CN103233726B - Experimental calibration method of saturation degree and water production rate logging evaluation model of water-flooded layer - Google Patents

Abstract

The invention provides an experimental calibration method, that is, adopting the method of joint measurement of unsteady relative permeability (simulating the process of water-flooded oil layer) and resistivity to simultaneously measure the water production rate, saturation, and water resistance of the mixed formation during the water-flooded process of the oil layer rate, rock sample resistivity, and statistical regression to determine the experimental statistical relationship and key coefficients between water production rate-saturation, water production rate-mixed formation water resistivity (salinity), resistivity-saturation, and serve water Logging evaluation of water production rate and saturation in flooded reservoirs.

Description

An Experimental Calibration Method for Logging Evaluation Model of Water-flooded Layer Saturation and Water Production Rate

technical field

The invention belongs to experimental physics testing technology, relates to a kind of experimental calibration method of the resistivity variation mechanism of the experimental calibration resistivity of water-flooded reservoir saturation, water production rate logging evaluation, can be directly used in oilfield water-flooded layers (fresh water flooded, salty water flooded, etc.) Quantitative evaluation of water flooding) saturation and water production rate. the

technical background

At present, the calculation model of water production rate of water-flooded oil layer is mainly based on the relative permeability curve to establish the equation based on the shunt equation. In specific use, electrical logging is often used to calculate the water saturation of water-flooded oil layer according to the Archie formula to determine the relative permeability. After the oil layer is flooded, the general rule is: the water saturation increases, the resistivity of the mixed formation water increases (fresh water flooding) or decreases (salt water flooding), the water production rate increases, and the saturation index n increases with the water saturation The resistivity of the core shows a monotonous decrease (salt water flooding) or a "V" or "S" shape and other non-monotonic (fresh water flooding) changes. Studies have found that there are functions or experimental statistical relationships between water production rate-saturation, water production rate-mixed formation water resistivity (salinity), and resistivity-saturation in water-flooded oil layers, which can be used for water production in water-flooded oil layers. Well logging evaluation of rate and saturation. the

At present, limited by the level of understanding or experimental ability, different laboratories often only carry out experimental measurements of relative permeability or resistivity of water-flooded oil formations alone, and cannot accurately measure the resistivity of mixed formation water during water-flooding, so it is difficult to establish Function or experimental statistical relationship between water production rate-saturation, water production rate-mixed formation water resistivity (salinity), resistivity-saturation of water-flooded oil layer to meet water-flooded oil layer water production rate and saturation well logging evaluation. the

Contents of the invention

The purpose of the present invention is to provide a water-flooded reservoir water production rate, an experimental calibration method for the saturation logging evaluation model, that is, to simultaneously measure the unsteady state relative permeability (simulating the water-flooded reservoir process) and resistivity joint measurement Water production rate, saturation, mixed formation water resistivity, and rock sample resistivity during the water flooding process of oil layers, statistical regression to determine water production rate-saturation, water production rate-mixed formation water resistivity (salinity), resistivity The experimental statistical relationship and key coefficients between rate and saturation are used for logging evaluation of water production rate and saturation in water-flooded oil layers. the

The experimental calibration method uses an unsteady-state water flooding oil relative permeability and core resistivity joint measurement device, and the device adopts the unsteady-state relative permeability and resistivity joint measurement method to simultaneously measure the water production rate during the water flooding process of the oil layer , saturation, mixed formation water resistivity, rock sample resistivity, statistical regression to determine the experimental statistical relationship and key coefficients between water production rate-saturation, water production rate-mixed formation water resistivity, resistivity-saturation, Described method specifically comprises the following steps:

1) Measure the resistivity of the saturated water sample and record it as R _o , and calculate the formation factor F according to the formula (1) to obtain the cementation index m;

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&Phi;</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

2) Put the water-saturated sample in the Hassler holder, and the oil drives the water to the state of irreducible water, and determine the irreducible water saturation Swi;

3) Measure the effective permeability of the oil phase in the state of bound water, measure three times continuously, and the relative error is less than 3%;

4) According to "SY/T5345-2007 Method for Determination of Relative Permeability of Two Phases in Rocks", set the initial pressure of water flooding and oil displacement;

5) Start the displacement experiment, and record the experimental parameters such as the experimental time, liquid output, oil output, and displacement pressure at the same time;

6) At the moment of water breakthrough, that is, when there are water droplets at the outlet, accurately record the water breakthrough time and oil output;

7) After the water breakthrough point occurs, collect a sample of mixed formation water every 0.2ml of oil. After collecting the sample, the experiment is suspended and the timing is stopped. After the resistivity is stable, the rock sample resistivity is measured, and the water production rate of the experimental sample is calculated during this period. , oil production rate, the collected mixed formation water samples are separated from oil and water, and the separated brine solution is doubled and diluted to measure the resistivity of the mixed formation water;

8) Replace the graduated cylinder for collecting liquid, resume the experiment, and continue timing. When the water production rate is less than 4 times the oil production rate, repeat step 7);

