Abstract

The Issaran Field, a heavy oil reservoir with an estimated OOIP (original oil in place) of approximately 1.6 billion bbls of oil, was discovered in 1981. The producing horizons are the carbonate formations of Miocene age occurring from depths of 1000ft to 2000 ft. The oil is of 10-12 degree API with viscosity of 4000 cps at standard conditions, The original reservoir temperature is around 120 °F.

It was not until early 2000, after the crude oil prices rose to favorable levels, that a concerted effort was made at developing this heavy oil. "Cold production" from the fractured carbonate Nukhul reservoir (depth ∼2000ft) was first targeted and the production from the field increased from 170 BOPD in 1998 to over 2000 BOPD in early 2004.

Each reservoir has its own characteristic, which requires special approach to overcome its problems and optimize its production and increasing recoverable reserves. As Zeit Formation contain variable sand, Upper and Lower dolomite due to its shallow depth, the oil could not be produced as cold production, Gahrandal formation is consisted of three limestone bodies with permeability below 20 md and the last one is Nukhul zone which give some cold oil production due to its naturally heavy fracture. Theses difference characterization lead to apply different ways of reservoir management and artificial left methods for each zone(5).

These different reservoir characteristics led to the application of different types of reservoir management for each zone. The Nukhul formation wells have been completed as openhole, Gharandal formation wells have been completed as cased hole and Upper and Lower Dolomite formation wells have been completed as cased /open hole steam injection wells, producing by cyclic steam stimulation.

About 50 wells producing using PCP which represent approximately 20 % from Issaran field artificial lift system, This paper describes the progressive cavity pump performance, factors affecting pumping parameters, failure analysis and recommended action to maximize pump run life and increase well productivity

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