Organic Shale Primer


Geology, Geochemistry and Petrophysics: Reserve estimation, hydraulic fracturing optimization and well productivity in “organic shale reservoirs” depends upon an accurate “shale” petrophysical evaluation. Course describes various depositional environments of shale reservoirs, factors affecting organic preservation, kerogene and its maturation, effect of clay mineral digenesis on stresses, generation of natural fractures. The shale petrophysical evaluation includes obtaining accurate mineralogy, porosity, hydrocarbon and kerogen volume estimates, along with mechanical rock properties. This section of the course will give brief overview of the key elements of performing a shale petrophysical evaluation from down hole measurements supplemented with up hole sample based techniques such as TOC analysis, X-ray diffraction, adsorbed/canister gas, vitrinite reflectance, detailed core and thin-section descriptions, porosity, permeability, fluid saturation and optical and electron microscopy. It will define prospective shale reservoir and give basic idea what information needs to be acquired.

Horizontal Well Drilling: Organic shale reservoirs are predominantly completed with horizontal wells. This section of the course will give a brief overview of the techniques that are being employed today to build the curve and steer the lateral. Drilling fluid and bit selection will be reviewed as will downhole assemblies used to build the curve and steer the lateral. Various LWD measurement systems and their application in organic shales will be addressed, with examples showing the value of these measurements included.

Geomechanics and Reservoir Stimulation: This part of the course will highlight the importance of geomechanics modeling and reservoir characterization to the commercial success of exploiting unconventional reservoirs. The nature of organic shale reservoirs is complex and hydrocarbon production is only possible after hydraulic fracturing of the reservoir. The selection of the appropriate lateral landing point is primarily driven by geomechanical parameters. These parameters can be separated into near-wellbore and far field regions. Parameters in the near-wellbore region will influence hydraulic fracture initiation. The far field parameters will control the dimensions of the created fracture system. The measurements required to quantify these parameters will be reviewed as well as utilization of these measurements for appropriate lateral placement and completion design. Lastly, a workflow for designing the appropriate completion system will be reviewed. Open hole and cased hole systems will be compared and contrasted, completion techniques such as “Zipper Fracs” will be reviewed, and means of sizing the stimulation treatments from a fluid volume and fracture conductivity perspective will be reviewed.

Well Performance & Reserves: Understanding well performance in shales is significantly driven by the extent and quality of the fracture stimulation treatment and completion systems. Upfront science and integration of different types of diagnostic data are critical for shortening the learning curve in shale play development and optimization. This course section will discuss how the understanding of shale production performance was advanced by an integration of microseismic fracture mapping results with petrophysical and geomechanical data. The concept of Effective Stimulated Volume (ESV) will be introduced along with its application and limitations. Reservoir modeling studies will show how different fracture network parameters influence well production and ultimately drainage area and reserves. Case studies from various shales will illustrate the concepts. One case study from the Haynesville shale will include detailed data on the integration of well production and fracture diagnostic data to better understand effective fracture dimensions and conductivities, and well performance. These insights provide important information for optimizing infill drilling, well placement, and fracture completion strategies in shales.

Who Should Attend

Geologists, geophysics, reservoir, production and stimulation engineers and exploration managers. Although intended as an introduction, content of the course is best suited for experienced professionals of oil and gas companies.


Rick Lewis is the unconventional petrophysics technical manager for Schlumberger Oilfield Services in Oklahoma City. Lewis was a developer of the gas shale evaluation workflow that was initially fielded eight years ago and has been applied to well more than 1000 wells in North America. In his current position, Lewis 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 organic shales. Prior to this assignment, he was responsible for wireline interpretation development for the central and eastern United States. Lewis 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.

George Waters is the unconventional completions technical manager for Schlumberger in Oklahoma City, Oklahoma. He joined Dowell Schlumberger in 1985 and has held numerous completion engineering assignments starting in 1992, focusing primarily on low permeability hydraulic fracturing optimization. Since 2000, he has concentrated on evaluation and completion of shale gas reservoirs, including horizontal wells. He is currently involved with the geomechanical evaluation and completion design of organic shale reservoirs under exploration outside of North America. He holds a BS in petroleum engineering from West Virginia University, an MS in environmental engineering from Oklahoma State University, and an MS in petroleum engineering from Institut Francais du Petrole. He was a 2009-10 SPE Distinguished Lecturer on the topic of Completion of Organic Shale Reservoirs.

John Robinson is a senior reservoir engineer for unconventional resources for Schlumberger in the Middle East (MEA/ARM). Robinson works in the Aramco offices in Dhahran for the NW area Exploration Department. Robinson is involved with tight gas and shale gas exploitation. He joined Schlumberger in 2006, but has been involved in un-conventional gas since 1989 while working closely with the Gas Research Institute (GRI) in various Coalbed Methane projects in the US. Robinson graduated from the University of Tulsa with a BS and MS in petroleum engineering. He has been involved with testing exploration wells and collecting the necessary data to evaluate the wells for not only short term potential but also long term gas recovery (EUR).