1. Introduction This document describes all additions/modifications in v2.60 and can be used as a jump start for existing users. Major changes have been brought to the interpretation of MPT tools, but also to conventional analyses which may be conducted in a continuous fashion as opposed to the usual zone based approach. A new energy temperature model is offered that solves the temperature problem in the wellbore and the reservoir, thereby removing the need for some dangerous adjustment parameters. A new method called
APERM has been included for the calibration of open-hole permeability logs from PL interpretation. Finally many smaller changes have been made to the display, the loading, editing, etc. in the permanent strive
for an improved, and fastest interaction. The present document gives an exhaustive account of the changes. There are also some new guided sessions that illustrate the new FSI workflow (B08), MAPS workflow (B09) and the energy temperature
model (B10).
2. View templates
Organisation and manipulation A clear distinction is now made between local templates, stored in file „LocalTemplates.kvt‟, saved in a user dedicated directory for Emeraude v2.60, and those loaded from external files. In this view, one can add files, create new files, or add containers to gather specific templates of the
same kind (for instance, dedicated to the same MPT, as shown opposite with an FSI). User defined containers appear in yellow. Drag and drop
operations from a container to another (relevant) one are supported. After changes have been made to an external file (the modified file names
are followed by an asterisk), you are prompted to save the changes when leaving the dialog. Note that when the mouse is moved on top of a file icon, the full path is displayed in a tooltip. New view types Individual view templates have been added for: Well views, Image views, and Interpretation views. The
latter correspond to match views and reference channel views. Note that now, the ‘Edit’ template option called from the Invoke template dialog drives the user directly to the definition of the view template. Repeat binding A view can be bound to more than one matching component (except in full layout templates). For
instance the Fig. below shows how you can apply an Image view template – here an FSI holdup – to
several passes at once.
An option allows removing all existing views in the display, and the above operation creates the layout shown next. The corresponding snapshot can be automatically created on demand.
Naming and suffix on the fly As illustrated above, a view template with a name (user, image, well) can be renamed on the fly before creation. The „Use suffix‟ option concatenates the short name of the pass automatically. In the example above the survey short name was „F1‟. This is followed by the pass type and index. Apply (current binding) to All This option tries to apply the binding of the current tab to all tabs as appropriate. So for instance, if you
are instantiating a template with 3 user views and you decide to bind the first user view to Up2, you can do the same pass selection for the other two user views with one click.
Snapshot creation When invoking a Full layout template, a checkbox allows the automatic creation of a corresponding snapshot. Note that snapshots may now be created without interpretations.
3. Display 3.1. Snapshots
They may now be created before the first interpretation: select „Add‟ in the Snapshot Manager dialog. The snapshot is then typed as a „Survey‟ snapshot, and its name is automatically prefixed with the Survey short name. If an interpretation exists, a new snapshot containing interpretation view(s) will be typed as an „Interpretation‟ snapshot, and prefixed with the interpretation short name. This information tells you what snapshot you can call from where: a „Survey‟ snapshot can be called whatever the active
interpretation is, whereas an „Interpretation‟ snapshot must have its parent interpretation active to be
called. Note that a snapshot can change type when updated, if interpretation view(s) are added or removed (the prefix then changes). 3.2. Hidden view dialog
This dialog has been modified to facilitate the interaction with a large number of views: a mask, based on the view types, allows an easy distinction of the different hidden views.
3.3. Cyclic display
In Emeraude, it is not possible to display more than 15 views side by side. To overcome this limitation, a new view management mode has been introduced: the „Cyclic display‟ mode. In essence, this mode allows cycling through a group of more than 15 views, by translating the views to the left when a view is added to the right (and vice versa).
This option can be selected in the Views tab of the Application Display Settings; the new status applies to the files opened or created after changing the flag.
When the cyclic mode is activated, a new toolbar (at the bottom-left of the application, see opposite) allows sliding through the defined cycle. The first button hides the leftmost view and shows to the right the view following the rightmost element.
The other option does exactly the opposite. While sliding the views, it is possible to keep some view positions
unchanged: press the small pin button appearing when the mouse cursor is on top of a view header. In the opposite example, the
Depth view position will not change, whereas the WTEP view position will.
A view cycle is defined via the „Show/hide views‟ dialog (see below): views outside the cycle are on the left, views inside the cycle are on the right. They can be moved from one list to the other, as usual. The
green rectangle indicates the visible range. This rectangle can be enlarged up to 15 elements, and moved up or down with the mouse. Note that the pinned views are labeled as such; their status is lost if they are
excluded from the list of visible views.
When views are added to the display (without using the „Show/hide views‟ dialog), they are inserted in the view cycle. Existing views will be moved to the left in order to make room for the new ones on the right, if the total exceeds 15.
When creating or updating a snapshot, the current view cycle is associated with the snapshot. Later on, when recalling the snapshot, the associated view cycle will then be automatically retrieved. Note that, because the hidden views inside the cycle are saved with the snapshot, they are taken into account to determine the snapshot type (‘Survey’ or ‘Interpretation’).
3.4. Zoom facilities
Horizontal scale dialog: The horizontal scale dialog now
offers the possibility to apply the scale to all the data of the same type belonging to the same MPT (e.g. a change on NCAP01 is applied to all the NCAPXX views).
Interactive horizontal scale: The horizontal scale setting menu (below) includes a new option causing the repeat application of interactive horizontal scale changes to all the views of the same type for MPT channels. For instance, an interactive zoom on RATMN01 would be repeated on all the other
RATMNXX views.
Depth scale: The default depth range of the
reset option can now be specified in the
„Depth scale...‟ dialog, as shown opposite. It can be set to a specific range, or to the
current display range. The default depth range is specific to each survey.
Ability to apply the settings of a given image view to several image views at once. For instance, the
color scale range can be set at once for several image views displaying the same tool in different
passes: select in the image view properties dialog. This
applies to all other options. Note that, if associated with the ‘Autoscale’ option, it will determine the best suited range for all the image views of interest.
For circular tools, the image view orientation can be changed based on the position of an imaginary observer positioned at the Top, Bottom, Left side or Right side of the tool. For the side views (the two last options), the top and bottom can be inverted.
