Methodology for Planning and Execution of Multilateral Well Design Together with Enhanced Geo-Navigation Techniques for Optimum Well Placement in Complex Geological Environment
Authors: Alenezi Barak , Diaz Nerwing , Qaddoura Dana , Odiase Paul , Al-Mutairi Abdulwahab , Otaibi Fahad , Chawla Deepanshu 
Published: November 2020

The Sabiriyah Mauddud calcareous reservoir, located in North Kuwait is one of the major hydrocarbon assets in the country. A study was prepared in order to maximize production by implementing a multilateral, multi-zones well path. The paper discusses the methodology for the planning and execution of the first in its class Mauddud reservoir multilateral producer.

This study illustrates the implementation of a unique approach for a challenging well design, including two lateral sections (L0 & L1) in a complex reservoir structure targeting multiple zones. Precise and continuous monitoring of the directional measurements was essential for the successful delivery of the mother wellbore, while fulfilling project constrains. The bottom hole assembly (BHA) used in the 6-1/8" horizontal sections was comprised of a rotary steerable system (RSS) with near bit gamma, azimuthal deep resistivity distance-to-boundary technology, and near bit density/porosity. Specialized software were used in creating geo-navigation models of the target reservoir zones. The real-time dynamic interpretation of the structure morphology was key in order to maximize exposure of the productive zones while minimizing the contact with non-productive zones. The openhole sidetrack technique for the startup of L1 involved a detailed procedure, and a special feature designed into the well plan to facilitate the sidetrack in the desired zone. Water based mud was used to optimize logging while drilling (LWD) measurements in order to clearly predict fractured zones, while mud weight recommendation and pressure hazard identification was based on geo-mechanical analysis.

The well was successfully executed, tripling the production when compared to a single horizontal producer recorded in the same reservoir zones. The sidetrack procedure implemented allowed to initiate the drilling of L1 with the same bottom hole assembly (BHA) from L0 without pulling out of the hole, this approach considerably helped to save rig time. The positioning of the LWD sensors close to the bit significantly reduced the reaction time and minimized the challenges induced by sudden changes in reservoir properties. Similarly, the enhanced geo-navigation technique of integrating near bit density/porosity and the azimuthal deep resistivity distance-to-boundary technology played an important role in successfully navigating the wellbore within the multiple reservoir zones with confidence. This multilateral well has proven the concept of implementing shorter lateral sections to target multiple zones of interest, aiming for enhanced production when compared to projects with single longer laterals.

The novelty of this work is the optimized methodology established for hydrocarbon extraction from a challenging reservoir. The implementation of these sidetrack procedures combined with enhanced geo-navigation techniques resulted in optimum well placement and the successful delivery of the first multilateral, multi-zones producer in North Kuwait.