The Eagle Ford Shale: A Renaissance in U.S. Oil Production
Known as a world-class source rock for years, the Eagle Ford Shale became a world-class oil reservoir early in the second decade of the 21st century. Oil production from the Eagle Ford grew from 352 barrels of oil per day (BOPD) in 2007 to over 1.7 million BOPD in March 2015. Since then, the play has been a victim of its own success. Production from shale oil in the United States has helped contribute to a glut in world oil supply that led to a precipitous drop in oil prices beginning in the summer of 2014. As prices fell from over $100 per barrel in July 2014, to less than $30 per barrel in January 2016, production from the Eagle Ford declined over 500,000 BOPD. Anyone interested in the geology behind this remarkable play and the new ideas that reshaped the global energy supply should read AAPG Memoir 110.
The Role of Integrated Reservoir Petrophysics in Horizontal Well Evaluations to Increase Production in the Eagle Ford Shale
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Published:January 01, 2016
Abstract
Drilling horizontal wells is the common mode of operation for field development in low-permeability unconventional reservoirs such as the Eagle Ford Shale. Assumptions are made regarding the homogeneity of the reservoir as wells are drilled away from the vertical pilot well. It is assumed that the reservoir characteristics remain uniform and also that the structure is constant based on the dip of the beds in the pilot hole wellbore. Making such assumptions can lead to wells being placed out of zone and in rocks with much different reservoir quality and stress magnitude than those in the pilot hole, which can adversely affect the production potential of the well. With the high cost of drilling and completing these wells, it is generally economically beneficial to do some evaluation of the lateral to ensure proper placement of the well and also the optimal placement of completion zones along the lateral. Lateral measurements and petrophysical interpretations can be used to define variations in reservoir quality (RQ) and completion quality (CQ) along the wellbore, which can then be used to optimize the completion design, for example, placing perforation clusters in similar rocks to increase production when compared to peer wells completed with a geometric design. The next step in integration is correlating pilot and lateral wellbore measurements with the structural component. This process is defined as geology quality (GQ). After taking together, RQ, CQ, and GQ, a comprehensive design of a wellbore-specific completion treatment can be achieved. This methodology of integrating data from many sources provides a better understanding of the variability and structural challenges of these complex reservoirs.
- bivariate analysis
- bulk density
- cores
- Cretaceous
- directional drilling
- drilling
- Eagle Ford Formation
- electron microscopy data
- FTIR spectra
- Gulfian
- horizontal drilling
- infrared spectra
- interpretation
- kerogen
- maturity
- measurement
- measurement-while-drilling
- Mesozoic
- mineral composition
- NMR spectra
- oil wells
- organic compounds
- petroleum
- porosity
- production
- pyrolysis
- regression analysis
- reservoir rocks
- resistivity
- SEM data
- spectra
- statistical analysis
- Terrell County Texas
- Texas
- total organic carbon
- United States
- Upper Cretaceous
- variations
- velocity
- well logs
- X-ray diffraction data
- X-ray fluorescence spectra