Abstract

The Bone Spring formation in the Delaware Basin, west Texas and southeast New Mexico, has seen a recent resurgence in drilling activity. Operators continue to drive efficiencies in drilling and completions to keep economics robust. Consequently, subsurface data is not collected thus hindering our understanding of the lateral productivity. This talk will focus on two aspects...

Part 1. Integrating 3D seismic to understand optimal lateral placement in a mass transport complex in the Delaware Basin

Operators are targeting the low-resistive sands within the channel and unconfined basinal lobe facies of the Bone Spring sands. General depositional trends of the Bone Spring indicate that better potential for oil production exists in the northern half of the basin where it is comprised of deepwater channels and subsequently, better reservoir quality. These channels naturally transition southward (down-dip) into more unconfined channels, lobes, and basinal deposits. Newly acquired seismic data located in the central Delaware Basin has revealed ~400 ft of chaotic strata and a series of imbricate faults within the down-dip section of 2nd Bone Spring play. These features are interpreted as the slumps and slides of a mass transport deposit (MTD). Several recent wells within the MTD are performing better than expected given their location in the depositional system and assumed poorer reservoir quality. Notably, these types of deposits in The Gulf of Mexico are avoided as drilling targets due to proven poor reservoir quality. Therefore, we are investigating how this MTD played a role in enhancing production in the 2nd Bone Spring sand of the Delaware Basin. A detailed study was conducted and showed better producing Bone Spring wells stayed within individual thrust imbricates.

Part 2. Integration of cutting analysis, petrophysical logs, and completion data along an Avalon horizontal well to understand optimal completion design.

Chevron drilled an exploration well targeting the Avalon shale (approximately 10000 feet TVD) in the central Delaware Basin. A robust formation evaluation was conducted which included a high quality logging suite, conventional core, side-wall core, well-site cutting analysis, and post-drill geochemical analysis of headspace gas, mud gas, and produced liquids. Ultimately, petrophysical logs and well-site cutting analysis were used to identify the optimal landing zone based primarily on organic richness. The Avalon shale shows moderate generation potential and uniformly type II/III kerogen (oil and gas prone). Additionally, the shale revealed low levels of maturity based on Rock Eval analysis, consistent with incipient generation of liquids. Geo-chemical parameters (i.e., Oil Saturation Index) indicate low levels of liquids concentration throughout the pilot and lateral sections. However, elevated TOC values were observed along the lateral section with varying heavier gas ratios. Changes in the heavier gas concentrations generally correlated with increases in molybdenum, selenium, uranium, and vanadium. Detailed rock-typing was conducted to better understand the relationship of hydrocarbon occurrence with lithology. Tracers were used in the completion with early results suggesting moderate stimulation efficiency. This correlation of rock type, petrophysical logs, and completion response will be carried forward on future completion strategies. Imaging logs in the pilot and lateral showed drilling-induced and natural fractures in the target interval, which may have influenced production.