CN104747149A - Detecting method of binary combined flooding agent migration channel - Google Patents

Abstract

The invention provides a detecting method of a binary combined flooding agent migration channel. The detecting method for reflecting the binary combined flooding agent migration degree and the agent migration channel is established to solve the problem that during a crude oil recovery rate improving process through oil field polymer flooding and surface active agent binary combined agents, agent migration exists, so that oil production increasing effect is poor. First, the oil yield and the liquid yield of an oil well and the concentration data of polymers and surface active agents in output liquid are collected, then the comprehensive production agent oil production increasing index is computed, and according to the comprehensive production agent oil production increasing index feature curve shape, the agent migration degree and the agent migration channel are distinguished. Based on practical oil deposit production performance data, detecting on the agent migration channel is easy and reliable, the binary combined flooding agent migration can be well found in time, effective blocking measures are carried out, and the yield-increasing effect of binary combined flooding is further improved.

Description

Detection method for channeling channel of binary compound flooding agent

technical field

The invention relates to a detection method for agent channeling in the process of binary compound flooding oil field development, especially provides a method for agent channeling based on oil field production dynamic data, in order to improve the development effect of binary compound flooding, further Provide technical support for improving recovery of binary compound flooding oilfields.

Background technique

Binary compound flooding is based on conventional water flooding, adding chemical agents (polymers and surfactants) to the injected water, so as to improve the sweep coefficient and oil washing efficiency, and achieve the purpose of enhancing oil recovery. Agent channeling channels in binary compound flooding oil fields are mainly fractures with different degrees of development, high-permeability layers, and high-permeability and large-pore dominant channels formed during the development process. The existence of agent channeling channels leads to the channeling of injected chemical agents (polymers and surfactants) along the high-permeability layer, and breaks through prematurely in the oil well, seriously affecting the oil enhancement effect of chemical flooding. The channeling of chemical agents not only leads to poor production stimulation effect, but also increases the development cost and the difficulty of processing the produced fluid. In order to efficiently utilize the injected chemical agents (polymers and surfactants) to achieve better production stimulation effects, the key problem to be solved is to detect the degree of agent channeling and agent channeling in the oil field.

At present, the detection of binary compound flooding agent channeling has attracted widespread attention at home and abroad, but the research work is mainly focused on the static parameters of the oilfield, the water cut and oil production of the oil well, and the judgment accuracy is low, and it cannot reflect the binary compound flooding channel. Agent channeling characteristics of polymer and surfactant in flooding.

To sum up, in the process of binary compound flooding oilfield development, an effective method has not been established for the detection and characterization of chemical agent channeling channels. In the process of binary compound flooding, due to the existence of agent channeling channels, the oil enhancement effect of chemical agents is seriously affected, and a large amount of chemical agents are displaced along the agent channeling channels with low efficiency along with the injected water. In order to improve the development effect of binary compound flooding and further increase the oil recovery of binary compound flooding, it is necessary to determine the channeling degree and agent channeling, so as to facilitate the implementation of plugging agent channeling measures, so the detection of agent channeling is of great significance.

Contents of the invention

Based on the dynamic change characteristics of binary compound flooding oil well production, the present invention establishes a channel detection technology for binary compound flooding agent channeling, which provides for improving the development effect of binary compound flooding and further improving the recovery rate of binary compound flooding oilfields. Technical Support.

Explanation of terms:

1. Binary compound flooding is effective: after chemical agents (polymers and surfactants) are injected into the formation, the swept volume increases and the oil washing efficiency increases. Therefore, compared with before chemical agent injection, oil production increases after chemical agent injection . When the oil production in a certain month after the injection of the chemical agent is greater than the average monthly oil production in the three months before the injection of the chemical agent, it is considered that binary compound flooding takes effect at this moment.

2. The pore volume multiple of the injected fluid: refers to the ratio of the injected fluid volume to the pore volume, and the symbol is represented by PV. For example, the reservoir pore volume V ₀ =10000m ³ , the injected fluid volume V=40000m ³ , expressed in PV is $\frac{V}{V_0}=\frac{40000}{10000}=4\mathrm{PV}.$

The present invention provides a detection method for the channeling channel of the binary compound flooding agent, which uses the characteristic curve of the comprehensive production agent oil increase index to measure the oil field, specifically:

(1) Collect the oil production rate, liquid production rate, polymer concentration and surfactant concentration in the injection fluid and production fluid of the binary compound flooding oil field at equal time intervals, and inject chemical agents (polymer and surface active agent) from the oilfield at the time interval active agent) start to test;

