The Experts below are selected from a list of 2448 Experts worldwide ranked by ideXlab platform

Roman Pevzner - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Sensitivity of Downhole Temperature Estimates From Distributed Temperature Sensing Measurements
    Energy Procedia, 2018
    Co-Authors: Ludovic Ricard, Roman Pevzner
    Abstract:

    Abstract A range of Australian CCS research activities (CO2CRC Otway Stage 3, CO2CRC Otway shallow controlled release and CSIRO Insitu-lab) involving subsurface characterisation and/or CO2 injection are at the planning stage. Fibre-optic sensing is considered as part of the Downhole reservoir characterisation and surveillance monitoring system for all of these projects. In this work, we investigate the sensitivity of DTS for the detection of thermal anomalies in view of the design of future geological storage activities in Australia. Ahead of Phase 2 of the CO2CRC Otway shallow CO2 controlled release experiment, a DTS system was installed in the CRC-3 well for equipment testing and baseline characterisation, at the same time as the acquisition of the CO2CRC Stage 2C M5 seismic survey. Temperature measurements were acquired from well-head to bottom-hole for 13 days at a rate of one-minute measurement every 4 minutes. The Temperature profile did not change significantly over time. The integration and processing of more than 3400 Temperature traces enabled estimation of a Temperature profile with a resolution of 0.01 °C. The use of DTS during the CO2CRC M5 survey highlights the detectability of a VSP tool producing 11W and 4W at two distinct depths. The setup was capable of detecting a 0.7 °C anomaly very quickly. A smaller anomaly (0.1 °C) was detected with the benefit of data processing of the long term dataset. The high spatial resolution of DTS enables location of thermal anomalies to within 2 metres.

Viacheslav V. Spichak - One of the best experts on this subject based on the ideXlab platform.

  • Neural Network Approach to the Temperature Estimation
    Electromagnetic Geothermometry, 2015
    Co-Authors: Viacheslav V. Spichak, Olga K. Zakharova
    Abstract:

    A neural network-based method for predicting the distribution of Temperatures in geothermal areas from Downhole Temperature logs is discussed. It is tested using an analytical Temperature model, showing that the errors in neuronet Temperature estimates based on well log data derive from (a) the neuronet “education level” (which depends on the amount and structure of information used for teaching), and (b) the distance of the point at which the estimate is made from the area for which data are available. These conclusions are confirmed when estimating Temperatures in eight actual wells, using 50 Downhole Temperature logs from other wells in the geothermal area. The effects of the teaching-data pattern (conductive versus convective type of Temperature profiles) are also studied, and an optimal strategy is discussed for the neuronet training, based on the information available.

  • Estimating Temperature distributions in geothermal areas using a neuronet approach
    Geothermics, 2006
    Co-Authors: Viacheslav V. Spichak
    Abstract:

    A method is proposed for predicting the distribution of Temperatures in geothermal areas using the neuronet approach and, in particular, Downhole Temperature logs. The method was tested against the results of an analytical model, showing that the errors in neuronet Temperature estimates based on well log data derive from: (a) the neuronet “education level” (which depends on the amount and structure of information used for teaching) and (b) the distance of the point at which the estimate is made from the area for which data are available. These conclusions were confirmed when estimating Temperatures in eight actual wells, using 50 Downhole Temperature logs from other wells in the geothermal area. It was found that, for this particular case, neuronet teaching utilizing 30 well logs results in an average forecast error of 20%. As the number of training logs increases (up to 50), the error slightly decreases (down to 16.9%). The effects of the teaching data pattern (conductive-type versus convective-type of Temperature profiles) were also studied, and an optimal strategy was developed for the neuronet training, based on the information available.

Ludovic Ricard - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Sensitivity of Downhole Temperature Estimates From Distributed Temperature Sensing Measurements
    Energy Procedia, 2018
    Co-Authors: Ludovic Ricard, Roman Pevzner
    Abstract:

    Abstract A range of Australian CCS research activities (CO2CRC Otway Stage 3, CO2CRC Otway shallow controlled release and CSIRO Insitu-lab) involving subsurface characterisation and/or CO2 injection are at the planning stage. Fibre-optic sensing is considered as part of the Downhole reservoir characterisation and surveillance monitoring system for all of these projects. In this work, we investigate the sensitivity of DTS for the detection of thermal anomalies in view of the design of future geological storage activities in Australia. Ahead of Phase 2 of the CO2CRC Otway shallow CO2 controlled release experiment, a DTS system was installed in the CRC-3 well for equipment testing and baseline characterisation, at the same time as the acquisition of the CO2CRC Stage 2C M5 seismic survey. Temperature measurements were acquired from well-head to bottom-hole for 13 days at a rate of one-minute measurement every 4 minutes. The Temperature profile did not change significantly over time. The integration and processing of more than 3400 Temperature traces enabled estimation of a Temperature profile with a resolution of 0.01 °C. The use of DTS during the CO2CRC M5 survey highlights the detectability of a VSP tool producing 11W and 4W at two distinct depths. The setup was capable of detecting a 0.7 °C anomaly very quickly. A smaller anomaly (0.1 °C) was detected with the benefit of data processing of the long term dataset. The high spatial resolution of DTS enables location of thermal anomalies to within 2 metres.

