Logging data and its interpretation results are one of the most important basic data for understanding reservoirs and oilfield development. Standardized and unified logging interpretation results play a decisive role ...Logging data and its interpretation results are one of the most important basic data for understanding reservoirs and oilfield development. Standardized and unified logging interpretation results play a decisive role in fine reservoir description and reservoir development. Aiming at the problem of the conflict between the development effect and the initial interpretation result of Yan 9 reservoir in Hujianshan area of Ordos Basin, by combining the current well production performance, logging, oil test, production test and other data, on the basis of making full use of core, coring, logging, thin section analysis and high pressure mercury injection data, the four characteristics of reservoir are analyzed, a more scientific and reasonable calculation model of reservoir logging parameters is established, and the reserves are recalculated after the second interpretation standard of logging is determined. The research improves the accuracy of logging interpretation and provides an effective basis for subsequent production development and potential horizons.展开更多
Tight and unconventional reservoirs have become the focus with the progress of petroleum exploration and development.Micro-fractures in these reservoirs can effectively improve reservoir permeability,and well-develope...Tight and unconventional reservoirs have become the focus with the progress of petroleum exploration and development.Micro-fractures in these reservoirs can effectively improve reservoir permeability,and well-developed micro-fractures can serve to directly improve productivity.Compared with the centered electrical well logging method,the Micro Spherical Focused Logging(MSFL)is more suitable for microfracture identification due to its high resolution and near borehole wall measuring method.In this study,an anisotropic model is used to depict micro-fractured formation.First,a forward model with microfractured formation,borehole,logging instrument and surrounding rock is established.Subsequently,MSFL responses under different micro-fracture porosity,resistivity,dip angle and borehole radius,are calculated based on the finite element method(FEM).Finally,the MSFL responses under different microfracture parameters are analyzed with the response laws clarified.展开更多
Since gas hydrate exists in three different forms at the same time such as pore filling,particle support and separate stratification,the calculation method of hydrate saturation using traditional shaly sand formation ...Since gas hydrate exists in three different forms at the same time such as pore filling,particle support and separate stratification,the calculation method of hydrate saturation using traditional shaly sand formation interpretation models is equivalent to considering only the simple case that hydrate exists as pore filling,and does not consider other complex states.Based on the analysis of hydrate resistivity experimental data and the general form of the resistivity-oil(gas)saturation relationship,the best simplified formula of hydrate saturation calculation is derived,then the physical meaning of the three items are clarified:they respectively represent the resistivity index-saturation relationship when hydrate particles are completely distributed in the pores of formation rocks,supported in the form of particles,and exist in layers,corresponding quantitative evaluation method of hydrate saturation is built.The field application shows that the hydrate saturation calculated by this method is closer to that obtained by sampling analysis.At the same time,it also provides a logging analysis basis for the effective development after hydrate exploration.展开更多
Electromagnetic Computer Tomography (ECT) is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity betwe...Electromagnetic Computer Tomography (ECT) is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity between oil and water in the well, Electromagnetic Tomography Well Logging (ETWL), a new flow imaging measurement system, is proposed to describe the distribution and movement of oil/water two-phase flow in the well by scanning the detected region and applying a suitable data processing algorithm. The results of the numerical simulation and physical modeling show that the system could provide a clear image of the flow profile.展开更多
One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest...One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest by comparing the species composition, diversity, density, recruitment, mortality, and growth of naturally established seedlings in 160 seedling plot samples of 50 m2 located randomly on main skid trails, secondary skid trails, felled tree gaps and unlogged parts of the same forest. The study was done within a 134-ha compartment in a selectively logged moist semi-deciduous forest in Ghana over a period of 33 months involving four enumerations. Seedlings population was initially dominated by pioneers, but after 33 months, population in all sites was dominated by non-pioneers. Seedling densities showed an increase initially in all the sites after logging, but declined after 10 months. The high seedling densities were driven by four (Albizia zygia, Ceiba pentandra, Celtis mildbraedii and Turreanthus africanus) out of the 37 species that regenerated. All four species exhibited a period of exceptionally high new seedling recruitment in the first 10 months. Diversity differed significantly among disturbance types initially, but after 33 months diversity was lower in the unlogged areas though not significant. Seedling mortality was initially greater in unlogged areas of the forest and growth rates higher in the logged areas. These results show that disturbed areas appear to be suitable sites for the regeneration of timber species following logging, although the long-term fate of trees growing on these areas remains uncertain as growth rates declined with time.展开更多
The development of shale gas reservoir is mainly based on horizontal well production.Slug flow of gas-liquid two-phase is invariably encountered in inclined wells and horizontal wells of a producing environment.Due to...The development of shale gas reservoir is mainly based on horizontal well production.Slug flow of gas-liquid two-phase is invariably encountered in inclined wells and horizontal wells of a producing environment.Due to gravitational differentiation,oil-water two-phase flow pattern,the local velocity and local phase holdup along the radial direction of pipe in near horizontal wells will perform complicatedly.This paper presented the results of an experimental study and a theoretical analysis of two-phase gas/water flow in horizontal and highly inclined systems.Extensive experiments were conducted using a test loop made of 124 mm diameter acrylic pipe with inclination angles from the horizontal of 0°,5°,15°,45°,°2°,°5°and°10°,and with the total flow rate ranging from 50 to 800 m3/day.Based on the research on the law of slug flow dynamics model for gas-water two-phase flow in near horizontal pipeline,the theoretical analysis and experimental researches were done to propose the expressions of stable and exact production logging interpretation model for two-phase flow in near horizontal pipeline.The performance of the proposed method for estimating water holdup and water superficial velocity is in good agreement with our measurements.As a result,the slug flow dynamics model of gas-water two-phase flow in near horizontal wellbore was developed.The application effect of production logging in near horizontal wells had been improved.展开更多
