Drilling Risk Management

Solving geomechanical problems and wellbore stability analysis for directional and horizontal well drilling. The software helps minimize drilling risks.

RN-SIGMA - Drilling Risk Management

What's new

New versions of RN-SIGMA are released every 4 weeks.

09/03/2021 Version

09/03/2021 Version

We added:

  • creating the curve of destruction criterion by zones and taking this curve into account during WBS calculation
  • calculating and displaying the curve of maximum wellbore wall shear stress during WBS calculation with "Synthetic Image" additional option
  • accounting for the zone cube, constant or trend cube when interpolating cubes
  • depth derivative/lateral cube calculation into the cube calculator

Besides:

  • error messages now appear in a popup while calculating scripts
  • the first update cycle for project items starts immediately during auto synchronizing initiation in WITSML client
07/30/2021 Version

07/30/2021 Version

We added:

  • selecting zones/lithotypes when calculating wellbore stability with additional options
  • importing, storing and displaying fractures, faults and points in space
  • supporting import of data on surfaces, polygones and points in CPS-3, Z-MAP, XYZ formats
  • data export in RESCUE format
  • a variogram analysis tool
  • calculating property cubes using Python scripts
  • the ability to set and change the dataset display name
  • the ability to use the context menu to change WITSML protocol connection
  • visualization of maximum trajectory TVD
  • optional output parameter calculation for the Traugott method ("Synthetic density" section) and for the method of calculating dynamic elastic moduli from interval velocities ("Dynamic properties" section) into the wellbore stability element
  • accounting for the domain when inserting zones

Besides:

  • creating the cubes using well logging data can now be performed simultaneously for various datasets, if the algorithms coincide completely
  • saving curves in the well logging calculator is fixed
  • the report on multivariate modeling is modified
  • now the sludge diagram data is displayed on one log plot track by default
  • sludge diagram visualization is fixed and accelerated
  • the trajectory determination area boundaries are now taken into account when entering and inserting zones
06/02/2021 Version

06/02/2021 Version

We added:

  • acounting for UOM when setting the well logging palette in 3D window
  • step-by-step curve import with the ability to set the maximum number of data lines requested at a time (WITSML-client)
  • time recording ang additional recording into mud logging interval (WITSML-client)
  • defining the mud window taking into account breakout width into WBS window
  • recoding into the lithology column
  • multivariate calculations using selected parameters into the Geomechanical model
  • an option to enter the scale into Visualization window (mud logging data vs time)

Besides:

  • now there is no need to recalculate safe mud window when Synthetic image and Synthetic caliper options are enabled in "Well stability" section of WBS window
  • the curves from a removed set are automatically combined into one project set in WITSML-client
  • "Combining curves" method has been returned to the available methods lists in "Static elastic properties" and "Strength properties" sections of WBS window
  • in the Eaton and Bowers methods the lithocolumn is plotted according to the averaged curve during gamma ray logging averaging (previously, averaging had no effect on lithology) in "Pore pressure" section of WBS window
  • the values entered in the table are automatically saved without pressing Enter in Zone editing window
04/09/2021 Version

04/09/2021 Version

We added:

  • an option of creating a 1D WBS model, which is a set of well logs containing information on mechanical, strength and other properties, including well stress state
  • importing only top zones or using marker data
  • custom point dataset creating tool
  • «Operations» module for point data
  • calculation of a derivative into well logging operations
  • description into the well logging window
  • cement ring destruction diagram into «Cement ring stability modeling» method
  • a movable depth mark line into «Cement ring stability modeling» and «Sand production modeling» methods
  • a tree for managing styles and visibility of objects into the 3D window
  • modeling clusters by lithology, with or without modeling by zones into «Clustering» module

Besides:

  • now calculations are performed in MD (in previous versions they were performed in TVD, which did not allow taking into account horizontal sections of the well)
  • «Fracture reactivation» and «Fracture reactivation potential» methods are now combined
  • Borehole geometry tool (two-finger caliper) data analysis is now available
  • «Fracture reactivation» method is supplemented by depth selection and the Mohr diagram visualization
02/16/2021 Version

02/16/2021 Version

We added:

  • a new mud log data vs time window, which allows forming individual polygonal chain and scale graphs and saving the resulting graph structure in templates
  • the ability to visualize zones in the form of a colored interval on an individual track within the log plot with the center caption

Besides:

  • the log plot filling option is modified, now it can be set with one color and on both sides of the curve simultaneously
  • the user manual is fully updated
12/21/2020 Version

12/21/2020 Version

We added:

  • a hole size and material grain dependence of strength into sand production simulation
  • saving the simulation result of one direction fracture propagation (injection induced fracture module)
  • managing the case of defined bottomhole pressure exceeding the pressure of crossing data availability interval (injection induced fracture module)
  • visualization of the reactivation density upper and lower limits in the «Wellbore stability analysis» method when «Weak plane» option is enabled

