URTeC 539: Compositional Tracking of a Huff-n-Puff Project in the Eagle Ford

URTeC is just a week away. Mathias Lia Carlsen will present our paper written together with EP Energy “Compositional Tracking of a Huff-n-Puff Project in the Eagle Ford” Wednesday 24 July 8.30 pm, room 705.

Authors: M.L. Carlsen*1, C.H. Whitson*1,3, M.M. Dahouk1, B. Younus1, I. Yusra1, E. Kerr2, J. Nohavitza2, M. Thuesen2, J.H. Drozd2, R. Ambrose2, S. Mydland3 1. whitson, 2. EP Energy, 3. NTNU

The objective of this paper is to help understand the mechanisms behind gas-based enhanced oil recovery (EOR) seen in actual field performance. This is accomplished by computing and interpreting daily wellstream compositions obtained from production data during the production period(s) of Huff-n-Puff (HnP) wells in the Eagle Ford, together with relevant PVT and numerical modeling studies.

Wellstream compositions are determined from readily available production data using an equation of state (EOS) model and measured oil and gas properties obtained from sampling at the wellhead. The wellstream composition is estimated daily in one of the following two ways: (1) if measured properties from field sampling are available, then regress to find a wellstream composition that matches all the measured oil and gas properties (e.g. stock-tank oil API, gas specific gravity, GOR, and separator fluid compositions). (2) if no measured properties from field sampling are available, then flash the most-recent wellstream composition estimated from (1) and recombine the resulting oil and gas streams to match the producing GOR.

Multiple lab-scale HnP EOR experiments and associated results have been published earlier, but only limited amounts of compositional data have been presented. In this study, we attempt to link produced wellstream compositions with simulated laboratory compositions reflecting different EOR recovery mechanisms. These results should enhance the understanding of the HnP EOR mechanisms to further optimize injection and production strategies, ultimately leading to higher recoveries. The data and observations from this analysis are presented in detail. The wellstream compositions before and after HnP implementation are shown and interpreted.

By providing daily estimates of oil and gas compositions, the compositional tracking technology presented in this paper can be used as a tool to understand key mechanisms behind the reported uplift seen in EOR in unconventional resources. The identification of these mechanisms is important for companies that are implementing EOR, because it allows them to optimize their EOR strategies, target higher recoveries, and increase the technical certainty in reserve booking.

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Curtis Hays Whitson

Kameshwar Singh

Middle East
Ahmad Alavian

Mathias Lia Carlsen

About whitson
whitson supports energy companies, oil services companies, investors and government organizations with expertise and expansive analysis within PVT, gas condensate reservoirs and gas-based EOR. Our coverage ranges from R&D based industry studies to detailed due diligence, transaction or court case projects. We help our clients find best possible answers to complex questions and assist them in the successful decision-making on technical challenges. We do this through a continuous, transparent dialog with our clients – before, during and after our engagement. The company was founded by Dr. Curtis Hays Whitson in 1988 and is a Norwegian corporation located in Trondheim, Norway, with local presence in USA, Middle East, India and Indonesia