Track: Case Studies

Abstract

More than two-thirds of oil discovered around the world still remains unrecovered, 40 – 70% of the original oil is still left in place after using the conventional production technique, namely, primary and secondary recovery techniques (J.A. Boon, 1984).

The world demand for petroleum has been steadily on the increase with the International Energy Agency (IEA) projecting that the world petroleum consumption will rise from 3564 MTOE in 2007 to as much 5471 MTOE in 2015 and 6301 MTOE in 2030.

Implementation of EOR methods is a must for maximizing production and recovery from Sudan’s oil fields. These methods must be studied carefully to assure proper selection and implementation.

Steam Injection is to inject steam to heat the oil to higher temperatures and to decrease its viscosity so that it will be more easily to flow; cyclic steam stimulation(CSS)consists of three stages and happened in single well , CSS is particularly attractive because it has quick payout, however, recovery factors are low (10-40% OOIP). In a variation, CSS is applied under fracture pressure,

There are Six EOR Projects in Sudanese Oil Fields Namely Three Thermal EOR (two CSS and one steam flooding) and two chemical EOR projects and one gas/N2 injection projects, the thermal projects are under implementation phase meanwhile the other Chemical /Gas projects are under Designing and Evaluation.

In this Paper there will be an overview of Thermal EOR Projects in Sudanese Oil Fields, illustrate and analyze the CSS Concerns and Challenges in Sudanese oil fields such as Depth limitation (more than 1400m), Conventional completion wells, Comingle Injection & Production.

The Result show that the thermal EOR projects are very successful and almost gave double production from 130 bbl/day to 300 bbl/day in FNE Oil Field and from 280 bbl/day to 440 bbl/day in Bamboo Oil Field.

In order to get maximum recovery from the wells it’s highly recommended to select shallow depth, thermal completion and to avoid comingle layer injection or to use special technique for separate layer injection.