Laslau Mare Field, a Successful Case of Production Optimization in Brownfield Rehabilitation

Abstract

Romgaz, the Romanian national gas company, and Schlumberger joined forces in 2003 through a 15-year collaborative agreement for the rehabilitation of the Laslau Mare gas field. One of the main focuses of the agreement is the acquisition of data in order to develop a deeper understanding of the field, and thereby optimize the field management plan. After a First Work Program campaign, executed in 2004—2005, field production was increased by 40%; the result of workover jobs performed and elimination of surface network bottlenecks. In addition to a portfolio of rig workovers, the approved Work Program for 2009 included an aggressive and challenging campaign of rigless interventions to optimize and maintain field production. The total production from the field has increased by 17% as a result of this rigless campaign, which mainly comprises coiled tubing interventions for water unloading (identified by slick line fluid level measurements) and the verification of the mechanical status of all active wells in the field. An additional 6% production increment was achieved with optimization of well soaping schedules, which is the current continuous water lifting method in Laslau Mare field. The encouraging results of the rigless campaign and the additionally achieved incremental production rate were realized by implementation of the production optimization workflow outlined in this paper. This workflow aims at close monitoring of individual wells, identification of production gaps and intervention opportunities. Finally, well candidates are selected based on economic analysis. The success of the campaign is demonstrated by the production gains and the short payout times achieved. The entire rigless intervention program paid out in a couple of months. This paper presents the optimization workflow, its implementation to select candidates for the rigless campaign and the production and economic results of the executed work in 2009.