Can IOR in Deepwater Gulf of Mexico Secure Energy for America?

Abstract

Deepwater Gulf of Mexico oil fields typically get modest ultimate recovery factors in the 10% -35% range because of challenging reservoir characteristics and high development costs. Yet the total target for Improved Oil Recovery (IOR) in deepwater (DW) Gulf of Mexico (GoM) is temptingly large, with about 44 Billion Bbl remaining oil expected to be left behind in discovered fields at abandonment. "Technical Gaps" make most IOR processes impractical in an environment of high well costs, complex reservoirs, and substantial logistical challenges. This paper describes original work done through a project funded under the Energy Policy Act of 2005 and directed by the non-profit Corporation RPSEA (Research Partnership to Secure Energy for America). The study includes a review and analysis of the performance of 83 developed DW oil fields consisting of 415 individual reservoirs. Also, data has been collected and evaluated for 15 discovered and undeveloped Lower Tertiary, Paleogene fields. The work has assessed reservoir properties, original oil in-place, expected recovery factor, volume of projected remaining oil, and the mechanisms by which oil is trapped and not produced. The analysis of performance was then used to select a group of IOR processes which could target specific trapped oil mechanisms.The results presented here are lessons learned to date on field performance, the remaining oil target for IOR, the IOR processes being considered, and the future evaluation plan. An objective of the work is to determine the "Technical Gaps" which currently prevent the economic implementation of selected IOR processes in the challenging conditions of deepwater GoM. Recommendations will be made for future Research & Development funding to address the technical gaps and to accelerate implementation of potentially high impact IOR processes. OTC 20678Although there are a range of reservoir types, fluid properties, field development methods, and reservoir drive mechanisms across a dataset this large, average numbers were derived for recovery factor and oil trapping mechanisms. The remaining or trapped oil was apportioned to mechanisms which included non-connected to wells, capillary bound, high abandonment pressure, poor sweep, and limited drive energy. Studies on a subset of fields and reservoirs were used to determine the individual percentage splits for the trapped oil mechanisms.An initial list of 79 IOR processes was reduced to a short list based on reservoir properties and the target trapped oil mechanisms. The high cost environment and technical challenges of the deepwater Gulf of Mexico translate to IOR being anything from technical breakthroughs to permit field development (i.e. increasing from 0% recovery) to artificial lift, low cost infill drilling, or water injection (Figure 1). Only twelve fields have used water injection for drive energy and reservoir sweep, and several of these fields have had limited injection volumes. Water injection is one of the short listed IOR processes and includes two low cost applications, r...

A Single-Well Gas-Assisted Gravity Drainage Enhanced Oil Recovery Process for U.S. Deepwater Gulf of Mexico Operations

“…Hence no single reservoir will be representative of the gamut of reservoirs encountered in DGOM. For our task, one of the prolific reservoirs in the DGOM, viz., the N/O reservoir in the Mars field was chosen [2]. N/O (Yellow) reservoir is a Miocene to Pliocene age sand with a thickness of 99 ft. and acreage of 4917 acres.…”

“…However, unlike onshore reservoirs, offshore is an extremely high cost environment, particularly in terms of drilling and completion, where a single well could cost in excess of $200 million [1] Even though the recovery factors upon primary depletion are dismal for these reservoirs, we still do not have a robust secondary or tertiary recovery process in place to sustain the production in the longer term. [2]. Waterflooding has met with significant challenges, including injectivity issues and induced fracking in these tight overpressurized turbidite reservoirs in DGOM.…”

Comparison of commingled and sequential production schemes by sensitivity analysis for Gulf of Mexico Paleogene Deepwater turbidite oil fields: A simulation study

“…Eocene and Paleocene (Wilcox Formation) are much deeper than Frio. The mean reservoir depth of the Eocene is 14,000 ft, which is 26,000 ft for Paleocene (Lach, 2010).…”

“…The average porosity values of Upper Wilcox are around 14–19% as it contains more lithic rock. Average permeability values can vary between 10 and 30 mD in Upper and Lower Wilcox (Lach, 2010). Fields like Jack and St Malo have a depth of 26,000 ft or more.…”

“…As depth increases, pressure and temperature increase, increasing the risks for drilling, completion, and producing hydrocarbons. (Lach, 2010; Meyer et al, 2005).…”