CN112682018B - Positive rhythm reservoir plugging fracturing method in high water-containing period - Google Patents
Positive rhythm reservoir plugging fracturing method in high water-containing period Download PDFInfo
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- CN112682018B CN112682018B CN202011447690.7A CN202011447690A CN112682018B CN 112682018 B CN112682018 B CN 112682018B CN 202011447690 A CN202011447690 A CN 202011447690A CN 112682018 B CN112682018 B CN 112682018B
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Abstract
The disclosure relates to a high water-cut period positive rhythm reservoir stratum blocking and fracturing method, and relates to the technical field of petroleum exploration and development fracturing engineering. The method comprises the following steps: inquiring the proportion of a regulating material corresponding to the target permeability and the ground stress of the target stratum in the permeability curve, and preparing the regulating material according to the proportion; the permeability curve is a relation curve of permeability, ground stress and proportion, the proportion is the proportion of elastic particles and fine silt in the regulating material, the permeability of the regulating material changes along with the change of the proportion and the ground stress, and the target stratum is the positive rhythm reservoir stratum; pumping the conditioning material into the target formation; and performing fracturing construction on the target stratum. The method can reduce the permeability of the high-permeability part, improve the utilization degree of fracturing on the low-permeability part, and simultaneously ensure that the original artificial fracture has certain flow conductivity.
Description
Technical Field
The disclosure relates to the technical field of petroleum exploration and development fracturing engineering, in particular to a high water-cut positive rhythm reservoir plugging fracturing method.
Background
In the field of petroleum, fracturing refers to a method of forming cracks in oil and gas layers by using the action of water power in the process of oil or gas production, and is also called hydraulic fracturing. Fracturing is the process of artificially cracking stratum, improving the flowing environment of crude oil underground, increasing oil well yield, and playing an important role in improving the flowing condition of oil well bottom, slowing down interlamination and improving the oil layer using condition.
In the positive rhythm reservoir fracturing process, hydraulic fractures extend preferentially at high-permeability parts, and the problems of poor extending effect and insufficient utilization of low-permeability parts exist. The low permeability sites are still difficult to access by the hydraulic fractures during repeated fracturing. In the related art, in order to increase the material for the in-situ formation, the original artificial fracture is plugged with resin sand or cement so that repeated fracturing acts more on a low-permeability part and a new fracture is generated in the low-permeability part.
However, the use of the methods of the related art results in a loss of oil reserves due to the large remaining oil distribution in the original artificial fractures.
Disclosure of Invention
The embodiment of the disclosure provides a method for blocking and fracturing a positive rhythm reservoir stratum in a high water cut period, which can reduce the permeability of a high-permeability part, improve the utilization degree of fracturing on a low-permeability part, and simultaneously ensure that an original artificial fracture has certain flow conductivity. The technical scheme is as follows:
according to a first aspect of the embodiments of the present disclosure, there is provided a method for high water-cut positive rhythm reservoir plugging fracturing, the method comprising:
inquiring the proportion of a regulating material corresponding to the target permeability and the ground stress of the target stratum in the permeability curve, and preparing the regulating material according to the proportion; the permeability curve is a relation curve of permeability, ground stress and proportion, the proportion is the proportion of elastic particles and fine silt in the regulating material, the permeability of the regulating material changes along with the change of the proportion and the ground stress, and the target stratum is the positive rhythm reservoir stratum;
pumping the conditioning material into the target formation;
and performing fracturing construction on the target stratum.
In an alternative embodiment, the resilient particles comprise rubber particles having a diameter of 1-2 mm.
In an alternative embodiment, the fine silt comprises quartz sand of 70-140 mesh.
In an optional embodiment, the method further comprises:
and (3) measuring the permeability curve of the permeability of the regulating material along with the change of the proportioning and the ground stress.
In an alternative embodiment, the permeability of the control material is inversely related to the proportion of the elastomer particles under the same stress.
