Decision matrix for liquid loading in gas wells for cost/benefit analyses of lifting options

摘要

Liquid loading in gas wells is a multiphase flow phenomenon where the liquid content of the well creates back pressure that restricts, and in some cases even stops, the flow of gas from the reservoir. It is estimated that 90% of the producing gas wells in the U.S. are operating in liquid loading regime. Field-proven solutions already exist to reduce the loss of gas production when liquid loading begins to occur. However, whether or not the chosen remedy is technically feasible and cost effective will depend on the field's location, export route capacity and the operator's experience. Although there are literature reviews available that describe the possible solutions to liquid loading problems in gas wells, no tool currently exists which is capable of helping an operator select the best remedial option for a specific field case. The selection of the best remedial technique and the timeframe within which the remedial action is undertaken are critical to a project's profitability. This paper describes a newly developed decision matrix to screen the possible remedial options available to the operator. The matrix not only provides a critical evaluation of technical solutions to the problem of liquid loading in gas wells vis-a-vis the existing technical and economic constraints, but also serves as a quick screening tool for the selection of production optimization strategies. In its current state of development the tool consists of an assessment algorithm used in conjunction with a decision tree. Being a data mining technique, the decision tree allows rapid subdivision of large initial data sets into successively smaller sets by a series of decision rules, which are based on information available in the public domain. The effectiveness of the matrix is now ready to be tested against real field data sets.