Enhancement of Vietsovpetro brown fields’ development efficiency considering the limited well stock at the offshore facilities

Introduction. Improvement of field development efficiency is the key issue at any operation stage, and is the most critical for Vietsovpetro, considering the declining production at the offshore fields. Production levels are maintained through the generation and implementation of well intervention programs. Main portion of incremental oil comes from drilling well interventions (new wells, side tracking). Well intervention planning for the offshore fields has some peculiarities, which should be considered at every stage of decision-making — from geological criteria for well selection to interventions. Such peculiarities may include approaches and technologies for well construction and casing. 

Materials and methods. The offshore fixed platforms (MSP) and mini MSP — wellhead platforms, are widely used in Vietsovpetro to operate the wells and technological equipment in Vietsovpetro. Well drilling on the wellhead platform is performed through the jack-up rigs, while MSPs engage drilling facilities. Most of MSP drilling facilities are currently dismantled.

MSP wells with low production rate, high water-cut and absence of promising overlaying formations decrease the production profitability, and the impossibility of side tracking negatively influences the efficiency of residual reserves production and ultimate recovery. The residual reserves are spread out across the area in a way, that drilling from the wellhead platform, using a jack-up rig, is impossible due to a significant offset, while poor residual reserves make construction of a new offshore facility economically inefficient. These reasons accompanied with the lack of available positions result in an impossibility of commencing new wells from the available MSPs. This trend negatively effects the current efficiency and may influence the production levels later on. 

Results and conclusions. The experts of the Research and Engineering Institute have developed the new technical decisions, previously never applied in Vietsovpetro, for organizing the additional well positions on MSP without involvement of a derrick barge for further well drilling with a jack-up rig. This decision allows developing the residual reserves and improving the oil recovery.

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