Petra will automatically close open polygons.ĭuring picking, press ESC picking to cancel the current polygon or DELETE to drop the last picked point. Pick polygon node points with the left mouse button and select the right mouse button to stop picking points. Drawing a polygon works exactly the same as drawing lines elsewhere in Petra. To establish a facies polygon, right click anywhere on the log plot and select ∺dd Polygon. Alternatively, select Polygons>Add from the menu bar at the top of the screen. Thought this example only shows one well, a single facies polygon file can be applied to any number of wells, making it a powerful way of interpreting crossplots over an entire project. The example below shows how a facies curve actually looks in the Main Module the depths where the gamma and deep resistivity curve values fall inside the polygon are coded with a facies value of 1. All the data points inside the polygon are coded with the facies polygons value of 1.
![rokdoc crossplot cutoff rokdoc crossplot cutoff](https://onlinelibrary.wiley.com/cms/asset/b6253d0f-6338-4bc6-8743-11e52ab69b3c/gpr12654-fig-0004-m.jpg)
Footage-wise, its from about 2905 to 2940 MD.Ĭarrying on the example, the polygon is converted to a facies log. On the curves to the right, the data points inside this polygon are highlighted in red. This polygon covers the data points where gamma is lower than about 90 API units and resistivity is above 10 ohmm in short, its the potentially productive sand. The example below shows a Gamma/Resistivity crossplot with a single pay polygon.
#Rokdoc crossplot cutoff code#
Additionally, multiple polygons means that a facies log can code for multiple facies at the same time. As such, facies polygons allow for a more nuanced cutoff criteria, since polygons vary the cutoff based on the relationship between logs. The MD of data points falling inside a polygons boundary are given that polygons facies value. When creating a facies curve, Petra compares the footage of the relevant curves to the log crossplot polygons. Each polygon in the Crossplot Module can have its own name, color, and facies value. A facies value is a way of coding a log crossplot polygon into a facies curve. As the region around the KGS 1 Hanson Aggregates well is underpressured and adjacent to faulted Precambrian basement, further research is needed to evaluate its induced seismicity risk during CO 2 injection.Facies polygons outline different areas of the crossplot. Static Rose Run reservoir pressure was 9.3 MPa, and fracture gradient under injection was 13.6 MPa/km, suggesting step-rate testing before CO 2 injection, and subsequent pressure monitoring to ensure confinement.
![rokdoc crossplot cutoff rokdoc crossplot cutoff](https://onlinelibrary.wiley.com/cms/asset/53306fcf-fc4a-4e63-8fcc-8d1a522c7925/gpr12654-fig-0003-m.jpg)
A step-rate test was conducted in a mechanically-isolated 18.6-m interval bracketing the Rose Run. Triaxial compressive strength measured in core plugs found the Rose Run and Beekmantown fractured at mean axial stresses of 156.5 MPa and 282.2 MPa, respectively, confirming the Beekmantown as suitable for confining CO 2 injected into the Rose Run. Mean Young's modulus and Poisson's ratio values of the Rose Run were 45 GPa and 0.23, respectively, whereas Young's modulus and Poisson's ratio values were 77.1 GPa and 0.28, respectively, in the overlying Beekmantown dolomite, suggesting the Rose Run may fracture if overpressured during CO 2 injection but be confined by the Beekmantown. The Rose Run elastic geomechanical properties were calibrated to values measured in core plugs to evaluate its fracturing risk as a CO 2 storage reservoir. Wellbore fractures in dolomites underlying and overlying the Rose Run follow the contemporary N53☎ Appalachian Basin stress field.
![rokdoc crossplot cutoff rokdoc crossplot cutoff](https://library.seg.org/cms/10.1190/INT-2020-0007.1/asset/images/medium/figure10.gif)
Maximum vertical stress gradient calculated in the wellbore was 26 MPa/km. Average porosity and permeability measured in core plugs were 9.1% and 44.6 mD, respectively. A 9.8-m thick section of the Rose Run was penetrated at 1000 m drilled depth and a whole-diameter core and rotary sidewall cores were taken. Geomechanical properties of the Rose Run sandstone (upper Ordovician Knox group) were tested for its suitability as a storage reservoir.
![rokdoc crossplot cutoff rokdoc crossplot cutoff](https://www.researchgate.net/profile/Honore-Yenwongfai/publication/316971727/figure/fig3/AS:614399802892298@1523495736464/a-Arbitrary-seismic-line-and-b-time-slice-showing-the-top-and-base-Havert-sand_Q320.jpg)
The Kentucky Geological Survey (KGS) 1 Hanson Aggregates stratigraphic research well, Carter County, Kentucky, USA, was drilled to a total depth of 1474 m as a field-scale test of potential CO 2 storage reservoir properties in the Central Appalachian Basin.