In an alternative embodiment, the permeability of the control material and the ground stress have a negative correlation trend under the same proportion.
In an optional embodiment, the method further comprises:
measuring formation permeability of the target formation;
and determining the target permeability according to the formation permeability.
In an alternative embodiment, said pumping said conditioning material into said target formation comprises:
and pumping the regulating material into the target stratum by using guanidine gum.
In an alternative embodiment, the method is applied to repeated fracturing, and the fracturing construction of the target stratum comprises the following steps:
and performing the repeated fracturing construction on the target stratum.
In an alternative embodiment, the positive prosodic reservoir changes from high permeability to low permeability from bottom to top, and the pumping of the conditioning material into the target formation comprises:
and pumping the regulating material into the target stratum, so that the regulating material is filled into the stratum fracture and is gathered at the bottom of the stratum fracture.
The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects:
by filling the cracks of the target stratum with the regulating material before fracturing, the permeability of the regulating material can be changed along with the change of the ground stress of the stratum, so that the proportion of the elastic particles and the fine silt in the regulating material can be determined according to the ground stress of the target stratum, and the permeability of the regulating material can be changed after the regulating material is filled into the cracks. Because the permeability of the positive rhythm reservoir has the characteristics of low upper permeability and high lower permeability, the regulating material is mainly gathered below the fracture due to the influence of gravity after being filled, and the permeability of the middle part and the lower part of the fracture can be reduced. When fracturing is performed again, the permeability of the high-permeability part below becomes low, and the fracturing fluid extends to the low-permeability part above during fracturing, so that more cracks are generated at the low-permeability part, and the mobility of the low-permeability part is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a schematic diagram illustrating a permeability curve according to an exemplary embodiment;
FIG. 2 is a schematic view of a permeability curve shown in accordance with another exemplary embodiment;
FIG. 3 is a schematic view of a permeability curve shown in accordance with another exemplary embodiment;
FIG. 4 is a flow chart illustrating a method for a high water period positive prosodic reservoir plugging fracturing method according to another exemplary embodiment;
FIG. 5 is a flow chart illustrating a method for a high water period positive prosodic reservoir plugging fracturing method according to another exemplary embodiment;
FIG. 6 is a schematic illustration of a fracture shown according to another exemplary embodiment;
FIG. 7 is a schematic illustration of a fracture shown according to another exemplary embodiment;
FIG. 8 is a schematic illustration of a log shown in accordance with another exemplary embodiment;
FIG. 9 is a schematic illustration of a production curve before and after fracturing of a test well according to another exemplary embodiment.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
First, terms related to embodiments of the present application will be described.
And (3) fracturing: in the field of petroleum, fracturing refers to a method of forming cracks in oil and gas layers by using the action of water power in the process of oil or gas production, and is also called hydraulic fracturing. Fracturing is the process of artificially cracking stratum, improving the flowing environment of oil in underground and increasing the yield of oil well, and plays an important role in improving the flowing condition of oil well bottom, slowing down the interlamination and improving the oil layer utilization condition.
After the oil well is produced to a certain stage, the productivity and permeability are reduced, and in order to enhance the oil discharge capacity and improve the oil well yield, the fracturing technology is invented. The hydraulic fracturing method comprises two categories of hydraulic fracturing and high-energy gas fracturing, wherein the hydraulic fracturing is that fluid is injected into a well at a high speed by a ground high-pressure pump truck group, and the rock of an oil layer is fractured to generate cracks by means of high pressure pumped up from the bottom of the well. In order to prevent the pressure from dropping and the crack from closing after the pump truck stops working, sand which is several times higher than the density of the stratum is mixed in the injected liquid after the stratum is broken, the sand and the fluid enter the crack and stay in the crack permanently, and the supporting crack is in an open state, so that the oil flow environment is improved for a long time. The current hydraulic fracturing technology is mature, and the oil well yield increasing effect is obvious, so that the hydraulic fracturing technology becomes a preferred common technology for people for a long time. The method is particularly remarkable in oil layer yield increasing effect with small oil flow channels, namely low permeability.