FSI holdup image view displays raw holdups corrected for droplet persistence if the correction is required by the user in the view cross section.
3.6. Other
One-pass display and Reference: In this mode the reference pass is displayed in addition to the
active pass. Zone markers: Reservoir, Perforation and Inflow zones can now be labeled. If so, the labels can also
be used as marker (zone name will appear at the top depth, except for inflow zones). Pass aspect: when the pass line thickness or the color index is changed in the Document Display
Settings, the change can be applied to all existing passes. Plot background color: the background color of plots embedded in dialogs (SIP, Calibration, PNL
cross-plot) follows that specified in the Document Display Settings. Calibration plot: Line thickness and symbol size can be changed in the Document Display Settings. SIP plot: Line thickness and symbol size can be changed in the Document Display Settings. PNL cross-plot: Line thickness, as well as symbol size and type can be changed in the Document
Display Settings.
Match views data aspect: the display settings (Views tab) gives access to matched data symbol, as well as line type and size.
4. Browser 4.1. Versus time plot for Station data
Aspects: The plot aspect can be modified in the Display Settings (Views tab) – see below left.
Display multiple data of a station: the versus time plot can show several curves of the same station together. To achieve this you need to click on a Station node first, then right click in the Plot area and select „Display multiple data‟. This calls the dialog shown above right, where the curves can be selected.
Display multiple data across stations: a plot can display one measurement for all stations together –
see Fig. next. You need to click on the Stations node first, then right click in the Plot area and select „Display multiple data‟. A popup appears where you select the desired measurement.
Use TIME: the versus time plots can be made with the Time curve or the points index on the X-axis.
Data edition: if the time data are invalid, the hide and delete options can be performed on the basis of the data indexes.
4.2. Other
Possibility to drag & drop a multiple selections from the list tab into a user view. This was allowed before only on the user view browser node.
When loading MPT data, the sub-folders under the passes and Stations have been split for different tools. So rather than having a single „MPT Raw data‟ folder, there are folders for FSI, PFCS,
GHOST, CAT, RAT, SAT, as shown opposite (up). In „Settings - Multiple Probe Tools‟ an option allows automatically
grouping into the sub-folder of the passes corresponding to a given MPT tool, the channels whose mnemo match a given string mask. In the example shown right, any channel whose mnemo contains „CAT‟ will be gathered in the „CAT raw channels‟ folder.
Channels resulting from a calculation within an interpretation are
stored and appear below this interpretation. This is extended to MPT process output channels – see MPT section.
Export nodes are now saved with the file, and the data dropped into the nodes appear in italic. If they are dropped from the Data
Store, they keep their original name.
5. Load The „Map mnemos‟ option has been extended to root mnemonics defined with „_‟ characters. For
instance „DFHF0_FSI_SL‟ will be recognized as „DFHF0_FSI‟.
The unit of normalized capacitance is now correctly recognized as ratio.
Clicking the left mouse button on the shown in front of a file name displays a popup menu with the options to skip all undefined mnemos in the current file, or in all files (see opposite).
6. Interpretation 6.1. Continuous Approach vs. Zoned Approach
In Emeraude v2.50 the result of the interpretation is fully determined from calculations made at the calculation zones only. This is obviously true with the Local Improve, the standard regression run in Zone
rates. This is also true of the Global Improve. This is illustrated on the diagram below. On the calculation zones, the Local Improve seeks the cumulative rates by minimizing an objective function on that zone. In the Global Improve, the unknowns are all the contributions, and the objective function is the sum of the local objective functions. To this error, other components might be added such as a constraint using the surface rates.
The clear advantage of this approach is speed, since only a few points are required to get an answer. The
drawback is that the results are influenced by the choice of calculation zones. The first idea for change is
to run a Global Improve with the errors evaluated everywhere on the logs, and not only at a few points. This corresponds to minimizing the difference between the data and the schematic logs everywhere. When we look at match views however, we see that the schematics are fairly squared in shape; this is because between inflow zones the mass rate does not change, and since we honor a slip model, there are little variations in holdups and deduced properties. The only way to account for the changes seen on the data is to let the holdups differ from the model prediction. And this leads to the final formulation of the
new „Global Improve‟ described below. The main regression loop is still on the contributions but its objective function considers an error on the log points. At each depth, the simulated log values are evaluated by running a regression on the holdups to minimize an error made of the difference between simulated and measured values, and at the same time, a new constraint using the slip model holdup predictions. In other words the holdups are freed, but the process tries not „to go too far‟ from the slip model prediction.
A word of caution: any regression will be biased by the weights assigned to the various errors. Different weights will lead to different answers. Also, starting point will be critical as a complex objective function
may well admit local minima. So the Continuous Approach is not a magical answer to everything. But it will help matching the whole log interval, an added value for instance when dealing with temperature.
Restrictions: it was decided to limit the application of the Continuous Approach to a single Flow model for all the zones. Slip model constraint: Sometimes there may be enough data to make the use of the slip model unnecessary. For instance, if you are dealing with an FSI and have provided the analysis with phase rates and holdups, then obviously no slip model is needed. Emeraude will automatically remove the additional
residual term(s) when not needed. Last regression used: In order to help the user identify the method used, the last regression method is visible in the browser Info tab, when selecting the interpretation node:
- „Zoned approach: solution obtained by means of zone improve‟,
- „Zoned approach: solution obtained by means of global improve‟,
- „Continuous approach (solution obtained by means of global improve)‟. Implementation The choice between the classical Zoned Approach, based on the Rate calculation zones, and the new Continuous Approach, based on the
Inflow zones, is made in the Interpretation Infos/New dialog. The typical workflow in the Continuous Approach is modified as follows: Choice of initialization: selected at the level of the
Interpretation Infos/New dialog, the default is based
on a series of local improves („Zone local values‟), but an arbitrary split of the surface rates is offered as an option („Surface rates and inflow types‟). This can
also be changed in the „Init‟ tab of the Zone rates dialog. Inflow zone typing: it is possible to type the different inflow zones (producing, closed, thieves or
undefined). As shown below, an inflow type can either be changed via: (i) the popup menu on a selected inflow zone, in the Zones view; (ii) the Zones dialog, by clicking in the „Inflow type‟ column for a zone; (iii) the Contributions tab in Zone Rates, by clicking in the „Contribution‟ column for a zone.