(2) From the time when binary compound flooding takes effect and the output polymer concentration and surfactant concentration are greater than 0.015 times of the respective injection concentrations, according to the output liquid volume and the output liquid polymer concentration and surfactant concentration, Calculating the equivalent yield and the equivalent yield of surfactant;

The converted polymer production is the ratio of the output polymer concentration to the injected polymer concentration multiplied by the liquid production volume, that is:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; pro</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; inj</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}$

In the formula, V _P —converted polymer production, m ³ ; C _P-pro —polymer concentration in the output liquid, mg/L; C _P-inj —injected polymer concentration, mg/L; V _L —output Liquid volume, m ³ ;

The converted surfactant production amount is the ratio of the output surfactant concentration to the injected surfactant concentration multiplied by the liquid production volume, that is:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; pro</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; inj</span>}}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}$

In the formula, V _S —equivalent surfactant production amount, m ³ ; C _S-pro —surfactant concentration in the produced fluid, %; C _S-inj —injected surfactant concentration, %; V _L —produced fluid Quantity, m ³ ;

(3) Summing the converted aggregate yield and the converted surfactant dose to obtain the converted comprehensive yield;

(4) Calculate the logarithm of the ratio of the comprehensive production amount and the accumulated oil increase to obtain the comprehensive production agent oil increase index;

(5) Taking the comprehensive production agent oil increase index and the pore volume of the injected fluid as the vertical and abscissa plots respectively to obtain the comprehensive production agent oil increase index characteristic curve;

(6) Discriminate the degree of agent channeling and the channel type of agent channeling in the binary compound flooding oilfield according to the shape of the characteristic curve of the comprehensive agent production increase index;

If the characteristic curve of the comprehensive agent production increase index is convex, the degree of agent channeling in the oil field is serious, and there are large-pore type agent channeling channels;

If the characteristic curve of the comprehensive agent production increase index is concave, the degree of agent channeling in the oil field is weak, and there are high-permeability agent channeling channels.

Due to the influence of various uncertain factors, the characteristic curve of oil production increase index obtained is inevitably not smooth, so the curve needs to be smoothed. The commonly used smoothing method is the least squares regression method, which is simple to calculate, but due to errors or human reasons, the regression is not robust. In order to make the data smoothing robust, this patent uses the robust smoothing method to smooth the above data. For the method, please refer to the reference (Cui Dong. A robust and smooth data processing method [J]. Computer Applications, 2008, 28(7), 1678-1680).

It is a routine operation in the daily work of the oilfield to collect the oil production rate, fluid production rate, polymer concentration and surfactant concentration in the injection fluid and the production fluid of the oil well at equal intervals. dose) to the test, the above-mentioned "equal time interval" is preferably one month.

Generally speaking, the existence of agent channeling will lead to significant changes in the dynamic characteristics of production, and these dynamic characteristics will be mainly reflected in the change of comprehensive agent production and oil increase index. It can be speculated that whether or not the oil layer contains channels for agent channeling, as well as different degrees of agent channeling, the change law of agent production increase index will have its own characteristics.

The present invention is based on binary compound flooding oilfield production dynamic data, and establishes a method for detecting agent channeling degree and agent channeling in binary compound flooding oil field. Provide technical support for improving the development effect and further improving the recovery of binary compound flooding oilfields.

Description of drawings

Fig. 1 is the characteristic curve of production agent oil enhancement index of oil well GO7-32-3135.

Fig. 2 is the characteristic curve of the agent production increase index of oil well GO7-32-166.

Detailed ways

The present invention will be described in detail below in conjunction with the embodiments and the accompanying drawings, but it is not limited thereto.

Take the detection method of agent channeling in a binary composite pilot block in Gudao Oilfield as an example. The oil-bearing area of a binary composite pilot test block in Gudao Oilfield is 0.94km ² , the geological reserves are 267×10 ⁴ t, the average oil saturation is 0.72, the average porosity is 0.34, and the air permeability is 3400×10 ^-3 μm ^2. The coefficient of variation of permeability is 0.74. There are 10 injection wells and 14 effective oil wells in this block.

The present invention selects 2 wells in the pilot test area to illustrate the actual application of the agent channel detection method.

Example 1

The following takes oil well 1 as an example to illustrate the process of making the characteristic curve of oil well production agent oil increase index.