Besides:

  • the trend curve is now calculated for the entire well trajectory in the well log window (in the previous versions the trend curve was plotted only for the initial well log curve depths)
  • the calculation algorithm in «Porothermoelastic dynamic wellbore stability analysis» method was improved
11/09/2020 Verison

11/09/2020 Verison

We added:

  • wellbore shape 3D visualization into multifinger caliper analysis
  • an option of using caliper fingers positioning into multifinger caliper analysis and visualization
  • an operation of well log curve shifting along MD

We implemented:

  • dynamic modeling module with the option to select a function to describe time dependence of input parameters
  • «Porothermoelastic dynamic wellbore stability analysis» method
  • «Viscoelastic dynamic wellbore stability analysis» method (Burger's model)
  • Options in the «Wellbore stability analysis» method to account for mud cake influence and plastic material properties
  • «Sand production modeling» method (Hettema's and Wilson's models)
  • «Cement ring stability modeling» method
10/01/2020 Version

10/01/2020 Version

We added:

  • operations for averaging, shifting, stretching and clearing well log values
  • 3D window in the Tools menu and also the ability to save the state of this window into a separate project element
  • UOM converter

We implemented:

  • visualization of accumulated histograms and a cumulative curve and quantiles in the histogram window
  • Traugott's method for calculating synthetic density
  • modification of the dynamic addition to the mud density calculation
08/13/2020 Version

08/13/2020 Version

We added:

  • coloring by filters in the cross-plot window and in the histogram window;
  • displaying statistics on clusters in the clustering window;
  • Miller's method and Amoco empirical relation for calculating synthetic density;
  • linear transformation and stretching / compressing in well log curve operations.

We implemented:

  • tectonic regime determination module;
  • the ability to set overlapping sections in the construction window;
  • sorting by depth when importing well log curves.
07/17/2020 Version

07/17/2020 Version

We added:

  • the ability to define sections of the wellbore open part in the well construction window
  • visualization and editing trajectory parameters: rotary table height, ground level height, wellhead height, local sea level height
  • accounting for normal compaction trends during properties transfer
  • saving plotted polygons in the cross-plot window

We implemented:

  • optional display of the determination coefficient R ^ 2 in the curve formula on the graph as well as font selection for the caption with the formula in the cross-plot window
  • model of associated porothermoelasticity in critical densities calculation
06/22/2020 Version

06/22/2020 Version

We added:

  • calculation of injection induced fracture height in an injection well;
  • calculation of pore pressure in the sandbody in clays (accounting for centroid effect);
  • creation of dependencies in the cross-plot tool using multiple wells data;
  • possibility to import the trajectory, using three curves: depth, zenith, azimuth (WITSML-client);
  • information display table into the preview window (WITSML-client).

We implemented:

  • algorithm for estimation of maximum and minimum horizontal stress components using borehole imager data;
  • algorithm for estimation of maximum horizontal stress and its direction using borehole imager data on breakout direction and width;
  • data synchronization when well logs changing (when simulating in the wellbore stability window, modeling workflow, when upgrading with WITSML-client).
05/19/2020 Version

05/19/2020 Version

We added:

  • an option of calculating and modeling critical density, stereograms, stress diagrams, synthetic images and the caliper taking into account elastic properties anisotropy;
  • static elastic properties calculation using the effective model of a layered medium;
  • an option of disconnecting from WITSML-server.

We implemented:

  • importing data by drag-and-drop on the element of the project tree;
  • viewing and editing parametres of methods in the workflow manager;
  • data curve operations window, including trend creating, interpolation, value averaging by wavelets, value averaging by facies.
04/22/2020 Version

04/22/2020 Version

We added:

  • loading and visualisation of cubes, maps and polygons;
  • clustering module, including clustering by machine learning methods;
  • exponent calculating methods for abnormal pressure zones prediction with Eaton's method.

We implemented:

  • cube building from WL set and properties profiles building from the cube;
  • operation of cube properties interpolation;
  • well shape visualisation using multifinger calipers data.

03/18/2020 Version

03/18/2020 Version

We implemented:

  • calculation of model properties by facies with / without zones;
  • methods for assessing the physical and mechanical properties of rocks according to well log and mud logs.

