In-depth profile control step by step method employing equipressure drop gradient

Abstract

The invention provides an in-depth profile control step by step method employing equipressure drop gradient , which relates to the technical field of deep profile control of a water flooding development oil reservoir. According to the practical condition of a test block, suitable profile control agent is selected, and the breakthrough pressure gradients of profile control agents of different compositions are tested. A stratum is divided into a near wellbore zone, a far wellbore zone and a stratum deep according to the pressure drawdown of the stratum; and the pressure gradients of the zones are different, so that slugs with different strengths are required. According to the principle of equipressure drop gradient, namely, the breakthrough pressure gradient of the profile control agent equals to the pressure gradient of the stratum, the composition of each slug is selected, profile control slugs are combined, and the combined profile control slugs are optimized according to the cost. According to the invention, profile control agents with different strengths can be placed in different positions of the stratum, and overall in-depth fluid diverting step by step of the space of the oil reservoir can be realized through the combination of profile control agents with different strengths, so that the conformance factor can be improved greatly, further the oil recovery efficiency can be improved.

Description

Technical field: [0001] The invention relates to a deep control and displacement technology, in particular to a step-by-step deep control and displacement method for water injection development reservoirs using the principle of equal pressure drop gradient. technical background: [0002] my country is one of the countries with a relatively high proportion of oil fields developed by water flooding in the world, and the reserves developed by water flooding account for more than 60% of the total reserves. In the process of water flooding, due to the serious heterogeneity of the reservoir, the injected water advances unevenly along the high permeability layer and high permeability area, resulting in low sweep degree of the middle and low permeability layers and poor oil displacement effect, which seriously affects the water flooding process. and the development effect of polymer flooding. To fundamentally solve this problem, the method of profile control and water blocking must...

AI Technical Summary

Problems solved by technology

However, conventional profile control methods such as clay-polymer flocculation system and water swelling have their limitations, mainly in the following aspects: (1) After repeated plugging in the near-wellbore area, the oil saturation is greatly reduced, and deep profile control is especially required technology to dig deep into oil reservoirs

(2) For thick oil layers, ordinary profile control and water plugging can only cause short-term liquid flow diversion in the near-wellbore area, and the injection water in the deep oil layer recirculates, which greatly shortens the effective period of profile control

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