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Posts Tagged ‘Univ. of Texas’

BSEE commingling policy change is a good example of how to regulate

Posted in energy policy, Gulf of Mexico, Offshore Energy - General, Regulation, tagged , , , , , on April 28, 2025| Leave a Comment »

fig. 1, UT study: analyzed deepwater Paleogene fields, stratigraphic column (MMS map 😉)

BSEE’s decision to revise downhole commingling policy by increasing the allowable pressure differential between reservoirs is sound and supported by an impressive University of Texas (UT) Petroleum Engineering study. Although the announcement hype is a bit much, this is the way regulation is supposed to work.

The main benefit of commingling (vs. sequential production) is the accelerated return on investment, which is fine as long as other risks are not introduced and ultimate oil recovery is not sacrificed. The UT study of Paleogene (Wilcox) reservoirs found that downhole commingling actually maximizes per-well oil production compared to sequential schemes. Over 30 and 50 years, commingling yields 61% and 21% more oil respectively.

The UT study analyzed 3 cases with 19 variables (Table 2 in their report). The reservoir pressure differentials were 500, 1000, and 1500 psi. Interestingly, pressure differential had essentially no impact on cumulative production in either the commingled or sequential scenarios.

Figure 13. Cumulative production over 50 years for commingled (left) and sequential (right) production scheme. The most significant variables are shown in the first four pairs of plots. The last pair of plots shows the least important parameter which is pressure difference between reservoir units.

Also note that (fig. 13):

  • As the upper reservoir thickness increases to 1000 ft (high case), total production increases by 41% for the commingled production scheme and 26% for the sequential production scheme.
  • The second most important field feature is upper reservoir facies proportion for both production schemes. A higher sand proportion in the reservoir results in higher production.

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Important scientific survey proposed for the US South Atlantic

Posted in Bahamas, Offshore Energy - General, tagged , , , , , , , on June 7, 2023| Leave a Comment »

Just as I was lamenting the absence of scientific surveying in the Atlantic, my former colleague Renee Orr brought this NOAA announcement to my attention. Researchers from the University of Texas Institute of Geophysics and Lamont-Doherty Earth Observatory, with funding from the National Science Foundation, propose to conduct seismic surveys in the Blake Plateau area of the South Atlantic (map below).

The proposed study would acquire two-dimensional (2-D) seismic reflection and seismic refraction data to examine the structure and evolution of the rifted margins of the southeastern United States, including the rift dynamics during the formation of the Carolina Trough and Blake Plateau.

The survey will lead to a better understanding of “the interaction between tectonic and magmatic processes that led to continental breakup and the onset of seafloor spreading in the central Atlantic Ocean 200 million years ago.” The investigators are particularly interested in the “stratigraphy of sediments that formed during and after rifting, the degree of crustal stretching at the continental margins, crustal faults that formed during extension of the margin, and the geometry of lava flows that were placed on the crust before the start of seafloor spreading.”

While not a primary purpose, the research should improve our understanding of the relationship between productive oil and gas fields offshore Africa and US analogs. Paul Post and his BOEM team estimated that the US Atlantic could contain >20 billion BOE (link to the latest report).

NOAA has conducted a detailed review of the proposal and made a “preliminary determination that the impacts resulting from this activity are not expected to adversely affect any of the species or stocks through effects on annual rates of recruitment or survival.”

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