In order to clarify the influence of the instrument’s own drag on the temperature distribution in the horizontal gas wellbore in temperature logging.By constructing an indoor gas-liquid two-phase horizontal tube flow...In order to clarify the influence of the instrument’s own drag on the temperature distribution in the horizontal gas wellbore in temperature logging.By constructing an indoor gas-liquid two-phase horizontal tube flow platform,the effects of the drag speed of the instrument on the temperature distribution in the wellbore were studied in the single-phase gas and gas-liquid two phases.In addition,during the process of instrument dragging,the influence of different perforation cluster opening methods and wellbore inclination on temperature distribution was also studied.The results show that the temperature fluctuation is reduced at higher drag speeds;Under a certain flow rate,the smaller the number of openings,the greater the influence of the instrument dragging inside the tube on the temperature distribution inside the tube;When the inclination angle is−5°,the drag of the instrument in the tube interferes greatly with the temperature distribution.When the inclination angle is 5°,the drag of the instrument in the tube has less interference with the temperature distribution.This study provides more reference for the future temperature calculation model of horizontal wellbore and has important research significance.展开更多
The Qassim province is one of the most arid regions of Saudi Arabia, however heavy rainfall events have led to water logging problems in the populated centers like Buraidah mainly as a consequence of construction in l...The Qassim province is one of the most arid regions of Saudi Arabia, however heavy rainfall events have led to water logging problems in the populated centers like Buraidah mainly as a consequence of construction in low lying areas and valleys. Urban rain storm water logging problem were reported at 4 localities in the Buraidah Municipal area after heavy rainfall in November 2008 and March 2009. The logged water from these sites were directed to 4 manmade lakes however the stagnant water in these lakes posed a serious environmental threat mainly in the form of water borne disease. Keeping this problem in mind, a detailed geophysical investigation in the form of Electrical Resistivity Tomography was carried out using the SYSCAL Pro Unit at these 4 locations with a dipole-dipole configuration. The survey was helpful in delineating the wet zones from the dry ones and based on the interpretations the optimum depth and sites of 4 injections bore-wells were determined at each locality. These injection bore-well would serve the dual propose of getting rid of the stagnant water in these lakes and also recharging the underlying aquifers.展开更多
In today’s world, the development ofeconomy has led to the continuous developmentand evolution of science and technology. Computertechnology and large-scale integration technologyhave been well developed and applied,...In today’s world, the development ofeconomy has led to the continuous developmentand evolution of science and technology. Computertechnology and large-scale integration technologyhave been well developed and applied, followed by thetechnology of digital signal processing DSP productionand application. In the field of logging, the applicationfunction of this technology plays a key role. It not onlyallows the imaging logging technology to be furtherdeveloped, but also enables fast and accurate processingof downhole signals. Therefore, among many loggingtools today, digital signal processing DSPs have beenwidely used, and their functions have been fullyutilized. This paper analyzes the application of signalprocessor DSP in logging instruments. It is hoped thatit can play a reference role in the good application anddevelopment of logging instruments.展开更多
Illegal logging has become a serious problem in forest management in ASEAN. In the paper, the illegal logging status in ASEAN is introduced, and it is sure that Indonesia, Malaysia, Brunei, Laos, Myanmar and Cambodia ...Illegal logging has become a serious problem in forest management in ASEAN. In the paper, the illegal logging status in ASEAN is introduced, and it is sure that Indonesia, Malaysia, Brunei, Laos, Myanmar and Cambodia are production countries, Thailand and Vietnam are the processing countries, and Philippines, Singapore are consumer countries in the whole supply chain of illegal logging. As well, the trade flows of illegal forest products of ASEAN are checked, the cause of illegal logging and its producing impacts are assessed. To tackle illegal logging, one feasible way is to design ecological supply chain to supervise illegal logging process, and under the concept of ecological supply chain, the production countries, processing countries and consumer countries should take actions together. Non-ASEAN countries should improve border control, introduce public procurement policies, promote market-based instruments, and strengthen international cooperation. For ASEAN countries, they should establish cooperation mechanisms within the region, take a unified action, increase governance capacity and promote legality verification or sustainability certification.展开更多
The influence of carbonate formation on Pulsed Neutron logging(such as Pulsed Neutron-Neutron logging)is quite different from that of sandstone due to the complexity of reservoir architecture and the development of fr...The influence of carbonate formation on Pulsed Neutron logging(such as Pulsed Neutron-Neutron logging)is quite different from that of sandstone due to the complexity of reservoir architecture and the development of fracture in carbonate reservoir.To study the factors affecting Pulsed Neutron-Neutron(PNN)logging in carbonate formation,the responses on fracture or cave are simulated by Monte Carlo method,getting the relationships among the macroscopic capture cross section(Σ),the count ratio of the thermal neutron at far spacing and near spacing detectors(RATIO),the fracture porosity,oil-bearing and shale content of fracture.The results show that PNN logging can be used to detect caves,and there exist linear relationships among the macroscopic capture cross section(Σ),the count ratio(RATIO)and the above factors.The research findings in this paper provides theoretical basis for the interpretation and data correction of the PNN logging in carbonate reservoirs.展开更多
