Low-cost and high-efficiency transformation process method for low-permeability reservoir of offshore oilfield

Abstract

The invention discloses a low-cost and high-efficiency transformation process method for a low-permeability reservoir of an offshore oilfield, and belongs to the technical field of oilfield reservoir transformation. The method mainly comprises the following steps: step 1, preferably selecting a measure horizon and a layered transformation part; 2, the maximum limited pressure of the shaft is calculated; 3, cable deflagration fracturing operation is carried out; 4, rock layering expansion operation is carried out; step 5, layered acidification operation; and 6, starting the pump to flow back the residual acid and recovering production. According to the method, the modification effect of the low-permeability reservoir of the offshore oilfield can be effectively improved through selective combination of several low-cost modification processes, and the problem of conventional hydraulic fracturing caused by limitation of platform space and water sources of the offshore oilfield, large span of the low-permeability reservoir, high operation cost and long period is solved; and a new thought is provided for low-cost and high-efficiency transformation of the low-permeability reservoir of the offshore oilfield.

Description

technical field [0001] The invention belongs to the technical field of oilfield reservoir transformation, and in particular relates to a low-cost and high-efficiency transformation process method for offshore oilfield low-permeability reservoirs. Background technique [0002] According to the relevant requirements of the national energy strategy, it is necessary to vigorously increase the intensity of oil and gas exploration and development. At present, the low-permeability reservoirs in China's offshore oilfields have large reserves and low production levels, making it difficult to develop effectively and economically on a large scale. Due to the differences in reservoir and engineering between onshore oilfields and offshore oilfields, the hydraulic fracturing technology commonly used in the development of low-permeability reservoirs in onshore oilfields is greatly restricted offshore. Taking the Changqing Oilfield on land as an example, the development of low-permeability r...

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Problems solved by technology

For low-permeability reservoirs in offshore oilfields, due to the large well depth and high construction pressure, there is a wellbore safety risk, and there is no long-span delamination method

[0005] Combining technologies such as deflagration fracturing and rock capacity expansion is a technological innovation that engineers can easily think of. However, simply combining deflagration fracturing and rock capacity expansion technologies may lead to longer operating time (deflagration fracturing string pressurization operation method) , gun accident in deflagration fracturing (deflagration fracturing cable operation method), pipe string rupture accident caused by long-term high pressure of rock expansion, rough combination of the two technologies is not conducive to operation timeliness, and cannot meet the characteristics of long-span low-permeability reservoirs in offshore oilfields A series of problems such as poor operation effect

It is impossible to effectively utilize the advantages of deflagration fracturing instantaneous high pressure, lower fracturing pressure, and rock expansion not limited by span reconstruction. It may also take advantage of the small coverage of deflagration fracturing in a single trip, high peak pressure damage to the pipe string, and long-term rock expansion. Disadvantages such as high pressure

[0006] To sum up, at present, there is a lack of a low-cost and high-efficiency reconstruction method for low-permeability reservoirs in offshore oilfields in China.

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