Abstract
The primary objectives of this paper are as follows:
To share the lessons learnt from a recent blockage remediation experience offshore West Africa.
To highlight the importance of sound engineering assessment in locating and identifying the nature of blockage and in the selection of appropriate blockage remediation technology.
To present the methodology applied which minimized the need for costly rental equipment which in turn resulted in significant OPEX savings and minimal impact to production.
The approach taken to remediate blockages is usually driven by the cost and time required, customer preference and remediation goals (i.e., establishing communication and flow Vs. full clean out), impact to production, operating conditions, production chemistry of the produced fluids and injected chemicals, geographical location of the field, field layout, available facilities, operating history and availability and access to specialized equipment and skilled personnel. If not properly assessed and planned, blockage remediation costs can easily go out of control with no guarantee for success and a long term solution. To minimize the required resources and maximize the chances for successful blockage remediation, a structured path needs to be developed.
This paper presents and highlights the importance of accurate produced fluid sample data, information on injected chemicals and production history to determine efficiently the nature and location of the blockage. Review of the pressure and temperature sensors data at key locations along the flowpath and a good understanding of the early blockage remediation attempts and their outcomes help are key inputs to the engineering assessment of the blockage. This paper shows how the right interpretations of the sensor data prior to and during remediation of the blockage are essential part of a sound engineering assessment. The assessment followed by the selection of suitable remediation options led to the successful remediation of the blockage. The options selected were those that could be readily implemented requiring no specialized or additional equipment, avoiding alternatives that involved considerable cost and time for deployment.
