Current Projects - Phase XVI
The integrated research environment at RCP focuses on projects to advance 4D, 9C and associated technologies for seismic reservoir characterization in a variety of geologic settings.
EAGLE FORD, TEXAS
RCP's new Phase XVII project monitors the stimulation of two wells in the Eagle Ford Basin, an unconventional reservoir located in South Texas. The unique dataset provided by our project sponsor, Devon Energy Corporation, allows for advanced research in technologies and techniques at the forefront of hydrocarbon exploration. It includes time-lapse VSP and multicomponent surface seismic, microseismic monitoring, and fiber optic DAS and DTS, among a variety of other types of data.
The Eagle Ford Team will work together to demonstrate the value of these various datasets in the characterization of the project area throughout stimulation. An improved understanding of the changes in the reservoir associated with hydraulic fracturing is important for optimization of well placement, spacing, and completion strategies.
PERMIAN BASIN, TEXAS
The Permian Project began in 2017 as part of Phase XVII of the Reservoir Characterization Project (RCP) and is sponsored by Apache Corporation. This project explores the usefulness of Distributed Acoustic Sensing (DAS) in reservoir and stimulation characterization. This project will center around the analysis of an interstage DAS VSP dataset, shot in a well located in the Midland Basin, a sub-basin of the Permian Basin, Texas. This unique dataset contains VSP records shot before fracturing and between each of the 78 stages of fracturing. This dataset will allow RCP to analyze how DAS records changes in the reservoir during stimulation. Apache has already observed a time-lapse signal from hydraulic fractures consistent across all fracturing stages. At this time, RCP's goal will be to verify the time-lapse changes in the dataset caused by hydraulic fractures in both the P-wave and S-wave arrivals that have already been observed by Apache. Findings about DAS will help design future optimal acquisition geometries and preliminary observations show that DAS will play a key role in industry's future.
WATTENBERG FIELD, COLORADO - Unconventional Shale Project
The Wattenberg project is the central focus of RCP's Phase XVI research in partnership with our field sponsor, Anadarko Petroleum Corporation. The study focuses on integrating static and dynamic characterization of the Niobrara/Codell unconventional reservoir. The collaborative effort from graduate students across geophysics, geology, petroleum engineering and economics has deepened the understanding of reservoir response to stimulation and production in the Wattenberg field.
Wattenberg, ColoradoThe key objectives of this integrated research are: characterization of natural faults and induced fractures as drivers of well performance; analysis of stress changes within the reservoir tying to both production and fracture efficiency; and interpretation and assessment of reservoir production through iterative simulations and integrated, multi-scale modeling. To accomplish these particular goals, a comprehensive data set including time-lapse 9C seismic, microseismic, well logs, cores, tracer data, DFIT, completion data and production data were provided. This data spans the main study area of four-square miles within the Wattenberg Field, with coverage emphasized over the central one-square mile Wishbone section containing 11 producing horizontal wells.
The 4D seismic shows increased gas saturation from pressure depletion which matches the reservoir simulation has validated our multi-scale 3D geologic and rock property models of the reservoir. Geomechanical simulations have shown non-uniform production controlled by vertical and lateral heterogeneities from the reservoir interval. The geomechanical model has not only improved reservoir simulation responses, but also produced evidence of preferential fracture growth downward. These stimulated reservoir volumes correlate with microseismic data, suggesting that geomechanical modeling can assist in optimizing future infill wells. With a new 3D geological discrete fracture model utilizing outcrop, microseismic, and image logs, and stimulated reservoir volume model, this reservoir simulation project should continue to increase the reservoir simulation accuracy correlation with seismic.
With the understanding that productivity is driven by effective fracture length in this unconventional field, current work investigates the mapping of the stress and fracture changes using multicomponent time-lapse seismic. Projects addressing these changes in stress and fractures include PP VVAZ and attenuation studies, as well as PS and SS shear-wave splitting analyses.
Preliminary interpretation of inverted PP impedance seismic data shows amplitude responses tied to the simulated increased gas saturation over time. Furthermore, the extracted impedance amplitude changes show strong correlation to the normalized gas production data at each of the 11 wells. This insight has spurred a joint PP-PS inversion study and AVO/AVAZ analysis to further explore the direct mapping and prediction of well production and change in rock properties using time-lapse, multicomponent seismic data.
The Wattenberg Team's overarching goal is to construct a fully integrated reservoir model to optimize exploitation and exploration initiatives in the Wattenberg Field that will ultimately lead to an increased recovery factor.
