Methodology for Capacity Estimation for Waste Disposal and Carbon Management

Abstract

Recent development in unconventional plays put unprecedented pressure in several regions of continental USA and other parts of the world on geological formations used for disposal of saline flow-back water, especially in plays with high water cuts. Normally, volumetric approach is taken to quantify storage or waste disposal capacity; however, since mentioned geological formations are also used by other industries, such as chemical, agricultural, and others for waste disposal and because these geological formations are also targeted as a potential sinks for anthropogenic CO2, it is important to quantify waste disposal and/or storage capacity resources more precisely taking into account multiple risk factors associated with these activities.

This work is using case studies from Kansas and Oklahoma to illustrate alternative methodology for waste management and resource capacity estimations. Originally, a detailed geological characterization was performed for a DOE funded project (DE-FE-0002056) where existing well log and core data was analyzed and new exploratory wells were drilled in central and western Kansas with extensive logging and coring programs. Based on this analysis several injection sites were selected, characterized, and geological models were produced. Calculation of storage capacity for south-central and south-western Kansas was performed where researchers used several different approaches including volumetric calculations, extrapolation based, detailed regional model numerical simulation, and using statistical approach. However, after this study was performed new variables that affect storage capacity were uncovered: seismicity, competing injection wells, and others that were not accounted for by original study.

To improve upon previous work and propose a different and more comprehensive approach, we decided to combine volumetric approach with other criteria that state and federal regulatory agencies use to regulate waste injection such as knowledge of structural elements, seismicity, protected freshwater aquafers above injection zones, hydrostatic in-situ head and fracture gradient of target formation, and others. The resulting product is a detailed aerial map where safe, intermediate, and risky for injection areas are highlighted. This map could be used by regulators and businesses to select future injection sites or to recognize and negotiate potential risks before acute developments.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018