A coordination chemical approach for delaying the gelation of Cr+3/polymer compositions has been explored. By screening organic ligands for their gelation delaying power with hydrated Cr+3/polymer and Cr(OAc)3/polymer solutions several powerful retarding ligands have been identified. Use of the pre-formed Cr+3 complexes of these ligands together with additional, uncomplexed ligand in the gelant solution provides outstanding control over the gelation time over the temperature range 60°-135°C. With these compositions gelation times spanning the range from several hours to one month or more have been obtained at temperatures up to 120°C; such gelation delays should be suitable for a number of near-well and in-depth gel treatments. In virtue of the low toxicity of Cr+3 and its complexes, the potential environmental impact of the new gelation compositions is notably reduced relative to those employing Cr+6 or formaldehyde. A number of variables have been evaluated for their influence on the gelation delay, and preliminary experimental results on the propagation of Cr+3 in porous media at high temperature are reported. Our current mechanistic understanding of the gelation delay chemistry is also described.

No abstract

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.

No abstract

One of main risks in natural gas transport is formation of hydrate deposits in pipelines and sealines. In order to mitigate this problem, a possible solution could be to apply an appropriate inner coating, avoiding adhesion of hydrate particles to the pipe wall. With this purpose, different commercial coatings were characterized with traditional laboratory methods (roughness, water contact angle and diiodomethane contact angle) and performed adhesion force test with model hydrates (THF hydrates) at atmospheric pressure. Nevertheless, such measurement conditions are far from the real field conditions. Therefore, in order to assess the technology, a new experimental tool was developed to perform adhesion stress measurements on hydrocarbon hydrates under more representative operating conditions. The results of these measure-ments clearly show that the tests carried out with model systems at room pressure may provide misleading outcomes.