New Test Method for Field Evaluation of Asphaltene Deposition

Abstract

Abstract Organic solids deposition such as asphaltene deposition in subsea wells and flowlines can lead to unacceptable levels of lost production revenue, high cleanout costs, and potentially losing a subsea well. Producers invest significant resources in assessing the risk associated with asphaltene deposition, by collecting and storing the needed high pressure reservoir samples, conducting exhaustive and expensive lab testing. In addition, Producers also incur significant OPEX (operational expenses) associated with chemical injection in the hope to mitigate asphaltene related challenges with limited to no success. Extensive research work has been done in the past 5 years to understand the asphaltene onset conditions and deposition tendencies in subsea flowlines and wellbore. A number of test methods and methodologies have been developed to date by producers, commercial laboratories, universities, and chemical vendors. Each test method that has been developed so far has its success stories of applicability and failures as well. A documented evidence of any one test method that would predict the asphaltene deposition issue consistently with high confidence and evaluate the performance of an inhibitor/dispersant accurately is still lacking. In addition to a testing method in the lab to predict asphaltene instability and deposition tendencies, field techniques are required to monitor performance and make changes to asphaltene dispersant injection requirements. A thorough and objective review of current test methods with data from different fields needs to be presented for the benefit of flow assurance engineers in the industry. Also, identifying possible research paths and outlining equipment needs that would cover the gaps with the current test methods is valuable. Asphaltene inhibitors and or dispersants are considered as part of the solution but lack of proven test method makes it difficult to validate the value of the chemical solution. Also, new product development requires a reliable, field proven test method. The new testing technique is being developed that would simulate the harshest of the conditions and without requiring high pressure reservoir samples and or expensive and time consuming experiments. The equipment available currently in the industry currently does not meet these requirements. This new test method could be used in the field and will produce results in a shorter time frame, will resolve the current limitations and has the potential to improve the accuracy. Evaluation studies with model fluids and black oils with severe asphaltene deposition tendency will be presented. Data with Evaluation of chemicals will be included as well.