Method for testing and analyzing liquid production profile of fractured horizontal well

Abstract

The invention discloses a method for testing and analyzing a liquid production profile after horizontal well fracturing. The method comprises the following steps that S1, after an oil well is fractured, well shut-in and pressure reduction are conducted; s2, oil well pretreatment is conducted, and downhole pressure is recorded into a well and communicated with a wellhead; s3, oil nozzles of different specifications are selected for open flow, the open flow liquid amount and the water content value are obtained, and the temperature value T1 and the liquid amount Q1 of the distribution point of the underground pressure gauge of each horizontal section are obtained; s4, closing the well for 12 hours, and collecting temperature data Ti within 12 hours; s5, an oil nozzle with a large specification is selected for open flow, and temperature data T2 and the liquid amount Q2 are obtained; s6, closing the well for 12 hours, and collecting temperature data Tu within 12 hours; and S7, determining the liquid production capacity and the oil production capacity of each horizontal section. The method avoids using an underground pressure gauge to monitor the underground temperature and convert the underground temperature into the liquid production profile, and reduces the cost of the coiled tubing carrying the optical fiber to enter the well.

Description

Technical Field

[0001] This invention belongs to the technical field of horizontal well fracturing effect evaluation, specifically relating to a method for testing and analyzing the production profile after horizontal well fracturing. Background Technology

[0002] Horizontal well fracturing is a very common and effective method for developing oil and gas reservoirs. However, there is interference between the fracturing well and the drilling and production wells during the fracturing process. In addition, horizontal well development of oil and gas reservoirs involves many segments and clusters, and the dynamic patterns of the profile are unclear. Inappropriate production systems make it difficult to achieve efficient development of oil and gas reservoirs.

[0003] Currently, distributed temperature monitoring systems are mainly used both domestically and internationally. Specifically, this involves sending multiple laser pulses per second into an optical fiber. As the laser pulses travel along the fiber, they strike the fiber wall, generating backscattered light that returns to the DTS (Distributed Temperature Detection and Retrieval) data acquisition system. The DTS system contains a built-in optical receiver that detects the returned scattered light signal. This backscattered light is the result of the interaction between the transmitted laser pulses and the fiber molecules. This signal is then processed to determine its temperature at a specific depth. However, this method is relatively simple, and the cost of using such a monitoring system is quite high. Summary of the Invention

[0004] The purpose of this invention is to provide a method for testing and analyzing the production profile of horizontal wells after fracturing, which solves the technical problems of the current single method and high testing cost for testing the production profile of horizontal wells.

[0005] The technical solution adopted in this invention is a method for testing and analyzing the produced fluid profile after horizontal well fracturing, specifically including the following steps:

[0006] S1, After fracturing the oil well, shut in the well to reduce pressure;

[0007] S2, pretreatment of oil wells, inserting downhole pressure gauges into the well and connecting them to the wellhead;

[0008] S3. Based on the wellhead pressure value, different specifications of nozzles are selected for venting to obtain the venting fluid volume and water content. At the same time, the temperature value T1 and fluid volume Q1 of the downhole pressure gauge distribution points in each horizontal section are obtained.

[0009] S4, well shut in for 12 hours, temperature data collected for 12 hours, with the most stable set of temperature values ​​being T. i ;

[0010] S5, select an oil nozzle one size larger than that in S3 for venting, and collect temperature data T2 and liquid volume Q2.

[0011] S6, well shut in for 12 hours, temperature data collected for 12 hours; one set of relatively stable temperature values ​​is T. u ;

[0012] S7. Based on the temperature values ​​and liquid volume obtained from S3-S6, determine the liquid production and oil production of each horizontal section.

[0013] The invention is further characterized by:

[0014] When the pressure at the wellhead of S1 is reduced to less than 3.5 MPa, the pressure reduction should be stopped.

[0015] S2 specifically involves: flushing the well with sand using coiled tubing, inserting a downhole pressure gauge into the well and placing it at the center of the radial perforation section, connecting the tool tubing to the downhole pressure gauge and the pump line to the wellhead.

[0016] In S3:

[0017] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours.

[0018] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours.

[0019] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is less than 5 * the number of horizontal sections; then successively replace with a 6 mm nozzle, an 8 mm nozzle, and a 10 mm nozzle for venting until the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal sections. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours;

[0020] When the wellhead pressure is <2.5 MPa, first use a 6 mm nozzle for venting. When the equivalent 24-hour production is less than 5 * the number of horizontal sections, then successively replace with 8 mm and 10 mm nozzles for venting until the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal sections. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours.

[0021] S5 specifically refers to:

[0022] If a 4mm nozzle is used for venting in S3, a 6mm nozzle will be used for venting after the well is shut in for 12 hours.

[0023] If a 6mm nozzle is used for venting in S3, then an 8mm nozzle will be used for venting after the well is shut in for 12 hours.

[0024] If an 8mm nozzle is used for venting in S3, then a 10mm nozzle will be used for venting after the well is shut in for 12 hours.

[0025] If a 10mm nozzle is used for venting in S3, the 10mm nozzle will still be used for venting after the well is shut in for 12 hours.