This work concerns the collecting field of the Abrobakro site, the objective of which is to determine the thickness of the layers crossed during drilling from electrical logging in order to propose the equipment plan ...This work concerns the collecting field of the Abrobakro site, the objective of which is to determine the thickness of the layers crossed during drilling from electrical logging in order to propose the equipment plan for the various boreholes. The electrical logging data sheets, particularly those on resistivity and expeditious granulometry using a 1.25 mm and 2 mm mesh sieve, were used. The layer thicknesses are determined with the inflection points on the graphs. The electrical logging shows that the sands in the study area have resistivity values between 400 and 5000 Ω.m. The decrease in resistivity observed at 50 m for all boreholes shows that the static level of the groundwater is at this depth. The results of the accelerated granulometry show that the first 20 meters contain more fine particles and coarse to very coarse sands from 20 m. The granulometry of the screen laying areas shows that the 1.5 mm slot openings are best suited for all drilling in the Abrobakro collecting field. The diameter d10 of the aquiferous sands of the collecting field is close to 1.25 mm.展开更多
Volcanic oil and gas reservoirs are generally buried deep,which leads to a high whole-well coring cost,and the degree of development and size of reservoirs are controlled by volcanic facies.Therefore,accurately identi...Volcanic oil and gas reservoirs are generally buried deep,which leads to a high whole-well coring cost,and the degree of development and size of reservoirs are controlled by volcanic facies.Therefore,accurately identifying volcanic facies by logging curves not only provides the basis of volcanic reservoir prediction but also saves costs during exploration.The Songliao Basin is a‘fault-depression superimposed’composite basin with a typical binary filling structure.Abundant types of volcanic lithologies and facies are present in the Lishu fault depression.Volcanic activity is frequent during the sedimentary period of the Huoshiling Formation.Through systematic petrographic identification of the key exploratory well(SN165C)of the Lishu fault-depression,which is a whole-well core,it is found that the Huoshiling Formation in SN165C contains four facies and six subfacies,including the volcanic conduit facies(crypto explosive breccia subfacies),explosive facies(pyroclastic flow and thermal wave base subfacies),effusive facies(upper and lower subfacies),and volcanogenic sedimentary facies(pyroclastic sedimentary subfacies).Combining core,thin section,and logging data,the authors established identification markers and petrographic chart logging phases,and also interpreted the longitudinal variation in volcanic petro-graphic response characteristics to make the charts more applicable to this area's volcanic petrographic interpretation of the Huoshiling Formation.These charts can provide a basis for the further exploration and development of volcanic oil and gas in this area.展开更多
Hydrate reservoirs are different from the host reservoirs of all other fossil energy sources because the characteristics of hydrate reservoirs are generally controlled by deep-sea fine-grained sedimentation. In such r...Hydrate reservoirs are different from the host reservoirs of all other fossil energy sources because the characteristics of hydrate reservoirs are generally controlled by deep-sea fine-grained sedimentation. In such reservoirs, the reliability of the classical logging evaluation models established for diagenetic reservoirs is questionable. This study used well W8 in the Qiongdongnan Basin to explore the clay content, porosity, saturation, and hydrate-enriched layer identification of a logging-based hydrate reservoir, and it was found that considering the effect of the clay content on the log response is necessary in the logging evaluation of hydrate reservoirs. In the evaluation of clay content, a method based on the optimization inversion method can obtain a more reliable clay content than other methods. Fine-grained sediment reservoirs have a high clay content, and the effect of clay on log responses must be considered when calculating porosity. In addition, combining density logging and neutron porosity logging data can obtain the best porosity calculation results, and the porosity calculation method based on sonic logging predicted that the porosity of the studied reservoir was low. It was very effective to identify hydrate layers based on resistivity, but the clay distribution and pore structure will also affect the relationship between resistivity, porosity and saturation, and it was suggested that the factors effecting the resistivity of different layers should be considered in the saturation evaluation and that a suitable model should be selected. This study also considered the lack of clarity of the relationships among the lithology, physical properties, hydrate-bearing occurrence properties, and log response properties of hydrate reservoirs and the lack of specialized petrophysical models. This research can directly help to improve hydrate logging evaluation.展开更多
Based on five types of conventional logging curves including GR,RLLD,CNL,DEN and AC,and 39 core samples from 30 representative boreholes,the logging characteristics and lithofacies and sub-facies of the basaltic rocks...Based on five types of conventional logging curves including GR,RLLD,CNL,DEN and AC,and 39 core samples from 30 representative boreholes,the logging characteristics and lithofacies and sub-facies of the basaltic rocks were studied.Three basaltic facies and four sub-facies are recognized from the well logs,includ-ing volcanic conduit facies(post intrusive sub-facies),explosive facies,and effusive lava flow facies(tabular flow,compound flow and hyaloclastite sub-facies).The post intrusive,tabular flow and compound flow sub-facies logging curves are mainly controlled by the distribution of vesiculate zones and vesiculate content,which are characterized by four curves with good correlation.Post intrusive sub-facies are characterized by high RLLD,high DEN,with a micro-dentate logging curve pattern,abrupt contact relationships at the top and base.Tabular flow sub-facies are characterized by high RLLD,high DEN,with a bell-shaped log curve pattern,abrupt contact at the base and gradational contact at the top.Compound flow sub-facies are characterized by medium-low RLLD,with a micro-dentate or finger-like logging curve pattern,abrupt contact at the base and gradational contact at the top.Explosive facies and hyaloclastite sub-facies logging curves are mainly controlled by the distribution of the size and sorting of rock particles,which can be recognized by four kinds of logging curves with poor cor-relation.Explosive facies are characterized by low RLLD,medium-low CNL and low DEN,with a micro-dentate logging curve pattern.Hyaloclastite sub-facies are characterized by low RLLD,high CNL,low DEN and high AC,with a micro-dentate logging curve pattern.The present research is beneficial for the prediction of basaltic reser-voirs not only in the Liaohe depression but also in the other volcanic-sedimentary basins.展开更多
