Abstract
We conducted a theoretical study to investigate the techniques for developing a geologically complex turbidite reservoir in highly constrained oil field underlying a city. Not only does the geology present significant challenge in terms of heterogeneity and anisotropy, the surface constraints make it very difficult to plan the development of wells because of health, safety, and environment (HSE) issues.
With a strong economic focus, the study incorporated various sensitivities and uncertainties in CAPEX and OPEX in establishing novel ways of optimizing infill well locations, drilling in an urban area, and enhancing hydrocarbon production through reservoir simulation practices. For reservoir simulation, well logs, production history, and laboratory data were taken from an analogous field. This, plus the presence of certain unique events in the history of some of the wells, imposed limits on the study.
The methodology of the dynamic modelling is unconventional in terms of analyzing the field for forecasting right after initialization, followed by a detailed history match considering the numerous complexities of a turbidite environment. This allows greater time for field development planning, which is typically given the least attention in modelling because of time constraints. The prediction comprises three cases—a no-further-action case, an infill drilling case, and a waterflood scenario. A combination of vertical and horizontal well trajectories was used to achieve the best output across a range of economic sensitivities over multiple scenarios. The study covered a broad range of realizations of well trajectories, well placement, optimized drilling, and production services, such as is done in a constrained urban environment like Los Angeles, California. Our modelled city was Houston, Texas, a well-known urban environment. As a result of the modelling, a technique was developed to account for environmentally safe development within this example.
The technological and economic conclusions make this a foundation study for profitable development of reservoirs underneath a populated area. The study may also be instrumental in exploitation of turbidite reservoirs, which present challenges in current North Sea and Brazil offshore development and in recently discovered submarine fans in the Gulf of Mexico deep marine environment.