We added:

  • taking into account bedding planes while calculating critical densities;
  • fracture reactivation simulation.
02/14/2020 Version

02/14/2020 Version

We added:

  • an output of friction angle for each given Mohr circle to the strength certificate;
  • the ability to display the depth axis on the log plot with the time axis;
  • the ability to set input parameters from the keyboard at the selected depth in the stereogram window;
  • taking into account osmotic stresses in the calculation of critical densities.
01/15/2020 Version

01/15/2020 Version

We added:

  • new icons and a dark theme option;
  • filters by zones and lithotypes, display of the trend line equation to the cross-plot window;
  • "Create by Template" option to the log plot;
  • sorting and searching for deleted objects in the WITSML client.
12/18/2019 Version

12/18/2019 Version

We added:

  • several curves from different wells to histogram window;
  • filters by zones and lithotypes;
  • Pressure-Gradient, Gradient-Pressure converters to the tools.
11/21/2019 Version

11/21/2019 Version

We added:

  • the tree with data update settings to the online maintenance module to select a method for updating and installing the workflow;
  • preview to online tracking module.

Besides:

  • the online tracking module implements the loading of time-dependent data;
  • User Guide is updated.
10/25/2019 Version

10/25/2019 Version

We implemented:

  • online drilling support module;
  • loading, storage and display of mud log data, sludge traces.

Besides, the graph for drilling data has been modified: curves can be placed on separate tracks as on the log plot.

09/28/2019 Version

09/28/2019 Version

New improvements:

  • in the correlation editor variable names are checked for compliance with Python language rules;
  • the ability to load point data into a separate project element is added;
  • equivalent circulating density (ECD) curve and synthetic caliper curve are synchronized.
08/26/2019 Version

08/26/2019 Version

We improved:

  • the inclination and azimuth dependencies of critical densities;
  • the crosshole property transfer module.

Besides, the correlation library is complemented.

07/30/2019 Version

07/30/2019 Version

New improvements:

  • wellbore stability analysis with account of strength anisotropy is introduced;
  • project well property transfer with account of several reference wells is implemented;
  • well data and geomechanical model export to RN-GRID is added.
07/02/2019 Version

07/02/2019 Version

We introduced:

  • recovering horizontal deformations method using well imaging data;
  • a new pore pressure calculating method using point data of fluid density changes with depth;

Besides, new petroelastic modeling methods are expanded.

05/29/2019 Version

05/29/2019 Version

New improvements:

  • saving and display options for cross-plot and histogram objects are expanded;
  • equivalent circulating density (ECD) profile now can be edited using context menu option;
  • variables in log calculator now can be renamed.
04/30/2019 Version

04/30/2019 Version

New improvements:

  • the inclination and azimuth dependencies of critical densities are introduced;
  • the depth for stress diagrams and density stereograms now can be set interactively using 3D well trajectory window;
  • the correlation library is complemented.
12/04/2019 Version

12/04/2019 Version

New improvements:

  • all functions from pandas, scipy and numpy libraries can now be used under 'pd', 'sp', and 'np' aliases in well log calculator and correlation editor;
  • type and measurement units now can be corrected for loaded well log curve;
  • logical operations description is added to the correlation editor.

The Basic Process of Building a 1D Geomechanical Model

Synthetic Density Calculation

Synthetic Density Calculation

Density curve is the basis for recovering a lot of reservoir parameters. The main source of information on rock density is density gamma-gamma-ray logging. This kind of logging cannot be held in the conductor area thus its log requires a recovery procedure up to the surface.

Geostatic Pressure Profile Building

Geostatic Pressure Profile Building

Geostatic pressure is the pressure of overlying rocks. The geostatic load is equivalent to the weight of the overlying stratum of sediments (rocks and fluids) at any point in the earth's crust and can be determined using density log recovered up to the surface.

Pore Pressure Calculation

Pore Pressure Calculation

Pore pressure is the fluid pressure in rock pores. Methods for determining pore pressure are hydrostatic pressure calculation, Eaton and Bowers methods with clay line determination, and also the method using pore pressure gradient data.

Elastic Properties Calculation

Elastic Properties Calculation

A saturated porous medium can be characterized by three elastic moduli: Young's modulus, Poisson's ratio, and poroelasticity coefficient. Dynamic elastic modules can be used to recover static ones.

Strength Properties Calculation

Strength Properties Calculation

Strength characteristics are parameters determining the critical loads , the excess of which leads to the material destruction. Three main parameters can be measured: uniaxial compression strength, tensile strength and internal friction angle.

Horizontal Stress

Horizontal Stress

Horizontal stresses are lateral stresses that arise in a rock under the rock pressure and tectonic forces influence. The main method of determination is direct calculation using function of rock and pore pressure and tectonic deformation values.

Safe Mud Density Window

Safe Mud Density Window

Safe Mud Density Window is the equivalent circulating density (ECD) range that guarantees the absence of critically dangerous incidents during well drilling operation, e.g. reservoir fluid inflow, borehole wall collapse, drilling mud loss and long crack formation.

Benefits

RN-SIGMA software product algorithms and approaches are based on the best world practices. RN-SIGMA contains all the necessary algorithms and interface solutions for constructing a one-dimensional geomechanical and wellbore stability model. RN-SIGMA includes a number of relevant non-standard capabilities, such as elastic and strength properties anisotropy, temperature influence on stress state, etc.