The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of o...The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or gas.Hence,accurately calculating the total organic carbon content in a formation is very important.Present research is focused on precisely calculating the total organic carbon content based on machine learning.At present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon content.However,the principles and perspectives of various machine learning algorithms are quite different.This paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation problems.Of various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better results.Additionally,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content prediction.The prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research block.According to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine learning.Deep learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon content.Evaluating the total organic carbon content based on machine learning is of great significance.展开更多
Downhole acoustic telemetry(DAT),using a long drill string with periodical structures as the channel,is a prospective technology for improving the transmission rate of logging while drilling(LWD)data.Previous studies ...Downhole acoustic telemetry(DAT),using a long drill string with periodical structures as the channel,is a prospective technology for improving the transmission rate of logging while drilling(LWD)data.Previous studies only focused on the acoustic property of a free drill string and neglected the coupling between pipes and fluid-filled boreholes.In addition to the drill-string waves,a series of fluid waves are recorded in the DAT channel,which has not been investigated yet.Unpredictable channel characteristics result in lower transmission rates and stability than expected.Therefore,a more realistic channel model is needed considering the fluid-filled borehole.In this paper,we propose a hybrid modeling method to investigate the response characteristics of the DAT channel.By combining the axial wavenumbers and excitation functions of mode waves in radially layered LWD structures,the channel model is approximated to the 1-D propagation,which considers transmission,reflection,and interconversion of the drillstring and fluid waves.The proposed 1-D approximation has been well validated by comparing the 2-D finite-difference modeling.It is revealed that the transmitted and converted fluid waves interfere with the drill-string wave,which characterizes the DAT channel as a particular coherent multi-path channel.When a fluid-filled borehole surrounds the drill string,the channel responses exhibit considerable delay as well as strong frequency selectivity in amplitude and phase.These new findings suggest that the complexity of the channel response has been underestimated in the past,and therefore channel measurements on the ground are unreliable.To address these channel characteristics,we apply a noncoherent demodulation strategy.The transmission rate for synthetic data reaches 15 bps in a 94.5 m long channel,indicating that the acoustic telemetry is promising to break the low-speed limitation of mud-pulse telemetry.展开更多
Observability and traceability of developed software are crucial to its success in software engineering.Observability is the ability to comprehend a system’s internal state from the outside.Monitoring is used to dete...Observability and traceability of developed software are crucial to its success in software engineering.Observability is the ability to comprehend a system’s internal state from the outside.Monitoring is used to determine what causes system problems and why.Logs are among the most critical technology to guarantee observability and traceability.Logs are frequently used to investigate software events.In current log technologies,software events are processed independently of each other.Consequently,current logging technologies do not reveal relationships.However,system events do not occur independently of one another.With this perspective,our research has produced a new log design pattern that displays the relationships between events.In the design we have developed,the hash mechanism of blockchain technology enables the display of the logs’relationships.The created design pattern was compared to blockchain technology,demonstrating its performance through scenarios.It has been determined that the recommended log design pattern outperforms blockchain technology in terms of time and space for software engineering observability and traceability.In this context,it is anticipated that the log design pattern we provide will strengthen the methods used to monitor software projects and ensure the traceability of relationships.展开更多
According to the capillary theory,an equivalent capillary model of micro-resistivity imaging logging was built.On this basis,the theoretical models of porosity spectrum(Ф_(i)),permeability spectrum(K_(i))and equivale...According to the capillary theory,an equivalent capillary model of micro-resistivity imaging logging was built.On this basis,the theoretical models of porosity spectrum(Ф_(i)),permeability spectrum(K_(i))and equivalent capillary pressure curve(pe)were established to reflect the reservoir heterogeneity.To promote the application of the theoretical models,the Archie's equation was introduced to establish a general model for quantitatively characterizing bi,K,and pei.Compared with the existing models,it is shown that:(1)the existing porosity spectrum model is the same as the general equation of gi;(2)the Ki model can display the permeability spectrum as compared with Purcell's permeability model;(3)the per model is constructed on a theoretical basis and avoids the limitations of existing models that are built only based on the component of porosity spectrum,as compared with the empirical model of capillary pressure curve.The application in the Permian Maokou Formation of Well TsX in the Central Sichuan paleo-uplift shows that the Ф_(i),K_(i),and p_(ci) models can be effectively applied to the identification of reservoir types,calculation of reservoir properties and pore structure parameters,and evaluation of reservoir heterogeneity.展开更多
文摘Logging data and its interpretation results are one of the most important basic data for understanding reservoirs and oilfield development. Standardized and unified logging interpretation results play a decisive role in fine reservoir description and reservoir development. Aiming at the problem of the conflict between the development effect and the initial interpretation result of Yan 9 reservoir in Hujianshan area of Ordos Basin, by combining the current well production performance, logging, oil test, production test and other data, on the basis of making full use of core, coring, logging, thin section analysis and high pressure mercury injection data, the four characteristics of reservoir are analyzed, a more scientific and reasonable calculation model of reservoir logging parameters is established, and the reserves are recalculated after the second interpretation standard of logging is determined. The research improves the accuracy of logging interpretation and provides an effective basis for subsequent production development and potential horizons.
