The challenge to maintain production in marginal field and to keep any related activities to be economically justified will require more optimization and innovation. Artificial lift fields using pump require many mechanical well service intervention: to install and to repair the downhole pump. Mechanical well service uses well service rig or pulling unit rig, mainly to pull and to run the tubing. One of main component of the rig is well control equipment system.

The complete package of the well control equipment system is about 30% of the rig service package. The equipment may consist of: complete BOP stack, hydraulic power unit with line, choke manifold, kill line and flare line, poor boy separator. The time needed to rig up, test, and rig down the well control equipment package has significant percentage. For simple job of artificial lift mechanical well service which main job is only pulling and running back the tubing, the percentage may be about 20% - 30%. Continuous and routine job of the mechanical well service will give significant cost impact to the total operation expenses.

One of the marginal on shore fields in Tunisia, with low productive oil production well, requires innovation to keep the production in economic limit. Cost reduction of the artificial lift well service operation is one of the main options. Optimization of the well control equipment was studied to reduce the field operation cost. Careful risk assessment had been done. Simple and low cost well control equipment was prepared. Additional procedure was introducedandsome documents related to risk control are prepared. Applying the approach, about 25% - 30% of cost saving is identified without sacrify the safety of the operation.

Well control equipment standard is an almost matured and well-regulated standard around the world. The main equipment standards are almost the same across regions, countries and companies. Mostly there are two categories of the standards related to well operation: drilling and well service. However, mostly the main well control equipment is the same for both drilling and well service. Off shore well control standard are more stringent than on shore operation. However, mechanical well service,which deals with existing perforation without any reservoir stimulation and very well-known production behaviors, are not specifically categorized in most of the standards. This type of on shore mechanical well service operation has much less risk than drilling or reservoir well service, so it is highly possible to use less well control equipment package with the proper risk assessment according to the field/well condition. The well control equipment applied in the Tunisia field will hopefully give more standard guidance for low risk marginal oil field.

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