Challenges in Sour Gas Handling for Kuwait Jurassic Sour Gas
Authors: Al-Qaoud Bader Naser 
Published: January 2012

Kuwait Oil Company started free gas production from its Jurassic sour gas field in May’2008 with the commissioning of Early Production Facility EPF-50. The field produces sour gas and light crude (API: 48) from a deep High Pressure High Temperature naturally fractured carbonate reservoir of low permeability and low porosity. The formation pressure and temperature are in the range of 10,000 psi and 275 deg. The well fluid is characterized by high H2S (5%) and CO2 content (5%). 26 wells are presently connected to EPF-50.

Development of the Jurassic gas field happens to be very vital for the company because of its important role in meeting the domestic gas demand for the country. It has also helped to free approx. 100,000 bbls/day of crude for export which was earlier being used as fuel in the domestic power plants in Kuwait. The light crude being produced in the field is also used to blend the Kuwait export crude (KEC) and improve its API, thereby generating additional revenue for the company.

The field is planned to be developed in 3 phases. Early Production Facility-50 is part of the 1st phase of development of the Jurassic Gas field. Work is presently on-going for Phase-II and is expected to be on-stream by 2013. By 2015 it is expected that phase-III will be rolled out and peak gas production will be achieved from this field.

Early Production facility-50 has been designed to process 175 MMscfd of sour gas and 50 Mbopd of crude to pipeline specifications. The export crude specifications being monitored for the facility is H2S in crude (11 ppm max.) BS&W (0.1% max.) Salt (21 PTB max.) RVP (10 psia max.) and API. For export gas, pipeline specifications is H2S (11 ppm max.) and Moisture (8 lbs/MMscf)

There are 2 trains for processing of the Jurassic well fluid in EPF-50, the Dry and the Wet train. The dry train has been designed to process 175 MMscfd gas and 50 Mbopd crude. The wet train is designed for 70 MMscfd and 20Mbopd. Design margin considered has been 20% for gas, 15% for crude and 25% for water. A test header has been provided to test wells inside the facility, apart from regular field testing. 3 wells are tested on a daily basis at the facility using a multiphase Vx meter. Separation is done in 3 stages with the bulk of gas being released in the HP dry separator. The gas separating out in the MP and LP seperators are compressed before being treated, along with the HP gas, in the Amine unit. After sweetening, the gas is dehydrated to meet pipeline specifications and sent to the downstream refinery unit. The acid gas generated in the Amine units is converted to sulphur using the Clause Process in 2 nos. of SRU’s provided in the facility. Molten sulphur produced is transported to the downstream refinery in tankers for further treatment, pellatisation and sale. A tail gas unit is also provided to ensure 99.8% conversion of the acid gas into sulphur and to meet emission norms.

Handling such highly corrosive well fluid throws up a wide range of unique challenges, from upstream, at the well head, to downstream, at the processing facility EPF-50. Given the importance this field holds for the company, these challenges need to be efficiently handled for safe plant operation and to prevent costly plant downtime. This has been achieved by carrying out need base modifications in the facility based on past operating experience and adopting advanced technology for Monitoring and Control of wells. Since the wells are at remote location, the implementation of I-field project has helped the company in managing its sour wells in a safe and efficient manner with minimum manpower and minimum intervention.The overall objective and focus for the company has therefore been sustained production using the best available technology and work practices and in the utmost safe manner.