Fabrice Okassa

Hydraulic Fracturing in the Congo Onshore: Continuous Optimization Improves Productivity

This paper describes the successful ongoing process of optimizing hydraulic fracturing designs in a well campaign in Congo onshore to create best practices for continuing development. The fracture design program began by characterizing and evaluating the rock formation and its compatibility with stimulation fluids, including mineralogical and geomechanical properties, as well as regained permeability. For example, laboratory testing determined that the formation was soft and highly sensitive to water, indicating that a water-based fracturing fluid would require specialty additives to minimize formation damage.

Successful First Offshore Fully Retrievable ESP System Installation in Congo

The world’s first offshore Rigless Fully Retrievable Electric Submersible Pump (RFR-ESP) system has been successfully installed in the eni Congo Foukanda Field (Republic of the Congo). The project was developed between eni Milan and eni Congo as an Innovation Technology Application (ITA), and it is the world’s first offshore RFR-ESP system. The RFR-ESP technology provided by ZEiTECS allows the rigless deployment and retrieval of a conventional Electric Submersible Pump (ESP) system through tubing by means of standard oil field wireline, rod or coil tubing technology. The RFR-ESP system technology is based around a specially designed oilfield wet connector system. This “plug and play” connector design permits the use of any ESP manufacturer’s equipment, allowing ESP optimization to match changing well conditions and replacement of failed ESPs without rig interventions; thereby providing an opportunity for OPEX savings, a significant reduction in workover costs and deferred production due to limited rig availability. The success of the first RFR-ESP completion and the positive results achieved to date are encouraging in the pursuit of extending this innovative and valuable ESP completion philosophy to eni Congo wells where ESP failures are primarily related to pump or motor and workover cost are high. The paper describes the technical features of the new RFR-ESP completion, the experience acquired on the Foukanda well and shows, via theoretical study, the economic implications of applying this new ESP philosophy in all the eni Congo high OPEX wells.