And (3) repeated fracturing: for a fractured formation, the production rate is reduced to two or more fractures to maintain the design production rate due to reservoir or process aspects, and the fracturing operation is called repeated fracturing. Or the same well layer is fractured again to be the repeated fracturing. The repeated fracturing can change the stress field around the hydraulic fracture, the inclined angle and the azimuth of the repeatedly fractured fracture can be changed, and well selection, problem diagnosis, process selection and design determine whether the repeated fracturing is successful.
Positive rhythm: the evolution sequence of lithology from bottom to top, which is gradually thinned, is called positive rhythm.
High water content period: the high water cut oil reservoir characteristics refer to the heterogeneity of the oil reservoir and the heterogeneity of the water flow condition of the oil reservoir in the process of exploitation due to long-term strong injection and strong extraction after the oil field enters the high water cut stage. After the oil field enters a high water cut period, because of long-term strong injection and strong mining, the underground oil-water distribution is changed greatly, and the mining and submerging object is not a large piece of communicated residual oil, but is turned to a region with highly dispersed residual oil and relative enrichment in local, so the oil deposit development management work in the later period is extremely important. Under severe economic conditions, it is imperative to increase production and ultimate recovery from discovered fields. The key to reducing the production cost, increasing the yield and improving the ultimate recovery ratio is to clean up the distribution rule of the residual oil. After years of high-speed development of oil fields, underground residual oil is in a highly dispersed state in space, and the analysis and research of the distribution rule of the residual oil are carried out by utilizing the current abundant dynamic and static data and combining with a fine oil reservoir description technology so as to guide the oil reservoir potential excavation in the future to be more necessary and urgent.
Ground stress (critical stress): stresses present in the earth's crust. I.e. the force per unit area inside the medium due to rock deformation. It generally comprises two parts: (1) Stress caused by the weight of the overlying rock, which is caused by gravitational forces and the inertial centrifugal force of earth rotation; (2) Tectonic stresses transmitted from adjacent terrain or the bottom. This stress is the part that differs from the standard state and includes, in addition to modern structural stresses transmitted from adjacent plots or the bottom, residual stresses that have remained from past construction movements and have not been completely relaxed, and stress variations caused by nearby man-made work (e.g., tunnels, mining faces). Tectonic stress directly reflects the power source of earth crust movement, which is an important factor causing earthquakes. When a tunnel is excavated in an area with strong structural stress, the tunnel wall becomes a free surface and is easy to deform, so that a tunnel body is gradually reduced or collapsed, and therefore, the research on the ground stress has important significance. The ground stress in the present disclosure is mainly considered as the closing pressure in the fracture because the ground stress in the present disclosure determines the proportion of the control material so that the permeability of the high permeability part becomes the target permeability after the control material is filled, and the ground stress to which the control material is subjected after the control material is filled into the fracture is mainly the closing pressure in the fracture.
Closure pressure (closure pressure): the cylinder is called a closure stress, and refers to a force which acts on the wall surface of the crack after the pumping is stopped to make the crack close and unclosed. Without taking into account the net pressure in the fracture, it can be approximated by: fracture closure pressure = instantaneous shut-in (wellhead) pressure + wellbore fluid column pressure. The magnitude of the fracture closure pressure is related to the minimum horizontal stress, which is an important factor affecting fracture conductivity.
Since the particle size in the positive prosody reservoir becomes thinner from bottom to top, the permeability of the positive prosody reservoir becomes lower from top to bottom. That is, the high-permeability part with high permeability is located below, and the low-permeability part with low permeability is located above.
