The Inglewood Field, located along the Newport-Inglewood fault trend in the Los Angeles Basin, was discovered in 1924 and has an estimated ultimate recovery (EUR) of 400 million barrels of oil. The traditional shallow reservoir production target zones are the Vickers and Rindge formations, which have been waterflooded since 1954. These intervals consist of a 1,200 ft -1,800 ft+ thick sequence of friable turbidite sands in the depth range of 1,000 ft -3,000 ft. Contemporary reservoir development in the complex, faulted reservoir rock has been connected with improved reservoir characterization, leading to infill drilling and waterflood pattern realignment. However, infill well success using conventional water-base cased-hole and open-hole gravel packing has been marginal and inconsistent, because the long intervals and large reservoir pressure variations across the completion column make it difficult to complete the wells with an effective gravel pack and without formation damage.
In 2003, a radically different frac pack completion strategy was developed and evaluated. This low-cost frac-packing strategy has the advantages of true wellbore stimulation (or at least skin minimization) and ability to effectively connect across the highly laminated formation layers. Eleven wells were completed with as many as 8 stacked frac pack stages per well, with each stage pumped over a wire-wrapped screen to enable fracturing and gravel packing in one step. In the new wells, a limited entry perforation strategy was used to effectively distribute the fracture treatments across each stage interval. 20° API Inglewood crude was used as both the frac fluid and completion fluid to virtually eliminate formation damage, reduce costs, and simplify completion procedures. Several innovative new downhole tools (based on cementing tool technology) and procedures were developed to enable multiple stages to be performed in a simple yet effective manner, and allow the technique to be applied in both new wells and to remediate existing cased-hole completions.
Average initial production rate from the frac pack wells was 110 BOPD and 1,250 BWPD. This response is much better than the rates from cased-hole gravel packs, and on par with open-hole gravel pack wells, but without the risk associated with gravel packing a thick open-hole interval in a single step. Stabilized oil cuts have settled in at >5%, which compares favorably to the field average of 3% due to more effective completion of the deeper, lower permeability intervals that have been less swept by the waterflood. In response, additional wells will be completed at Inglewood and several other Los Angeles Basin fields in 2004.
Author(s): D. Lockman, Plains Exploration & Production; W. Burgett, Jr., Weatherford Completion Systems, W.A. Minner; StrataGen Engineering, M. Fernandez, W.H. Moodie; Plains Exploration & Production
Paper Number: SPE 90975