Concept




THE HIGH-PRECISION TEMPERATURE LOGGING IS ONE OF THE MOST INFORMATIVE WELL–SURVEYING TECHNIQUES TO ANALYSE THE OPERATING CONDITIONS AND INTEGRITY OF WELLS, FEATURING AS FOLLOWS:




For injectors:

  • 1. Locate of injection zones;
  • 2. Detect wellbore cross-flows;
  • 3. Detect cross-flows behind casing;
  • 4. Fix integrity issues of casing and tubing;
  • 5. Ascertain injected fluid loss below the well bottom or logging zone.


For producers:

  • 1. Locate inflow zones;
  • 2. Detect wellbore cross-flows;
  • 3. Detect cross-flows behind casing;
  • 4. Fix integrity issues of casing and tubing;
  • 5. Ascertain zones of water breakthrough from nearby injectors.


The HPT logging is run using temperature gauges. The temperature gauges used by TGT for temperature logging operations are described in Section HPT.

The TERMOSIM simulator developed by TGT is used for numerical temperature modelling of wellbore, multilayer reservoir and surrounding rocks as well as fluid flows in multilayer reservoir system and wellbore with respect to cross-flows and channelling between the units and thermodynamic effects occurring while fluid flows through the reservoir and wellbore.

The comparison of computed model results with HPT logging data enhances the interpretation of temperature data and quantifies wellbore and reservoir performance. Using TERMOSIM for survey planning allows an optimum logging program for each well.

The TERMOSIM operates in two modes: Injection mode is for injection temperature modelling and production mode is designed for production temperature modelling. Refer to Sections iTSM and pTSM for description of performance and features of simulation software.



HPT – High Precision Temperature Logging


The DMPT gauge is a downhole battery-powered memory tool for measuring pressure and temperature. The combination of a sapphire pressure gauge and a high-resolution fast-response platinum temperature sensor ensures top-level measurements. The tool has an outstanding operational lifetime of one year. High-capacity memory and a programmable interface provide flexibility in downhole measurements. The fast USB bus provides a convenient interface for data downloading. The tool has a robust design to ensure reliable data acquisition in hard wellbore conditions. AutoMAN user-friendly software provides simple communication with the tool memory, a programming interface, primary data processing and export to popular data file formats.


FEATURES

  • High resolution and fast response temperature sensor
  • Temperature compensated pressure gauge
  • Long Battery lifetime – 1 year
  • Large Memory – more than 500,000 data points
  • Built-in clock
  • Programmable start
  • Programmable sampling rate

Hardware & software tools


HPT


iTSM


The iTSM Injection Temperature Simulator provides numerical solution of the general thermo-mechanically coupled problem of fluid flows (water or gas) and conjugated heat transfer in an injection well, anisotropic surrounding rocks and reservoir units with account for cross-flows and channelling between the units, calorimetric mixing of inflows in the injectors across the reservoir formation, and Joule-Thompson (choke) effect in matrix flows.

The iTSM is used for temperature modelling of the “injector – reservoir” system, 3D distribution of disturbed rock and reservoir temperature, wellbore temperature profiles, initial background (geothermal) temperature.


The iTSM has the following basic features:

  • Models wellbore flowing and rock temperature profiles with a careful account for the well low-curvature inclination and can be applied for deviated and horizontal wells;
  • Accounts for any injection fluid as a heat or cold carrying agent, which should be specified in the model input;
  • Accounts for all historical wellhead injection rates and temperatures with various combinations of alternating flowing and shut-in periods;
  • Accounts for well completion elements through a number of parameters related to the thermal skin produced by cement bond, casing and A/B annulus as well as the filling fluid properties;
  • Can start simulation for a previously disturbed zone and account for two interacting processes: relaxation of previously disturbed temperature caused by historical injection and the most recent disturbance caused by wellbore injection;
  • Modelling complete changing-in-time hydrodynamic flow pattern of transient fluid flows in the multilayer “injection – reservoir” system;
  • Accounts for original background temperature perturbations caused by secular (geologically long-term) ground-water and historically young (recent) flows (due to industrial flows of warm or cold fluid or operation of nearby wells);
  • Account for the full climate history on the Earth’s surface, including seasonal and diurnal temperature variations of the air or sea floor.

The simulator is recommended for interpretation of wellbore temperature logs in injection wells to obtain injection profiles. It can also be used for estimation of the reservoir unit pressures, localization and quantification of channelling, estimation of fluid volumes flowing outside the logging zones, verification of well completion integrity. Simulator can also be used for adjustment of different model parameters, e.g. rock properties, as well as for predicting temperature perturbation zones created by fluid injection, identification of historical injection zones, and updating of the geothermal profile.


The Simulator uses the following input data:

   
Well completion
Well trajectoryLogs
Inner tubing radiusLog
Casing radiusLog
Annulus fluid typeLog
Annulus pressureLog
Tubing wall thicknessNumber
Casing wall thicknessNumber
Injection history
RatesTime records
Entry temperaturesTime records
Injection profiles
Injection profile along the holeLog
Historical injection profile along the holeLog
Thermophysical properties of injection fluid and well completion
Volumetric heat capacity(Fluid – pressure-temperature table, completion steel – number)
Density Pressure-temperature table
Volumetric expansion coefficient Pressure-temperature table
Thermal conductivity (Fluid – pressure-temperature table, completion steel – number)
Dynamic viscosity Pressure-temperature table
Compressibility coefficientPressure-temperature table
Thermo-physical rock properties
Volumetric heat capacityLog
Vertical thermal conductivityLog
Lateral thermal conductivityLog
Reservoir porosity profileLog
Geothermal rock model
Regional geothermal fluxNumber
Geothermal temperature reference depthNumber
Geothermal temperature reference valueNumber
Earth’s surface climate history: air or sea-floor temperaturesTime records
Surface heat transfer coefficientNumber
Secular lateral flowsLog
Young lateral flowsLog and numbers
Grid data
Depth grid
                     Vertical step across the reservoir                      formation                     Number
                     Axial step along the well trajectory                     Number
Radial grid
                     Borehole mean radius                     Number
                     Near zone step                     Number
                     Far zone step                     Number
                     Radial grid type (uniform/logarithmic)                     Flag
                     Outer boundary multiplier                     Number
Logging tool
Logging tool (thermometer) velocity Log

