Total Systems Approach to Reduce Fouling and Improve System Efficiency Using Hydrogen Sulfide Scavengers

The Cotton Valley sand and Haynesville shale formations are situated in East Texas, USA, producing oil, gas, and condensate on land. Most of the producing assets are mature and souring, and the presence of hydrogen sulfide in the produced fluids and gas provides both operational concerns in terms of solids deposition and asset integrity in the production facilities as well as complexity when considering the processing, export, and sale of condensate and gas. Produced gas was traditionally treated with MEA triazine hydrogen sulfide scavenger prior to liquification by LNG plant. There have been historical issues with both the levels of hydrogen sulfide left in the gas and also solids formation in the process, which threatened periodic shutdown of the LNG plant. A holistic approach was used to improve the overall sulfur removal process. This includes the reduction or elimination of solids formation as well as improvement in the system scavenging efficiency. The approach considered current operating procedures, system parameters, equipment design (contactors), and H2S scavenger chemistry.

A Stochastic Model for the Fractal Dimension Estimation of Asphaltenes Aggregation

Some of the problems associated with the transportation of crude oils are due to the presence of heavy compounds as asphaltene molecules. This work developed a stochastic model that predicts the fractal dimension of the asphaltene aggregates. It was found that the maximum value of the fractal dimension is 1.71, which corresponds to the reported experimental results. The model can be applied as a universal growing behavior for the analysis of surface roughness when solids deposition is observed in the production systems involving crude oils

Verifying Production Losses due to Petroleum Flow Improving Well Intervention and Design

The purpose of this research is to identify in the literature: causes, factors, case study descriptions and adopted solutions for production losses regarding the petroleum flow in offshore oil wells. Those facts will be organized and structured to identify potential zones of intervention for planning the well maintenance during well design phase to avoid production losses. This paper focuses on four offshore regions: Campos Basin, Gulf of Mexico, North Sea, and West Africa. These regions represent the most significant share of offshore oil production in the world. Data set available in the last thirty five years through academic, technical and governmental reports in the literature were the basis of this study. The procedure was accomplished in three steps: (1) data research (2) analysis of the data (3) guidelines establishment. The main cause of production loss regarding the petroleum flow is the solids deposition in the well/line system, such as hydrates, asphaltenes, wax, scales (barium sulfate, strontium sulfate, calcium sulfate, calcium carbonate, and naturally occurrence radioactive material), and calcium naphthenates. In this work the superposition of graphics (hydrate curve, wax appearance temperature, asphaltene onset pressure, and saturation index) resulted in a region free of solids deposition, denominated as “flow assurance envelope”. The main expected result is to propose a guideline to be used during the well design phase in order to minimize and facilitate the well intervention. The main contributions of this paper to the oil industry are the identification of potential zones of intervention due to solids deposition in the well/line system, the foresight of well intervention before the beginning of the oilfield production, and finally, possibilities to improve the well or intervention design.