Transforming the Harash carbonate reservoir in Libya: A collaborative success story

Sirte Oil Company (SOC) successfully revitalized a 90% water‑cut well in Libya's Harash carbonate reservoir, transforming it into a 100% oil producer. By leveraging advanced stimulation technologies, including Kinetix™ reservoir‑centric stimulation‑to‑production software, Petrel™ subsurface software, Broadband Shield™ fracture‑geometry control service, FracCON™ water‑conformance fracturing fluid, the well's oil production surged from 150 bbl/d to 1,000 bbl/d, while reducing the water cut to just 2%. This achievement sets a new benchmark for oil recovery in complex carbonate reservoirs.

The Harash carbonate reservoir, located in Libya's desert, has long posed challenges for oil production due to its complex geology. The C50‑6 well, drilled in 1963 by SOC, was producing from multiple oil‑bearing layers situated above a high‑permeability water zone. Over time, the well's oil production declined significantly as the water/oil contact moved upward, leaving the well producing only 150 bbl/d with a 90% water cut.

SOC's primary objective was to enhance oil production while minimizing water production, thereby improving the well's profitability and operational efficiency. Traditional hydraulic fracturing methods were ineffective due to the lack of a strong barrier between the oil‑producing zone and the water zone below. Previous attempts to address the issue failed to deliver satisfactory results, prompting SOC to seek an innovative solution to isolate the water‑producing zones and optimize oil recovery.