| Rustam D. Gafarov | chief specialist | Tyumen Petroleum Research Center, Tyumen rdgafarov@tnnc.rosneft.ru |
| Tatyana I. Sinitsyna | team leader | Tyumen Petroleum Research Center, Tyumen tisinitsyna@tnnc.rosneft.ru |
| Andrei N. Gorbunov | head of division | RN-Nyaganneftegaz, Nyagan angorbunov@nng.rosneft.ru |
| Sergey P. Kanaikin | manager | RN-Nyaganneftegaz, Nyagan spkanaykin@nng.rosneft.ru |
In recent years, horizontal drilling with multi-stage hydraulic fracturing (Hz with MSHF) is becoming more widely used in the development of both greenfields and brownfields. In this regard, the issue of carrying out well interventions in horizontal wells to maintain their productivity is getting more urgent.
One of the most promising types of well interventions today is repeated multi-stage hydraulic fracturing. Despite the considerable experience in conducting repeated hydraulic fracturing in directional wells, there are no proven engineering solutions for repeated MSHF in horizontal wells.
This paper describes the experience of performing repeated MSHF in horizontal wells of the Kamenny license area of Krasnoleninsky field (RN-Nyaganneftegaz). The main engineering procedures were evaluated and measures were developed to adjust the technology to the field conditions.
Materials and methods
As part of the selection and testing the re-MSHF technology at the Kamenny LA of Krasnoleninsky field of RN-Nyaganneftegaz, a pilot project was executed to determine the feasibility and performance of repeated selective multi-stage hydraulic fracturing using the existing completion assemblies.
Results
The article describes the results of the pilot project on repeated selective multi-stage hydraulic fracturing in horizontal wells of Vikulov series reservoirs (RN-Nyaganneftegaz); the efficiency of well interventions performed was proved.
Conclusions
The assessment confirmed the high economic efficiency of the operations: PI amounted to more than 2.0 units. In the period of 2019–2020, in accordance with the Business Plan, repeated hydraulic fracturing has been scheduled in another eight horizontal wells.
The pilot project helped to evaluate the main engineering procedures and develop actions to adjust the technology to the field conditions.
The efficiency of repeated hydraulic fracturing between the zones of primary fracture initiation was confirmed, which made it possible to achieve a planned increase in oil production and increase the reservoir drainage zone by a well. By restricting the proppant mass, it was possible to avoid the risk of a fracture breakthrough into the underlying water-saturated VK3 reservoir. The efficiency of cup-2-cup technology for repeated hydraulic fracturing has been confirmed. At the same time, there is a significant excess of the actual time spent on preparing the wellbore for hydraulic fracturing due to a longer wellbore normalization to install a packer.
The pilot operations confirmed the efficiency of repeated fracturing between previous fracs in a horizontal well with cemented liner. As part of expanding the potential of technology implementation, tests are planned in wells with non-cemented liners and behind-casing packers. Also, the performance of repeated hydraulic fracturing in previously fractured areas should be studied. The estimated incremental oil potential of such wells meets the Business Plan requirements, which means this method might be an alternative to the first one.