(i) (ii)
(iii)
Note that shortcuts have been introduced into the Contributions grid: when clicking on a zone name,
all contributions for this zone are locked / unlocked; when clicking in the header of the Lock column of a particular phase, the corresponding contributions are locked / unlocked for all zones.
Zone Rates: choice of a common model, direct access to Contributions. When in the Contributions tab, the granularity for the match can be changed for evenly spaced points (see next paragraph), as
well as the maximum slippage value authorized. It is also possible to constrain the slippage sign depending on the well orientation (positive uphill and negative downhill).
Choice of the granularity for the match: currently restricted to evenly spaced points. Improve: the global and holdup errors are displayed during the regression, and the schematics are
updated during the process. As part of the diagnostic, the „Slip velocity match‟ view displays the deviation from the slip model predictions.
The Fig. below illustrates the result of running the Continuous Approach on a data set with Spinner, Density, and Gas Holdup on a 3-phase well. The match looks perfect: the „Slip velocity match‟ view shows the deviation from the slip models; only the deviation from the models allows reproducing the density
and gas holdup curves exactly.
Automatic mode: hold the shift key down and press the ‘Inflow rate’ button (the
button appears with a small red flash, see opposite). This option allows running the
global regression without launching the ‘Inflow rates’ dialog, using all defaults (provided that the inflows, PVT and the interpretation inputs are properly defined). 6.2. Internal diameter
The determination of the internal diameter is based on a preference order, for the interpretation as well as when processing a pass. This order can now be changed in the interpretation information dialog with
the relevant icon . A change will only affect the current interpretation.
The default order is shown opposite: 1- Internal diameter channel. 2- Any caliper other than C1, C2 and C1C2.
The internal diameter will be defined by the first channel found, in the defined order, in the interpretation inputs or the processed pass. If it is not found, Emeraude will try to locate the data, in the same order, in
the „General Well Data‟.
6.3. Spinner calibration and apparent velocities
Spinner calibration If the interpretation holds several spinners, the „All results‟ option in the Calibrate dialog allows displaying all spinner slopes and thresholds for all zones at once (see below). This helps when one wants to
manually change the calibration characteristics.
For the FSI and the SAT, when a zone is selected (by clicking on a row header in the table shown above), the „Copy to…‟ option allows to easily copy the spinner calibration of the selected zone to another survey. Apparent velocities
For a spinner tool, the apparent velocities of each pass can now be stored within the interpretation,
rather than keeping only the average value in the interpretation inputs (stored under the „Calculated log data‟ node, below the interpretation browser node). This is meant to improve the QAQC of the calibration results. An automatic view is created per spinner, to display the corresponding apparent velocity calculated for each pass.
6.4. Log generation
When generating a schematic log, a temperature log, or processing a MPT, it is possible to automatically limit the number of depths considered (this can be useful when dealing with MPT data). This limit can be set in the application „Interpretation settings‟, in the „Misc‟ tab, as shown.
If the option is activated, whenever the number of points exceeds the limit, a message is issued, as shown opposite, and the limit is honored.
6.5. Miscellaneous
PVT: pure CO2 and pure N2 correlations have been implemented. Spinner calibration dialog: active zone data points color honors the pass color coding (Up triangles
are used for Up passes and Down triangles for Down passes). Vslip multiplier: the value can now be changed manually in Zone rates – Surface Match tab (Zoned
Approach): when the value is changed, all calculation zones using the same correlation as the top
zone are improved.
m-weighted spinner: this option is now zone specific. Zone rates – Contributions tab: inflow zone intervals are displayed for better identification.
Sondex RAT When loading RATMN channels, they are treated as water holdups but they can be renormalized in Survey Tool Infos – below left. Often the delivered data shows the range below with Water=0.5 and
Hydrocarbon=1. The calibration values are provided for each of the 12 probes, and it is possible to force the normalized values to lie within the interval defined by the normalization (e.g. [0.35,1] in the example below).
RAT mean normalization
CAT.RGB
Sondex CAT In v2.50 the MPT process option treated the CAT in isolation, converting the CAT readings into holdup values. This was done using a Sondex rgb file as shown above right (excerpt from the Sondex CAT
manual). This approach combines two 2-phase calibrations, for Gas-Oil first, then Oil-Water; it does not provide a full 3-phase tool response, which for any triplet (Yw,Yo,Yg) gives the corresponding CAT reading. A 3-phase calibration is defined in v2.60 from the side (2-phase) responses of the rgb file, as
Note that, as for the RAT tool, when applying a normalization to CAT raw data, it is possible to force resulting values to lie within the interval defined by the normalization.
FSI The FSI spinner calibration mode based on pro-rated slopes and thresholds has been removed. This is
replaced by a „Constant‟ calibration mode with a slope/threshold couple per spinner (default values are provided, as shown below). The Conventional calibration mode remains.
The FSI spinner measurements can be strongly influenced by the tool body during the up and down
passes. To account for this effect, the raw measurements are corrected a priori by multiplying them by the Up correction factor shown above. However, for negative rps values, the Down correction factor
should be used. Emeraude 2.60 offers this possibility when selecting 'Use negative rps correction factor' in the Survey – Tool Info – Calibration option for the FSI tool. If selected, the correction is applied on the fly in the spinner „Calibrate‟ option, and when calculating the apparent velocities.
7.2. MPT process as a regression
When dealing with MPT data the hope is that the discrete values of holdups and velocity can be combined to define local phase velocities. By integrating this information over the cross-section at every depth, we can produce phase rates, hence waving the need for slippage models. The main challenge is to define a 2D representation of the holdups and the velocity using the discrete measurements. We first recall how this is done in v2.50 and then explain the differences in v2.60.
V2.50 process
In v2.50 the 2D mapping always comprises two steps: (1) Definition of a vertical interpolation profile: linear, spline, smooth spline, Mapflo. At each depth the
local ID is used together with the tool position and geometry to calculate the probe position and project this position on the vertical axis. The selected profile is then applied to the data. Except with Mapflo (and smooth spline) the profile goes exactly through the points – see diagram below.
