CN103233730B - Experimental measurement method for resistivity of mixed stratum water in rock core displacement process - Google Patents

Abstract

The invention provides an experimental measurement method for resistivity of mixed stratum water in a rock core displacement process. The resistivity of the mixed stratum water in the rock core displacement process is obtained by utilizing relative permeability and resistivity co-measurement device and utilizing mixed stratum water discrete sampling and proportion dilution and resistivity measurement method measurement. According to the mixed stratum water discrete sampling, a measuring cylinder is adopted to obtain oil-water mixed liquid samples by discretization and a centrifugation method is adopted to separate oil-water so as to calculate an oil outflow volume and water outflow volume by accumulation; according to the proportion dilution and resistivity measurement, distilled water is added into the centrifugally purified mixed stratum water according to some proportion to enable the volume of the mixed stratum water to be large enough so as to meet the requirements of an electrolyte solution resistivity measurement device measuring the resistivity, and then the resistivity is converted into the resistivity prior to dilution so as to finally determine the resistivity of the mixed stratum water. Through the experimental measurement method, the shortcomings in an existing measurement device are overcome, and the resistivity of the mixed stratum water is obtained by accurate measurement.

Description

The experimental measurement method that mixes formation water resistivity in a kind of rock core displacement process

Affiliated technical field

The invention belongs to expeimental physics measuring technology, relate to a kind of experimental measurement method that mixes formation water resistivity in rock core water drive oil process.

Technical background

At secondary phase of oil production, during field produces, can inject fresh water, salty sewage to keep stratum energy to oil-gas Layer, the result of water filling can cause reservoir water flooding and its resistivity is changed.For can the qualitative identification of application of electrical measurement well data and quantitative assessment Water Flooding Layer, laboratory often adopts the mode of water drive oil plunger rock sample to be carried out to the change mechanism research of Water Flooding Layer resistivity, and emphasis is to investigate Water Flooding Layer resistivity with producing water ratio (corresponding water logging stage), water saturation, the isoparametric Changing Pattern of mixing formation water resistivity.

At present, the experimental facilities that the research of Water Flooding Layer resistivity response mechanism adopts is equivalent to relative permeability and resistivity translocation device, referring to Fig. 1, combines the measurement of plunger sample resistivity on the basis that measuring process is equivalent to measure in relative permeability.Wherein: the metering of water saturation, producing water ratio and plunger sample resistivity realizes than being easier to, but be just difficult for realizing as the experiment measuring of the mixing formation water resistivity of one of plunger sample resistivity effects factor.First, be difficult for obtaining interference-free mixing formation water water sample.Main cause is while adopting existing apparatus to carry out experiment, displacement starts the mixing formation water of back-plunger sample inside and the initial condition before displacement (for water-oil separating and accurate-metering producing water ratio and saturation ratio, need to retain in the oil water separator the inside of the displacement port of export prime stratum water of certain volume) and the displacement formation water of discharging communicate, the mixing formation water water sample directly extracting in water-oil separating pipe is with injected water volume (pore volume injected of commonly using rock sample defines), producing water ratio, resistivity can not be corresponding well.That measurement mixing resistivity of water is more difficult on the other hand, main cause is that the mixing water volume (1ml at most) of the discharge of (particularly early stage) corresponding a certain producing water ratio, resistivity in displacement process is limited, is difficult to meet the needs of mixing water resistivity measurement.

At present, the experimental measurement method that mixes formation water resistivity in a kind of rock core displacement process is not yet developed in laboratory.Owing to not obtaining the mixing formation water resistivity in watering-out process by Measurement accuracy, be difficult to quantitative expedition water logging on the impact of mixing water resistivity and Water Flooding Layer resistivity the Changing Pattern with water saturation, greatly affected the order of accuarcy of the qualitative identification of application of electrical measurement well data and quantitative assessment Water Flooding Layer.

Summary of the invention

The object of the invention is to provide the experimental measurement method that mixes formation water resistivity in a kind of rock core displacement process on the basis that does not affect relative permeability and resistivity measurement.

Concrete design philosophy is to do technological improvement on the basis of existing relative permeability and resistivity translocation apparatus and method, and application under the prerequisite that does not affect the parameter measurements such as producing water ratio, relative permeability, resistivity, saturation ratio " mixes formation water discrete sampling " and " dilution proportion and resistivity measurement " method comes experiment measuring to obtain mixing formation water resistivity in rock core displacement process.Wherein: " mixing formation water discrete " sampling no longer adopts the oil water separator of usual means shown in Fig. 1 and balance " continuously " to measure oil volume and water outlet volume, but adopt graduated cylinder " discrete " to obtain oil-water mixture sample, be aided with the separated profit of centrifugal method and come cummulative metering to go out oil volume and water outlet volume part, referring to Fig. 2, thereby realize the object that " discrete " extracts the mixing stratum water sample corresponding with injecting volume, producing water ratio, plunger sample resistivity, can effectively avoid the interference of the formation water of initial condition before displacement and the discharge of displacement in advance; " dilution proportion and resistivity measurement " is to the mixing formation water of centrifugal purification, to add distilled water to make its volume enough large to meet the needs of electrolyte solution resistivity test device measured resistivity in a certain ratio, and then the resistivity being converted into before dilution is mixed formation water resistivity finally to determine.Above-mentioned technology path can overcome the drawback that existing measurement mechanism exists, and accurately measures and mixes stratum resistivity of water.

