Well distribution method based on offshore oilfield reservoir subdivision

Abstract

The invention relates to a well distribution method based on offshore oilfield reservoir subdivision. The method includes the steps of 1, in connection with existing oil formation division in a fluvial deposition reservoir, subjecting a logging curve of an actual drilled oilfield to maximum entropy method calculation, and preliminarily determining depositional cycles according to changes in knee points of an INPEFA curve; 2, in each high-level deposition cycle, determining low-level deposition cycles, and calculating channel sand thickness to a sand thickness to formation thickness ratio in each low-level deposition cycle; 3, in a target oilfield reservoir, dividing the low-level deposition cycle having 3-10 m of channel sand thickness and greater than 40% of sand thickness to formation thickness ratio, into a first development layer series, dividing the low-level deposition cycle having 3-8 m of channel sand thickness and 30%-40% of sand thickness to formation thickness ratio, into a second development layer series, and dividing the low-level deposition cycle having 1-4 m of channel sand thickness and less than 30% of sand thickness to formation thickness ratio, into a third development layer series; 4, using horizontal wells at positions satisfactory to the first development layer series of step 3, using the combination of horizontal wells and directional wells at positions satisfactory to the second development layer series, and using directional wells at positions satisfactory to the third development layer series.

Description

technical field [0001] The present invention relates to a method for drilling wells in an oil field, in particular to a method for drilling wells based on the subdivision of offshore oilfield reservoirs. Background technique [0002] Reservoir subdivision is an important basis for offshore oilfield production planning, dynamic analysis and adjustment of development process. Because my country's continental deposition is a complex and heterogeneous system, it has the characteristics of multiple cycles, large changes in lithofacies and lithology, and complex internal structure. Therefore, in the process of water injection development in offshore oilfields, due to the severe heterogeneity of continental reservoirs, problems such as obvious inrush of injected water monolayer, rapid rise of water cut and low recovery degree are gradually exposed. At present, the subdivision of reservoirs is mainly based on the theory of sequence stratigraphy and the method of biostratigraphy, wh...

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Problems solved by technology

Therefore, in the process of water flooding development in offshore oilfields, due to the serious heterogeneity of continental reservoirs, problems such as obvious single-layer breakthrough of injected water, rapid water cut rise, and low recovery degree are gradually exposed.

At present, reservoir subdivision is mainly based on the sequence stratigraphy theory and biostratigraphy method, and it is aimed at dividing formation oil groups in oilfields with dense well pattern. Difficult to be directly applied to the division of development strata in production oilfields

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