CN102519853A - Calculating method of porosity lower limit of recovery industry for effective reservoir under pore structure restraint - Google Patents

Abstract

The invention relates to a method for calculating the lower limit of the industrial porosity of effective reservoir recovery under the constraint of pore structure. The invention calculates the lower limit of the industrial porosity of recovery under the constraint of different pore structure types on the basis of pore structure classification, and solves the problem of The influence of pore structure on the lower limit of industrial porosity for effective reservoir recovery is discussed. The method obtains different lower limits of industrial porosity for recovery of effective reservoirs for reservoirs of different pore structure types, thereby improving the accuracy of calculation of lower limit of industrial porosity for recovery of effective reservoirs.

Description

Calculation method for the lower limit of industrial porosity in effective reservoir recovery under the constraint of pore structure

technical field

The invention belongs to the field of petroleum and natural gas exploration and development, in particular to a method for obtaining the lower limit of the industrial porosity of effective reservoir recovery under the constraint of pore structure.

Background technique

The lower limit of industrial physical properties of effective reservoir recovery refers to the reservoir that can accumulate and seepage fluid, and can produce industrially valuable liquid production (hydrocarbons or water with the same volume as hydrocarbons) under the existing technological conditions The lowest porosity and permeability a layer has. The existing techniques for obtaining the lower limit of industrial physical properties of effective reservoirs are based on the comprehensive utilization test method, empirical statistics method, minimum effective pore throat radius method, oil testing method, distribution function curve method, oil occurrence method, irreducible water saturation method, etc. On the basis of calculating the industrial porosity and permeability lower limit of effective reservoir recovery in different burial depth ranges by using the method, relative permeability method, drilling fluid invasion method, porosity-permeability intersection method, productivity simulation experiment method, productivity method, etc. , to fit the functional equation of the lower limit of the industrial porosity (or permeability) of the effective reservoir recovery and the buried depth, and then calculate the lower limit of the industrial physical properties of the effective reservoir recovery at any depth. However, this technology does not consider the influence of pore structure on the lower limit of the porosity of effective reservoir recovery. Under the condition of other factors being the same, due to the different pore structure of the reservoir, the lower limit of industrial permeability of the same effective reservoir corresponds to multiple effective reservoirs. The lower limit of industrial porosity for layer recovery. With the continuous improvement of oil and gas exploration, the accuracy of the lower limit of industrial physical properties of effective reservoir recovery is getting higher and higher, and the existing technical methods can no longer meet the requirements. It is necessary to develop more accurate technology for calculating the lower limit of industrial physical properties of effective reservoir recovery.

Contents of the invention

The purpose of the present invention is mainly aimed at the shortcomings of the prior art, and provides a solution to the problem of the influence of pore structure on the lower limit of industrial porosity in effective reservoir recovery.

The technical solution of the present invention is: a method for obtaining the lower limit of the industrial porosity of effective reservoir recovery under the constraint of pore structure, the steps are as follows:

(1) According to the data of the specific research area, select the calculation method for the lower limit of industrial permeability of effective reservoir recovery suitable for the research area, calculate the lower limit of industrial permeability of effective reservoir recovery in different buried depth ranges, and fit the effective reservoir recovery The functional relationship between the lower limit of industrial permeability and buried depth, and use this functional relationship to find the lower limit of industrial permeability for effective reservoir recovery at any depth;

(2) Use the mercury injection data to classify the pore structure; on the basis of the classification of the reservoir pore structure, respectively fit the functional relationship between K/Φ and K of different pore structure types of reservoirs, and determine each pore structure type K and K/Φ range corresponding to the reservoir;

(3) Substituting the lower limit value of the industrial permeability of effective reservoir recovery obtained at any depth into the functional relationship between K/Φ and K according to the K and K/Φ interval ranges corresponding to reservoirs of different pore structure types, The lower limit of industrial porosity of effective reservoir recovery under the constraint of the pore structure type can be obtained, and then the functional relationship between the lower limit of industrial porosity of effective reservoir recovery and depth of different pore structure types can be established;

Among them: K--permeability, Φ--porosity.

Preferably: the calculation method for the lower limit of the industrial permeability of the effective reservoir production suitable for the research area includes the test method, the empirical statistical method, the minimum effective pore throat radius method, the oil test method, the distribution function curve method, and the oil occurrence method , irreducible water saturation method, relative permeability method, drilling fluid invasion method, porosity-permeability intersection method, productivity simulation experiment method, and productivity method.

The beneficial effects of the present invention are as follows: on the basis of pore structure classification, the present invention obtains the lower limit of industrial porosity of production under the constraints of different pore structure types, and solves the influence of pore structure on the lower limit of industrial porosity of effective reservoir recovery question. Figure 2 shows the result of the lower limit of the industrial physical properties of effective reservoirs obtained by using the existing technology in a certain area, and Figure 3 shows the results of the lower limit of the industrial physical properties of the recovery under the constraints of the pore structure obtained by the present invention. Comparing the two figures, it can be seen that this method obtains different lower limits of industrial porosity for effective reservoir recovery for different pore structure types of reservoirs, thereby improving the accuracy of calculation of the lower limit of industrial porosity for effective reservoir recovery.