基金This research is funded by SINOPEC Group Project P20039-2.
文摘Tight and unconventional reservoirs have become the focus with the progress of petroleum exploration and development.Micro-fractures in these reservoirs can effectively improve reservoir permeability,and well-developed micro-fractures can serve to directly improve productivity.Compared with the centered electrical well logging method,the Micro Spherical Focused Logging(MSFL)is more suitable for microfracture identification due to its high resolution and near borehole wall measuring method.In this study,an anisotropic model is used to depict micro-fractured formation.First,a forward model with microfractured formation,borehole,logging instrument and surrounding rock is established.Subsequently,MSFL responses under different micro-fracture porosity,resistivity,dip angle and borehole radius,are calculated based on the finite element method(FEM).Finally,the MSFL responses under different microfracture parameters are analyzed with the response laws clarified.
文摘Since gas hydrate exists in three different forms at the same time such as pore filling,particle support and separate stratification,the calculation method of hydrate saturation using traditional shaly sand formation interpretation models is equivalent to considering only the simple case that hydrate exists as pore filling,and does not consider other complex states.Based on the analysis of hydrate resistivity experimental data and the general form of the resistivity-oil(gas)saturation relationship,the best simplified formula of hydrate saturation calculation is derived,then the physical meaning of the three items are clarified:they respectively represent the resistivity index-saturation relationship when hydrate particles are completely distributed in the pores of formation rocks,supported in the form of particles,and exist in layers,corresponding quantitative evaluation method of hydrate saturation is built.The field application shows that the hydrate saturation calculated by this method is closer to that obtained by sampling analysis.At the same time,it also provides a logging analysis basis for the effective development after hydrate exploration.
基金This work was supported by the National Natural Science Foundation of China(60472019).
文摘Electromagnetic Computer Tomography (ECT) is a method to probe the interior of an inhomogeneous medium via surface measurement in a non-linear way. Due to the great differences in conductivity and permittivity between oil and water in the well, Electromagnetic Tomography Well Logging (ETWL), a new flow imaging measurement system, is proposed to describe the distribution and movement of oil/water two-phase flow in the well by scanning the detected region and applying a suitable data processing algorithm. The results of the numerical simulation and physical modeling show that the system could provide a clear image of the flow profile.
文摘One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest by comparing the species composition, diversity, density, recruitment, mortality, and growth of naturally established seedlings in 160 seedling plot samples of 50 m2 located randomly on main skid trails, secondary skid trails, felled tree gaps and unlogged parts of the same forest. The study was done within a 134-ha compartment in a selectively logged moist semi-deciduous forest in Ghana over a period of 33 months involving four enumerations. Seedlings population was initially dominated by pioneers, but after 33 months, population in all sites was dominated by non-pioneers. Seedling densities showed an increase initially in all the sites after logging, but declined after 10 months. The high seedling densities were driven by four (Albizia zygia, Ceiba pentandra, Celtis mildbraedii and Turreanthus africanus) out of the 37 species that regenerated. All four species exhibited a period of exceptionally high new seedling recruitment in the first 10 months. Diversity differed significantly among disturbance types initially, but after 33 months diversity was lower in the unlogged areas though not significant. Seedling mortality was initially greater in unlogged areas of the forest and growth rates higher in the logged areas. These results show that disturbed areas appear to be suitable sites for the regeneration of timber species following logging, although the long-term fate of trees growing on these areas remains uncertain as growth rates declined with time.
基金Educational Commission of Hubei Province of China(D20141302)Open Fund of Key Laboratory of Exploration Technologies for Oil and Gas Resources(Yangtze University),Ministry of Education(No.K2018-02)National Natural Science Foundation of China(41474115).