From the monthly production report of oil well 1, the liquid production rate, oil production rate, polymer concentration and surfactant concentration were selected to calculate the cumulative oil increase and the equivalent comprehensive production rate, and then to obtain the agent oil increase index, starting from the test area The pore volume multiple of the injected fluid was calculated at the beginning of chemical agent injection, and the composite oil production index and the pore volume of the injected fluid were plotted as the abscissa and vertical coordinates respectively to obtain the characteristic curve of the agent oil increase index (see Fig. 1).

The characteristic curve of comprehensive agent production increase index of oil well 1 is obviously concave as a whole. According to the detection method of the present invention, the degree of agent channeling in this well is weak, and there is a high-permeability agent channeling channel;

Example 2

The steps of making the characteristic curve of production agent oil increase index of oil well 2 are the same as that of oil well 1.

The characteristic curve of oil production increase index of oil well 2 (see Fig. 2) is an obvious convex body on the whole. According to the detection method of the present invention, the degree of agent channeling in this well is serious, and there is a large-pore type agent channeling channel.

Claims (6)

1. alter the detection method of passage for polymer, the agent of surfactant binary combination flooding, it is characterized in that, utilize synthetic obstetric agent to increase oily index characteristic curve and binary combination flooding oil field is measured, comprising:

(1) constant duration collects polymer concentration in the oil production of binary combination flooding oilfield, Liquid output, injection liquid and production fluid and surfactant concentration, the time from chemical agent (polymer and surfactant) is bet in oil field to test;

(2) according to polymer concentration and the surfactant concentration of output liquid measure and production fluid, calculate to amount to produce poly-amount and amount to and produce surfactant amount;

(3) will amount to and produce poly-amount with amounting to and produce surfactant amount and sue for peace and obtain amounting to synthetic obstetric dosage;

(4) synthetic obstetric agent is asked to increase oily index;

(5) increase oily exponential sum with synthetic obstetric agent respectively and inject the pore-body product of fluid for ordinate and abscissa mapping, obtain synthetic obstetric agent and increase oily index characteristic curve;

(6) increase oily index characteristic tracing pattern according to described synthetic obstetric agent, differentiate that the type that passage is altered in degree and agent is altered in the agent in binary combination flooding oil field;

It is convex that described synthetic obstetric agent increases oily index characteristic tracing pattern, then oil field agent alters degree seriously, there is the agent of macropore channel type and alters passage;

It is spill that described synthetic obstetric agent increases oily index characteristic tracing pattern, then to alter degree weak in oil field agent, exists highly to ooze type agent and alter passage.

2. the detection method of passage is altered in binary combination flooding agent as claimed in claim 1, it is characterized in that, amount to and produce poly-amount and amount to that to produce surfactant amount be calculate from when binary combination flooding takes effect and output polymer concentration and surfactant concentration are all greater than 0.015 times of respective implantation concentration.

3. the detection method of passage is altered in binary combination flooding agent as claimed in claim 1, it is characterized in that, amounts to that to produce poly-amount be that the ratio of output polymer concentration and injection of polymer concentration is multiplied by Liquid output, that is:

$V_P=\frac{C_{P-\mathrm{pro}}}{C_{P-\mathrm{inj}}}\&times;V_L$

In formula, V _p-amount to and produce poly-amount, m ³; C _p-propolymer concentration in-production fluid, mg/L; C _p-inj-injection of polymer concentration, mg/L; V _l-output liquid measure, m ³.

4. the detection method of passage is altered in binary combination flooding agent as claimed in claim 1, it is characterized in that, amounting to product surfactant amount is that output surfactant concentration is multiplied by Liquid output with the ratio injecting surfactant concentration, that is:

$V_S=\frac{C_{S-\mathrm{pro}}}{C_{S-\mathrm{inj}}}\&times;V_L$

In formula, V _s-amount to and produce surfactant amount, m ³; C _s-prosurfactant concentration in-production fluid, %; C _s-inj-inject surfactant concentration, %; V _l-output liquid measure, m ³.

5. the detection method of passage is altered in binary combination flooding agent as claimed in claim 1, and it is characterized in that, it is the logarithm amounting to synthetic obstetric dosage and tired oil increment ratio that synthetic obstetric agent increases oily index.

6. the detection method of passage is altered in binary combination flooding agent as claimed in claim 1, it is characterized in that, also comprises and the synthetic obstetric agent obtained in (4) is increased the step that oily index characteristic curve carries out sane smooth treatment.