Petrel Workflow Tools 5 Day Introduction Course Edit of Input Intro to Petrel Edit Input Data Import data Seismic Well Correlation Fault Modeling Pillar Gridding Depth Conversion Facies Modeling Petrophysical Modeling Volume Calculation Plotting Well Design Process Manager

Facies Modeling Objectives Discuss Different Facies Modeling Techniques Deterministic techniques Stochastic techniques Learn How to Use Common Settings Setting filters Learn How to Use Zone Settings Define zones Use The Different Algorithms Sequential Indicator Simulation Object Modeling, adaptive channel modeling Interactive Modeling

Overview FACIES Interactive drawing, Seismic volume extraction If well logs are up-scaled, they can be used in Deterministic and Stochastic modeling If no logs are available, deterministic methods cannot be used, only unconditional stochastic methods and interactive drawing. Interactive drawing, Seismic volume extraction Indicator kriging Deterministic Indicator Simulation (blurred facies – Sequential Indicator Simulation or facies transitions) FACIES Pixel based Stochastic Deterministic techniques Are typically used when dense data is available (e.g., many wells, wells + seismic). The deterministic methods yield a single estimated result (i.e., they do not produce multiple realizations). Stochastic techniques Are often in conditions where sparse data is present. These methods produce a possible result and can be used to produce multiple equally probable realizations.   Facies with defined shapes Object, Fluvial, adaptive channels Object based

Common Settings Two Modeling Settings buttons are available: 1. Common 2. Zone Settings 1 2 Define Common settings for all zones: 3. Use filter 4. Ensure that all cells get a value 5. Number of realizations 3 4 5 Facies Modeling – Common Settings When opening the process for either the Facies or the Petrophysical process, the settings are similar: All settings are entered under the main tab, called Modeling Settings. Under the Modeling Settings tab you have two tabs, the Common tab and the Zone Settings tab. All the settings that are common for all zones are entered under the Common tab, while the zone specific settings are entered under the Zone Settings tab. Common This is where to enter the common settings for all the zones: Filter – Toggle this option on if you want to use the filter. This can be the Property filter (e.g. Filtered on certain facies codes), the Zone filter or the Segment filter. Note that if you toggle this option on, all the active filters will be used, so make sure that if you want to use it, only the filter you want to use is active! Ensure that all cells get a value – Toggled on by default. Number of realizations – Toggle this on and write the number of realizations to run, if more than one.

Zone Settings Define Zone settings for ALL zones: 1. Leave the Zones button off. 2. Press the Leave Zone. Unchanged button. You will now use one algorithm for All Zones. 1 5 2 Define Zone settings for EACH zones: 3. Press the Zones button. 4. Select the zone of interest from the drop-down menu. 5. Press the padlock icon to deselect Leave Zone Unchanged to activate the zone settings. 6. Select a method from the drop-down menu Method for zone/facies. 6 3 4 Facies Modeling – Zone Settings tab All the settings that are specific for each zone are entered under the Zone Settings tab. This include the method/algorithm to be used for each zone and the settings for the method that has been chosen. Procedure: Select the zone to model Select the method to be used Specify the settings for the chosen algorithm for the selected zone Facies Modeling – Methods Both stochastic and deterministic methods can be used. The stochastic methods are the Sequential Indicator Simulation and the Object Modeling while the other methods are deterministic. Depending on the selected method, you will get a corresponding set of tabs with settings that must be specified. Hint: Use the Shift key to Lock or Unlock all Zones. 5