Shi Ying - One of the best experts on this subject based on the ideXlab platform.

  • Numerical simulation of Downhole Temperature distribution in polymer injection well
    2007
    Co-Authors: Shi Ying
    Abstract:

    In the paper a new numerical simulation method is proposed to calculate Downhole Temperature distribution in polymer injection wells.Based on rheological property of polymer solution in porous medium and energy conservation equation,2D Temperature field models for wellbore fluid,injection zone and adjacent zone in cylindrical coordinates are developed with seeoage velocity derived from generalized Darcy Low.In the model injected polymer solution in the hole is considered as non-Newtonian fluid,and variation of its velocity is also taken into account.Three models are coupled by correct boundary conditions.An alternating direction implicit difference method(ADI) is used to solve the Temperature models for Downhole Temperature distribution.We study the effects of injection rate,injection time,power law index and consistency coefficient,injection fluid Temperature on Downhole Temperature distribution,and draw conclusion that Temperature in injected zone decreases with increase of injection rate or injection time,and with decrease of viscosity of polymer solution while Temperature of injected polymer solution is less than initial Temperature in injected zone,and also the greater the Temperature difference between injected polymer solution and injected zone,the more obvious deflection on Temperature curve opposite the injected zone.The results can be used to instruct actual interpretation of Temperature log in polymer injection wells.

  • Radial Temperature distribution in production oil wells
    Journal of Daqing Petroleum Institute, 2006
    Co-Authors: Shi Ying
    Abstract:

    Being informed of Downhole Temperature distribution is very important in knowing producing development and producing condition.On the basis of the energy conservation equation,based on the heat transfer theory of continuous medium and porous medium,the 2-D mathematical models of Downhole Temperature field in cylindrical coordinates have been constructed for production wells.Proper initial and boundary condition wellbore parameter and formation property parameter are selected.Downhole Temperature distribution with multiple pay zones in different distance from producing oil wellbore have been simulated by finite difference algorithm,and simulated result corresponds to general knowledge,which is the theoretical basis for further observing oil field production condition.

  • Numerical simulation for shutdown Temperature profile in Oil Wells
    Journal of Daqing Petroleum Institute, 2005
    Co-Authors: Shi Ying
    Abstract:

    A method is put forward to calculate Downhole Temperature distribution while oil wells have been shut for days.Here,the actual situation of multiplayer production in most oil wells are considered.According to energy conservation equation,the Temperature field models of the wellbore and adjacent formation have been constructed for shutdown production wells,and an alternate direction implicit finite difference algorithm(ADI) is used to solve Temperature models.The effects of different distance from wellbore and off production time on Downhole Temperature distribution are developed.The results show that the longer off production time,wellbore Temperature more near original formation Temperature.The results also show that the effect of wellbore fluid of distant formation from wellbore is very small,and no effect is exerted on the infinitely distant formation.

Robert G. Jeffrey - One of the best experts on this subject based on the ideXlab platform.

  • A model for Downhole fluid and rock Temperature prediction during circulation
    Geothermics, 2014
    Co-Authors: Xi Zhang, Robert G. Jeffrey
    Abstract:

    Abstract In this paper, we present a model to investigate the evolution of fluid and rock Temperature during fluid circulation in a wellbore. The analysis considers circulation of a fluid down a centralized drill or tubing string with the returned fluid travelling up the annular space between the tubing and the wellbore. Under such conditions, which typically occur during drilling, the cooler injected fluid is heated as it travels down the tubing and cools the wellbore rock as it returns up the annulus. Based on the established governing equations for heat transfer between fluid and rock, a semi-analytic method is developed by applying Laplace transformation and numerical inversion to find the results in time and space. The heat transfer coefficients between rock and fluid are dependent on flow behaviour and material properties, characterizing advective heat transfer under complex flow. A dimensional analysis is conducted to identify the controlling dimensionless parameters. The solutions are validated by comparisons with theoretical predictions of heat diffusion inside the rock and with measured Downhole Temperature variations. The results show that the injection rate plays an important role in the Downhole Temperature evolution. The surface outlet Temperature of the fluid from the annulus typically reaches a pseudo-steady state in a relatively rapid manner. Additionally, the strong cooling resulting from injection of cold fluid with circulation back up the annulus may cause significant thermoelastic changes in rock stress near the wellbore, potentially leading to tensile hydraulic fracturing initiation.