Estimation of multistage hydraulic fracturing parameters using 4D simulation

Abstract

At the present stage, most oil and gas condensate fields in the southern part of the East Siberian oil and gas province are characterized by an increasing proportion of difficult oil reserves in tight reservoirs. Multistage hydraulic fracturing (MHF) is proposed for the offshore Challenger Sea field (Southeast Dome). The implementation of this technique at a shelf will be a source of additional risks. For example, the properties of the RR-2 overlying seal have not been unambiguously assessed, and there are a number of geological uncertainties, such as the tectonic regime. However, there are a number of arguments in favor of MHF: heterogeneity of the reservoir; low permeability; low water cut of the field; sufficient thickness of the pay zone; and the overlying seal. One more positive factor is that sand ingress is not observed in the process of oil production. The selection of a principal well completion scheme on the eastern side of the RR-7 formation is aimed at effectively recovering the remaining reserves. The objectives of the study performed are: to create a geological and hydrodynamic model of the Challenger Sea (Southeast Dome); develop 1D and 3D geomechanical models; evaluate oil production forecasts based on fundamentally different well completion schemes; and determine the optimum parameters for multistage hydraulic fracturing. The research methods included: petrophysical methods; logging methods; core studies; drilling reports and formation testing data; and 3D, 4D geomechanical simulation. Other geophysical methods included acoustic logging, density logging, and gamma-ray logging. After building a geomechanical model of the reservoir at the beginning of drilling, a hydrodynamic calculation was performed. This established the reservoir pressures and saturations at certain points in time. The results made it possible for the principal stress directions, the values of effective and principal stresses, and the values of elastic strains to be determined. In order to assess MGF process efficiency, production forecasts were made using a hydrodynamic model for an exploration well with conventional completion (perforated liner) and with five-stage MGF. In the first case, the accumulated production was 144 kt over 15 years, and in the second case, 125 kt over 17 years. The difference in cumulative production is due to different initial well flow rates, as well as the rate of oil withdrawal during the first few years of development. Thereafter, the production and daily flow rate curves showed similar behavior. In order to select the most effective option, an economic analysis of the efficiency was performed.

Effect of Mineral Grain and Hydrate Layered Distribution Characteristics on the Mechanical Properties of Hydrate-Bearing Sediments

“…Therefore, the reservoir stimulation strategy is particularly important. Hydraulic fracturing technology can increase the artificial fractures of hydrate-bearing sediments, which is an important exploration direction to improve the exploitation process of natural gas hydrate [5][6][7]. Submarine hydrate reservoirs are usually characterised by non-diagenesis and weak cementation.…”

“…Submarine hydrate reservoirs are usually characterised by non-diagenesis and weak cementation. Hydrate decomposition can easily cause reservoir sedimentation and process of natural gas hydrate [5][6][7]. Submarine hydrate reservoirs are usually characterised by non-diagenesis and weak cementation.…”

Influence of Natural Gas Hydrate Distribution Patterns on the Macroscale–Mesoscale Mechanical Properties of Hydrate-Bearing Sediments

“…Zhu et al [17] used the Tough + Hydrate to construct a 3D model of a hydrate reservoir, which proved the important impact of reservoir fluctuations and physical properties on gas hydrate recovery and emphasized the need to use more realistic 3D models for production dynamics prediction. Bosikov et al [18] established a preliminary 4D geological model via 4D simulation and analyzed the characteristics of the geological model to evaluate multi-stage hydraulic fracturing parameters. And to study the mechanical properties of hydrate sediments, many scholars use the PFC to conduct numerical simulation studies.…”

Heterogeneity of Pore and Fracture Structure in Coal Reservoirs by Using High-Pressure Mercury Intrusion and Removal Curve

“…The application of mercury intrusive porosimetry (MIP) into the estimation of the soil water characteristic curve (SWRC) of soft clayey soil under wetting and drying cycling conditions should be reviewed as well because the MIP greatly contributes to the soil water retention behavior of deformable soil (Hu et al, 2013) [4]. Therefore, pore structure has become important in determining coalbed methane productivity [5][6][7][8][9].…”