During the fracturing process of the normal rhythm reservoir stratum, because the lower permeability is higher, the fracture generated by hydraulic fracturing can preferentially extend at a high-permeability part, and a low-permeability part extends less, so that the problem of insufficient utilization of the low-permeability part exists. Hydraulic fractures still have difficulty accessing low permeability sites during repeated fracturing of an already fractured well. Aiming at the deposition characteristics and water injection development characteristics of the current positive rhythm reservoir stratum, the knowledge of oil testing data, core data, residual oil, a composite perforation technology and the like is used for finding that the potential of the residual oil of the positive rhythm reservoir stratum is mainly distributed in low-permeability parts in a high-water-cut period and an ultrahigh-water-cut period. In conventional repeated fracturing, new fractures generated in a target stratum still preferentially extend in high-permeability parts and extend in original old fractures, the residual potential of low-permeability parts in the stratum cannot be excavated, and injected water only carries out crude oil displacement along the high-permeability parts.
In order to solve the problem that the low-permeability part is difficult to use in the repeated fracturing and improve the using degree in the stratum, the original artificial fracture is plugged before the repeated fracturing, for example, the artificial fracture is temporarily plugged by using a temporary plugging agent or the artificial fracture is completely plugged by using expensive resin sand.
The temporary plugging agent is generally an oil-soluble material, can be automatically dissolved within 24 hours, is generally used for plugging blastholes on a casing and cannot plug high-permeability parts of an oil layer for a long time.
The plugging and fracturing technology using the resin sand can only completely plug the original artificial crack, and the crack has no permeability after plugging, so that crude oil cannot be produced. By analyzing the distribution rule of the residual oil in the oil field, a large amount of residual oil is still distributed at the high-permeability part of a partial positive rhythm reservoir, and partial reserve loss can be caused by using a plugging fracturing technology.
Aiming at the problems of repeated fracturing of a positive rhythm reservoir stratum, the invention needs to invent a fracturing technology, which can reduce the permeability of an original fracture, improve the longitudinal exploitation degree of repeated fracturing and ensure that the original fracture has certain flow conductivity.
Based on conventional repeated fracturing effect is poor, and shutoff fracturing technology can cause the problem of reserves loss, this disclosure provides a controllable material of permeability, can reduce former fracture permeability, improves the vertical degree of using of repeated fracturing, can guarantee again that original artificial crack has certain water conservancy diversion ability. According to the method provided by the disclosure, the permeability of a high-permeability part in the fracture is changed, so that the injected water can displace crude oil along the low-permeability part, meanwhile, the displacement direction in a target stratum can be changed, and the water injection effect can be seen in surrounding oil wells.
Aiming at the difficult problem of high water content after fracturing of a positive rhythm reservoir in a high water content period, the numerical simulation calculation finds that the permeability of the original fracture is reduced, and then the repeated fracturing is carried out, so that the longitudinal extension range of the fracture can be effectively improved.
The regulating material is formed by mixing elastic particles and fine silt according to different proportions and is used as a fracturing filling material. Illustratively, the elastic particles are rubber particles having a diameter of 1-2mm (millimeters), and the fine silt is quartz sand of 70-140 mesh.
Experiments prove that the regulating material has the characteristic of large permeability change under different closing pressures.
As shown in FIG. 1, it is a curve 201 of permeability change of 70-140 mesh quartz sand and elastic particles under different mixture ratios under a closing pressure of 15MPa (megapascals). Under the same closing pressure, the permeability of the regulating material tends to increase along with the increase of the quartz sand proportion in the regulating material. Namely, the permeability of the regulating material is in a positive correlation trend with the quartz sand ratio and in a negative correlation trend with the elastic material ratio.
As shown in fig. 2, the curve 202 is a curve of the change relationship between the permeability of the control material and the closing pressure under the condition that the ratio of the quartz sand of 70-140 meshes to the elastic particles is 6. Under the same proportion, the permeability of the regulating material tends to decrease with the increase of the closing pressure. That is, the permeability of the control material tends to be inversely related to the closure pressure.
