Petrophysics Aspects of Shale Gas
This course provides a general introduction to the use of well logs to evaluate organic shale reservoirs. Primary focus will be on estimating basic components of reservoir quality—TOC, primary mineralogy, porosity, saturation, permeability, hydrocarbon in place. Additional focus will be on estimating basic components of completion quality—minimum horizontal stress for isotropic and anisotropic systems. The combination of the two criteria will be use to identify, qualify and pick a lateral landing point for an organic shale.
The curriculum is designed for petroleum engineers and geologists with limited expertise in petrophysics. Most of the relevant algorithms can be estimated either with a calculator or instructor-provided spreadsheets. Organic shale logs will be evaluated using these tools throughout the week.
Goal will be for the students to determine viability of an organic shale as a reservoir with a basic well logging suite. With the inclusion of a sonic log, the students will be able to determine stress and the optimum lateral landing point for horizontal wellbores. The use of basic spreadsheets will be employed to quantify reservoir and completion quality of a shale reservoir.
- Definition of productive organic shale reservoir
- TOC/Kerogen identification and quantification
- Adsorbed gas quantification using Langmuir isotherm
- Quantification of mineralogy through log evaluation and relationship to producibility
- Porosity—effective vs. total and their estimation
- Hydrocarbon saturation calculation and accounting for clay water
- Estimation of pore gas hydrocarbon with adsorption correction
- Delineation of shale gas beds and identification of potential pay
- Determination of stress for completion design
- Estimation of producibility based on porosity, permeability, fractures, pressure etc.
- Determination of lateral landing points using stress profiles and rock quality
Richard Lewis is the Petrophysics Technical Manager, Unconventional Reservoirs for Schlumberger Oilfield Services.
Rick was a developer of the gas shale evaluation workflow that was initially fielded nine years ago and has been applied to more than 2000 wells in North America. Prior to his current assignment, Rick was responsible for wireline interpretation development for the central and eastern United States. He is located in Oklahoma City. Rick has also worked for Shell Oil and the U.S. Geological Survey. He received a BS degree from UCLA and MS and PhD degrees from Cal Tech, all in geology.
In his current position, Rick manages a group responsible for the continual improvement for this workflow, and for its introduction and application to the international market. He is also the interface to the Schlumberger research and engineering groups for the development of evaluation technologies for unconventional reservoirs.
Engineers and Geoscientists