Full Well Stability Modeling Cycle

RN-SIGMA introduces a full cycle workflow from data gathering, analysis and preliminary processing to 1D geomechanical model construction. A safe drilling mud density range can be calculated based on the simulation algorithms, and prediction of complications while drilling can be made for further well trajectory and construction optimization.

Custom Processing Templates of Typical Calculations

RN-SIGMA introduces a workflow creating — a sequence of calculation methods for processing a set of wells with similar characteristics and logs.

This tool can significantly reduce the project development time in the presence of several reference wells.

Additional Non-Standard Features

RN-SIGMA core allows to calculate wellbore stability for anisotropic media. The implemented algorithms make it possible to take into account the elastic and strength properties anisotropy.

RN-SIGMA core allows to calculate wellbore stability taking into account thermal effects.

Custom Python Programming Solutions

RN-SIGMA allows to implement and transfer user-own calculation methods using the built-in correlation editor and well log calculator. These tools use the Python programming language that is simple to learn due to minimal syntax. Well log calculator allows to make a quick one-time calculation, and the correlation editor is designed to add and edit permanent custom calculation methods. The transferring option can significantly increase the rate of experience exchange among different users and project groups.

Real-time Geomechanical Tracking

WITSML server data acquisition while drilling will clarify the pre-drilling geomechanical model and improve complications prediction quality in unstable rock intervals

Structural Changes in Rocks Over Time

The solutions with time-dependent properties will allow the wellbore stability calculations to be performed with the dynamic conditions during the drilling process in the near-wellbore zone. Dynamic modeling main advantage is estimating the acceptable time between the moment of opening an unstable interval to the time of well casing.

Calculation of fracture and fault reactivation

The software helps determine critically stressed faults/fractures and calculate critical reservoir pressure for breaking fault/fracture stability.

Assessment of Sand Production Risk

Advanced algorithms for sand production prediction define higher risk zones, calculation of maximum allowable depression cubes and optimal perforation position and orientation.

Intuitive and Simple Interface

The developers of RN-SIGMA tried to design the interface so that it could be accessible and understandable from the very beginning of use. Based on the actual users feedback RN-SIGMA is successfully developing and becoming a more simple and flexible tool.

Solving Problems Easily

A set of implemented tools allows to perform a full cycle workflow on data gathering, analyzing and pre-processing, building and transferring one-dimensional geomechanical models, predicting drilling complications and risks arising from geological reasons, optimizing the wellbore trajectory and construction and calculating a safe drilling mud density range.

Plans

New versions of RN-SIGMA are sent out every 4 weeks.

  • Geomechanical 3D Well Modeling

    3D modeling allows solving the problems of rock stress-strain state around the wellbore and joints.

    Advantages:

    • Wellbore stability assessment in difficult geological conditions
    • Prediction of complications while drilling complex wells
    • Improving model accuracy and predictive ability
    • Prediction of complications while drilling through rock intervals with nonlinear elastic behavior
  • Geomechanical 4D Field Modeling

    4D modeling includes the functionality of geomechanical and hydrodynamic simulators to account for geomechanical effects during field development.

    Advantages:

    • Prediction of changes in stress and deformation fields, rock destruction during development
    • Accounting for the stress state influence on reservoir quality
    • Prediction of reservoir productivity changes caused by geomechanical effects
    • Accurate transfer of the mechanical properties model from the reference well to the design trajectory
  • Assessment of Reservoir Compaction and Day Surface Subsidence

    Provides simulation of reservoir rock deformations, over- and underlying rocks, day surface.

Training Courses

Regular training activities help to improve the efficiency of use and acceleration of the process of RN-SIGMA software product implementation in workflows.

About Course

About Course

As a result of training, the course participants get knowledge about the subject and task of geomechanics in the drilling wellbore processes and skills of work with RN-SIGMA software.

The target audience of this course includes specialists in drilling planning and support, geomechanics and related fields.

Course Content

Course Content

Lecture on the theory of geomechanics with practical examples (3.5 + 3.5 hours).

Lecture on principles and general approaches to the construction of one-dimensional geomechanical models (2 hours).

Acquaintance with RN-SIGMA, work with tools (1.5 hours).

An example of building a one-dimensional model of wellbore stability (3.5 hours).

Independent work with a ready-made sample of data, or with examples of participants (5 hours).

Examples of working with auxiliary modules (2 hours).

Course Experience

Course Experience

We have conducted 9 trainings in Ufa, Moscow and Tyumen in 2 years. More than 100 participants attended our training courses.

Who Uses (Clients)

RN-SIGMA software is used by geomechanical specialists from more than 15 Rosneft subsidiaries (150+ license).