Calculation method for water saturation of water flooded layer of ultralow permeability reservoir

A technology of water saturation and calculation method, which is applied in the field of water saturation calculation of water-flooded formations in ultra-low permeability reservoirs, and can solve problems such as lack of adaptability to water-flooded formations in ultra-low permeability reservoirs

Active Publication Date: 2015-04-08
PETROCHINA CO LTD
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Problems solved by technology

These methods have solved the problems related to the identification and evaluation of water-flooded zones in oilfields to varying degrees, but they lack the adaptabil

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  • Calculation method for water saturation of water flooded layer of ultralow permeability reservoir
  • Calculation method for water saturation of water flooded layer of ultralow permeability reservoir
  • Calculation method for water saturation of water flooded layer of ultralow permeability reservoir

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Embodiment 1

[0072] This embodiment introduces the present invention by taking the Wangyao Block of Changqing Ansai Oilfield as an example, and the specific description is as follows:

[0073] First, it is necessary to qualitatively identify the flooded layer. At least one of the following four ways can be selected for discrimination.

[0074] According to the change of formation water salinity in the production data of oil production wells;

[0075] Or the cross plot of natural potential amplitude and resistivity change can distinguish low flooding, medium flooding and strong flooding;

[0076] Or through the change of resistivity during the water flooding process, the original oil layer in this area is 20-30Ω.m. If the resistivity of the oil layer in the infill well exceeds the original oil layer obviously, it indicates that the oil layer has been flooded; through the amplitude difference of the radial resistivity of the oil layer Water-flooded layer can also be identified;

[0077] A...

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Abstract

The invention relates to the technical field of oil-field development, in particular to a calculation method for water saturation of a water flooded layer of an ultralow permeability reservoir. The method includes: acquiring water flooding degree of the reservoir; establishing a first relation between cementation factors in rock-electro parameters of the water flooded layer and porous structure parameters as well as a second relation between saturation exponent and the porous structure parameters; solving resistivity of mixed fluid of the water flooded layer; calculating the water saturation of the water flooded layer to be evaluated by the aid of the first relation, the second relation and the resistivity of the mixed fluid. By the method, the water saturation of the water flooded layer, specifically the water flooded layer of the ultralow permeability reservoir can be obtained more accurately, and the water flooded layer can be evaluated more accurately under the background of highly mineralized formation brines.

Description

technical field [0001] The invention relates to the technical field of oilfield development, in particular to a method for calculating the water saturation of a water-flooded layer in an ultra-low permeability reservoir. Background technique [0002] In view of the technical problems of how to maintain long-term stable production and water flooding to further improve recovery in ultra-low permeability reservoirs entering the medium and high water cut stage, the oil recovery rate is low, the decline increases, and the water cut rises rapidly. Distribution and controlling factors. There are many methods for identification of water-flooded layers and quantitative evaluation of saturation at present, but the factors affecting water-flooding law of ultra-low permeability reservoirs are complex and the characteristics of the reservoir itself are affected, so it is suitable for the remaining oil evaluation logging method of medium and high permeability reservoirs It is not suitabl...

Claims

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Application Information

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IPC IPC(8): E21B49/00
CPCE21B49/00
Inventor 惠钢王友净闫林辉李佳鸿高兴军
Owner PETROCHINA CO LTD
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