Determining Reservoir Stratigraphic Continuity via Well Testing in Deepwater Gulf of Mexico, Fuji Prospect

Abstract

The Fuji Prospect is located in the Green Canyon Blocks 505 and 506 approximately 180 miles south-southwest of New Orleans in a water depth of 4,280 ft. The discovery well, Fuji Well #1 (Green Canyon 506 Well #1) encountered 182 ft of oil pay in four Lower Pliocene age sandstones and was temporarily abandoned in 1995. The second well, Fuji Well 2 (Green Canyon 505 Well #1) was drilled in 1997. The well encountered 214 ft of oil pay, in sands equivalent to the pay sands and some wet sands seen in the discovery well. Well tests were performed on two pay sands. Both tests had low productivity rates of less than 5000 BOPD and recorded pressure depletion. The 1st test indicated a small compartment. The 2nd test was inconclusive and could be explained by either a small compartment with high permeability or a larger compartment with very low permeability. The Fuji Well 3 (Green Canyon 506 Well No. 2) was drilled next, in a structural position between Fuji Wells 1 and 2 in order to confirm stratigraphic continuity of the reservoirs. It penetrated 227 ft total of oil pay sands and 123 ft of oil pay in the shallower interval. The main field pay sand was the Magenta Sand, which was tested in Fuji Well 3 at a rate of 7,192 BOPD. The Magenta Sand in Fuji Well #3, however, showed pressure depletion during the test. Fuji Well #3 was temporarily abandoned in March 1998. The Fuji #2 and Fuji #3 well test design and results will be presented. Pressure transient interpretation challenges and conclusions will be discussed. This work will also demonstrate the impact of well testing on determining stratigraphic continuity and reserves calculations. Introduction Reservoir geologic models are often built based on available seismic and log data. Reservoir pressure and permeability data also might be available from several sources, such as wireline testing, NMR or well testing1,2. Reservoir stratigraphic continuity is often based on defining sealing barriers evident from seismic and log data. This paper is intended to provide a field study example that demonstrate that seismic, log and pressure data alone, may not have enough resolution and/or measurement depth and extent to predict all types of reservoir compartmentalization. Extended well testing3 provide a dynamic measurement that can extended further into the reservoir and help in better defining reservoir continuity. Integrating1,2,4 well test results with any other available data, such as seismic, log and core data, will usually lead to a better reservoir continuity characterization. This work is based on well test design and results from the Fuji deepwater field in the Gulf of Mexico. A brief description of the Fuji field is provided in the following sections1,2. Subsurface System Overview. Introduction to Fuji Prospect1, Green Canyon Blocks 505 and 506 are located 180 miles south-southwest of New Orleans in a water depth of 4,280 ft (see Fig. 1). The discovery well, Fuji Well #1 (Green Canyon 506 Well #1) encountered 182 ft of oil pay in four Lower Pliocene age sandstones (as shown in Fig. 2) and was temporarily abandoned in 1995. The second well, Fuji Well 2 (Green Canyon 505 Well #1) was drilled in 1997. The well encountered 214 ft of oil pay, in sands equivalent to the pay sands and some wet sands seen in the discovery well. Production tests were performed on two pay sands. Both tests had low productivity rates of less than 5000 BOPD and recorded pressure depletion. The 1st test indicated a small compartment. The 2nd test was inconclusive and could be explained by either a small compartment with high permeability or a larger compartment with very low permeability. Introduction to Fuji Prospect1, Green Canyon Blocks 505 and 506 are located 180 miles south-southwest of New Orleans in a water depth of 4,280 ft (see Fig. 1). The discovery well, Fuji Well #1 (Green Canyon 506 Well #1) encountered 182 ft of oil pay in four Lower Pliocene age sandstones (as shown in Fig. 2) and was temporarily abandoned in 1995. The second well, Fuji Well 2 (Green Canyon 505 Well #1) was drilled in 1997. The well encountered 214 ft of oil pay, in sands equivalent to the pay sands and some wet sands seen in the discovery well. Production tests were performed on two pay sands. Both tests had low productivity rates of less than 5000 BOPD and recorded pressure depletion. The 1st test indicated a small compartment. The 2nd test was inconclusive and could be explained by either a small compartment with high permeability or a larger compartment with very low permeability.

Unreciprocated sedimentation along a mud-dominated continental margin, Gulf of Mexico, U.S.A.: Implications for sequence stratigraphy in muddy settings devoid of depositional sequences

“…Black lines identify picked surfaces. Channelized sandy turbidites below ≥ 1.89 Ma marker (D. brouweri) were drilled and found to contain 65.2 m (214 ft) of oil pay in Green Canyon block 505(Haddad and Cribbs, 2002). Modified fromMadof (2010).…”