[0026] S7 specifically refers to:

[0027] Take the average value T of the temperature baseline values ​​of each segment. ia =(T i +T u ) / 2;

[0028] Take the average value T of the measured temperature values ​​of each segment. am = (T1+T2) / 2; Take the discharge volume Q = (Q1+Q2) / 2;

[0029] but:

[0030] The liquid production volume of each stage is:

[0031] Oil production per segment Q o =Q i ×f w ×100%.

[0032] The relatively stable set of temperature values ​​between S4 and S6 is specifically the stable temperature values ​​for the middle 4 hours of the 12-hour period.

[0033] The beneficial effects of this invention are:

[0034] This invention avoids the need for existing technologies that use downhole pressure gauges to monitor downhole temperature and calculate production profiles, thus reducing the cost of deploying fiber optic cables into the well via coiled tubing. Furthermore, this invention specifies the nozzle size for different wellhead pressure conditions, preventing tubing from becoming buried in sand during production profile testing and saving on tubing retrieval costs. Detailed Implementation

[0035] The present invention will be further explained and described below with reference to specific embodiments.

[0036] Example 1

[0037] The method for testing and analyzing the produced fluid profile after horizontal well fracturing disclosed in this invention specifically includes the following steps:

[0038] S1. After fracturing the oil well, shut it in for about 60 days until the wellhead pressure is less than 3.5 MPa.

[0039] S2, flush the well with sand using coiled tubing, insert the downhole pressure gauge into the well and place it at the center of the radial hole section, connect the tool tubing to the downhole pressure gauge and the pump line to the wellhead, and require a pressure test of 30 MPa to pass.

[0040] S3. Based on the wellhead pressure value, different specifications of nozzles are selected for venting to obtain the venting fluid volume and water content. At the same time, the temperature value T1 and fluid volume Q1 of the downhole pressure gauge distribution points in each horizontal section are obtained.

[0041] S4, well shut in for 12 hours, temperature data collected for 12 hours, with the most stable set of temperature values ​​being T. i That is, the stable temperature value of the middle 4 hours of the 12-hour period is taken as the basis for analysis;

[0042] S5, select an oil nozzle one size larger than that in S3 for venting, and collect temperature data T2 and liquid volume Q2.

[0043] S6, well shut in for 12 hours, temperature data collected for 12 hours; one set of relatively stable temperature values ​​is T. u That is, the stable temperature value of the middle 4 hours of the 12-hour period is taken as the basis for analysis;

[0044] S7. Based on the temperature values ​​and liquid volume obtained from S3-S6, determine the liquid production and oil production of each horizontal section.

[0045] Example 2

[0046] Based on Example 1, S3 specifically includes:

[0047] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle section for 4 hours as the basis for analysis.

[0048] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle to release the fluid: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is less than 50%, release the fluid until the water content is greater than 50%, continue releasing the fluid for 12 hours, collect the temperature data for 12 hours, and take the relatively stable temperature value of the middle section for 4 hours as the basis for analysis.

[0049] When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is less than 5 * the number of horizontal sections, switch to a 6 mm nozzle for venting; when the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal sections, and the water content after sampling is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle 4 hours as the basis for analysis; when the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle 4 hours as the basis for analysis. If the liquid volume still cannot reach a 24-hour production volume greater than or equal to 5 times the number of horizontal segments, replace the 8mm nozzle and then the 10mm nozzle sequentially for venting until the 24-hour production volume is greater than or equal to 5 times the number of horizontal segments. When the water content after sampling is greater than 50%, continue venting for 12 hours and collect the temperature data for 12 hours. Take the relatively stable temperature value of the middle 4 hours as the basis for analysis. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours and collect the temperature data for 12 hours. Take the relatively stable temperature value of the middle 4 hours as the basis for analysis.

[0050] When the wellhead pressure is <2.5 MPa, first use a 6 mm nozzle to release the blowout, and the rest is the same as S4 to S5;

[0051] When the wellhead pressure is <2.5 MPa, first use a 6mm nozzle for venting. When the equivalent 24-hour production is less than 5 * the number of horizontal segments, switch to an 8mm nozzle for venting. When the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal segments, and the water content after sampling is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle 4 hours as the basis for analysis. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle 4 hours as the basis for analysis. If the liquid volume still cannot reach a 24-hour production volume greater than or equal to 5 times the number of horizontal segments, replace the nozzle with a 10mm nozzle and continue venting until the 24-hour production volume is greater than or equal to 5 times the number of horizontal segments. If the water content after sampling is greater than 50%, continue venting for 12 hours and collect temperature data for 12 hours. Take the relatively stable temperature value of the middle 4 hours as the basis for analysis. If the water content after sampling is less than 50%, continue venting until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the relatively stable temperature value of the middle 4 hours as the basis for analysis.