As shown in fig. 3, it is a curve 203 of the change relationship between the permeability of the control material and the closing pressure under the condition of 7-mesh quartz sand and elastic particles. Under the same proportion, the permeability of the regulating material tends to decrease with the increase of the closing pressure. That is, the permeability of the control material tends to be inversely related to the closure pressure. Compared with fig. 2, the permeability of the control material is increased due to the increase of the quartz sand ratio under the same closing pressure.
For the water washing part and old cracks formed in the positive rhythm reservoir stratum after the primary fracturing, the purpose of plugging the old cracks and the water drive channel for a long time can be realized by utilizing the regulating and controlling material. By combining the magnitude of the closing pressure, the permeability of the regulating material can be designed according to the characteristics of the stratum, and the potential excavation of the residual oil at different parts in different stratums is realized.
FIG. 4 illustrates a flow chart of a method for infrared spectroscopy-based analysis of logging gas as provided by an exemplary embodiment of the present application. The method comprises the following steps:
103, inquiring the proportion of the regulating material corresponding to the target permeability and the ground stress of the target stratum in the permeability curve, and preparing the regulating material according to the proportion; the permeability curve is a relation curve of permeability, ground stress and proportion, the proportion is the proportion of elastic particles and fine silt in the regulating and controlling material, the permeability of the regulating and controlling material changes along with the change of the proportion and the ground stress, and the target stratum is a positive rhythm reservoir stratum.
Illustratively, the modulating material is used to adjust the permeability of a high permeability site in the target formation to a target permeability.
The target formation is the formation to be subjected to the fracturing construction. Illustratively, the target formation is a formation that has undergone primary fracturing, and in the target formation, artificial fractures (old fractures) formed by the primary fracturing exist. Illustratively, the artificial fractures in the target formation tend to extend laterally.
Illustratively, the control material has the characteristic of permeability variability, the permeability of the control material is related to the proportion of the elastic particles and the fine silt in the control material, and the permeability of the control material is also related to the magnitude of the ground stress. Illustratively, the geostress to which the conditioning material is subjected after filling into the fracture is primarily the fracture closure pressure.
Illustratively, according to the ground stress of the target stratum and the target permeability to be achieved, the proportion of the elastic particles and the fine silt can be found in the permeability curve of the regulating material, and the regulating material is prepared according to the found proportion.
In the method, as the high-permeability part is arranged below the positive rhythm reservoir and the low-permeability part is arranged above the positive rhythm reservoir, after the regulating material is pumped into the crack, the regulating material is mainly gathered at the lower part of the crack under the influence of gravity, or gathered at the tail end of the crack under the influence of pressure generated by fracturing, the permeability of the lower part (high-permeability part) and the tail end of the crack can be reduced, and then the hydraulic crack generated by fracturing can extend upwards to improve the utilization degree of the low-permeability part.
Illustratively, high permeability and low permeability sites are relative concepts, in one fracture, due to the nature of the positive prosodic reservoir, the site above the fracture is a low permeability site and the site below the fracture is a high permeability site. For example, in order to clearly define the high-permeability part and the low-permeability part, the position 1/2 of the total height of the fracture may be used as a standard line, the position above the standard line is the low-permeability part of the fracture, and the position below the standard line is the high-permeability part of the fracture. Or, the position of 1/2 of the total height of the target stratum is determined as a standard line, wherein the part above the standard line is the low-permeability part of the stratum, and the part below the standard line is the high-permeability part of the stratum.
And pumping the regulating and controlling material prepared according to the searched mixture ratio into a crack of the target stratum, and regulating the permeability of a high-permeability part in the target stratum.
Illustratively, the conditioning material is pumped into the old fracture.
And step 109, performing fracturing construction on the target stratum.