(2) Lateral extension of this vertical representation: this is always done assuming a stratified model,
hence values on the axis are extended laterally. The next Figure shows the example of a PFCS using Mapflo interpolation - on the left – compared to a linear profile - on the right.
The plot distinguishes the raw and the reconstructed values. In the Mapflo case the profile does not honor
the projected values exactly hence the difference. With a linear model there is no distinction, which could easily lead to a situation incompatible with the assumption of stratification based on gravity. In addition, if the pass comprises conventional tools and we would like to use their reading as a constraint for the
whole process, this is not possible. v2.60 addresses those issues as follows. V2.60 framework The general framework considers that we have a set of discrete values, and „some‟ model with which we
want to match those values. We can treat this situation as a standard optimization problem where the model parameters are found by minimizing the error between the raw and the reconstructed values.
Basically, if we write the list of values and their coordinates and our model the
function we seek to minimize is:
In v2.50, using Mapflo or Smooth spline actually led to doing just that behind the scene. The main advantage of using this general formulation is that we can then easily add external constraints. In v2.60 for instance, a physical constraint can be incorporated that expresses vertical segregation: water holdup decreases from bottom to top, and gas holdup increases from bottom to top. We can also easily add constraints using other tools. So for instance, if we are seeking the holdup profile and want to constrain the results by a density measurement, we can simply add a term in the above objective function comparing the density derived from the 2Dmodel and the measured one.
The exact list of possibilities is given in the next sections. 7.3. Generic 2D models
Linear
This model uses as many internal variables as the number of valid (non N/A) distinct projections of discrete values on the vertical axis. The model assumes a vertical interpolation on the „z‟ axis between the internal values, and a horizontal extension of the central values. Mapflo This model uses two internal parameters. The model defines the shape of the vertical profile. The central
values are extended laterally by identity. Prandtl This model represents the velocity profile by a deformation of the holdup profiles, followed by a deformation near the edge. 7.4. Model application to Schlumberger tools
Electrical probes: for a PFCS or an FSI the discrete measurements represent Yw. They are matched
independently with a 2D Model that defines Yw everywhere in the cross-section. Optical probes: GHOST, or FSI; same as above for Yg. FSI spinners: it is assumed that the Vapparent for each spinner is calculated beforehand. An
independent 2Dmodel matches the local Vapps.
7.5. Model application to Sondex tools
CAT: The CAT does not relate directly to the holdup of a particular phase except in 2-phase. When matching the CAT independently, the user is thus requested to make a hypothesis. Possible
hypotheses are that one phase is absent, or that the probe is in 2-phase Water-Oil or Oil-Gas mixtures; the latter is similar to the assumption made implicitly with rgb files.
RAT: The RAT readings relate directly to Yw. They can be matched independently to give Yw. RAT+CAT: A single 2Dmodel with internal variables as Yw and Yg can be used to match
simultaneously the two measurements. This relies on the availability of a 3-phase CAT. SAT spinner: as with the FSI we assume that Vapparent have been calculated before. We match the
probes independently. 7.6. Model options
Tool Holdup Velocity Discrete output Mnemonics
PFCS Linear - Yw YW_FLV
PFCS Mapflo - Yw YW_FLV
GHOST Linear - Yg YW_GHT
GHOST Mapflo - Yg YW_GHT
FSI Linear Linear Vapp, Yw, Yg VT_FSI, YW_FSI, YG_FSI
FSI Mapflo Linear Vapp, Yw, Yg VT_FSI, YW_FSI, YG_FSI
The following constraints can be imposed where relevant:
One phase absent. W-O/O-G: used for the CAT to consider either Water-Oil or Oil-Gas. Gravity segregation (this can also be applied to the Mapflo model). Holdups bound to 1. This is for the cases where Yw and Yg for instance are treated separately. 7.8. Multiple pass application
In v2.50 it was possible to repeat the processing on multiple passes. This option is supported in v2.60 but augmented with the ability to treat multiple passes at once. In this combined passes mode, the readings of all the selected passes are matched simultaneously at any given depth. In case of faulty probes with a rotating tool – and a stable well....- this can help get a good answer.
7.9. Image views and cross-sections
Image views Combined pass image views can be created by selecting „Combined passes‟ rather than a single pass
when defining the image views. This applies to the raw data for all circular tools: the user can select the passes to combine in the display. Below is an example with a RAT tool: 6 passes (the first views) are combined together in a unique image view (the last view).
This also applies to the reconstructed data (the properties dialog uses a bold font to ease identification of interpretations and passes holding MPT processed data). If the MPT processing was using independent passes, it is possible to select different reconstructed passes for combination in the display. If the MPT processing was using the combined passes mode, all the reconstructed passes are used in the combined
pass display.
Note that: 1- With an FSI, a combined view can only be obtained if the MPT process is applied on combined passes.
The view in this case displays the reconstructed holdups for an imaginary tool arbitrarily supposed to be in a vertical position (with 0 bearing).
2- It is possible to create image view templates dedicated to reconstructed data. When such a view template is invoked, the view(s) created will search for the reconstructed data in the selected
interpretation. If not found, then raw data will be displayed.
Cross-sections The cross-section of an image view displaying combined passes shows the position of the different probes or spinners in each pass, the corresponding raw measurements, and the model applied to the data (which corresponds to that of the MPT process if the image view displays reconstructed data). Two examples are shown below. The first one is for an FSI tool with three combined passes during a MPT processing: the Mapflo model is
applied to the gas holdup probes and the Prandtl model is applied to the velocity profile. The tool is not rotating and the probes are all located at the same position, reading different values (small squares) from one pass to the other.
The second example is for a PFCS tool with two combined passes (raw data): the cross-section displays the probe positions for D1 in light blue and D2 in green; the probe short names - 2D1 stands for probe DFH2 in pass Down1 - can be removed from the display. The XY-plot besides the cross-section shows the probe positions (Y axis) versus the probe readings (X axis), and the corresponding Mapflo model in red.
In a survey, if some data are identified as MPT measurements, the PL interpretation automatically offers a „MPT processing‟ option in the control panel. This new option replaces the former one located in the browser.
