SAND CONTROL AND MANAGEMENT AT LAGAN GAS FIELD, OPTIMIZING WELLHEAD DE-SANDER

摘要

Lagan is a Medco E&P Indonesia gas field which has 30 wells and produces from 20 different sand layers separated by three faults. On November 2009, after 24 years production lifetime, there was an indication of sand being produced at this field, since sand accumulation was found inside the production separator, and a considerable amount of surface control equipment was being eroded due to sand abrasion. Since Lagan field produces up to 36 MMSCFD, a major contribution, sand control and management were urgently needed to maintain operational reliability. The initial challenge of applying sand control at Lagan field was to identify which wells and which sand layers caused the sand production. To meet this challenge, four wellhead de-sanders were installed at four different wells, all of which produce from different sand layers. By installing these de-sanders, sand layers that contributed to sand production could be identified and follow-up action could be carried out. By considering several aspects, such as the urgent need to accelerate the application of sand control, poor well accessibility and rig mobility, and cost- and application effectiveness, wellhead de-sander was finally chosen as the most suitable sand control technique for this field. The design and fabrication of the wellhead de-sander was completely home-made and continuously improved and modified to enhance the quality and quantity of the sand trapping. After one year's application, wellhead de-sander has proven its effectiveness by reducing the amount of sand carried out to Lagan station from 20 liters/day to 2 liters/day. This means a reduction in production separator downtime for sand clean-up from 3-5 stoppages a day down to 1 stoppage every 2 days, a reduction in maintenance and repair of surface control equipment to zero cases per year, and a total saving of up to USD 340.000.