文摘The development of shale gas reservoir is mainly based on horizontal well production.Slug flow of gas-liquid two-phase is invariably encountered in inclined wells and horizontal wells of a producing environment.Due to gravitational differentiation,oil-water two-phase flow pattern,the local velocity and local phase holdup along the radial direction of pipe in near horizontal wells will perform complicatedly.This paper presented the results of an experimental study and a theoretical analysis of two-phase gas/water flow in horizontal and highly inclined systems.Extensive experiments were conducted using a test loop made of 124 mm diameter acrylic pipe with inclination angles from the horizontal of 0°,5°,15°,45°,°2°,°5°and°10°,and with the total flow rate ranging from 50 to 800 m3/day.Based on the research on the law of slug flow dynamics model for gas-water two-phase flow in near horizontal pipeline,the theoretical analysis and experimental researches were done to propose the expressions of stable and exact production logging interpretation model for two-phase flow in near horizontal pipeline.The performance of the proposed method for estimating water holdup and water superficial velocity is in good agreement with our measurements.As a result,the slug flow dynamics model of gas-water two-phase flow in near horizontal wellbore was developed.The application effect of production logging in near horizontal wells had been improved.
基金supported by the Foundation of the Educational Commission of Hubei Province of China[grant numbers No.Q20191310]the National Natural Science Fund Project[grant number 61572084].
文摘In order to clarify the influence of the instrument’s own drag on the temperature distribution in the horizontal gas wellbore in temperature logging.By constructing an indoor gas-liquid two-phase horizontal tube flow platform,the effects of the drag speed of the instrument on the temperature distribution in the wellbore were studied in the single-phase gas and gas-liquid two phases.In addition,during the process of instrument dragging,the influence of different perforation cluster opening methods and wellbore inclination on temperature distribution was also studied.The results show that the temperature fluctuation is reduced at higher drag speeds;Under a certain flow rate,the smaller the number of openings,the greater the influence of the instrument dragging inside the tube on the temperature distribution inside the tube;When the inclination angle is−5°,the drag of the instrument in the tube interferes greatly with the temperature distribution.When the inclination angle is 5°,the drag of the instrument in the tube has less interference with the temperature distribution.This study provides more reference for the future temperature calculation model of horizontal wellbore and has important research significance.
文摘The Qassim province is one of the most arid regions of Saudi Arabia, however heavy rainfall events have led to water logging problems in the populated centers like Buraidah mainly as a consequence of construction in low lying areas and valleys. Urban rain storm water logging problem were reported at 4 localities in the Buraidah Municipal area after heavy rainfall in November 2008 and March 2009. The logged water from these sites were directed to 4 manmade lakes however the stagnant water in these lakes posed a serious environmental threat mainly in the form of water borne disease. Keeping this problem in mind, a detailed geophysical investigation in the form of Electrical Resistivity Tomography was carried out using the SYSCAL Pro Unit at these 4 locations with a dipole-dipole configuration. The survey was helpful in delineating the wet zones from the dry ones and based on the interpretations the optimum depth and sites of 4 injections bore-wells were determined at each locality. These injection bore-well would serve the dual propose of getting rid of the stagnant water in these lakes and also recharging the underlying aquifers.
文摘In today’s world, the development ofeconomy has led to the continuous developmentand evolution of science and technology. Computertechnology and large-scale integration technologyhave been well developed and applied, followed by thetechnology of digital signal processing DSP productionand application. In the field of logging, the applicationfunction of this technology plays a key role. It not onlyallows the imaging logging technology to be furtherdeveloped, but also enables fast and accurate processingof downhole signals. Therefore, among many loggingtools today, digital signal processing DSPs have beenwidely used, and their functions have been fullyutilized. This paper analyzes the application of signalprocessor DSP in logging instruments. It is hoped thatit can play a reference role in the good application anddevelopment of logging instruments.
基金supported by the National Social Science Foundation of China (Grant No. 13BGL101)financial support from Jiangsu Education Administration Bureau
文摘Illegal logging has become a serious problem in forest management in ASEAN. In the paper, the illegal logging status in ASEAN is introduced, and it is sure that Indonesia, Malaysia, Brunei, Laos, Myanmar and Cambodia are production countries, Thailand and Vietnam are the processing countries, and Philippines, Singapore are consumer countries in the whole supply chain of illegal logging. As well, the trade flows of illegal forest products of ASEAN are checked, the cause of illegal logging and its producing impacts are assessed. To tackle illegal logging, one feasible way is to design ecological supply chain to supervise illegal logging process, and under the concept of ecological supply chain, the production countries, processing countries and consumer countries should take actions together. Non-ASEAN countries should improve border control, introduce public procurement policies, promote market-based instruments, and strengthen international cooperation. For ASEAN countries, they should establish cooperation mechanisms within the region, take a unified action, increase governance capacity and promote legality verification or sustainability certification.
基金Supported by Project of Sinopec Northwest Oilfield Branch(No.ky2019s023)
文摘The influence of carbonate formation on Pulsed Neutron logging(such as Pulsed Neutron-Neutron logging)is quite different from that of sandstone due to the complexity of reservoir architecture and the development of fracture in carbonate reservoir.To study the factors affecting Pulsed Neutron-Neutron(PNN)logging in carbonate formation,the responses on fracture or cave are simulated by Monte Carlo method,getting the relationships among the macroscopic capture cross section(Σ),the count ratio of the thermal neutron at far spacing and near spacing detectors(RATIO),the fracture porosity,oil-bearing and shale content of fracture.The results show that PNN logging can be used to detect caves,and there exist linear relationships among the macroscopic capture cross section(Σ),the count ratio(RATIO)and the above factors.The research findings in this paper provides theoretical basis for the interpretation and data correction of the PNN logging in carbonate reservoirs.
