Research and Practice on Eor of Three Dimensional Well Pattern in the Thin Interbedded Oil Reservoir in the Middle and Deep Layers of the Sea

In order to solve the problems of thin interbedded deposition, strong heterogeneity and large interlayer interference in early development of offshore K oilfield, this paper proposes a research idea of three-dimensional adjustment of injection production well pattern based on multi-layer flow field control in early development. Through the combination of reservoir numerical simulation method, reservoir engineering and field test, the expression formula of sweep efficiency of water drive area in different stages of injection production unit is established in plane, the injection production well pattern optimization technology based on plane heterogeneity is formed; The quantitative expression formula of multi factor inter layer interference coefficient is put forward vertically. Combining with Lorentz curve, the evaluation template and technical limit of early subdivision layer system of thin interbedded reservoir are established, and the early subdivision layer system technology based on the dynamic interference representation between layers is formed. By analyzing the seepage characteristics of thin interbedded multi-layer sandstone reservoir and combining with the field practice, the plane well layout model of offshore medium deep thin interbedded reservoir is established, Based on the quantitative characterization of interlayer interference, the technical limits of early subdivision of thin interbedded reservoirs are as follows: the permeability gradient is controlled within 3, the longitudinal span is controlled within 200m, the number of sand control sections is controlled within 4, and the water cut is less than 40%. The horizontal and vertical combination can effectively reduce the interlayer interference and start the poor reservoir area, forming a three-dimensional well pattern deployment technology suitable for the early development of offshore K oilfield. It can effectively improve the plane injection production relationship, increase the sweep range of water flooding as a whole, and improve the development level of oilfield. It can effectively reduce the more serious interlayer interference in the middle and later stage of water injection development of formation, improve the water absorption capacity of thin interbeds, and form balanced displacement and efficient development. The recovery was increased by 4.7%. The field test results show that the technology is effective. This paper is the first time to form a three-dimensional well pattern deployment technology suitable for the early development of offshore K oilfield, which provides effective development experience for the efficient development of offshore medium and deep thin interbedded reservoirs.