THE VACA MUERTA, ARGENTINA
The project began in the fall of 2013 as an early stage unconventional project in collaboration with Wintershall in the Vaca Muerta Formation of the Neuquén Basin, Argentina. The primary focus of this study is to understand the factors that control production from the reservoir using an integrated approach with geology, geophysics, geomechanics and engineering.
In unconventional reservoirs where permeability is low, stimulation is required to allow for economic production. The mechanical behavior of the reservoir, as it relates to the ability of natural and induced fractures to sustain hydraulic conductivity pathways, is the primary factor controlling the economics. Characterization of the mechanical properties of the formation, the stress state at the reservoir level, and analysis of the natural fractures is essential for targeting well locations, horizontal well direction, and guiding stimulation programs.
Initial work examined fracture distributions and elastic parameter variability across the study area using cores, seismic inversion, interpretation of image logs, VSP, microseismicity, multi-stage hydraulic stimulation data, and production data into depositional controls on rock properties.
Wintershall acquired a new multi-component seismic survey in 2016 over the northern area of the current 3D survey. Data has been processed by Unified Geosystems and was delivered to RCP early this fall. Current work will use this new 3C seismic survey along with the 3C VSP to determine the value added by multi-component data. The focus will be on characterizing anisotropy to improve the understanding of natural fractures, hydraulic fracture development, and propose new drilling and landing locations. A joint PP-PS inversion is planned along with analysis of anisotropy attribute volumes delivered by Unified Geosystems, and a differential horizontal stress (DHSR) analysis is proposed to study stresses in the reservoir and hydraulic fracture propagation.
CABIN CREEK FIELD, WILLISTON BASIN, MONTANA - Reservoir Characterization for CO2 Monitoring
Cabin Creek Field, located on the southwestern flank of the Williston Basin, is planned to undergo CO2 tertiary EOR operations by Denbury Onshore LLC. (Denbury). In January 2016, the Reservoir Characterization Project (RCP) at Colorado School of Mines (CSM) started a new collaboration with Denbury to characterize the Red River Formation. The objective of this project is to understand the geologic complexity of the target reservoir, predict controls on CO2 flood, and determine the efficacy of time-lapse multicomponent seismic. Available data includes P-wave seismic survey, acquired in 2014, and borehole logs from 27 existing wells within, or in close proximity to, the area of study.
The product of the current research is a static reservoir model for production history matching. Flood simulation modeling assists in identifying the optimal location and type (horizontal or vertical) for injector and producer wells and recognize potential bypassed pay by waterflood. In addition, the value of this research provides the operator a chance to be proactive at an early stage to regulate the flood if it is not achieving the desired results.
Characterizing anomalies detected on seismic-generated attributes is crucial while interpreting any formation of interest. A rock physics model developed for the Red River Formation indicates the largest variations on compressional and shear velocities is due to porosity followed by fractures, pressure, and mineralogy. Understanding the reservoir's geologic complexity, heterogeneities and spatial properties was achieved by a simultaneous pre-stack inversion in conjunction with 2D Bayesian classification to delineate dolomite (reservoir) and calcite (non-reservoir) rich zones. In addition, seismic derived porosity distribution was determined using the rock physics model and inverted elastic volumes. In general, locations of high seismic amplitudes corresponded to dolomitic zones with high porosity values. Future work within Cabin Creek Project involves characterizing the natural fracture network via an amplitude variation with angle and azimuth (AVAZ) inversion.
RAUDHATAIN FIELD, KUWAIT - Characterization of Deep Jurassic Shale
The project is a collaboration between Kuwait Oil Company (KOC) and RCP to characterize the deep, thin and tight carbonate and organic-rich shale reservoirs of late Jurassic Najmah Formation in the Raudhatain Field within the Jurassic Gas Field of the Arabian basin in the Northeast corner of Kuwait. Current research utilizes geological, geophysical and reservoir engineering datasets, including VSP data and high-resolution wide azimuth seismic data. The ongoing geophysical work focuses on the processing of an azimuthal walkaway VSP to improve the imaging and enable anisotropy analysis of the fractured reservoir. The result of this study builds a foundation by which to identify optimal fracture zones for production within this deep unconventional play.
POUCE COUPE FIELD, CANADA
The Pouce Coupe Project focuses upon the characterization of the Montney Formation. The project is a partnership with Talisman (now Repsol), that began in 2009. The project has previously focused upon characterization utilizing time-lapse multicomponent seismic, downhole microseismic, and geomechanical evaluation. Currently, the downhole microseismic data is being reprocessed to improve the understanding of the induced and stimulated natural fractures. Additionally, RCP is developing a Matlab based processing toolbox for downhole microseismic that includes new processing algorithms for improved reservoir characterization.