Comparison of Barnett and Fayetteville Technically Recoverable Reserves and Estimated Ultimate Recovery

Browning, John R.
[email protected]

The presentation develops an estimate for the Barnett and Fayetteville shales of their technically recoverable reserves (TRR) and their estimated ultimate recovery (EUR). The key drivers of both reserve estimates are discussed and the key distinguishing characteristics between the two fields are discussed.

The analysis is based on field wide geologic mapping and well-by-well production analysis of every producing well in each field. Well-by-well EUR’s are determined using an innovative decline analysis technique. The acreage is then divided 10 production quality tiers per field. Individual drainage areas are then determined for each well. The remaining acreage available for development is then used to determine a drillwell location inventory assuming an average well for each rock quality tier. The location inventory added to the EUR of existing wells creates a theoretical technically recoverable reserve for each field. A production model is then used to predict the pace of development of the drillwell location inventory constrained by well economics. The pace and production impact of expected drilling is then tracked for each year through 2030 to determine a field-wide EUR. The study investigates how EUR will be impacted by many of the underlying drivers.

Several results of the study are new to industry. Our approach to decline analysis assuming linear transient flow better aligns with physical models. Our study generally points to higher recovery across smaller drainage areas than is commonly accepted. These estimates result in a higher estimate of TRR than has been estimated previously by EIA and USGS. However, the development of the TRR will be greatly constrained by the economic thresholds for development in each rock quality tier leading to a smaller EUR as a percent of TRR than previous estimates.

The study will highlight the differences in the Fayetteville and Barnett. The study draws insights that will be helpful as other shale gas fields are developed with each exhibiting their individual characteristics. This study serves to highlight the key issues that control industry’s ability to estimate TRR and to fully develop into EUR.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013