| Popis: |
The article describes an approach to creating, in conditions of limited input information, a strategy for performing the first hydraulic fracturing operations on deviated and horizontal wells in the A. Zhagrin field. The field is in the active phase of exploration, the planned count is mainly composed of horizontal wells with multi-stage hydraulic fracturing. Approaches to the design of pilot works with control of the height of hydraulic fractures, which have proved their effectiveness by well logging studies and the obtained oil productivity, they have been successfully introduced into the technology of multistage hydraulic fracturing in horizontal wells. Due to the minimum number of reference wells, a significant area of the field (100 km2), the uncertainty of the distribution of water-saturated zones in the target and adjacent formations, the spread in the thickness of clay layers from 10 to 30 m, there is a risk of unwanted introduction of these interlayers by hydraulic fractures. The project team was able to assess the risks in terms of hydraulic fracturing, depending on the geological and physical characteristics (thickness of the target formation and clay layers, saturation) and in joint cross-functional work (with geological, geomechanical and hydrodynamic support) to implement hydraulic fracturing technologies that have confirmed their efficiency in oil production. To test hypotheses at the initial stage, various scenario conditions with a probabilistic assessment of uncertainties were selected at the deviated wells, as a result, the matrix of technological solutions was developed. In directional wells, the capabilities of technologies selected for pilot testing were confirmed using methods for diagnosing the height of hydraulic fracturing. The performed correction of stress profiles in a modern corporate hydraulic fracturing simulator increased the correctness of the 3D geomechanical model, which made it possible to optimize fracture geometry and horizontal wellbore drilling direction. Due to a thorough study of the conditions for the applicability of the considered hydraulic fracturing technologies, it was excluded the inclusion of water-saturated horizons without losing the effective half-length of hydraulic fractures. The workflow, during the implementation of which a matrix of solutions for successful well development was created, will ensure the achievement of planned oil production rates in the future for a field without rich field practice in hydraulic fracturing. |
