Electric Submersible Pump Application and Operation in Small Openhole Completions
Authors: McClung W.J. , Johnson J.A. 
Published: December 2007

Summary
Amoco Production Co. has operated electric submersible pumps (ESP's) in 4 3/4 -in. (12.1-cm) open holes in the Grayburg formation of its Midland Farms Unit, Andrews Dist., since 1977. The Midland Farms (Grayburg) reservoir is a low-pressure [400- to 600-psi (2.8- to 4.1 -MPa) static bottomhole pressure (BHP)], high-PI (ranging from one to seven) formation that requires artificial lift drawdown to 70-psi (4.8 × 10 -Pa) BHP for maximum oil recovery in a high-water-cut production (89%). The 28 ESP's operating in small open holes (1979) comprise 10% of the producing wells (270 total producers) in the unit, yet they generate 34% [2,340 B/D (372 m /d)] of the field's total oil production. Through Dec. 1979, ESP's have been credited with 850 B/D (135.1 m /d) in incremental production, and secondary reserves have been increased by approximately 4% [2 million bbl (317 975 m )], or 71,400 bbl (11 352 m ) per installation. Pulling and repair costs for the ESP wells are $0.04/bbl fluid lifted less than for artificially lifted (beam lift) wells.

Introduction
This study was completed in 1980 with data taken through Dec. 1979 (Table 1). In July 1982 there were 84 ESP's operating in 4 3/4 -in. (12.1 -cm) open hole completions in the unit. This is 31 % of the producing wells in the unit. These wells produce 5.055 B/D (803.7 m /d) oil, which is 52% of the unit's production. There have been two additional wells plugged and abandoned because of ESP's that stuck and were unretrievable since this paper was written.
The study has not been updated to include any additional performance data other than those presented here. These installations are still performing satisfactorily and resulting in optimized pumping conditions. During primary recovery, the unit wells were produced by flowing under reservoir pressure and later by artificial lift. Water cuts reached 65% during primary recovery, with water being disposed in the aquifer and later in the oil column [4.800 ft (1.463 km)] in peripheral wells. A secondary recovery pilot began in 1971. When water cuts exceeded 85 %, it became apparent that beam lift, limited by 4 3/4 -in. (12.1 -cm) open hole completions, could not match lift capacity with production capability. ESP's have been used in this reservoir since 1977. While beam-unit capacity is 650 B/D (103.3 m /d) fluid, ESP's have produced 600 to 1,700 B/D (95.4 to 270.3 m /d) per installation with a producing BHP of 70 psi (0.5 MPa). ESP's have reduced operating costs and increased secondary reserves. The small open hole, while limiting beam-lift capacity, has had little effect on ESP applications. There are currently 33 ESP's in operation (1979), 28 of which are set in the 4 3/4-in. (12.1-cm) open holes. Operations have been successful and only one ESP lost downhole because of hole size limitation. Currently, 40% of the total produced fluid of 6,910 B/D (1099 m /d) oil and 56,400 B/D (8967 m /d) water is lifted by ESP's.

Assumptions and Qualifications
1. This study is based on data taken from ESP's and beam units installed in Amoco Production Co.'s Midland Farms Unit, Andrews County, TX.2. Several pumps from different vendors were evaluated.
JPT
P. 1719^