Petroleum reservoir studies

Amy Berger helped me write Chapter 10 (Surface Complexation), and Chapter 31 (Acid Drainage) is derived in part from her work. Edward Warren and Richard Worden of British Petroleum s Sunbury lab contributed data for calculating scaling in North Sea oil fields, Richard Wendlandt first modeled the effects of alkali floods on clastic reservoirs, and Kenneth Sorbie helped write Chapter 30 (Petroleum Reservoirs). I borrowed from Elisabeth Rowan s study of the genesis of fluorite ores at the Albigeois district, Wendy Harrison s study of the Gippsland basin, and a number of other published studies, as referenced in the text. 

This article reviews information gathered from these areas of research which provides the bulk of our present knowledge of metabolism of OSC in petroleum. The order of presentation is that of increasing experimental control over the microbial activities. First, observations of the persistence of OSC in petroleum-contaminated environments and their occurrence in petroleum reservoirs will be presented. In these situations, we exert little or no control over the microbial activities which occur. Next, results from laboratory studies with crude petroleum or petroleum fractions will be presented. Finally, laboratory work with pure OSC will be summarized. Using the latter controlled conditions, metabolic intermediates and pathways for a few OSC have been elucidated. 

A novel physical micromodel with a well-defined three-dimensional pore network and with pore sizes comparable to those in petroleum reservoirs has been developed to study multiphase flow through porous media. This cell can be used to visualize pore level mechanisms as well as larger scale phenomena. 

P7-28i An understanding of bactoria transport in porous media is vital to the efficient operation of the watar flooding of petroleum reservoirs. Bacteria can have both beneficial and harmful effects on the reservoir. In enhanced microbial oil recovery, EMOR, bacteria are injected to secrete surfactants to reduce the interfacia] tension at the oil-water interface so that the oil will flow out more easily. However, under some circumstances the bacteria can be harmful, by plugging the pore space and thereby block the flow of water and oil. One bacteria that has been studied, Leuconostoc mesentroides, has the unusual behavior that when it is injected into a porous medium and fed sucrose, it greatly... 

Reverse Mieelles. Reverse Micelles in supercritical fluids are currently being studied for several distinct applications (15-18). Normal micelles and microemulsions in aqueous solutions are known to be capable of increasing solution viscosity in several applications including the surfactant flooding of petroleum reservoirs.(19) If reverse micelles or microemulsions can be formed in C02> an increase in solution viscosity could possibly occur. The surfactants chosen as candidates for CO2 flooding application should be characterized by low water solubility and a strong CO2 solubilityi minimal adsorption onto the porous media and stability at reservoir conditions. (20)... 

The major reservoirs of natural CO occur around the Permian Basin area. Sheep Mountain, in southeastern Colorado is estimated to contain one trillion cubic feet (TCF) of CO2 of 97% purity. Productive capacity is approximately 300 MCF per day. Other important sources include Brano Dome in New Mexico with reserves of 5 TCF and with total productive capacity of approximately 350 MCF per day. The McElmo Dome has reserves of greater than 8 TCF (97% purity) of the same productive capacity as the Brano Dome Unit. The potential for the McElmo Dome is believed to be approximately 1 billion cubic feet per day. In addition, other units include Jackson Dome, Mississippi (1 TCF proven) and the LaBrage area of southwestern Wyoming which is believed to have reserves in excess of 20 TCF. These data, based on the 1984 National Petroleum Council study of enhanced oil recovery, indicate that the aggregate supply is approximately 2 billion cubic feet per day. 

Irwin H., Hurst A. (1983) Applications of geochemistry to sandstone reservoir studies. In Petroleum Geochemistry of Europe (ed. Brooks J.) Geol. Soc. Spec. Publn 12, 127—46. Oxford Blackwell Scientific. 

Salt Sensitivity. The viscosity of mobility control polymers is a strong function of their environment. The ionic composition of a petroleum reservoir determines the conformation that the polymer chains assume in it. This very fact is one of two reasons why the salt sensitivity of the polymer solutions need to be studied. The second incentive for an investigation of this kind is the possibility of using the water produced from a flooded field in making the new polymer solution. Since the produced water contains many salts and minerals, knowing how the viscosity changes as a function of ion concentration is important. 

The nature and properties of common clay minerals found in petroleum reservoirs are briefly discussed to set the stage for a review of the colloidal and hydrodynamic forces acting on the fine particles. This is followed by a review of reported experimental studies of permeability damage by fines movement under purely hydrodynamic forces. 

Although the equation of state can be and has been used to predict phase behavior for petroleum reservoir fluids for which no physical property data are available, it is recommended that some data, at least a saturation pressure, be measured in addition to a detailed component analysis of the fluid. This is particularly recommended when expensive compositional model studies are to be performed. 

In most of our reservoir studies on clastic reservoirs we come across cases with generally more petroleum inclusions having formed in the upper and most permeable and porous layers of the reservoirs, and this may reflect that oil has occurred for more time in the upper part of the reservoir, giving inclusions more time to form than deeper down. Still, it could also simply be that the higher pressures in the oil column in the top of the reservoir as compared with farther down forces the oil into more intimate contact with the cementing quartz grains and that this results in more entrapment of oil as inclusions higher up in the oil column. 

We also suggest application of GC-FID analysis of gas, long chained alkanes and biomarkers to realize the full potential of inelusions to reservoir studies as these may represent hermetically sealed testers of palaeo-petroleum. Furthermore, only the use of fluid inclusions in combination with standard geochemical core bitumen quantification, compositional analysis and GC-FID plus GC-MS characterization, can fully realize the potential of these methods for deciphering movement of OWCs during time and determining the time for field filling. 

There has been very little progress in calculating the flow of water, oil, or gas in naturally occurring rocks without experimental test because naturally occurring rocks are much, much less uniform than the beds of uniform sized spheres described by Fig. 12.4, Thus, in the study of groundwater movement and in petroleum reservoir engineering, it is customary to simplify Eq. 12.13 to... 

Not all petroleum reservoirs can be exploited successfully by the in situ combustion method. The applicability of this method depends on such factors as depth to the oil reservoir, thickness of the oil-bearing bed, amount of oil in place within the reservoir, degree of water saturation of the petroliferous formation, specific gravity of the crude and its fractional composition, reservoir pressure, geological type of the oil trap, physical characteristics of reservoir rocks, and the initial oil recovery factor prior to fire flooding. All of these factors must be thoroughly studied before it is decided to apply the in situ combustion method. 

This study is most impressive. Dr. Makhows spent 17 years in the Research Center of SONATRACH evaluating 10 000 samples mineralogically and petrologically, and 5 000 by chemical analysis. The book s ten chapters summarize the most detailed petroleum reservoir analysis I have seen in recent years. For those working in the Sahara this book is a gift. For those working elsewhere it should serve as a case history for their own areas of study. 

A number of laboratory investigations were made into different aspects of consumption of sodium hydroxide and sodium orthosilicate in alkaline flooding of petroleum reservoirs for enhanced oil recovery. One investigation studied the role of reversible adsorption and of chemical reaction v en petroleum reservoir sands are contacted with alkaline solutiais. Another investigation studied the effect of flow rate on caustic consumption by means of a series of flow experiments through reservoir sand packs. A third series of high rate flow experiments studied changing alkaline consumption with time. 

The long term pulse study was devised to determine the time required for the alkalinity of a solution in the pores of a sand pack to reduce to zero, lliis method provides a means for estimating the Icxigevity of a given volime and concentration of alkaline chen-ical solution injected into an actual petroleum reservoir. 

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