Artificial-Lift Systems Overview and Evolution in a Mature Basin: Case Study of Golfo San Jorge

Abstract

The Golfo San Jorge basin, located in the central Patagonia, is the oldest productive basin of Argentina, where the first economic discovery took place in 1907, in Comodoro Rivadavia. With 11,680 active oil wells, is the first oil producer basin of Argentina producing 258,549 bpd of oil and 2.56 MM bpd of water. The main characteristics of the basin are:Faults and sand stone lensHWORIncreasing fluid flow rate per wellComplex fluids: corrosive, heavy oil, gas, sand and scaleMultiphase fluidsMultilayer reservoir: from 1.800 to 9000 feet In this context, the selection, operation and optimization of the different Artificial Lift Systems (ALS) plays an important role for following the development of the basin. This paper describes the best practices, experiences and trends, using ALS as Progressing Cavity Pump(PCP), Electric Submersible Pump(ESP) and Sucker Rod Pumping(SRP); and a basic description about Gas Lift, Plunger Lift and Hydraulic jet Pumping experiences. Information as pump depth, flow rates, operational conditions, surface and sub-surface installations description, technical limits, failures statistic and new technologies from more than 9,000 active wells from different oilfields were collected and analyzed. As result of this overview, an ALS reference guide was completed with parameters and benchmarking indicators; and some important conclusions appear. Complementary information will be presented in the Appendix (Fig-A1, A2, Table-A1, etc) Introduction The East-West trending Golfo San Jorge basin is the oldest and most prolific oil basin of Argentina It covers 28,000 M Acre, with 1,127 MMbo (Dec-05) of OOIP and is located in the central Patagonia. (Fig-A1) The first commercial oil discovery took place in 1907 and since then close to 2,900 MMBOE were extracted. Located in the central part of Patagonia Terrane, it is an intracratonic extensional basin. During late Jurassic-early Cretaceous times, the extension related to the Gondwana break-up generated many isolated small half-graben basins, with a NW-SE structural trend. Later, a new extensional-transtensional stress field originated a WNW-ESE trending, and reduced extensional deformation continued until the Oligocene. The basin is essentially asymmetric; in the eastern section the dominant extensional faults are on the northern flank with the southern flanks being a less faulted, flexural type margin. In contrast, the western section is asymmetric but its major faults are on the southern flank, being the northern flank a flexural margin. The central section of the San Jorge basin is dominated by NW and NNW trending extensional faults that were reactivated by compression in Tertiary times. The basin produces 258,549 bpd of oil (44 % of the oil production of Argentina), and 2.56 MM bdp of water (91%) at November 2006. Close to 2.6 MMbpd of water are injected in 2,400 wells in water flooding projects, therefore 41% of the oil is produced from this method. (Fig-A2) Close to 97 % of the wells were completed with 5½" casing, and depending on the companies, new wells are completed with 7" casing. Vertical wells are the most common and directional wells are drilled in some projects (water flooding, parallel to faults)

Artificial lift management: Recommendations and suggestions of best practices

“…The use of performance indicators is important when it comes to making decisions or monitoring the evolution of a field as regards failures in ALS elements. Classic indicators include: (Hirschfeldt, 2001;Hirschfeldt, 2006;Hirschfeldt, 2003) Figure 7. "In-House" testing of PCP.…”

“…Diadema Field (CAPSA). Patagonia Argentina (Year 2001) (Hirschfeldt, 2001;Hirschfeldt, 2006;Hirschfeldt, 2003) Figure 8. Testing of centrifugal pumps and inspection of ESP equipment stages in service company workshops (WoodGroup ESP.…”

“…"A production well may require more than one type of Artificial Lift System during its productive life (Hirschfeldt, Distel & Martínez, 2007)."…”

“…Diadema Field (CAPSA). Patagonia Argentina (Year 2001)(Hirschfeldt, 2001;Hirschfeldt, 2006;Hirschfeldt, 2003)…”

An energy-saving pumping system with novel springs energy storage devices: Design, modeling, and experiment

“…With the development of oilfield exploitation, artificial lifting methods by mechanical equipment are becoming increasingly prevalent. 1 In oilfield production, mechanical lifting equipment is one of the major energyconsuming equipment. The 85% of lifting system used in the oilfield production is rod pumping system, which is composed of pumping unit, pumping rod, and motor.…”