Features of the Mongi oil-gas-condensate field development (Sakhalin Island)

UDK: 553.98

DOI: 10.24887/0028-2448-2020-8-30-33

Key words: Mongi field, Sakhalin, faults, fluid migration, infiltration system

Authors: R.R. Haliulin (RN-SakhalinNIPImorneft LLC, RF, Yuzhno-Sakhalinsk), S.N. Zakirov (Oil and Gas Research Institute of RAS, RF, Moscow), G.S. Sun (RN-SakhalinNIPImorneft LLC, RF, Yuzhno-Sakhalinsk), U.L. Enikeev (RN-Sakhalinmorneftegas LLC, RF, Yuzhno-Sakhalinsk), P.V. Zelenin (RN-Sakhalinmorneftegas LLC, RF, Yuzhno-Sakhalinsk)

The article presents unique geological conditions of the largest field on Sakhalin Island - Mongi. The field has 10 main tectonic blocks that contain the main development objects and are limited by a series of high-amplitude normal faults. The dynamics of reservoir pressures in the deposits of the Mongi field is closely related to the presence and capacity of the aquifer. The Mongi water horizon is presented by an infiltration system, which determines the state of the field development system and characterizes the operation modes of deposits. The Mongi water horizon has a constant supply of infiltration surface water, as evidenced by seismo-geological data, dynamics of well operation modes and changes in reservoir water mineralization during 42 years of development. Properties of water-driven horizons for productive deposits of the sedimentary cover of Sakhalin depend on belonging to three types of fluid systems: infiltration, elision, and geodynamical. The presence of hydrogeological windows along the fault planes has a significant influence. Contribution to the creation of a modern image of deposits made normal faults having consediment character. Faults in the field determined the presence of vertical and lateral fluid flows. These faults are not perceived as a plane, since these dislocations are independent three-dimensional bodies. Dislocations of the Mongi field play a major role in the migration and accumulation of hydrocarbons. The features of the various modes for Sakhalin deposits are described in detail by hydrogeologists of RN-Sakhalinnipimorneft LLC in previous works and are of high practical significance when conducting geological exploration. The authors of the article confirmed the main characteristics of the water drive belonging to the infiltration system and developed a method for calibration of the aquifer operating mode with actual well data: operating modes, logs, well testing, and seismic information. A detailed study of the geological situation of the Mongi deposit allowed us to choose an effective way to develop deposits and reasonably plan geological and technological measures.
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