The new MPT workflow follows the steps:
Information Choose the spinners and their calibration mode. [Possibly define reference channels for conventional tools].
Calibration
All spinners are calibrated.
V apparent An apparent velocity channel is generated in all the source
passes. The result is stored below a „Calculated Log Data‟ sub-level of the interpretation. Automatic views are built with the
created channels, providing an instant QAQC check. At the end of the apparent velocities calculation, it is possible to generate the „Average Vapp for conventional spinners‟ and set it as an interpretation input.
As noticed earlier, for conventional PL interpretations, the apparent
velocities can now also be stored in a ‘Calculated Log Data’ sub-level of the interpretation, for QAQC purposes.
MPT processing Choice of the source tools, and passes; Choice of the 2Dmodel and possible constraints; Calculation of the reconstructed probes and average outputs: holdups, phase rates and/or velocities;
mixture velocity. The comparison of raw and reconstructed data can be done on automatic views or image view, the error checked, etc. The next section details the options of the MPT processing steps.
Zone Rates Reference channels are built from the MPT processing output. They are supplied to the analysis.
Tool type: The list allows selecting the tool to be processed; the Settings button is to select the tool
components to be considered in the process; the Tool Info button accesses the tool parameters. For the components, for instance in a 2-phase Water-Oil with a full MAPS, we could decide to unselected the CAT. If we had both RATHU and RATMN we could indicate which one to use, etc. The reason for a quick access to Tool Info is to avoid going back and forth with the Survey-Tool Info option.
2D Model: Model selection among the choices listed in 7.6. The velocity limit at the pipe wall and the
Prandtl power can be changed via the associated settings button. Note that if the Prandtl velocity model is selected and if the water holdup probes or the gas holdup probes are not included in the MPT processing, the corresponding phase is considered as absent: Yw=0 or Yg=0 (resp.). Average: When a Linear model is selected, an „Arithmetic average‟ option is offered as in earlier versions. The average calculations can either use the diameter found in each processed pass, or a unique diameter for all passes, defined at the interpretation level (select „Current interpretation‟). In both cases,
the diameter information is determined by following the preference specified by the user (see section 6.2). The deviation is that defined at the interpretation level for both combined and independent process. From, To, Increment: The process can be applied on a selected range, at the data increment or a user choice. Beware that very fine increments on a long log range will be very slow to process for no benefit.
Phase constraints: The logic is that a global phase constraint is offered unless an included tool gives the holdups of that phase directly. So with FSI, only Yo=0 is offered unless the electrical or optical probes are unselected in „Tool type‟. The same applies with the MAPS tool. FSI complete: None or „Yo=0‟; No Electrical probes: Yo=0, Yw=0; No optical probe: Yo=0, Yg=0.
MAPS complete: None or „Yo=0‟; No RAT: [W-O,O-G], Yw=0, Yo=0, Yg=0; No CAT: Yo=0, Yg=0
Physical constraints: vertical gravity segregation, bound holdups (for when they are obtained independently).
Tool constraints: Additional residual on a conventional tool present in the string. Vapps, density, capacitance, phase rate, velocity. The reconstructed channels use the average outputs of the process as follows:
Vapps: When the 2D integration is done, the velocity is integrated on the inner-disk defined by the spinner diameter.
Density: the average holdups are combined with the local phase properties to get a fluid density.
This is then transformed into a tool response. Frictions are disregarded in this step. Capacitance: based on the average holdups and the tool response if cps values are used.
A relative weight can be assigned to the residuals (constant or zoned value, click on ).
Note that a tool may be present, but not available to constrain the process because the model does not allow calculating the corresponding average. In this case, the tool appears in the list of potential
constraints with a question mark: . Clicking on explains why the tool cannot be selected as a constraint. Reconstructed channels for conventional tools can also be obtained without acting on the MPT channels reconstruction process: select „Simulate‟ rather than „Match‟, as shown opposite
for a density tool. This is a way of checking whether consistency
can be obtained directly or whether it needs to be imposed. After all, in a deviated well, there is no reason why the results deduced form the discrete measurements and the readings of conventional tools should necessarily agree... Input passes: Selection of the source passes and mode.
Additional output: Phase rates and velocities are the main goal. They should always be produced (at least the phase rates), except if „Arithmetic average‟ is selected, in which case the average phase rate is calculated by a simple product of the (arithmetic average) phase holdup and the (arithmetic average) mixture velocity: for phase p, the rate is Qp=Yp.Vt.area. „Error channels‟ are the relative errors between the raw and the reconstructed data. „Average of outputs‟ generates the MPT process averages and copies them to the interpretation inputs (a lateral average is performed in case of independent passes). „Clean
all existing MPT process outputs‟ allows deleting all existing MPT process outputs prior to processing independent passes. Bubble rate: this is offered with Schlumberger tools. See section 8.5 further. The process is started on OK. The duration will depend on the models, the number of passes, and the number of depths to be treated. All outputs are stored within the interpretation and can be visualized on
the different view types. This is detailed below. 8.3. MPT process output
Reconstructed and error channelsFor any measurement with mnemo XXXX that is matched, Emeraude outputs a reconstructed version with mnemo XXXX_K, as well as the error between them with mnemo XXXX_KERR. The reconstructed values are also generated for ignored or disabled probes. The reconstructed and error channels are located in a sub-structure of the interpretation under the pass where they belong. So, imagine we process an FSI and include „Up 2‟, under the Interpretation
„Calculated Log Data‟ we will see a pass „Up 2‟ containing the original apparent velocities: VAPSIF0, VAPSIF1, etc… and the average outputs (see below); a „MPT-reconstruction‟ node containing the reconstructed channels VASPIF0_K, VASPIF1_K, etc…; an „MPT-Error‟ node containing VASPIF0_KERR,
VASPIF1_KERR, etc. The MPT processed passes appear in bold under the „Calculated Log Data‟ node, while those only containing apparent velocities are not emphasized. Note that, when processing an FSI tool in combined mode, reconstructed values are automatically output at the probe positions corresponding to a tool in a vertical position (in „MPT – Reconstruction‟ below the
„Calculated Log Data‟ node). This output is only used for display purposes, in the FSI holdup image view, when showing the reconstructed data of the combined passes.
