Production Analysis and Evaluation of Well Parameters Affecting Production: Case Study: Songo Songo Gas Field
Abstract
Production of natural gas in Tanzania started during 2004 from a gas field called Songo Songo. Recently, there has been a desire to increase gas production from the field due to an increase of natural gas demand. The purpose of this thesis work is to analyse the ongoing production and evaluate parameters that affect the production capacity of the field. The study will bring understanding of the field production system and its performance as well as the extent at which well parameters affect production (important for production increase strategies). Achieving this study, important information and data were collected from TPDC and during site visit. Analytical method was used to perform several calculations whereby, important equations for the study were identified from the literature. Computer tools like excel models and Hysys computer program were applied to some cases. The study involved producing and suspended wells as well as surface facilities like flow lines. Results show that, the field has already produced 28.6% of its recoverable volume until late 2013 considering a R.F of 67.5%. The estimated GIIP is 3.4 x 103 MSm3/d, which is 97 % of the 2010 reported GIIP. The abandoned pressure of 65 bar for 67.5 % R.F can be achieved if the operating separator pressure is reduced to about 60 bar. Currently, four wells are on production. Four parameters (WHP, TD, skin and well trajectory) were considered during the study of parameters that affect production flow rate of each well. For all wells, a decrease of WHP and increases TD increases well deliverability. However, maximum well flow rate, is achieved with low skin factor and inclined or horizontal orientation. The extent of each well response to each parameter is different. However, maximum WHP should be about 140 bar for SS wells, optimum TD for all wells should be 5 1/2". Following the desire to increase SS production, optimisation studies can be carried out considering the constraints of demand and economy. It will help to decide the values of each well parameter. Suspended wells can be worked over as an option to increase production. However, studies of compression effect near wells are important to achieve highest R.F.