1、StratWorks Chapter 10: Calculating Volumetrics,Presenter Title Landmark Graphics Corporation,Part No. 625579 Rev. J,10-1,Chapter 10: Calculating Volumetrics,The Volumetrics module in MapView allows you to complete your interpretations by computing the volume of your grid over a given interval, while

2、 considering constraint grids and polygon cutoffs. Ideally, the input grid is a preprocessed isochore representing perhaps, hydrocarbon saturation-pore thickness, so that Volumetrics yields some quantity of hydrocarbon in place. However, any isochore or structural grid will result in some volumetric

3、 output. If the input grid is structural, the output is always gross rock volume.,10-1,Overview,In this chapter you will use the Volumetrics module to compute a variety of volumes over the Sand 2 formation. You will learn: to create gross pay grids for use in volumetrics to creatively use Operations

4、 to “evaluate” a constant value oil/water contact grid to use various constraints for controlling where volumes are computed to use Free-form Drawing for building polygon constraints to display and use volumetric output,10-2,Training Workflow,10-3,Performing Grid Operations: Revisited,With StratWork

5、s you can perform logical and arithmetic operations on a single grid (grid-to-constant) or between two grids (grid-to-grid). The result of such an operation is a new output grid that you can display and contour. You can do multiple computations in a serial fashion, inputting as many as six grids and

6、 applying constants between each grid-to-grid operation.,MapView Mapping Operations,10-3,Grid-to-Constant Operations With a single grid, you can: Add - Add a constant to each node. Subtract - Subtract a constant from each node. Multiply - Multiply each node by a constant. Divide - Divide each grid n

7、ode by a constant. Output Maximum - Output whichever is greater, a grid or a constant. Output Minimum - Output whichever is smaller, a grid or a constant. Blank A if A C - Output null if the grid is greater than the constant; if not, output the grid. Blank A if A C - Output null if the grid is less

8、than the constant; if not, output the grid.,Performing Grid Operations: Revisited,10-4,Performing Grid Operations: Revisited,Grid-to-Grid Operations With two grids, you can: Add - Add the two grids at each node. Subtract - Subtract one grid from the other at each node. Multiply - Multiply one grid b

9、y the other. Divide - Divide one grid by the other. Output Maximum - Output the value of the greater grid. Output Minimum - Output the value of the smaller grid. Blank A if A B - Output the first grid if it is less than the second; if not, output null. Blank A if A B - Output the first grid if it is

10、 greater than the second; if not, output null. Output A if (A if it is null, output the second grid. If the two grids have different areas of interest and/or grid increments, the application resamples one or both grids. The output grid will have an area of interest equal to the intersecting area of

11、the two input grids except in the case of Output A if A!=Null else B. In this case, the output grid will use the union of the two grids AOI. a grid increment equal to that of the smaller of the two input grids.,10-8,Volumetrics: An Introduction,Mapping Volumetrics,MapViews Volumetrics module lets yo

12、u calculate volumes between a grid and base plane that may be constrained by up to three polygons and two constraint grids.,10-9,Volumetrics: The Problem,The Side Panels are typically defined by your property boundaries. The Base Plane is a constant or grid of the OWC or GOC. The Grid is the top of

13、the reservoir created from well or seismic data.,The Volumetrics module computes the volume of a body formed by an input grid on top, a flat base plane on the bottom, and vertical side panels.,10-10,Quantities Computed by Volumetrics,Volumetrics differentiates between the volume above and below the

14、base plane. Volumes above the Base Plane and below the Input Grid are Positive Volumes. Volumes below the Base Plane and Above the Input Grid are Negative Volumes.,10-11,How Volumetrics Works,When you use volumetrics, volumes and areas are calculated on a cell by cell basis according to the followin

15、g procedure.,Volume is computed by integrating an orthogonal polynomial function over the grid cell. Area is also calculated. Once calculated, the volumes and areas are added to totals, and the operation proceeds to the next cell.,10-12,Volumetric Constraints,Volumetrics allows you to constrain your

16、 volumetrics by inputting any or all of the various constraints illustrated below.,10-12,Volumetric Constraints,10-13,Volumetric Outputs,There are two types of output from Volumetrics:,MapView Information Window,ASCII File,10-15,Volumetric Scenarios,The ideal volumetric situation is to input a grid

17、of hydrocarbon saturation pore thickness and calculate some quantity of in-place hydrocarbons. A first step in the process of developing this grid is to compute a gross pay isochore from structural grids. Gross pay is then multiplied by net/gross ratio, porosity, and hydrocarbon saturation to produc

18、e the desired hydrocarbon saturation pore thickness. This section identifies four common geologic scenarios for computing a gross pay isochore, and discusses how to use grid operations to prepare the proper input grid.,10-15,Single Surface, Single Contact,In this case, the upper surface is your Inpu

19、t Grid, and your fluid contact (OWC or GOC) is your Base Plane Level. Volumetrics outputs Gross Pay.,Gross Pay,10-16,Dual Surfaces, Single Contact,In this more complex situation, you compute Gross Pay between the layers, but above the fluid contact.,Gross Pay,10-18,Single Surface, Dual Contacts,In t

20、his case you want to calculate the volume of rock between the two fluid contacts above the lower surface.,Gross Pay - Oil,Gross Pay - Gas,10-19,Dual Surfaces, Dual Contacts,In this case, two fluid contacts intersect both the upper and lower surfaces of your anticlinal structure. You want to calculat

21、e the volume of rock between two surfaces and between two contacts.,Gross Pay - Gas,Gross Pay Oil,10-21,Free-form Drawing: An Intro,MapView, Cross Section, Correlation, and Single Well Viewer allow you to add various free-form drawings and graphics to your displays,Tools Free-form Drawing,10-22,Free

22、-form Drawing: Purpose and Use,You can add, edit, or delete text, lines, polygons, symbols, and boxes on your displays. Instructions for drawing each type of feature are presented in the applications (MapView, Correlation, etc.) status area. Free-form Drawing polygons are converted into Constraint Polygons for Volumetrics with the Tools Create Volumetric Polygon Set option. Free-form drawings are stored as layers on your pictures. You can remove them with the Free-form Drawing D