After the regulating material is pumped in and the permeability of the high-permeability part is adjusted, fracturing construction is carried out on the target stratum, so that hydraulic fractures can be generated at the low-permeability part by fracturing, the flow conductivity of the low-permeability part is improved, and effective utilization of the low-permeability part is realized.
Illustratively, after the control material is pumped in and the permeability of the high-permeability part is adjusted, the fracturing construction is continued, and 16-30 meshes of quartz sand is pumped into the target stratum to fill new cracks.
In summary, in the technical scheme provided by the embodiment of the present disclosure, the control material is used to fill the fracture of the target formation before fracturing, and since the permeability of the control material can be changed along with the change of the ground stress of the formation, the ratio of the elastic particles and the fine silt in the control material can be determined according to the ground stress of the target formation, so that the permeability of the control material can be changed after the control material is filled into the fracture. Because the permeability of the positive rhythm reservoir has the characteristics of low upper permeability and high lower permeability, the regulating material is mainly gathered below the fracture due to the influence of gravity after being filled, and the permeability of the middle part and the lower part of the fracture can be reduced. When fracturing is performed again, the permeability of the high-permeability part at the lower part becomes low, and the fracturing fluid extends to the low-permeability part at the upper part during fracturing, so that more cracks are generated at the low-permeability part, and the mobility of the low-permeability part is improved.
Illustratively, the elastic particles in the regulating material are rubber particles with the diameter of 1-2mm, and the fine silt is quartz sand with the mesh of 70-140. As shown in fig. 5, a flow chart of a method for infrared spectroscopy-based logging gas analysis provided by another exemplary embodiment of the present application is shown. Based on the embodiment shown in fig. 4, step 103 further includes step 101 and step 102, step 106 further includes step 1061, and step 109 further includes step 1091.
101, measuring a permeability curve of the permeability of the regulating material along with the change of the ratio and the ground stress through experiments.
As an example, permeability curves of the control material at different proportions and different stresses (closure pressures) are measured in advance. The permeability curve may be as shown with reference to fig. 1, 2 or 3.
Illustratively, the permeability of the control material tends to be inversely related to the proportion of the elastomer particles in the permeability curve under the same stress. Under the same proportion, the permeability of the regulating material and the ground stress show a negative correlation trend.
And 102, measuring the formation permeability of the target formation, and determining the target permeability according to the formation permeability.
Illustratively, formation permeability of a formation of interest to be fractured is measured.
Illustratively, the formation permeability of the target formation includes a high permeability at high permeability sites and a low permeability at low permeability sites in the target formation. For example, in order to increase the mobility to the low permeability site, the permeability of the high permeability site needs to be adjusted to be close to the permeability of the low permeability site.
For example, the lowest permeability (low permeability) of the measured formation permeabilities may be determined as the target permeability. Alternatively, the target permeability may be determined based on the lowest of the measured formation permeabilities (low permeability), for example, increasing the low permeability by a certain amount to obtain the target permeability, or decreasing the low permeability by a certain amount to obtain the target permeability, i.e., the target permeability is higher than the low permeability, or the target permeability is lower than the low permeability.
103, inquiring the proportion of the regulating material corresponding to the target permeability and the ground stress of the target stratum in the permeability curve, and preparing the regulating material according to the proportion; the permeability curve is a relation curve of permeability, ground stress and proportion, the proportion is the proportion of elastic particles and fine silt in the regulating and controlling material, the permeability of the regulating and controlling material changes along with the change of the proportion and the ground stress, and the target stratum is a positive rhythm reservoir stratum.
Illustratively, guar gum is used to carry the conditioning material pumped into the target formation. Illustratively, the guanidine gum and the conditioning material are mixed to prepare a fracturing fluid, and the fracturing fluid is pumped into the target stratum.
Illustratively, the guanidine gum has certain adhesiveness and can adhere to the side wall of the crack, so that the high-permeability part in the crack can be well covered, and the permeability of the high-permeability part is reduced.