9) When the water production rate is greater than 4 times the oil production rate, adjust the sampling interval to collect 1ml of the mixed solution sample for every 20ml of liquid output. After the sample is collected, the experiment is paused, the timing is stopped, and the resistivity of the rock sample is measured after the resistivity is stable. Measure the resistivity of the mixed formation water after doubling the diluted brine solution;

10) When the water content of the discharged liquid reaches 99.95% or when the volume of the injected liquid is 30 times the pore volume, the displacement experiment ends, and the water phase permeability under the residual oil is measured;

11) Through data processing, the experimental statistical relationship between water cut, oil (water) relative permeability and water saturation can be finally obtained;

12) Observing water production rate and mixed formation water resistivity statistics to establish experimental statistical relationship;

13) Observing the resistivity of rock samples, resistivity of mixed formation water and water saturation to determine the saturation index. the

Among them, the experimental method of mixed formation water resistivity (salinity) is particularly important. On the one hand, it is necessary to use it to establish the experimental statistical relationship with water production rate, so as to organically combine the relative permeability curve and resistivity logging; on the other hand, it is also necessary to use it to investigate the relationship between saturation index n Water production rate or oil displacement efficiency index characterization and division) changes. The experimental measurement method of mixed formation water resistivity (salinity) during water flooding belongs to the prior art in this field, and will not be discussed in detail herein. the

Description of drawings

Figure 1 shows the unsteady-state water flooding oil relative permeability and core resistivity joint measurement device;

Figure 2 shows a diagram of the mixed formation water resistivity measurement device;

Fig. 3 shows the flow chart of the experimental calibration method of the water-flooded reservoir water production rate and saturation logging evaluation model according to the present invention;

Fig. 4 has shown GD oilfield water cut and water saturation intersection figure according to the present invention;

Fig. 5 shows the GD oilfield mixed formation water resistivity and the water cut intersection diagram according to the present invention;

Fig. 6 shows the GD oilfield resistance increase rate and saturation cross diagram according to the present invention;

Fig. 7 shows DX oil field water cut and water saturation intersection figure according to the present invention;

Fig. 8 shows the DX oilfield mixed formation water resistivity and the water cut intersection diagram according to the present invention;

Fig. 9 shows a cross plot of resistance increase rate and saturation in DX oil field according to the present invention. the

Detailed ways

The techniques and characteristics of the present invention will be described in detail below through examples in conjunction with the accompanying drawings, but these examples are not intended to limit the protection scope of the present invention. the

Example 1

Taking the core of GD Oilfield as an example, the salinity of the original formation water in the reservoir is 3000mg/L, and the salinity of the injected water is 14000mg/L. Experimental measurement is carried out after sampling. The specific operation steps are as follows:

1) Measure the resistivity of the saturated water sample and record it as R ₀ , and calculate the formation factor F according to formula (1) to obtain the cementation index m.

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&Phi;</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

2) Flood the water-saturated sample oil to the state of irreducible water, and determine the irreducible water saturation Swi. the

3) Measure the effective permeability of the oil phase in the state of bound water, measure three times continuously, and the relative error is less than 3%. the

4) Connect the experimental device according to the schematic diagram of the device shown in Figure 1. According to "SY/T5345-2007 Method for Determination of Relative Permeability of Two Phases in Rocks", set the initial displacement pressure. the

5) Start the displacement experiment, and record the experiment time, liquid output, oil output, displacement pressure and other experimental parameters at the same time. the

6) At the moment of water breakthrough (there are water droplets at the outlet), accurately record the water breakthrough time and oil output. the

7) After the water breakthrough point occurs, collect a sample of the mixed formation water for every 0.2ml of oil produced. After the sample was collected, the experiment was suspended, the timing was stopped, and the resistivity of the rock sample was measured after the resistivity was stable. During this period, parameters such as water production rate and oil production rate of the experimental samples were calculated, oil-water separation was performed on the collected mixed formation water samples, and the separated brine solution was doubled and diluted to measure the resistivity of the mixed formation water. the

8) Replace the graduated cylinder for collecting the liquid, resume the experiment, and continue timing. When the water production rate is less than 4 times the oil production rate, repeat step 7). the

9) When the water production rate > 4 times the oil production rate, adjust the sampling interval to collect 1 ml of the mixed solution sample for every 20 ml of liquid output. After the sample was collected, the experiment was suspended, the timing was stopped, and the resistivity of the rock sample was measured after the resistivity was stable. During this period, parameters such as water production rate and oil production rate of the experimental samples were calculated, oil-water separation was performed on the collected mixed formation water samples, and the separated brine solution was doubled and diluted to measure the resistivity of the mixed formation water. the

10) When the water content of the discharged liquid reaches 99.95% or the injected liquid volume is 30 times the pore volume, the displacement experiment ends, and the water phase permeability under the residual oil is measured. the

11) The experimental data is processed with reference to the national standard "SY/T5345-2007 Method for Determination of Two-phase Relative Permeability in Rocks", and finally the experimental statistical relationship f _w of water content, oil (water) relative permeability and water saturation can be obtained =f(S _w ). In this example, the experimental statistical relationship is f _w =0.5488ln(Sw)+1.1219, and the coefficient is R ² =0.87 (see FIG. 4 ).