When Tool constraints are considered, the corresponding reconstructed channels are also output, e.g.
„VASPIN_K‟ for a flowmeter constraint (mnemo SPIN).
Process output The outputs we seek eventually are average holdups, mixture velocity, phase rates and/or velocities. Their mnemo will depend on the tool type, e.g. YW_MAPS, QO_FSI, etc. Their position will depend on the
processing type. With „independent pass‟ the output of each pass appears below this pass. In „Combined‟
mode there is only one output, and it is one level higher. Global errors They represent the average of the normalized error for all selected passes and probes. For instance, DFHF_KERR is the average of the DFHFx_KERR channels on all the processed passes. They are located in an „MPT- Global Error‟ node below „Calculated Log Data‟. Note that if stationary data are processed, a single value is given at each station depth, averaging the normalized error over the time range of the
station. 8.4. MPT process output display
Most views have been modified to easily access the reconstructed channels.
MPT errors view
After the process is executed this view is built automatically and shows a summary indicating the global error and errors on additional tools (matched or simply simulated). MPT constraints view
If Physical constraints have been imposed, this view is built automatically after the process is executed and shows a summary indicating whether or not the Physical constraints were satisfied: the closer to 0, the best the constraints is honored.
Automatic views:
The Pass toolbar receives the two additional icons above. When the first one is activated, views that show a mnemonic that has been matched by the process will display the raw and reconstructed channels, only
for the passes that were treated. The raw data are in solid lines, the reconstructed in dashed lines (aspect can be changed in the Document Display Settings).
When the second option is selected, only the error is displayed. Note that this only impacts the relevant views.
Image views Inside the Image view Properties dialog, the option is now given to use the raw values, the reconstructed ones, or the error. Also, for a combined processing, it is possible to generate a composite image view. This is done by selecting the MPT Interpretation as the source (see corresponding section on image views above).
Cross-sections A cross-section made on an image view showing the reconstructed values uses stored parameters and is locked on the process options (see corresponding section on cross-sections above). 8.5. Bubble flow rate calculation for Schlumberger tools
This option is based on a processing developed by Schlumberger to derive the oil / gas rate from the electrical / optical bubble counts. The calculation uses the average holdup and the bubble counts. It needs the recognition of a proper bubble tool. For PFCS, GHOST those tools existed. One has been added for the FSI called „FSI Bubbles‟, and an image view can be associated with this tool. The output rates bear the mnemonic QO_BR, QG_BR. Note that in this case the process is a forward
process (there is no matching) but the average holdup is the output of the MPT process.
For the PFCS or the GHOST, if averages of the outputs are created for interpretation inputs, the bubble rates are part of the data given to the interpretation if they are calculated. For the FSI, this will be done only if no phase rates were generated. 8.6. MPT outputs and interpretation inputs
As explained in the paragraph on „Additional outputs‟ section 8.2, you have the possibility to automatically feed the interpretation input with lateral averages of the MPT process outputs. Note that, if averages resulting from a previous MPT process are present in the interpretation inputs, they will be wiped out and replaced by the outputs of a new MPT process (if it generates the averages for the
interpretation input). You may also execute this averaging later (after QAQC) in the Interpretation Infos/new dialog. In fact, this dialog will be launched automatically if you click on Zone rates after an MPT process where averages were not computed. Note that this path will be offered only if none of the interpretation inputs correspond
A new temperature model is available in addition to the former implementation. The new model solves the material and energy balance equations in the reservoir and the wellbore using a formulation in terms of enthalpy that couples pressure and temperature. This method offers a number of improvements:
No more exclusive segmentation with either conduction or enthalpy balance: everything is treated simultaneously.
The formulation integrates the thermal compressibility effects in the wellbore and the reservoir. Joule-Thomson effects are automatically included without relying on some user defined pressure drop.
The thermal effects within the reservoir are the result of the coupled influence of the compressibility effects and the conduction.
The choice of model is made within the „Temperature‟ tab in the Interpretation Infos dialog. When the „Energy equation‟ model is used, some reservoir parameters are required: the external radius, the pressure drawdown (Pe). Pressing the „Layer and
inflow parameters‟ button enters a dialog where Pe can be given directly (select the „User input drawdown‟ option), or from a calculation based on the reservoir geophysics (select the „Computed (Pseudo-skin evaluation)‟ option), as shown below.
Note that this model requires agreement between the inflow and reservoir zones: each inflow zone must be defined within the limits of a reservoir zone. If this is not the case, the reservoir zones are automatically created / resized accordingly. However, the thickness shown in the table above is left unchanged, and the user must ensure that the values are correct. The thermal exchanges between the wellbore and the reservoir are described in all models with the „Heat loss coefficient‟ (HLC), which can be set constant over the entire interval, or can be varied from depth to
depth. The HLC can be obtained by a definition of the individual completion elements and properties, eventually including a production time to compute the unsteady reservoir thermal:
It is possible to consider the tubing and the annular in the temperature calculations (eventually including natural convection and radiation in the annular, except for the leak option – see below). As shown below,
the tubing and the annular are considered from 0 to 1000ft. A HLC value different from that calculated using the flowstring components characteristics appears in read.
The HLC defined in the Segmented Model (HLCs) differs from that defined in the Energy Model (HLCe) by a function of the time (t) and rock thermal conductivity (Ce): HLCs=HLCe+f(t,Ce). When changing the thermal model, the HLC value is updated accordingly upon user request.
A leak option is now integrated, allowing the simulation of a tubing leak for injectors, in PL design mode.
It can only be activated with the „Energy equation‟ model. Emeraude starts from the wellhead conditions (imposed pressure, temperature and rate) and iterates until the pressure and temperature stabilizes at „max depth‟, fulfilling the mass and energy conservation equations. It takes into account the heat transfer in the tubing and the annular by convection, between the tubing and the annular by conduction (and convection at the leak level), and between the annular and the reservoir by conduction. The thermal conduction along the tubing and the annular is also
accounted for: the vertical thermal conduction may be a dominant phenomenon when very small rates occur in a vertical well. The temperature in the tubing (TEMP_K) and in the annular (TANN_K) are calculated. As shown opposite, the tubing leak is defined by its size and position, and a pressure loss
between the inner tubing space and the
annular. If the resolution interval is lower than the leak height, the leak injection rate is linearly distributed over the leak interval (e.g. the total mass rate injected is weighted with the relative length of a given segment with respect of the total leak length).
