Characterizing vertical drainage in unconventional reservoirs developed using horizontal hydraulically-stimulated wells is a major challenge facing the E&P industry because there are few inexpensive, robust methods designed to measure vertical contributions. To overcome this challenge, ConocoPhillips has developed novel time-lapse geochemistry and production allocation techniques that utilize produced fluids (oil, gas, and water) to cost-effectively ascertain vertical drainage heights and provide information about vertical connectivity (or lack thereof) between stacked/staggered wells. In this paper, we present an overview of the geochemistry technique as well as geochemistry-based production allocation results in the Eagle Ford play. Over 3,000 time-lapse geochemistry samples have been collected over the last five years from over 150 Eagle Ford wells comprising more than 30 different pilot projects across ConocoPhillips more than 200,000-acre land position. The ‘fingerprints’ of the produced fluids have been quantitatively linked to specific stratigraphic layers using Eagle Ford core data. Key insights from this analysis are that vertical drainage is limited, varies across the acreage position, and is dynamic during production, usually shrinking with time. Results from time-lapse geochemistry have been integrated with multiple well pilot datasets (e.g., microseismic, soluble tracers, cores, image logs, pressure gauges in vertical and horizontal wells, and permanently-installed fiber optic cables) to optimize ConocoPhillips Eagle Ford development strategy. The outcome of these analyses has been the addition of approximately 1,200 drilling locations to the plan of development, which has significantly increased recoverable resources and asset value.


Significant hydrocarbon resources are unlocked by horizontal drilling and hydraulic stimulation in low and ultra-low permeability (micro- and nano-darcy) reservoirs. Hydraulic fracturing creates a stimulated rock volume (SRV) around each producing lateral well from which hydrocarbons are accessed. The dimensions of the SRV are thought to be controlling factors in determining the optimal stacking and spacing of horizontal wells in a field development strategy.

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