Sequential Indicator Simulation (SIS) 1. Property and zone selection A. Make sure to pick the correct property; must be upscaled i.e. have (U) as suffix B. Select SIS as method for one zone 1B 3B 2A 2B 2. Facies: A. Select the facies from the template B. Use the Blue arrow to insert 3. Variogram: A. Specify Range, Nugget and Type B. or get a variogram from Data Analysis Sequential Indicator Simulation When using the Sequential Indicator Simulation, as a default the fractions from the upscaled well logs are used, but these can be edited. The function to use for the variogram (exponential, spherical, gaussian) together with the sill, range and nugget can be defined under the Variogram tab. Discrete properties are integer properties such as facies where the values fall into groups (either sand or shale etc.) as oppose to continuous properties where decimal values are possible (e.g. porosity). When using results from Data Analysis, the corresponding data tab in this dialog box will be grayed out. There are three buttons that are linked to the Data Analysis results: Variogram button -Use the Variograms made in the Data Analysis Process Probability curves button -Use the Attribute Probability curves made in the Data Analysis Process Vertical proportion button -Use the vertical Proportion curves made in the Data Analysis Process 3A 4. Fraction: A. Use Global fraction from Upscaled cells B. or use probabilities (property/trend) 4A 4B

Sequential Indicator Simulation (SIS) – Results SIS is a krig-based stochastic method The facies distribution will be honored. The upscaled cells will be honored. The facies will be distributed in a blurred manner. There is no facies relationship. The amount of accumulation of a facies depends mainly on the Variogram input.

Object Modeling – Fluvial Channels 1. Property and zone selection A. Make sure to pick the correct property; must be upscaled i.e. have (U) as suffix. B. Select Object Modeling as method for one zone. 1A 1B 2. Facies body: A. Select the Fluvial channels icon to insert a channel body. B. Select facies properties to match Channel and Levee. 2A 3. Fraction: Use fraction of Channels and Levees from upscaled cells. or type in a fraction. 2B Fluvial modeling - settings The channel modeling algorithm is fully integrated within the general object modeling tool kit, allowing the user to combine the modeling of channel objects with other general objects. The user can digitize flow lines or use source points to control the orientation of the deposition. This semi stochastic option can, for example, force the channel distribution around salt domes or to stay inside deepwater turbidities. Major depositional directions can be controlled by applying 2D trend maps, source points and flow lines. Modeling rules can be used to nest facies, e.g. channels attached to levees. When combined with Petrel's other object and pixel based modeling algorithms, complex environments can be generated. The channel object modeling algorithm uses fractal functions to control the drift of each channel parameter, such as thickness, width, orientation, wavelength and amplitude. 3

Object Modeling – Fluvial Channels 1. Layout: Specify Orientation, Amplitude and Wavelength. Note: Drift will Apply randomness to each parameter. 2. Channel: Specify the width and thickness of the channel Thickness can be in distance units or as a fraction of the width. Facies modeling - geometry An important part of any object-based modeling program is the geometric form and parameters used to represent each facies unit. A fluvial object could be a channel with all related levees. More specifically, the object is a template of cells that would be coded as channel sand and levee sand. The template provides significant CPU advantages; However, the connectivity of simulated realizations is sensitive to the choice of an underlying grid size. The grid size must be chosen small enough to preserve the geological shapes represented by the templates. The algorithm will use well information, source points, aerial distribution and vertical distribution as well as complying with the shape specified by the user for controlling the distribution of the channels. 3. Levee: Levees are the wing shaped deposits on the side of the channel. Specify width and thickness (smaller than channel).

Object Modeling – Fluvial Channel Background facies After the channel is inserted select a background facies. It can be undefined, a single facies type or a previously generated property.

Object Modeling – Fluvial Channels Result No drift applied (0) Drift applied (>0, <1)

Object Modeling – Fluvial Channels Use Channel trends: Flow lines are digitized polygons used as fairways for the channels to follow Source points are indications of paleohighs/provenance; where channels begin. Facies modeling - trends The algorithm will use well information, source points, aerial distribution and vertical distribution as well as complying with the shape specified by the user for controlling the distribution of the channels.

