The goal of XRF Solutions is to use X-ray fluorescence (XRF) technology to provide chemical logs in vertical and horizontal wells. These logs help to in increase hydrocarbon production while reducing exploration and completion costs. XRF analyses are a rapid and relatively inexpensive way to gather large quantities of information at low cost per sample. Bulk rock chemistry is gathered in terms of both major elements and trace elements. Algorithms are applied to the data to provide geologic interpretations and rock property information for the client. Chemical analysis on drill cuttings allows for horizontal wells to be logged without the need for any tools down hole or impedance on drilling operations.
The most important data from each of the chemical log sets for a particular formation are combined into a single reservoir quality logs suite. Major rock forming minerals provide an overall lithology. The calculated mechanical properties for Young’s Modulus and Poisson’s Ratio help to assess areas in which it may be easier to induce fractures and also define potential fracture barriers. Calculated TOC suggests zones which may result in higher production through increased hydrocarbon storage and natural fractures. All these factors combined allow for the selection of a target interval which has the highest potential for success. Figure A is an example of the reservoir quality chemical log suites developed from a core taken in the Duvernay formation. This analysis allows for the ideal target zone to be selected for well placement and the identification of chemical markers to aid in post well analysis or geo steering applications.
Figure A. XRF Reservoir Quality Factors from a Vertical Well in the Duvernay Formation.
The XRF model developed from vertical wells can be used to log horizontal wells through the analysis of drill cuttings. Chemical logging of the horizontal well can be completed during or after drilling with no effect on rig operations and without putting any tools in the well. On-site analysis can help the geologist determine the stratigraphic location of the well in order to remain within the target interval. Post well analysis is useful for evaluating the production potential of the entire well or a particular interval in that well. There are also applications for customizing the hydraulic fracture plan based on the comparing the chemical well logs with previous hydraulic fracturing results. Figure B depicts the reservoir quality factors of a horizontal Duvernay well, while Figure C shows the well trajectory in terms of vertical stratigraphy.
Figure B. XRF Reservoir Quality Factors from a Horizontal Well in the Duvernay Formation.
Figure C. Cross Section of Well trajectory and Stratigraphic Units in the Duvernay Formation.