12) Establish the experimental statistical relationship from the experimentally observed water production rate and mixed formation water resistivity statistics, in the form of R _w =f(f _w ). In this example, the experimental statistical relationship is R _w =1.1537f _w ² -2.4326f _w +1.8215, and the coefficient is R ² =0.95 (see FIG. 5 ).

13) The saturation index n is determined from the experimentally observed rock sample resistivity, mixed formation water resistivity and water saturation, and the experimental statistical relationship is established from the experimentally observed water production rate and saturation index, in the form of n=f(f _w ). In this example, the water production rate is not related to the saturation index n, and the saturation index n is determined to be 1.61 (see Figure 6). Saturation index n determination method:

Example 2

The salinity of the original formation water in the DX oilfield reservoir is 4200mg/L, and the salinity of the injected water is 10000mg/L. The core is selected for experimental measurement. The specific operation steps are the same as in Example 1, and the experimental data processing is the same as in Example 1. Finally, the experimental statistical relationship between water content and water saturation is obtained as f _w =0.4868ln(Sw)+1.0856, and the coefficient is R ² =0.96 (see Figure 7). The experimentally observed water production rate and the mixed formation water resistivity establish a statistical relationship as R _w =0.7137f _w ² -1.5902f _w +1.466, and the coefficient is R ² =0.97 (see Figure 8). The resistivity of rock samples, resistivity of mixed formation water, water saturation and saturation index n were observed experimentally, and the saturation index n was determined to be 1.65 (see Figure 9).

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention within. the

Reference signs:

1. Constant speed and constant pressure pump;

2. Fluid pipeline;

3. Intermediate container;

4. Pressure gauge;

5. Hassler gripper;

6. Intelligent LCR measuring instrument;

7. Power wire;

8. Valve;

9. Several measuring cylinders (5ml or 10ml);

11. Intelligent LCR measuring instrument;

12. Power wire;

13. Salt water holder.

Claims (1)

1. An experimental calibration method, used for water-flooded reservoir water production rate, experimental calibration of saturation logging evaluation model, characterized in that, the method adopts unsteady state water flooding oil relative permeability and core resistivity joint measurement device , the device measures the water production rate, saturation, mixed formation water resistivity, and rock sample resistivity in the oil layer water flooding process simultaneously by means of joint measurement of unsteady relative permeability and resistivity, and statistical regression determines the water production rate -Saturation, water production rate-mixed formation water resistivity, resistivity-experimental statistical relationship and key coefficient between saturation, the method specifically includes the following steps: 1) Measure the resistivity of the saturated water sample and denote it as R _o , and calculate the formation factor F according to the formula (1) to obtain the cementation index m; (1) 2) Put the water-saturated sample in the Hassler holder, oil drives the water to the state of bound water, and determines the saturation of bound water; 3) Measure the effective permeability of the oil phase in the state of bound water, three times in a row, and the relative error is less than 3%; 4) According to "SY/T5345-2007 Method for Determination of Relative Permeability of Two Phases in Rocks", set the initial pressure of water flooding and oil displacement; 5) Start the displacement experiment, and record the experimental parameters such as the experimental time, liquid output, oil output, and displacement pressure at the same time; 6) At the moment of water breakthrough, that is, when there are water droplets at the outlet, accurately record the water breakthrough time and oil output; 7) After the water breakthrough point occurs, collect a mixed formation water sample once every 0.2ml of oil is produced. After the sample is collected, the experiment is suspended and the timing is stopped. After the resistivity is stable, the resistivity of the rock sample is measured, and the water production rate of the experimental sample is calculated during this period. , Oil production rate, the collected mixed formation water samples are separated from oil and water, and the separated brine solution is doubled and diluted to measure the resistivity of the mixed formation water; 8) Replace the graduated cylinder for collecting liquid, resume the experiment, and continue timing. When the water production rate is less than 4 times the oil production rate, repeat step 7); 9) When the water production rate is greater than 4 times the oil production rate, adjust the sampling interval to collect 1ml of the mixed solution sample for every 20ml of liquid output. After collecting the sample, the experiment is suspended and the timing is stopped. After the resistivity is stable, the rock sample resistivity is measured. Calculate the water production rate and oil production rate parameters of the experimental samples, conduct oil-water separation treatment on the collected mixed formation water samples, and measure the resistivity of the mixed formation water after doubling the separated brine solution; 10) When the water content of the discharged liquid reaches 99.95% or when the injected liquid volume is 30 times the pore volume, the displacement experiment is over, and the water phase permeability under the residual oil is measured; 11) Through data processing, the experimental statistical relationship between water cut, oil and water relative permeability and water saturation can be finally obtained as ; 12) Observing the water production rate and the mixed formation water resistivity statistics to establish the experimental statistical relationship as ; 13) Observing the resistivity of rock samples, mixed formation water resistivity and water saturation, it is determined that the saturation index n is 1.61, wherein the saturation index n passes to make sure.