Using Real-Time High-Resolution LWD Images to Navigate and Optimize Multi-Stage Completions in a Carbonate Reservoir

Abstract

Abstract The Permian Basin of West Texas in North America is one of the most mature and prolific oil fields in the United States, continually evolving in production potential via the use of horizontal well drilling. Although initial well productivity has increased with new drilling and completion technologies, forecasting the success of a single well is still difficult because results may be inconsistent within the same section or across the play. This paper reviews the factors affecting well productivity and focuses on optimized completions design to grasp a better understanding of the geology and fracture network. Determining and identifying the zone of interest within the carbonate interval and then navigating within it with conventional LWD technology is a major challenge. To overcome these challenges, real-time high-resolution LWD images were proposed. Azimuthal gamma ray and multiple propagation resistivity measurements were used to determine bed dip, correlate position within the reservoir and indicate formation porosity variations. Advanced LWD imaging tools provide visual confirmation of steering up and down within the reservoir and identify structural information, porosity changes, rock type, faults and fracture types. Electrical images were incorporated as a crucial part of the completion strategy. Non-productive stages were eliminated by identifying and avoiding brecciated and faulted zones during completion, and improved completion efficiency and cycle time resulted in operator savings. In conclusion, LWD images are used to more efficiently drain the reservoir by providing necessary information to stay longer in the target zone and optimize completion. LWD images also help explain production variances between wells targeting the same interval. This paper highlights sub-seismic faults and brecciated intervals that were not resolved using traditional gamma resistivity. By characterizing structural changes through the lateral, completion techniques can be customized to the specific well and maximize recoverable hydrocarbons. The new method enabled the lateral interval to increase from 77% in the offset well to 100% in-zone. The combination of factors, including better wellbore permeability, resulted in an 8% increase in oil production and 68% increase in gas production compared to the offset well during the first five full months of production.