文摘This work concerns the collecting field of the Abrobakro site, the objective of which is to determine the thickness of the layers crossed during drilling from electrical logging in order to propose the equipment plan for the various boreholes. The electrical logging data sheets, particularly those on resistivity and expeditious granulometry using a 1.25 mm and 2 mm mesh sieve, were used. The layer thicknesses are determined with the inflection points on the graphs. The electrical logging shows that the sands in the study area have resistivity values between 400 and 5000 Ω.m. The decrease in resistivity observed at 50 m for all boreholes shows that the static level of the groundwater is at this depth. The results of the accelerated granulometry show that the first 20 meters contain more fine particles and coarse to very coarse sands from 20 m. The granulometry of the screen laying areas shows that the 1.5 mm slot openings are best suited for all drilling in the Abrobakro collecting field. The diameter d10 of the aquiferous sands of the collecting field is close to 1.25 mm.
基金Supported by projects of the National Natural Science Foundatio n of China(Nos.41972313,41790453).
文摘Volcanic oil and gas reservoirs are generally buried deep,which leads to a high whole-well coring cost,and the degree of development and size of reservoirs are controlled by volcanic facies.Therefore,accurately identifying volcanic facies by logging curves not only provides the basis of volcanic reservoir prediction but also saves costs during exploration.The Songliao Basin is a‘fault-depression superimposed’composite basin with a typical binary filling structure.Abundant types of volcanic lithologies and facies are present in the Lishu fault depression.Volcanic activity is frequent during the sedimentary period of the Huoshiling Formation.Through systematic petrographic identification of the key exploratory well(SN165C)of the Lishu fault-depression,which is a whole-well core,it is found that the Huoshiling Formation in SN165C contains four facies and six subfacies,including the volcanic conduit facies(crypto explosive breccia subfacies),explosive facies(pyroclastic flow and thermal wave base subfacies),effusive facies(upper and lower subfacies),and volcanogenic sedimentary facies(pyroclastic sedimentary subfacies).Combining core,thin section,and logging data,the authors established identification markers and petrographic chart logging phases,and also interpreted the longitudinal variation in volcanic petro-graphic response characteristics to make the charts more applicable to this area's volcanic petrographic interpretation of the Huoshiling Formation.These charts can provide a basis for the further exploration and development of volcanic oil and gas in this area.
基金funded by the Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology(No.MGQNLM-KF202004)Hainan Provincial Natural Science Foundation of China(Nos.422RC746 and 421QN281)+2 种基金the National Natural Science Foundation of China(No.42106213)the China Postdoctoral Science Foundation(Nos.2021M690161 and 2021T140691)the Postdoctorate Funded Project in Hainan Province.
文摘Hydrate reservoirs are different from the host reservoirs of all other fossil energy sources because the characteristics of hydrate reservoirs are generally controlled by deep-sea fine-grained sedimentation. In such reservoirs, the reliability of the classical logging evaluation models established for diagenetic reservoirs is questionable. This study used well W8 in the Qiongdongnan Basin to explore the clay content, porosity, saturation, and hydrate-enriched layer identification of a logging-based hydrate reservoir, and it was found that considering the effect of the clay content on the log response is necessary in the logging evaluation of hydrate reservoirs. In the evaluation of clay content, a method based on the optimization inversion method can obtain a more reliable clay content than other methods. Fine-grained sediment reservoirs have a high clay content, and the effect of clay on log responses must be considered when calculating porosity. In addition, combining density logging and neutron porosity logging data can obtain the best porosity calculation results, and the porosity calculation method based on sonic logging predicted that the porosity of the studied reservoir was low. It was very effective to identify hydrate layers based on resistivity, but the clay distribution and pore structure will also affect the relationship between resistivity, porosity and saturation, and it was suggested that the factors effecting the resistivity of different layers should be considered in the saturation evaluation and that a suitable model should be selected. This study also considered the lack of clarity of the relationships among the lithology, physical properties, hydrate-bearing occurrence properties, and log response properties of hydrate reservoirs and the lack of specialized petrophysical models. This research can directly help to improve hydrate logging evaluation.
文摘Based on five types of conventional logging curves including GR,RLLD,CNL,DEN and AC,and 39 core samples from 30 representative boreholes,the logging characteristics and lithofacies and sub-facies of the basaltic rocks were studied.Three basaltic facies and four sub-facies are recognized from the well logs,includ-ing volcanic conduit facies(post intrusive sub-facies),explosive facies,and effusive lava flow facies(tabular flow,compound flow and hyaloclastite sub-facies).The post intrusive,tabular flow and compound flow sub-facies logging curves are mainly controlled by the distribution of vesiculate zones and vesiculate content,which are characterized by four curves with good correlation.Post intrusive sub-facies are characterized by high RLLD,high DEN,with a micro-dentate logging curve pattern,abrupt contact relationships at the top and base.Tabular flow sub-facies are characterized by high RLLD,high DEN,with a bell-shaped log curve pattern,abrupt contact at the base and gradational contact at the top.Compound flow sub-facies are characterized by medium-low RLLD,with a micro-dentate or finger-like logging curve pattern,abrupt contact at the base and gradational contact at the top.Explosive facies and hyaloclastite sub-facies logging curves are mainly controlled by the distribution of the size and sorting of rock particles,which can be recognized by four kinds of logging curves with poor cor-relation.Explosive facies are characterized by low RLLD,medium-low CNL and low DEN,with a micro-dentate logging curve pattern.Hyaloclastite sub-facies are characterized by low RLLD,high CNL,low DEN and high AC,with a micro-dentate logging curve pattern.The present research is beneficial for the prediction of basaltic reser-voirs not only in the Liaohe depression but also in the other volcanic-sedimentary basins.
