Petrel Advanced Completion Optimization
Using Intersect high-resolution reservoir simulator
Incorporates a workflow for reservoir-centric lower completion design and interval control valve optimization across well life.
Transforming the Harash carbonate reservoir in Libya: A collaborative success story
Location
Libya, Africa, Onshore
Summary
SLB collaborated with Pertamina Hulu Rokan to enhance oil recovery in Sumatra's TE-2 sandstone. By implementing multistage fracturing (MSF) in a horizontal well, oil production increased to 500 bbl/d, surpassing the results in the same number of vertical wells, while reducing costs by 25%.
Objective
Pertamina Hulu Rokan faced challenges in the TE-2 sandstone formation in Sumatra, Indonesia, where vertical and deviated wells yielded unsatisfactory production results. With only 15% oil recovery and an average production of 60 bbl/d, the hydraulic fracturing treatments were not meeting expectations.
The presence of a thin shale barrier further limited optimization efforts, necessitating a more effective approach to enhance production and economic viability.
Results
SLB collaborated with Pertamina Hulu Rokan to address the production challenges in the TE-2 sandstone formation by implementing an MSF solution. This approach aimed to enhance reservoir contact and reduce costs compared to multiple vertical wells. A single MSF well was designed to deliver equivalent reservoir coverage at 25% less cost, establishing it as a sustainable solution for long-term operations.
The horizontal MSF well demonstrated superior operational efficiency, reducing surface infrastructure needs and streamlining connections to existing production facilities. The plug-and-perf technique utilized SLB Copperhead™ drillable bridge and frac plug and ABRASIJET™ hydraulic pipe-cutting and perforating service, combined with ACTive™ real-time downhole coiled tubing services, allowing precise control over fracture placement. This method optimized stimulation performance in areas with lateral heterogeneity.
Despite the high permeability range of 50–100 mD in TE-2, adequate fracture conductivity was achieved, enhancing productivity.
The formation's thin nature required optimized fracturing techniques, and TE-2's high hydrocarbon saturation levels confirmed its suitability for stimulation treatment.
Well placement was optimized using movable oil index and pore pressure index mapping, combined with water-cut evaluation from adjacent wells to minimize water breakthrough risk. The lateral orientation was based on microseismic measurements, ensuring optimal frac orientation.
The well was designed for an 8-stage plug and perf, with Copperhead plugs for zonal isolation. Openhole logs and cement bond log evaluations were integrated into the Kinetix™ reservoir-centric stimulation-to-production software and Petrel™ subsurface software for optimal stage placement. Intelligent Stimulation workflows in Kinetix and Petrel software were used to optimize frac stage placement, incorporating advanced reservoir measurements to enhance the fracturing design. ACTive services ensured accurate depth control during operations, and the ABRASIJET service process was optimized based on initial breakdown responses.
Postfrac execution, CT was used for milling out frac plugs, minimizing formation damage with nitrogen-assisted milling. The well achieved a production rate of 500 bbl/d, with a decline rate lower than nearby wells, demonstrating stable production levels. The ESP-based artificial lift system maintained consistent production rates, preventing premature water breakthrough.
Hydraulic fracturing plot of Well C50-6 in Libya’s Harash reservoir, highlighting stable slurry rate and controlled pressure during proppant placement.
Treatment plot of Well C50-6 highlighting stable pressure management and controlled proppant placement across multiple fracturing stages.
Integrated petrophysical analysis and fracture modeling of Stage 1 in the Harash reservoir, highlighting fracture geometry and optimized completion design.