The simulator output data (at any moment of time):

1. Pressure distribution and hydrodynamic description of fluid flows in «wellbore – reservoir» system;

2. Wellbore flowing temperature profile in tubing;

3. Wellbore channelling temperature profile in completion;

4. Temperature profiles in rocks and reservoir at any distance from the wellbore;

5. Geothermal temperature profile within the model domain with account for secular and young lateral flows;

6. Wellbore pressure profile.


iTSM has Graphical User Interface (GUI) to show and modify input data and start the solver.

iTSM


After completion of model calculations, the simulator results are saved in LAS-file.


HD-inj



pTSM


The pTSM Production Temperature Simulator provides numerical solution of the general thermo-mechanically coupled problem of fluid flows (water or gas) and conjugated heat transfer in a producer, in surrounding anisotropic rocks and reservoir units with account for cross-flows and channelling between the units, thermal mixing of inflows in the producer across the reservoir formation, and Joule-Thompson (choke) effects in the reservoir matrix.

pTSM is used for hydrodynamic modelling of the “producer – reservoir” system, 3D distribution of disturbed rock and reservoir temperature, wellbore temperature profiles, initial background (geothermal) temperature.


The Simulator has the following basic features:

  • Can be used for modelling of wells with high or low watercut;
  • Can model three-phase (water+oil+gas) steady flow in wellbore;
  • Models wellbore flowing and casing temperature profiles in vertical and near-vertical wells and can be applied for deviated and horizontal wells;
  • Accounts for all historical wellhead production rates with various combinations of alternating flowing and shut-in periods;
  • Accounts for well completion elements through a number of parameters related to the thermal skin produced by cement bond, casing and A/B annulus as well as the filling fluid properties;
  • Accounts for the complete changing-in-time hydrodynamic picture of transient fluid flows in the multilayer “producer – reservoir” system;
  • Accounts for reservoir temperature variation due to breakthrough of cold water;
  • Acccounts for original background temperature perturbations caused by secular (geologically long-term) ground-water and historically young (recent) flows (due to industrial flows of warm or cold fluid or operation of nearby wells).

The simulator is recommended for interpretation of wellbore temperature logs in producers to obtain inflow profiles. It can also be used for estimation of the reservoir unit pressures, localization and quantification of channelling, assessment of production volumes from zones that are not under development, verification of well completion integrity. pTSM is also useful for adjustment of different model parameters, e.g. rock properties, as well as for prediction of temperature perturbation zones created by the producer performance.


The Simulator uses the following input data:

   
Well completion
Well trajectoryLogs
Inner tubing radiusLog
Casing radiusLog
Annulus fluid typeLog
Annulus pressureLog
Tubing wall thicknessNumber
Casing wall thicknessNumber
Production history
RatesTime records
Production profiles
Reservoir and wellbore production profiles along the holeLogs
Thermophysical properties of production fluid and well completion
Volumetric heat capacity(Fluid – pressure-temperature table, completion steel – number)
Density Pressure-temperature table
Volumetric expansion coefficient Pressure-temperature table
Thermal conductivity (Fluid – pressure-temperature table, completion steel – number)
Dynamic viscosity Pressure-temperature table
Compressibility coefficientPressure-temperature table
Thermo-physical rock properties
Volumetric heat capacityLog
Vertical thermal conductivityLog
Lateral thermal conductivityLog
Reservoir porosity profileLog
Geothermal rock model
Regional geothermal fluxNumber
Geothermal temperature reference depthNumber
Geothermal temperature reference valueNumber
Secular lateral flowsLog
Young lateral flowsLog and numbers
Reservoir/well hydrodynamic/hydraulic parameters
Reservoir (outer boundary) unit pressuresLog
Productivity coefficients of the reservoir unitsLog
Drainage cell radiusNumber
Resistances of the wellbore completion perforationsLog
Resistances of the completion channelling pathsLog
Grid data
Depth grid
                     Vertical step across the reservoir                      formation                     Number
                     Axial step along the well trajectory                     Number
Radial grid
                     Borehole mean radius                     Number
                     Near zone step                     Number
                     Far zone step                     Number
                     Radial grid type (uniform/logarithmic)                     Flag
                     Outer boundary multiplier                     Number
Logging tool
Logging tool (thermometer) velocity Log

The simulator output data (at any moment of time):

1. Pressure distribution and hydrodynamic description of fluid flows in «wellbore – reservoir» system;

2. Wellbore flowing temperature profile in tubing;

3. Wellbore channelling temperature profile in completion;

4. Temperature profiles in rocks and reservoir at any distance from the wellbore;

5. Geothermal temperature profile within the model domain with account for secular and young lateral flows;

6. Wellbore pressure profile.


pTSM has Graphical User Interface (GUI) to show and modify input data and start the solver.

pTSM


After completion of model calculations, the simulator results are saved in LAS-file.

HD-prod