The influence of pH, temperature, and gelation delaying ligands on the stability of Cr(III) complexes in bulk solution and on Cr(III) propagation in porous media has been investigated for acetate, glycolate, and malonate complexes of Cr(III). For a given complex, Cr(III) instability to hydrolysis and Cr(III) retention increase with increasing pH and temperature. The chemical nature of the gelation delaying ligands bound to Cr(III) and their coricentration in the solution have a profound influence on the resistance of the Cr(III) complex to hydrolysis and on Cr(III) retention. Thus, whereas the Cr(III) acetate crosslinker, by itself, propagates poorly at elevated temperature, addition of sodium glycolate to the solution markedly reduces retention. We show that Cr(III) retention in sandstone cores can be virtually eliminated at 90°C by appropriate formulation of the gel-forming solution. Other experiments establish that Cr(III) precipitation at elevated temperature is reversible in the presence of polymer and that significant accumulation of the Cr(III) precipitate can have a negative impact on injectivity.

Liquid loading is a common problem affecting hydrocarbon production both in well and pipeline. Pipelines transporting hydrocarbons from the wells to the downstream facilities often come across a hilly terrain, which could be considered the main reason of liquid loading phenomenon. Currently the main technique used to solve the problem is the mechanical pigging. Nevertheless, this technique is not free of risks, in fact when the mechanical pigging is possible, operators and engineers have to deal with several issues. This paper presents an alternative method to deliquify pipelines, by using foamer injection. Even if in its preliminary stage, this research work represents a breakthrough since the feasibility of the method can allow an easier, safer and cheaper solution of the water accumulation in pipelines.The effectiveness of pipeline deliquification treatments by foaming injection is difficult to predict a priori, due to a high number of variables affecting the foam formation and transport within the pipeline. In this paper the issues related to the application of this method are described and some preliminary results on foam formation conditions, obtained on an experimental test bench are presented.

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Mercaptans are naturally occurring components of sour crude oil and natural gas condensate. When present in appreciable concentrations, they generate a very disagrenable smell which can be a nuisance to operators and to surrounding communities. Regulatory authorities aften require that mercaptan odors be controlled. A practical example of that has occurred to a gas field located in southern Italy which was suffering nuisance odor problems originating from a gas well whose fluid contained over 500 ppm total mercaptans. Production from this and several surrounding wells is collected in a shared collection tank, centrally located near officies and visitor entrances, where fluids undergo initial condensate/water separation. Despite dilution from well fluids containing far less mercaptan, the collection tank still emitted odors. The tank averaged 14Sm3 of condensate throughput per day and contained, on average, approximately 60 ppm total mercaptan. There was no issue about condensate delivery specification of mercaptan level, since the condensate can be diluted in other streams but the odor control issue was an opportunity to test the scavenging performance in the perspective of future, large scale mercaptan content management in other production sites. Contractor was involved as consultant to consider options for reducing mercaptan odors emanating from the condensate collection tank. On the basis of cost- performance and ease of implementation, an innovative mercaptan scavangers was chosen as the preferred means to reduce odors from the tank. The use of mercaptan scavangers is new to the oil industry. The mechanism is a chemical reaction which converts mercaptan into a different chemical species. In this way the amount of mercaptan in the condensate is reduced and the unpleasant odor is controlled; if a specification exist for the level of mercaptan in the condensate, it allows this to be met without introduction of any additional unit operation or process. Even if it isn't the case for the present case history, mercaptan scavangers are a very promising method to control streams that are out of specification. The targeted key performance indicator (KPI) for this application was a reduction of mercaptan levels in the condensate by 50–75%. After considering several potential injection sites, it was agreed that the new mercaptan scavenger would best be continuosly injected directly into the mixed fluids collection tank. From this point, the most efficient and effective mercaptan scavenging treatment could be realized, and condensate could then be readily transferred to the sales tank.