Unconventional Petroleum Reservoirs: fluid-rock interactions and induced seismicity during hydraulic fracturing and reservoir characterisation

点击翻译按钮获取中文摘要

Over the last 15 years there has been a paradigm shift in North America from hydrocarbon production from conventional, permeable reservoirs to ultra-low permeability, unconventional reservoirs. The exploitation of unconventional resources is made possible by injection of large volumes (millions of litres) of fluid at high pressures to hydraulically create a permeable fracture network in the reservoir. The process of hydraulically fracturing in some areas result in anomalous induced seismicity (AIS), and the fluids used may damage the reservoir and are viewed by some as potential contaminants. The potential for AIS and real or perceived problems associated with the large volume of fluid utilised are the most important issues currently facing sustainable development of unconventional hydrocarbon resources. Our research will contribute to: 1) prevention and/or mitigation of AIS due to hydraulic fracturing; 2) understanding fluid rock interactions to minimize reservoir and fluid damage; and 3) better characterisation of reservoirs to optimise exploration and production. Our studies on AIS are multifaceted and include real time monitoring of seismicity during hydraulic completions to develop a traffic light/early warning system that can be used during fracing. The field data will be interpreted in the context of hydraulic fracturing metrics, including pressure, temperature and fluid properties, to understand processes. The results of the field studies will be combined with laboratory and well tests to provide input for numerical models that will be in turn used to develop protocols to prevent or mitigate AIS. To minimize fluid damage to the reservoir we will experiment with drilling and completion fluids on important reservoirs and analyse flowback fluids following hydraulic fracturing. This research will contribute to optimising reservoir completions, and recognising, preventing and/or remediating damage to the reservoir and fluid system. Knowledge of the chemistry and volumes of flowback water will further contribute to the design of fluid blends for recycling, treatment and/or disposal and minimizing total freshwater use. We will continue to develop and refine novel protocols to better characterise reservoir rocks. We will contribute to the fundamental understanding of hydrocarbon storage in and transport through, ultra-fine grained reservoirs utilising well log analyses and laboratory experiments coupled with numerical analyses. We propose to investigate those geological factors controlling the distribution of producible natural gas liquids, condensate, and oil from unconventional reservoirs. Our studies will include well log analyses and laboratory studies to ground truth petroleum system analysis models that will provide insight into the generation, migration and retention of hydrocarbons of important unconventional formations.