Selection of the optimal development system in conditions of a low-permeability, thin, dissected reservoir complicated by an underlying washed formation

   Introduction. Oil recovery factor (ORF) is one of the key indicators of the oil field development. There are two main group of factors that infl uence ORF: is affected by two main group of factors: geological features of the oil field and technological parameters of its development. Currently, oil fields development requires an increasing volume of hard-to-recover reserves (HRR). HRR involved in the development are usually characterized by complex, low-power, low-permeability, highly dissected reservoirs. The cost of geological errors in the development of such oil fields increases. There are often additional negative factors. For example, low thickness of the clay barrier separating HRR from adjacent water-saturated layers. The main purpose of this article is to select the optimal system of the development with HRR separated by a thin clay barrier from the underlying water-filled layer.

   Purpose. The article proposes a strategy to develop АВ1(1-2) («Ryabchik») oil fi eld with HRR. Its development is complicated by the presence of the washed object AB1/3 with a thin fl uid seal between them. The purpose of selecting the optimal parameters of the development is to improve the well placement system. The selection of the optimal development system is carried out on a two-dimensional synthetic geological-hydrodynamic model.

   Materials and methods. The two-dimensional hydrodynamic simulator “NumEx2”, Gazprom neft company group own development, is used to solve the problem of selecting the optimal parameters of the development system and conducting a sensitivity analysis of the results.

   Results. An optimal development system is proposed in the conditions of HRR with an additional complicating factor in the form of an underlying washed formation. This development system is characterized by the following parameters: a row confi guration of longitudinally directed horizontal wells along the line of regional stress (340 degrees) with BPS (Burst port system) technology for conducting multi-stage hydraulic fracturing with a length of GU = 1200 m with a PSS = 28 ha/well (a = 1400 m, b = 200 m) with the formation of a reservoir pressure maintenance system in the form of a wellbore support system with hydraulic fracturing. The use of BPS technology for hydraulic fracturing reduces the starting water cut of the well by approximately 40 % and increases the half-length of hydraulic fracturing fractures by 90 m.

   Conclusion. A strategy is proposed for drilling a HRR object complicated by the presence of an underlying water-saturated layer separated by a thin clay barrier.

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