Be implemented as follows:

First, change and oil volume, water outlet volume metering mechanism and method of measurement and purify to mix stratum water sample, this be the inventive method be achieved basic.Specific implementation is: 1) shorten the length of rock core port of export pipeline, to reduce residual liquid in port of export pipeline dead volume to mixing the interference of formation water and to going out the measure error of oil volume and water outlet volume as far as possible; 2) do not re-use oil water separator and electronic balance and measure oil volume and water outlet volume, change into and use one group of precision for 0.025mL graduated cylinder " discrete " collection profit; 3) adopt the separated profit of centrifugal method to obtain mixing stratum water sample with the go out oil volume and water outlet volume purification obtaining sometime.

Secondly, the mixing stratum water sample that uses distilled water to obtain different time is diluted to the measurement requirement that can meet salt solution resistivity test device, uses Fig. 3 shown device to measure the rear stratum resistivity of water that mixes of dilution.

Finally, according to dilution ratio inverse, obtain diluting front mixing stratum resistivity of water.

Accompanying drawing explanation

Fig. 1 shows the Experimental equipment that current Water Flooding Layer resistivity response mechanism research adopts;

Fig. 2 shows relative permeability according to an embodiment of the invention and resistivity translocation setting drawing;

Fig. 3 is the salt solution resistivity test device figure of prior art;

Fig. 4 is the experimental measurement method flow chart of rock core displacement test resistivity of mixed according to one embodiment of present invention.

The specific embodiment

Below in conjunction with accompanying drawing, by embodiment, describe technology of the present invention and feature in detail, but these embodiment are not intended to limit protection scope of the present invention.

The experiment measuring that mixes formation water resistivity in the rock core displacement process in example 1:GD oil field

1 ^#rock core underlying parameter is L=49.18mm; D=24.97mm; Φ=34.89%; K=1086mD.After connecting experimental facilities according to the device schematic diagram shown in Fig. 2, start experiment measuring, operating procedure is as follows:

(1) the water sample rock core of satisfying is inserted Hassler clamper oil and is driven prime stratum water (3000mg/l) to irreducible water state, determines that irreducible water saturation is 26.1%, and measuring formation water resistance is 1.88 Ω m (during measurement, room temperature is 22 ℃);

(2) measure oil phase effective permeability under irreducible water state, three results of METHOD FOR CONTINUOUS DETERMINATION are 299.80mD, 299.98mD, 298.06mD, relative error is less than 3%, meets the requirement of two-phase relative permeability assay method > > in standard < < SY/T5345-2007 rock;

(3) change the fluid line between intermediate receptacle and intermediate receptacle and Hassler clamper, change and use the salt solution that salinity is 14000mg/l to start displacement test, and use graduated cylinder to collect the profit liquid of discharging, record the experiment parameters such as experimental period, liquid outlet quantity, oil pump capacity, displacement pressure simultaneously;

(4) in (port of export is shown in water droplet) time-out experiment constantly of water breakthrough point, stop timing, accurate recording water breakthrough time, oil pump capacity;

(5) change the graduated cylinder of collection liquid, every fuel-displaced 0.2ml left and right gathers mixed liquor sample once.After sample collection, experiment suspends, and stops timing.With centrifuge, the mixed liquor sample gathering is done to water-oil separating and process, the parameters such as the producing water ratio of experiment with computing sample, oil productivity, extract certain volume V ₁(ml) mixing stratum water sample.

(6) the mixing formation water after separation is arrived to certain volume V with distilled water diluting ₂(ml), with the resistivity test device of salt solution shown in Fig. 3, measure its resistance r (Ω) at a certain temperature, utilize calibrated curve electrode coefficient k (resistance r and resistivity R at a certain temperature calculates k=R/r by normal solution) that mixing stratum water resistance r is converted into resistivity R, utilize Schlumberger formula (formula 1) to calculate the salinity C of the rear solution of dilution _w2, then according to formula C ₁=V ₂* C _w2/ V ₁before calculating dilution, mix formation water salinity C ₁after (before and after dilution, the principle that solion sum is constant), according to Schlumberger formula, calculate under uniform temperature and mix stratum resistivity of water R _wz

$R_{\mathrm{wz}}=\frac{1+\frac{3*{10}^5}{{C_{\mathrm{wz}}}^{1/1.05}}}{1.8*T+39}---\left(1\right)$