Description of drawings

Fig. 1 Technical flow chart for calculating the lower limit of industrial porosity in effective reservoir recovery under the constraint of pore structure

Figure 2 shows the results of the lower limit of industrial physical properties of effective reservoir recovery obtained by using existing technology in a certain area

Fig. 3 is the result of the lower limit of the industrial physical properties of production under the constraint of the pore structure obtained by the present invention

Fig. 4 The relationship between the lower limit of industrial permeability and depth of effective reservoir production in a certain area

Figure 5 The classification of pore structure and the fitting diagram of physical property relationship in a certain area

Fig.6 The lower limit of industrial porosity of effective reservoir recovery under the constraint of pore structure type in a certain area

Detailed ways

The specific embodiment of the present invention is described below in conjunction with accompanying drawing:

Taking the calculation of the lower limit of industrial physical properties of production under the constraint of pore structure in a certain area of Shengli Oilfield as an example to illustrate the specific technical solution of the invention:

Firstly, the lower limit of industrial permeability of effective reservoirs under different buried depths is obtained by using oil testing method, irreducible water saturation method, minimum effective pore throat radius method, and distribution function curve method (Table 1), and the fitting effective reservoir The functional relationship between the lower limit of industrial permeability of reservoir recovery and buried depth (Fig. 4), and use this functional relationship to calculate the lower limit of industrial permeability of effective reservoir recovery at any depth.

Table 1 The lower limit of industrial permeability of effective reservoir recovery under different buried depths in a certain area

method Top depth/m Bottom depth/m Median depth/m Lower limit of permeability/md test method 3000 3400 3200 1 Distribution function method 2500 3000 2750 1.62181 Distribution function method 3000 3500 3250 0.749894209 Minimum pore throat radius method 2500 3200 2850 1.83 oil test method 2900 3100 3000 1 oil test method 3100 3300 3200 1 oil test method 3300 3500 3400 0.51

Second, using the mercury injection data, the pore structure is classified according to the displacement pressure (P _d ) and capillary pressure median (P ₅₀ ), and the relationship between K/Φ and K of reservoirs with different pore structure types is respectively fitted. Functional relationship (Fig. 5), and determine the K and K/Φ intervals corresponding to various pore structure types of reservoirs (Table 2).

Table 2 Permeability range corresponding to different pore structure types in a certain area

Pore Throat Structure Type Permeability range/10 ^-3 μm ² K/Φ range IA ＞228 ＞14.64 IB 2.92-304 0.218-18.077 IIA 0.1-50.48 0.0123-2.723 IIB 0.0289-2.486 0.0056-0.164 IIIA 0.0181-0.97 0.00337-0.109 IIIB ＜0.133 ＜0.105

Thirdly, the lower limit of the industrial permeability of effective reservoir recovery obtained at any depth is substituted into the functional relationship between K/Φ and K according to the K and K/Φ interval ranges corresponding to reservoirs of different pore structure types. The lower limit of industrial porosity for effective reservoir recovery under the constraint of this pore structure type is obtained (Fig. 6).

Claims (2)

1. a pore texture retrains down effective reservoir extraction industry porosity cutoff acquiring method, and described step is following:

(1) according to concrete study area data situation; Select to be fit to effective reservoir extraction industry permeability lower limit computing method of study area; Ask for the effective reservoir extraction industry of different buried depth scope permeability lower limit; The funtcional relationship of effective reservoir extraction industry permeability lower limit of match and buried depth, and utilize this funtcional relationship to obtain the effective reservoir extraction industry permeability cutoff under any degree of depth;

(2) utilize pressure mercury data, carry out the pore texture classification; On the basis of RESERVOIR PORE STRUCTURE classification, simulate the funtcional relationship between different pore structures types of reservoir K/ Φ and the K respectively, and confirm K and K/ Φ interval range that each pore texture types of reservoir is corresponding;

(3) with effective reservoir extraction industry permeability cutoff of being tried to achieve under any degree of depth; K and the K/ Φ interval range corresponding according to the different pore structures types of reservoir; The funtcional relationship of substitution K/ Φ and K; Can try to achieve the effective reservoir extraction industry porosity cutoff under this pore texture type constraint, and then set up the funtcional relationship of the effective reservoir extraction industry porosity cutoff of different pore structures type and the degree of depth;

Wherein: K--permeability, Φ--factor of porosity.

2. the down effective reservoir extraction industry of pore texture as claimed in claim 1 constraint porosity cutoff acquiring method is characterized in that: effective reservoir extraction industry permeability lower limit computing method of described suitable study area comprise that method of testing, empirical statistics method, smallest effective pore throat radius method, formation testing method, distribution function curve method, oil-containing occurrence method, irreducible water saturation method, relative permeability method, drilling fluid invade at least a in method, factor of porosity-permeability intersection, productivity simulation experimental method, the production capacity method.

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