Object Modeling – Adaptive Channels Truncated Gaussian simulation Adaptive channel modeling: an object-based facies modeling technique, allowing the user to model channels with enhanced well control Based on the principle of generating an irregular surface (invisible) and intersecting it with a dipping plane. Its intersection with the dipping plane is a curve which approximates the shape of a channel centerline The irregular surface is first converted to produce a channel that is confined within a fairway, and to reduce the possibilities of artificial intersections. The channel cross section is generated to produce the final channel. The method can honor data by suitably fixing the value of certain points on the surface. Object Modeling – Adaptive Channels Adaptive channel modeling is an object-based facies modeling technique, allowing the user to model channels with enhanced well control. Traditional object modeling techniques first model the channel, and subsequently try to place it in the model. If the wells do not fit, the channel is rejected. The new algorithm uses a truncated Gaussian simulation, to take into account all the well data, when creating each channel; this means that channels are never rejected. This notably improves the speed and quality when modeling a lot of well data. Channels can also be assigned to selected observations, in particular wells, such that the same channel passes through several wells. The assignment is made by creating a discrete log of arbitrary body index that spans the same area as the interpretation of facies in the facies log. The channels honor the stratigraphy of the grid; therefore, in order to allow channels in different wells to be connected, their topmost upscaled cells must also be in the same layer.

Object Modeling – Adaptive Channels 1. Property and zone selection A. Make sure to pick the correct property; must be upscaled i.e. have (U) as suffix. B. Select Object Modeling as method for one zone. 1B 2. Facies body: A. Select the Adaptive channels icon to insert a channel body. B. Select facies properties to match. 2A 3. Fraction: Use fraction of Channels and Levees from upscaled cells. or type in a fraction. Object Modeling – Adaptive Channels Adaptive channel modeling should be preferred when: a.  a large number of hard data must be honored, b.  channel connectivity information is available and must be honored. Traditional fluvial-object modeling should be used when: a.  there is little hard data to honor and channel connectivity information, b.  levees must be modeled, c.  geometric regularity (i.e. evenly cyclic channel shapes with little drift in geometric properties) is important. 2B 3

Object Modeling – General Objects Create a new facies object: Select Object Modeling as the method. Insert an Ellipse as Facies Body. Facies and fraction: Select Facies type from the drop-down menu. Use the upscaled fraction or type a value.

Object Modeling – General Objects Geometry: Select the Body Shape from drop down menu. Set the Orientation, Width and Thickness Rules: Specify whether the facies will replace other facies or not. Object modeling - geometry All geometrical inputs controlling the body shape (orientation, width and thickness) are defined by the user. For triangular/uniform distribution, the values will be stochastically drawn from these distributions. Object modeling - trends It is possible to insert Vertical probability trend and/or Areal probability trend under the Trend tab when doing Object modeling. Both Vertical trend functions and Areal probability maps can be created in Petrel. To make a function insert a new Function Folder, right-click on the folder and Create a new function. To make a probability map create some polygon lines, set values to each line within the polygon and create a surface using the polygon lines as input. Probability: Vertical (function curve) Areal (probability map)

Interactive Modeling (draw facies) Brush type Irreversible process: Use Simbox view. Make a copy of the property. This will overwrite all other facies, including upscaled cell values. No undo! Initial facies model Edited facies model Facies type Radius Interactive Facies Modeling In the interactive facies modeling, discrete 3D properties can be edited or made from scratch interactively using various tools. It works almost like a drawing tool where the user may switch between different drawing styles like pencil, brush or airbrush and fill the facies bodies directly into the 3D grid. In this way a completely new facies property can be made and used to condition the petrophysical modeling. Height Profile

More Facies Modeling in Petrel Property Modeling course (3 days) Data analysis and basics of geostatistics Data preparation, including well correlation Facies Modeling; sequential indicator simulation, facies transition simulation, object facies modeling (adaptive channel), interactive facies modeling Petrophysical modeling; data analysis, porosity modeling, permeability modeling Modeling based on seismic attributes

EXERCISE Facies Modeling