Peculiarities of Thin Oil Rim Development

Kolbikov, Sergey Valentine (Novatek Inc.)


Thin oil rims associated with gas-condensate field development have one common problem - low oil recovery. The main reasons are fast gas and water conning of the producers resulted in sharp oil rate decline and low cumulative oil production per well. One of the main reasons of low recovery efficiency is that with oil saturated thickness less than 10 m most of oil in place volumes allocated to transition zones. 


Thin oil rim development was studied based on the 3D numerical simulation of one of the pay zones in Low Cretaceous formation of Western Siberian gas-condensate field.  Several development scenarios (on depletion, with water injection, with and without simultaneous gas production from cap, different well completion) were analyzed.


Thin oil rim development was studied based on hydrodynamic modeling of West Siberian gas-condensate fields with oil rims at Low Cretaceous sands. Analysis of several scenarios of oil rim development with different well completion, and gas cap development at different timing are given.


Several factors were estimated with strong impact on the effectiveness of oil rim development (oil rates decline, water cut and gas-oil ratio growth, cumulative oil production per well): capillary pressure definition, well completion (horizontal vs. deviated), gas production from cap. Derived several conclusions: cumulative oil production from thin rims is very sensitive to the capillary pressure value, horizontal completion is most effective for rim development; limited production from the gas cap simultaneously with oil production could lead to a higher oil recovery at certain geological conditions.