An Integrated Solution in Drilling First Successful Horizontal Well in a Deep Carbonate Reservoir of North Kuwait

Published: 03/26/2013

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Schlumberger Oilfield Services

As part of development of hydrocarbon plays of North Kuwait, the first horizontal well was planned and drilled within the deep carbonates (over 14500ft TVD) consisting of layered Kerogen and tight limestone (average 3pu and 0.1 mD rock), divided mainly into Upper (approx. 50ft) and Lower (approx. 30ft) reservoir zones. The well profile was designed to target multiple fractures and corridors for accessing the secondary porosity and consequently increase permeability which will enhance productivity and hydrocarbon recovery.

The main challenge in the effective development of this reservoir is the ability of the well to access the permeable interconnected vertical fracture network overlain by massive Kerogene at the top and water bearing carbonates at the bottom. In addition to this known challenge was the unexpected bedding dip changes due to local structural variations observed in the dip data of the borehole image logs in the pilot hole drilled just before horizontal lateral drilling. Natural fracture clusters encountered in the pilot hole were analyzed for orientation and extent. This helped in optimizing the drainhole trajectory to achieve the main objective of intersecting as many open natural fractures as possible.

A multidisciplinary team consisting of Well Placement, Geology, Petrophysics, Geophysics and Drilling utilized 3D seismic interpretation, real-time logging-while-drilling data from distance-to-boundary (DTB) resistivity mapping techniques, Gamma image coupled with Rotary Steerable drilling assembly and placed this first horizontal well, almost entirely within the target zone of fractured Carbonate section. Despite the challenge for real-time telemetry data transmission due to high predicted pressure regime, the team was able to achieve 90% NTG lateral through seamless integration. The well trajectory was revised in real-time as needed to overcome unexpected geological challenges encountered while drilling. The integration of real-time measurements, real-time decisions, interpretation and multidisciplinary approach was the basis of success of this project.

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