOEs and non-SOEs

This paper investigates the free cash flow productivity of SOEs compared with non-SOEs and examines its possible determinants.We find that SOEs have slightly weak free cash flow productivity but significantly stronger than non-SOEs.Similar performance exists among commercial class I and II SOEs and public-benefit SOEs.Further analyses suggest that firm size,age,sales growth,ownership concentration,government subsidies,and industry monopoly factors cannot explain this phenomenon.The common driver for all types of SOEs to generate stronger free cash flows than non-SOEs is their stronger expense control capability.

Characterization of Organic-Rich Shales for Petroleum Exploration & Exploitation: A Review-Part 3: Applied Geomechanics, Petrophysics and Reservoir Modeling

Modeling geomechanical properties of shales to make sense of their complex properties is at the forefront of petroleum exploration and exploitation application and has received much re- search attention in recent years. A shale＇s key geomechanical properties help to identify its ＂fracibility＂ its fluid flow patterns and rates, and its in-place petroleum resources and potential commercial re- serves. The models and the information they provide, in turn, enable engineers to design drilling pat- terns, fracture-stimulation programs and materials selection that will avoid formation damage and op- timize recovery of petroleum. A wide-range of tools, technologies, experiments and mathematical techniques are deployed to achieve this. Characterizing the interconnected fracture, permeability and porosity network is an essential step in understanding a shales highly-anisotropic features on multiple scales （nano to macro）. Weli-log data, and its petrophysical interpretation to calibrate many geome- chanical metrics to those measured in rock samples by laboratory techniques plays a key role in pro- viding affordable tools that can be deployed cost-effectively in multiple well bores. Likewise, micro- seismic data helps to match fracture density and propagation observed on a reservoir scale with pre- dictions from simulations and laboratory tests conducted on idealised/simplified discrete fracture net- work models. Shales complex wettability, adsorption and water imbibition characteristics have a sig- nificant influence on potential formation damage during stimulation and the short-term and long-term flow of petroleum achievable. Many gas flow mechanisms and models are proposed taking into ac- count the multiple flow mechanisms involved （e.g., desorption, diffusion, slippage and viscous flow op- erating at multiple porosity levels from nano- to macro-scales）. Fitting historical production data and well decline curves to model predictions helps to verify whether model＇s geomechanical assumptions are realistic or not. This review discusses the techniques applied and the models developed that are relevant to applied geomechanics, highlighting examples of their application and the numerous out- standin~ questions associated with them.