Insights Into Recovery Mechanisms in Shales Through Digital Rock Technology

摘要

The impact unconventional plays have had in the energy industry has been nothing short of revolutionary. The presence of source rocks has long been known. Shale extraction technologies have matured, such as horizontal drilling and multi-stage hydraulic fracturing, and their correlation to oil and gas recovery is well understood. However, even after billions of dollars invested and billions of barrels of oil produced from these nano pore reservoirs, the causality between many of the variables responsible for production still remains unknown or uncertain: 1. How is oil released from nano sized matrix pores? 2. Is gas release good for oil recovery? 3. Does fluid composition matter? 4. What is the technical limit for oil and gas recovery? This paper describes the application of digital rock technology in the Eagle Ford unconventional shale play in Texas. Consistent with the findings of thousands of papers written on the Eagle Ford, the reservoir is generally described as a world-class source rock. A typical well has a horizontal lateral exceeding 5500 ft and is fractured with a multiple of different pump designs. Oil and gas is produced through fracture networks reactivated by hydraulic fracturing, connected to the tight matrix that serves as storage. The release and transport of oil and gas from the nano porosity matrix to the fractures are processes that are not well understood. These processes are complex and include specific nano scale phenomena and mechanisms.