Codell Sandstone – DJ Basin

Geological, Petrophysical and Completions Study for Improved Formation Evaluation and Optimal Well Performance

The Integrated Reservoir Solutions division of Core Laboratories is offering to interested companies participation in a project designed to optimize operators’ exploitation of the liquids-rich, Codell Sandstone in the DJ Basin. This project is a follow-up to our highly successful Niobrara joint industry study.

In exploring for and developing the Niobrara oil reservoirs operators have also been taking a look at the potential of horizontal wells in the Codell. The Codell ranges from 20 to 100 feet thick in the DJ Basin and consists of three marine depositional facies. Porosity is generally less than 10% and permeability is typically less than 1md. The oil in the Codell is typically light and may be sourced from the overlying Niobrara. An integrated study of the Codell is warranted and should be directed at geology, formation evaluation and stimulation-production techniques to maximize exploitation. Some of the issues to be addressed in this project include the following:

  • What are the factors controlling reservoir quality? Are they depositional facies or diagenetic?
  • What is the relationship between the Niobrara hydrocarbon kitchen and the Codell?
  • What are the various reservoir rock types and their petrophysical properties, and how do they vary regionally?
  • What are pay recognition criteria and the appropriate water saturation model for the reservoir and does it change regionally?
  • What are the optimal completion and stimulation fluids?
  • What is the optimal fracture stimulation design(s) to maximize production?
  • How should the reservoirs be produced in order to maximize liquids production?
  • Can reservoir quality be correlated or benchmarked to production performance?

These questions can only be solved from the geological, petrophysical and completion/stimulation analysis and evaluation of wells with conventional cores. The resultant data can be used to calibrate open-hole logs in order to better predict rock types and petrophysical properties essential for formation evaluation and proper well completion and stimulation designs. The rock types and their measured petrophysical properties can also serve as analogs when evaluating new reservoirs in wildcats or field step outs.

Each participating company will be required to contribute conventional core from two (2) wells for analysis and inclusion into the study. All participating companies will share in the project results and interpretations.