[0052] Example 3

[0053] Based on Example 2, S5 specifically includes: if during the first 12 hours of data collection in S3, a 4mm nozzle is used for venting, then a 6mm nozzle is used for venting, and 12 hours of temperature data are collected; if during the first 12 hours of data collection in S3, a 6mm nozzle is used for venting, then an 8mm nozzle is used for venting, and 12 hours of temperature data are collected; if during the first 12 hours of data collection in S3, an 8mm nozzle is used for venting, then a 10mm nozzle is used for venting, and 12 hours of temperature data are collected; if during the first 12 hours of data collection in S3, a 10mm nozzle is used for venting without changing the nozzle, and 12 hours of temperature data are collected.

[0054] Example 4

[0055] Based on Example 3, let T be the relatively stable set of temperature values ​​monitored by S4. i Let the relatively stable set of temperature values ​​monitored by S6 be T. u Let the temperature value under the production system monitored by S3 be T1; let the temperature value under the production system monitored by S5 be T2; let the 12-hour liquid volume under the production system of S3 be Q1; let the 12-hour liquid volume under the production system of S5 be Q2;

[0056] Take the average value T of the temperature baseline values ​​of each segment. ia =(T i +T u ) / 2;

[0057] Take the average value T of the measured temperature values ​​of each segment. am = (T1+T2) / 2; Take the discharge volume Q = (Q1+Q2) / 2;

[0058] but:

[0059] The liquid production volume of each stage is: Oil production per segment Q o =Q i ×f w ×100%.

[0060] After fracturing a horizontal well, the same number of downhole pressure gauges as the perforated section are installed to cover the entire horizontal well section. A suitable production regime is selected for venting, and the vented fluid volume and water cut are obtained without causing sand burial of the tool string. At the same time, the temperature values ​​of the distribution points of the downhole pressure gauges in each horizontal section are obtained, and the production volume and oil production of each horizontal section are determined based on the temperature values.

Claims

1. A method for testing and analyzing the produced fluid profile after horizontal well fracturing, characterized in that, Specifically, the following steps are included: S1, After fracturing the oil well, shut in the well to reduce pressure; S2, pretreatment of oil wells, inserting downhole pressure gauges into the well and connecting them to the wellhead; S3. Based on the wellhead pressure value, different specifications of nozzles are selected for venting to obtain the venting fluid volume and water content. At the same time, the temperature value T1 and fluid volume Q1 of the downhole pressure gauge distribution points in each horizontal section are obtained. S4, well shut in for 12 hours, temperature data collected for 12 hours, with the most stable set of temperature values ​​being T. i ; S5, select an oil nozzle one size larger than that in S3 for venting, and collect temperature data T2 and liquid volume Q2. S6, well shut in for 12 hours, temperature data collected for 12 hours; one set of relatively stable temperature values ​​is T. u ; S7. Based on the temperature values ​​and liquid volume obtained from S3-S6, determine the liquid production and oil production of each horizontal section.

2. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 1, characterized in that, The pressure reduction in S1 is stopped when the wellhead pressure is reduced to less than 3.5 MPa.

3. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 2, characterized in that, S2 specifically involves: flushing the well with sand using coiled tubing, inserting a downhole pressure gauge into the well and placing it at the center of the radial borehole section, and connecting the tool tubing to the downhole pressure gauge and the pumping line to the wellhead.

4. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 3, characterized in that, In S3: When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours. When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is greater than 5 * the number of horizontal sections, and the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours. When 2.5 MPa < wellhead pressure < 3.5 MPa, first use a 4 mm nozzle for venting: when the equivalent 24-hour production is less than 5 * the number of horizontal sections; then successively replace with a 6 mm nozzle, an 8 mm nozzle, and a 10 mm nozzle for venting until the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal sections. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours; When the wellhead pressure is <2.5 MPa, first use a 6 mm nozzle for venting. When the equivalent 24-hour production is less than 5 * the number of horizontal sections, then successively replace with 8 mm and 10 mm nozzles for venting until the equivalent 24-hour production is greater than or equal to 5 * the number of horizontal sections. When the water content after sampling is less than 50%, vent until the water content is greater than 50%, continue venting for 12 hours, collect temperature data for 12 hours, and take the stable temperature value of the middle section for 4 hours.

5. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 3, characterized in that, Specifically, S5 is: If a 4mm nozzle is used for venting in S3, a 6mm nozzle will be used for venting after the well is shut in for 12 hours. If a 6mm nozzle is used for venting in S3, then an 8mm nozzle will be used for venting after the well is shut in for 12 hours. If an 8mm nozzle is used for venting in S3, then a 10mm nozzle will be used for venting after the well is shut in for 12 hours. If a 10mm nozzle is used for venting in S3, the 10mm nozzle will still be used for venting after the well is shut in for 12 hours.

6. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 3, characterized in that, Specifically, S7 is: Take the average value T of the temperature baseline values ​​of each segment. ia =(T i +T u ) / 2; Take the average value T of the measured temperature values ​​of each segment. am = (T1+T2) / 2; Take the discharge volume Q = (Q1+Q2) / 2; but: The liquid production volume of each stage is: Oil production per segment Q o =Q i ×f w ×100%.

7. The method for testing and analyzing the produced fluid profile after horizontal well fracturing according to claim 3, characterized in that, The relatively stable set of temperature values ​​in S4 and S6 is specifically the stable temperature values ​​for the middle 4 hours of the 12-hour period.

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