Petroleum reservoir

About: Petroleum reservoir is a research topic. Over the lifetime, 5403 publications have been published within this topic receiving 83535 citations. The topic is also known as: petroleum deposit.

Wettability Alteration of a Heavy Oil/Brine/Carbonate System with Temperature

Abstract: The wettability of reservoir rock is a crucial factor controlling displacement efficiency and ultimate oil recovery. In this study, the wettability of carbonate reservoir rocks as a function of temperature has been studied by measuring the Amott index to water using an X-ray computed tomography (CT) scanner. The cores for the Amott test were carefully prepared and aged at reservoir conditions to achieve restoration of reservoir wettability. The reservoir cores contain dolomite and chert based on the results of Fourier transform infrared spectroscopy (FT-IR) and energy dispersive X-ray spectroscopy (EDS). The porosity, permeability, and saturation profiles were measured with a core-flooding system and an X-ray CT scanner. The wettability test was carried out at reservoir temperature (70–80 °C) and elevated temperatures (130 °C, 170 °C). The rock components were dissolved at elevated temperature (170 °C) and resulted in a slight increase of porosity and absolute permeability. Also, OOIP and Amott water inde...

Porosity prediction from seismic attributes of the Ordovician Trenton-Black River groups, Rochester field, southern Ontario

Abstract: This article integrates three-dimensional (3-D) seismic attributes and log data to determine porosity distribution of the Ordovician Trenton-Black River groups within the Rochester field, southern Ontario. The rocks are composed of tight limestone, parts of which were dolomitized to form porous reservoir rock. Previous studies of the Trenton-Black River dolomite reservoirs have indicated a close relationship between faulting and reservoir development, but few published studies have attempted to examine these relationships using 3-D seismic data. This study explores the stratigraphy and structure of the Rochester fault-related dolomite reservoir using 3-D seismic data and neural networks to predict porosity. By predicting porosity using seismic attributes, vertical and lateral distributions of porosity that can be used to guide development and exploration drilling for optimal hydrocarbon recovery were obtained. The sites of highest porosity were found to be along and within the fault zones. Faults extending from the basement into overlying Paleozoic rocks are composed of several short-plane, vertical, and subvertical fault segments. However, some of these faults appear to have originated and died within the Paleozoic rocks; they cannot be traced to the basement because of little or no offset where they penetrate the basement. Although the five identified attributes are considered important in exploration for fault-related dolomite reservoirs, the single most important attribute to employ is the amplitude envelope because the other attributes are mathematically related to it. Furthermore, the sags that are seen in the Rochester field are due to the combined effects of low-velocity pushdown and faulting. Methods and results presented in this study can be used to explore and develop fault-related dolomite reservoirs elsewhere in similar geologic settings.

Relationship between deformation bands and petroleum migration in an exhumed reservoir rock, Los Angeles Basin, California, USA

Abstract: An oil-bearing sandstone unit within the Monterey Formation is exposed in the Los Angeles Basin along the Newport-Inglewood fault zone in southern California. The unit preserves structures, some original fluids, and cements that record the local history of deformation, fluid flow, and cementation. The structures include two types of deformation bands, which are cut by later bitumen veins and sandstone dikes. The bands formed by dilation and by shear. Both types strike on average parallel to the Newport-Inglewood fault zone (317°–332°) and show variable dip angles and directions. Generally the older deformation bands are shallow, and the younger bands are steep. The earlier set includes a type of deformation band not previously described in other field examples. These are thin, planar zones of oil 1–2 mm thick sandwiched between parallel, carbonate-cemented, positively weathering ribs. All other deformation bands appear to be oil-free. The undeformed sandstone matrix also contains some hydrocarbons. The oil-cored bands formed largely in opening mode, similar to dilation bands. The oil-cored bands differ from previously described dilation bands in the degree of carbonate cementation (up to 36% by volume) and in that some exhibit evidence for plane-parallel shear during formation. Given the mostly oil-free bands and oil-rich matrix, deformation bands must have formed largely before the bulk of petroleum migration and acted as semi-permeable baffles. Oil-cored bands provide field evidence for early migration of oil into a potential reservoir rock. We infer a hydrofracture mechanism, probably from petroleum leaking out of a stratigraphically lower overpressured reservoir. The deformation bands described here provide a potential field example of a mechanism inferred for petroleum migration in modern systems such as in the Gulf of Mexico.

Pore-scale mechanisms of CO2 storage in oilfields.

Abstract: Rapid implementation of global scale carbon capture and storage is required to limit temperature rises to 1.5 °C this century. Depleted oilfields provide an immediate option for storage, since injection infrastructure is in place and there is an economic benefit from enhanced oil recovery. To design secure storage, we need to understand how the fluids are configured in the microscopic pore spaces of the reservoir rock. We use high-resolution X-ray imaging to study the flow of oil, water and CO2 in an oil-wet rock at subsurface conditions of high temperature and pressure. We show that contrary to conventional understanding, CO2 does not reside in the largest pores, which would facilitate its escape, but instead occupies smaller pores or is present in layers in the corners of the pore space. The CO2 flow is restricted by a factor of ten, compared to if it occupied the larger pores. This shows that CO2 injection in oilfields provides secure storage with limited recycling of gas; the injection of large amounts of water to capillary trap the CO2 is unnecessary.