In formula, C _wzfor salt water salinity, mg/L; R _wzfor resistivity of mixed, Ω m;

(7) change the graduated cylinder of collection liquid, restart to test and continue timing.In experimentation, during 4 times of oil productivity of producing water ratio <, repeating step 5)-6);

(8), when 4 times of oil productivity of producing water ratio >, adjusting the sampling interval is that every fluid 20ml left and right gathers mixed liquor sample 1ml.After collected specimens, experiment suspends, and stops timing.The parameter such as the producing water ratio of calculation sample, oil productivity, does water-oil separating to the sample gathering and processes during this time, and to isolated saline solution measured resistivity;

(9), when fluid moisture content reaches 99.95% or after filling liquid volume is 30 times of voids volumes, displacement test finishes, measure the water phase permeability under residual oil;

(10) experimental data is carried out data processing with reference to two-phase relative permeability assay method > > in industry standard < < SY/T5345-2007 rock, finally can obtain moisture content, oil (water) relative permeability with the Changing Pattern of water saturation, the parameters (in Table 1) such as moisture content when the simultaneously corresponding sampling time can be determined collected specimens and water saturation.

Table 1 GD oil field 1 ^#rock core mixing formation water resistivity experimental measurements (22 ℃)

Illustrate: before displacement, mixing formation water is prime stratum water; Experiment is last, due to " salinize " of water, mixes formation water and has become injected water.

The experiment measuring that mixes formation water resistivity in the rock core displacement process in example 2:DB oil field

2 ^#rock core underlying parameter is L=46.61mm; D=24.71mm; Φ=24.89%; K=141mD.After connecting experimental facilities according to the device schematic diagram shown in Fig. 2, start experiment measuring, concrete operation step is as follows:

(1) the water sample rock core of satisfying is inserted Hassler clamper oil and is driven prime stratum water (3000mg/l) to irreducible water state, determines that irreducible water saturation is 35.5%, and measuring formation water resistance is 1.83 Ω m (during measurement, room temperature is 23 ℃);

(2) measure oil phase effective permeability under irreducible water state, three results of METHOD FOR CONTINUOUS DETERMINATION are 163.68mD, 159.85mD, 160.57mD, relative error is less than 3%, meets the requirement of two-phase relative permeability assay method > > in standard < < SY/T5345-2007 rock;

Residue experimental procedure is identical with example 1, and experimental measurements is in Table 2.

Table 2 DB oil field 2 ^#rock core mixing formation water resistivity experimental measurements (23 ℃)

Illustrate: before displacement, mixing formation water is prime stratum water; Experiment is last, due to " salinize " of water, mixes formation water and has become injected water.

The foregoing is only embodiments of the invention, not in order to limit the present invention, all any modifications of making within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Reference numeral:

1, constant speed and constant pressure pump;

2, fluid line;

3, intermediate receptacle;

4, pressure meter;

5, Hassler clamper;

6, intelligent LCR measuring;

7, power lead;

8, valve;

9, oil water separator

10, electronic balance

11, constant speed and constant pressure pump;

12, fluid line;

13, intermediate receptacle;

14, pressure meter;

15, Hassler clamper;

16, intelligent LCR measuring;

17, power lead;

18, valve;

19, graduated cylinder some (5ml or 10ml);

20, intelligent LCR measuring;

21, power lead;

22, salt solution clamper

Claims (2)

1. in a rock core displacement process, mix the experimental measurement method of formation water resistivity, by utilizing relative permeability and resistivity translocation device to adopt mixing formation water discrete sampling and dilution proportion and method of measuring resistivity to measure in rock core displacement process, mix formation water resistivity, it is characterized in that:

Described mixing formation water discrete sampling adopts the discrete oil-water mixture sample of obtaining of graduated cylinder to be aided with the separated profit of centrifugal method and to come cummulative metering to go out oil volume and water outlet volume part, described dilution proportion and resistivity measurement are to the mixing formation water of centrifugal purification, to add distilled water to make its volume enough large to meet the needs of electrolyte solution resistivity test device measured resistivity in a certain ratio, and then the resistivity being converted into before dilution is mixed formation water resistivity finally to determine.

2. experimental measurement method according to claim 1, described method further comprises:

First, change and oil volume, water outlet volume metering mechanism and method of measurement and purify and mix stratum water sample, specific implementation step comprises:

1) shorten the length of rock core port of export pipeline, to reduce residual liquid in port of export pipeline dead volume to mixing the interference of formation water and to going out the measure error of oil volume and water outlet volume;

2) use one group of precision for 0.025mL graduated cylinder " discrete " collection profit;

3) adopt the separated profit of centrifugal method to obtain mixing stratum water sample with the go out oil volume and water outlet volume purification obtaining sometime;

Secondly, the mixing stratum water sample that uses distilled water to obtain different time is diluted to the measurement requirement that can meet salt solution resistivity test device;

Finally, according to dilution ratio inverse, obtain diluting front mixing stratum resistivity of water.