Note that all existing inflow zones are disregarded when simulating a tubing leak. 9.3. Steam injection option
Steam injection can be of great help to enhanced oil recovery, especially when considering high viscosity
oils: the heat transfer from the vapor phase to the oil phase, in the reservoir, allows lowering the oil viscosity and therefore facilitates its displacement towards the well. It is then of primary importance to correctly quantify the quality of the injected fluid at the level of each inflow (fluid quality = mass of vapor / total mass of injected fluid).
The thermodynamic surface for water is shown opposite (from „Atmospheric
Thermodynamics‟, Iribarne and Godson, p60), and a dedicated PVT model has been
implemented (Chlen-SPE 20319): In the two phase region (e.g. water and vapor), one can see that a direct relationship exists between pressure and temperature: if P is known then T is known (and conversely). The unknown is then the fluid
quality. In the single phase region (e.g. water only or vapor only), the relationship between
pressure and temperature is not unique, but the quality of the fluid remains known and constant (0 or 1).
The problem is solved using the „Energy equation‟ model: the enthalpy balance is used to calculate the fluid quality when in the two phase region, and the temperature in the single phase region.
Phase changes are correctly modeled thanks to the enthalpy balance. The heat loss to the annular and
the formation can contribute to the condensation or the cooling of the injected fluid. Also, it can be noticed that the heat radiation and natural convection in the annular space makes the Heat Loss Coefficient temperature dependent, which adds non-linearity to the model. Hence, one cannot ensure, for
instance, that pressure will increase as temperature increases down the well, while undergoing two-phase flow.
The flow in the well is modeled by considering the Liquid-Gas flow model. The possible choice of correlations has been limited to Petalas and Aziz, Stanford Drift Flux and Constant slippage. However,
third party correlations are still possible, if one has developed his own specific correlation in the framework of the Emeraude External Flow Correlations.
The steam injection option is selected in the Temperature tab of the Interpretation Info dialog for PL simulation. PL simulation The PL simulation option allows the user to optimize a steam injection job: a key result is the injected fluid quality at the level of each inflow. Please note that it is assumed that the injected fluid is either two-
phase at equilibrium, or is vapor but at saturation pressure. The problem is defined by:
- The injection pressure (or the injection temperature), - The injection rate, in terms of „Cold Water Equivalent‟. It is the injected liquid rate at standard
conditions.
- The injection quality, in terms of fraction. It is the mass of injected vapor divided by the total
mass of injected fluid.
As noticed earlier, a specific PVT has been implemented and is automatically selected when the Steam
option is chosen. This PVT cannot be edited or viewed in Emeraude. The Zone Rates option allows selecting the flow correlation. In the Contribution tab, it is possible to define the total injection rate at the level of each inflow (in situ conditions). Please note that the calculation honors the mass balance, hence the total injection rate will not be exceeded, whatever the total rate entries are. When going to the Rate Calculation tab, a calculation is launched, giving the flow
conditions, the holdups and the injected fluid quality at the level of each Qcalc zone.
Emeraude calculations proceed as follows. Starting from the conditions at a given depth (P, T, Qg, Qw), the flow correlation gives access to the pressure and the phase holdups at a depth below. Then, the enthalpy balance equation gives the temperature or the fluid quality, depending on the phase diagram. If the (P,T) conditions are such that two-phases are in equilibrium, the temperature is obtained from the PVT.
The main results are the pressure and temperature profiles, and the water and vapor rate profiles. The Rate Calculation tab of the Zone Rate dialog gives the injected fluid quality.
The effective reservoir permeability can be dramatically different from the matrix permeability measured in core plugs (in vuggy or fractured reservoir, for instance). A new method is provided, allowing estimation of the effective reservoir permeability: APERM (SPE 102894).
This option is available in the Control Panel Special tab, provided that (1) a permeability log is present in the General Well Data (klog), and (2) a valid interpretation exists (e.g. with calculated zone rates). The purpose of the APERM method is to correct the permeability log by matching it on a calculated (effective) permeability curve.
Starting from an existing PL interpretation, the Darcy‟s law is applied to each inflow to determine an effective permeability (kplt). Considering the oil rate for a given inflow:
kplt h = 141.2 Qi Bo µo [Ln(re/rw)-0.75+s] / (Pavg-Pwf)
where Qi is the oil contribution of the considered inflow (stb/d), µo is the oil viscosity (Cp), Bo is the oil formation volume factor, re and rw are in consistent units, s is the skin, Pavg is the layer average pressure and Pwf is the well flowing pressure. If a liquid mixture is considered, the mixture rate is used and kplt
corresponds to the oil effective permeability (or the water effective permeability if no oil is present). If gas is considered, pseudo-pressures are used and the formulation is:
kplt h = 1.42248e+6 Qi T [Ln(re/rw)-0.75+s] / (m(Pavg)-m(Pwf))
where T is the inflow zone temperature. If a gas mixture is considered (e.g. condensate), the pseudo-pressures are calculated using a modified gas gravity, weighted by the condensate.
A permeability height product value (khplt) is then calculated by integration over the entire interval, and a normalized permeability is obtained for each inflow, by introducing a kh value determined by means of a well test analysis (khbu):
kplt norm = kplt . (khbu/khplt) A boost factor is then applied to the permeability measurement (klog) in order to match kplt norm at the level of each inflow. The matched klog channel represents the reservoir effective permeability.
When entering the option, the user selects an interpretation and for each inflow defined in this interpretation, values must be entered to calculate kplt (see below):
- The downhole rates are given from the interpretation QZI; - Pavg can be calculated from a selected SIP (e.g. Pavg=Pwf+PSIP, where PSIP is calculated from the
Inflow Performance curve and the inflow rate); - Pwf (and T) is calculated at the inflow top from the interpretation inputs;
- µ is calculated at Pavg (and can be recalculated when Pavg is changed); - Rw is an average value over the inflow zone; - Re and skin are user entries.
