QUANTIFYING FRESH WATER AND PROPPANT REQUIREMENTS FOR OIL AND GAS PRODUCTION FROM THE EAGLE FORD GROUP, GULF COAST, TEXAS

In May 2018, the U.S. Geological Survey (USGS) completed a quantitative assessment of undiscovered oil and gas resources for the Eagle Ford Group and associated Cenomanian-Turonian mudstones. In low-permeability reservoirs like the Eagle Ford Group, oil and gas production commonly requires significant volumes of water and proppant (typically sand) for hydraulic fracturing. Following completion of the Eagle Ford Group hydrocarbon assessment, the USGS is now conducting a complementary assessment that will quantify the potential water and proppant demands associated with hydrocarbon production from the Eagle Ford Group.

The USGS has previously developed a methodology for estimating water and proppant requirements, as well as water production associated with development of oil and gas resources in continuous reservoirs. This methodology is built on USGS assessments of technically recoverable hydrocarbons in continuous (unconventional) accumulations. The objective of the USGS water and proppant assessments is to quantify the resources required to recover the assessed oil and gas, based on historical completion data that include water and proppant used for hydraulic fracturing.

Key inputs into the proppant and water assessment will include estimates for the water per well and proppant-to-water ratio for hydraulic fracturing treatments, and water-to-oil and water-to-gas ratios for produced fluids. During the oil and gas assessment of the Eagle Ford Group, individual assessment units (AUs) were determined based on primary hydrocarbon type, thermal maturity, and geologic characterization of the source rock. Individual AU’s will be examined from the water and proppant perspective by analyzing quantities used to complete recent petroleum wells; estimates will then be made of likely future demands corresponding with the assessed petroleum resources. Additionally, where data is available, future water production will be estimated, based on historical production rates.