heavy gas condensate reservoirs (>0.75) present interesting challenges in their study, production and reservoir management. Simulation and history matching are often hindered by the lack of appropriate PVT properties. Furthermore, it is well established that they experience properties. Furthermore, it is well established that they experience hysteresis effects following a shutin. Remedial action is cumbersome but possible. This work presents a simulation of the behavior of both lean and possible. This work presents a simulation of the behavior of both lean and heavy (rich) gas condensate reservoirs, shows radial liquid profiles for various flowing bottomhole pressures (compared with a phase diagram), demonstrates degree of gas relative permeability reduction and explains the hysteresis effect. Lean gas injection is a remedial action, reducing the near-wellbore liquid saturation. The study shows that the degree of the adverse gas relative permeability reduction can be minimized or tempered by the appropriate choice of the flowing bottomhole pressure, ie., production can be optimized. Introduction The producing rate of gas condensate reservoirs is affected greatly by the flowing bottomhole pressure and not only because of the pressure gradient in the reservoir. The value of the bottomhole pressure controls the amount and distribution of liquid condensate accumulation near the well with an unavoidable relative permeability reduction. The higher the gas gravity, the more the liquid condensate will be and therefore the relative permeability-to gas reduction will be more pronounced. The classification permeability-to gas reduction will be more pronounced. The classification of lean and heavy (rich) gas condensate has been presented by Cronquist. A separation between the gas condensate region and the volatile oil region appears to be at 11% heptane-plus. Figure 1 contains the initial condition of two reservoir fluids from two different fields that are studied in this paper. One of these is well within the lean gas condensate region where the paper. One of these is well within the lean gas condensate region where the second is very near the volatile oil line. This fluid can be readily classified as a heavy (rich) gas condensate. Fussell in a frequently referenced paper has stated "productivity (from gas condensate producing wells) is severely curtailed when the flowing bottomhole pressure is less than the saturation pressure of the in-place fluid." While this contention is true, the implication that gas condensate reservoirs can be produced with a bottomhole pressure above the dew point pressure produced with a bottomhole pressure above the dew point pressure ("saturation pressure" in Fussell's nomenclature) is rarely, if ever, feasible. A survey of several gas condensate reservoirs has shown that invariably, the initial reservoir pressure is at, or very near, the dew point pressure. As a consequence, to have any appreciable driving force in the reservoir, production from gas condensate reservoirs should be the result of an production from gas condensate reservoirs should be the result of an optimization of (1) The producing rate and the reservoir pressure in Eq. 1 are, of course, time functions while the relative permeability to gas, krg, is a function of both space and time. Therefore, to maximize the cumulative production within any time period (transient, steady state or pseudosteady production within any time period (transient, steady state or pseudosteady state) it is necessary to attempt a number of simulations ahead of time. This must be augmented by laboratory-determined relative permeability curves. There exists an optimum flowing bottomhole pressure for a given average reservoir pressure and operational constraints, that would result in a relative permeability reduction distributed in the reservoir and especially around the well, such that the product (P -Pwf) : krg is maximized. The bottomhole pressure "path", ie., its evolution with time is very important. Once condensate is formed near the well, very little can revaporize into the gas phase even if the pressure is built up to the original reservoir pressure. Thus, if a condensate well is shut in and then re-opened the production rate of the new flow period will continue largely unaffected by the buildup. P. 471

IZVOD Biodizel, alternativno gorivo fosilnim, dobija se reakcijom transesterifikacije triacilglicerola iz biljnih ulja i životinjskih masti nižim alifatičnim alkoholima. I pored brojnih prednosti u odnosu na fosilna goriva, glavna prepreka široj komercijalnoj upotrebi biodizela je visoka cena jestivih biljnih ulja. U poslednje vreme, posebnu pažnju zaslužuju nusproizvodi industrije proizvodnje jestivih ulja kao izvori triacilglicerola, jer se njihovim korišćenjem ostvaruju pozitivni ekonomski i ekološki efekti. U radu su analizirani postupci dobijanja biodizela iz nusproizvoda procesa rafinacije jestivih ulja (sapunske smeše, otpadna zemlja za beljenje, deodorisani destilat), sa osvrtom na faktore koji utiču na reakciju sinteze estara masnih kiselina. Cilj rada je da se istraže mogućnosti korišćenja ovih otpadnih sirovina u proizvodnji biodizela.