Note that right clicking in a cell allows applying the value to all inflows. If invalid kplt values are calculated, the KHplt column is highlighted in red, as well as the erroneous cells in the table. The corresponding inflow zones will not be considered in the matching procedure, unless
entries are changed to correct KHplt. On OK, the match procedure is launched on the
inflows where valid data exist (e.g. positive kplt). The results are stored within the selected interpretation and can be viewed in the browser,
under the „Calculated Log Data‟ node: - K_APERM is the mnemonic for the matched
permeability, - BOOST is the mnemonic for the permeability
Principles Water injection wells in China are usually analyzed by means of tracer logs interpretation, using 131Ba in Ba(NO3)2. A particular method has been developed to conduct interpretations of these tests, mainly based on empirical observations from the Dagang field. Prior to any injection, a reference gamma ray log is acquired. Then, water containing the radioactive tracer is injected, and the gamma ray is measured during different passes. Interpretation of the data
allows calculating the water injection rate profile, on the basis of the following observation: each zone injection rate is linearly proportional to the amount of deposited radioactive particles. And the amount of deposited radioactive particles is derived from the area between the reference gamma ray (GRr) and a selected gamma ray among the flowing passes (GRs, hence assumed to be representative of the injection job). For an injection zone i, this is expressed as:
Where Qi is zone i injection rate, Qt is the total injection rate, Si is zone i surface between GRs and GRr, and S is the total surface between GRs and GRr. However, this ideal situation is modified due to the tracer particles deposition on the completion elements. For instance, two zones with the same injected rates can present different surface Si, just because less tracer reaches one zone compared to the other. This phenomenon, called contamination, is taken into account by introducing an area correction factor (b), depending on the completion elements
and whose values have been empirically determined based on numerous Dagang field measurements. The table below shows some recommended values for b:
The principle of contamination redistribution is then to multiply all contaminated areas by the relevant correction factor, and evenly redistribute the corrected areas to the relevant inflows, determined by the flow direction, which depends on the type of injection job.
Two different types of injection jobs are conducted:
- Massive injection jobs, where all injection zones are subjected to flow together:
- Zonal injection jobs, where zones are isolated from each other by packers. Hence, when dealing with redistribution of contaminated areas, the flow string can be divided into segments defined
from each choke to the neighbouring packers just above and below. Each of these segments can then be considered as a massive injection job section. Some configurations are shown below:
In the end, after redistribution of the contaminated areas on each inflow, the surface calculation gives: - The injection rate profile Qi; - A reconstructed version of the gamma ray log injection log (identical to the reference gamma ray
if there is no contamination).
Workflow The following workflow allows interpreting these Tracer logs in Emeraude:
a- Load a reference gamma ray in the General Well Data (GWD).
This defines the reference gamma ray; b- Define the well sketch, positioning the packers and the chokes (one of the following elements:
„sliding sleeve‟, „slotted pipes‟, „perforated pup joint‟ will be considered as such) if zonal injection is occurring.
c- Load the flowing pass data, among which the gamma ray measuring the tracer absorption; d- Create an new interpretation: select „Tracer logs‟ in the interpretation information dialog; e- Define the interpretation inputs: pressure, temperature and gamma ray.
This defines the gamma ray log considered as the representative record of the tracer absorption;
f- Define the injected water PVT;
g- Define the inflow zones;
This defines, when combined to the well sketch information, the different flow string segments that are identified as ‘massive injection’ zones;
h- Go to Zone rates (see Fig. below): this is where all calculations are done, in order to determine the characteristics of each injection zone. Enter the total injection rate, select the flow configuration (tubing or annular), and decide if you wish to use or not the contamination correction; Contamination areas can be edited and default correction factor modified.
Once this is set, the following characteristics are computed (and updated after each modification):
o SSi: the redistributed injection area of inflow zone i; o Qi: the injected rate of inflow zone i; o βi: the relative contribution of inflow zone i;
o INTi = Qi/hi: the injection intensity of inflow zone i (hi is the zone height); o Sij: the contamination area before inflow zone i ; o The direction of the flow in the flow string before entering the inflow zone i;
The „Generate logs‟ button allows calculating Qi, and generates the water rate injection log and the reconstructed gamma ray channel. The latter is stored in the interpretation under the
Possibility to increase the size of the recent file list (in application settings/misc). New built-in system of unit: “Metric Oilfield”. Possibility to honor the survey chronological order in the browser and the list of surveys (in
application settings/misc). This option uses survey dates entered in the survey information dialog.
Data edition: Most of the repeat options are not restricted anymore to data with the same mnemo or the same
type. They can also be applied, on request, to any other type of data. User DLL: Possibility to reset a constant to its default value given by the DLL, rather than keeping
the value previously entered by the user. Math pack: the ratio type now correctly gives access to the % and fraction units. Deleting a data channel can now be applied to several passes at once.
Stationary data: Resampling, Derivative and Fill gaps options are now available.
Zones: Squeezed perforation: a check is present in the perforation grid; squeezed perforations appear with
a distinct color.
The name of Reservoir zones is now displayed in the zone tooltip ( ).
When creating zones, a new Application Setting, „Keep zone edition mode active after first call‟ in Default Display – Views, allows keeping active the zone edition mode to facilitate the creation of several zones of the same type.
PNL: Cross plot: it is now possible to move each end-point individually.
Tools:
Tuning fork/vibrating density tool is available. MS-Word report template:
Perforations and reservoir zones are now available, as well as the average value of the total porosity over each of these zones (if provided in the General Well Data). Geothemal gradient,
temperature above and temperature below the inflow zones are also now exported. For clarity, the zoned results are now ordered by zone type when Selecting Emeraude Variables in
the MS-Word Report, as shown below.
Units: Velocity units „ft/sec‟, „ft/min‟ and „ft/hr‟ respectively appear as „fps‟, „fpm‟ and „fph‟ when combined
with other units (e.g. in the spinner calibration slope unit). Well sketch:
If a block shift is applied, all elements composing the well sketch are showing the original depths as well as the corresponding shifted depths, as shown below.