基金This project was funded by the Open Fund of the Key Laboratory of Exploration Technologies for Oil and Gas Resources,the Ministry of Education(No.K2021-03)National Natural Science Foundation of China(No.42106213)+2 种基金the Hainan Provincial Natural Science Foundation of China(No.421QN281)the China Postdoctoral Science Foundation(Nos.2021M690161 and 2021T140691)the Postdoctorate Funded Project in Hainan Province.
文摘The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or gas.Hence,accurately calculating the total organic carbon content in a formation is very important.Present research is focused on precisely calculating the total organic carbon content based on machine learning.At present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon content.However,the principles and perspectives of various machine learning algorithms are quite different.This paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation problems.Of various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better results.Additionally,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content prediction.The prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research block.According to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine learning.Deep learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon content.Evaluating the total organic carbon content based on machine learning is of great significance.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174421 and 11734017)the Scientific Instrument Developing Project of the Chinese Academy of Sciences,China(Grant Nos.YJKYYQ20200072 and GJJSTD20210008).
文摘Downhole acoustic telemetry(DAT),using a long drill string with periodical structures as the channel,is a prospective technology for improving the transmission rate of logging while drilling(LWD)data.Previous studies only focused on the acoustic property of a free drill string and neglected the coupling between pipes and fluid-filled boreholes.In addition to the drill-string waves,a series of fluid waves are recorded in the DAT channel,which has not been investigated yet.Unpredictable channel characteristics result in lower transmission rates and stability than expected.Therefore,a more realistic channel model is needed considering the fluid-filled borehole.In this paper,we propose a hybrid modeling method to investigate the response characteristics of the DAT channel.By combining the axial wavenumbers and excitation functions of mode waves in radially layered LWD structures,the channel model is approximated to the 1-D propagation,which considers transmission,reflection,and interconversion of the drillstring and fluid waves.The proposed 1-D approximation has been well validated by comparing the 2-D finite-difference modeling.It is revealed that the transmitted and converted fluid waves interfere with the drill-string wave,which characterizes the DAT channel as a particular coherent multi-path channel.When a fluid-filled borehole surrounds the drill string,the channel responses exhibit considerable delay as well as strong frequency selectivity in amplitude and phase.These new findings suggest that the complexity of the channel response has been underestimated in the past,and therefore channel measurements on the ground are unreliable.To address these channel characteristics,we apply a noncoherent demodulation strategy.The transmission rate for synthetic data reaches 15 bps in a 94.5 m long channel,indicating that the acoustic telemetry is promising to break the low-speed limitation of mud-pulse telemetry.
文摘Observability and traceability of developed software are crucial to its success in software engineering.Observability is the ability to comprehend a system’s internal state from the outside.Monitoring is used to determine what causes system problems and why.Logs are among the most critical technology to guarantee observability and traceability.Logs are frequently used to investigate software events.In current log technologies,software events are processed independently of each other.Consequently,current logging technologies do not reveal relationships.However,system events do not occur independently of one another.With this perspective,our research has produced a new log design pattern that displays the relationships between events.In the design we have developed,the hash mechanism of blockchain technology enables the display of the logs’relationships.The created design pattern was compared to blockchain technology,demonstrating its performance through scenarios.It has been determined that the recommended log design pattern outperforms blockchain technology in terms of time and space for software engineering observability and traceability.In this context,it is anticipated that the log design pattern we provide will strengthen the methods used to monitor software projects and ensure the traceability of relationships.
基金Supported by the National Natural Science Foundation of China(U2003102,41974117)China National Science and Technology Major Project(2016ZX05052001).
文摘According to the capillary theory,an equivalent capillary model of micro-resistivity imaging logging was built.On this basis,the theoretical models of porosity spectrum(Ф_(i)),permeability spectrum(K_(i))and equivalent capillary pressure curve(pe)were established to reflect the reservoir heterogeneity.To promote the application of the theoretical models,the Archie's equation was introduced to establish a general model for quantitatively characterizing bi,K,and pei.Compared with the existing models,it is shown that:(1)the existing porosity spectrum model is the same as the general equation of gi;(2)the Ki model can display the permeability spectrum as compared with Purcell's permeability model;(3)the per model is constructed on a theoretical basis and avoids the limitations of existing models that are built only based on the component of porosity spectrum,as compared with the empirical model of capillary pressure curve.The application in the Permian Maokou Formation of Well TsX in the Central Sichuan paleo-uplift shows that the Ф_(i),K_(i),and p_(ci) models can be effectively applied to the identification of reservoir types,calculation of reservoir properties and pore structure parameters,and evaluation of reservoir heterogeneity.