And 1091, performing repeated fracturing construction on the target stratum.
Illustratively, the method is applied before repeated fracturing operations. Before repeated fracturing, a regulating material is pumped into the fracture to reduce the permeability of the high-permeability part of the target stratum.
To sum up, in the technical scheme provided by the embodiment of the present disclosure, a control material is pumped into the fracture before the repeated fracturing, so as to adjust the permeability of the high permeability part. And then, repeated fracturing is carried out, so that the repeated fracturing mainly acts on the low-permeability part, the longitudinal utilization degree of the repeated fracturing is improved, the original fracture can be ensured to have certain flow conductivity, and the oil production potential of the low-permeability part can be better developed.
As shown in fig. 6, the effect of the cracks after the control material is pumped is shown. Under the influence of the characteristics of the positive rhythm reservoir stratum and the sedimentation characteristics of the fracturing sand, the regulating material 301 is filled into the original fracture 302 and gathered at the bottom of the positive rhythm reservoir stratum, so that the aims of blocking a high-permeability part (the lower part of the fracture) and improving the net pressure in the fracture are fulfilled.
As shown in fig. 7, the simulation effect diagram after repeated fracturing is performed for pumping quartz sand. The net pressure in the seam is increased after the first stage is finished, so that the hydraulic fracture can be longitudinally extended, and the quartz sand continuously pumped and injected is mainly filled in the upper part of the original fracture 302 and a new fracture, so that the flow conductivity of a low-permeability part can be improved, and the effective utilization of the part of the reservoir can be realized.
Illustratively, after a test well is repeatedly fractured by applying the method provided by the disclosure, the average daily fluid increment of a single well is reduced from 5.0t to 2.0t, and the daily oil increment is increased from 0.3t to 0.6t. The daily fluid gain is the daily fluid production of the test well before the method provided by the disclosure, minus the daily fluid production of the test well after the method provided by the disclosure. The daily fluid production includes water used to displace oil, and oil displaced by the water. The daily oil gain is the daily oil yield of the test well before the method provided by the disclosure, minus the daily oil yield of the test well after the method provided by the disclosure.
As shown in fig. 8, the log curve of another test well is shown, wherein the left side of the graph is four strata, namely, stratum 1, stratum 2, stratum 3 and stratum 4, and the right side of the graph is a natural gamma curve 303, a natural potential curve 304 and a well diameter curve 305. It can be seen from the natural potential curve 304 that there are two convex arcs to the left, illustrating the formation 2, the formation 3, and the formation 4 sands. From the natural gamma curve 303, it can be seen that the formation 2, the formation 3 and the formation 4 are typical positive rhythm reservoirs as the sandstone layer gradually decreases from bottom to top to the right.
As shown in fig. 9, for a daily fluid production curve 306, a daily oil production curve 307, a water cut curve 308, and a meniscus 309 for another test well, a vertical line 310 represents a date of use of the method provided by the present disclosure. Before the method provided by the disclosure is used, the daily liquid production of the test well is 7.1 tons, the daily oil production is 0.43 tons, and the water content is 94%. It is found that when the stratum is used in 2008, the proppant for fracturing is 8 and the reservoir permeability is 95-275X 10 -3 μm 2 And under the condition of regional ground stress, wherein the minimum horizontal ground stress sigma h =7MPa, and a regulating material (the ratio of 1-2mm rubber particles to 70-140 meshes of quartz sand is 6. In 2019 and 3 months (date shown by vertical line 310), the fracturing method provided by the disclosure is implemented on three small layers of the well stratum 2, the stratum 3 and the stratum 4, the regulation and control material is pumped in the first stage for 5 parts, and the quartz sand (16-30 meshes) is pumped in the second stage for 8 parts. After fracturing, the daily fluid increase of the well is reduced by 7.1-6.9=0.2 tons, the daily oil increase is increased by 1.27-0.43=0.84 tons, and the water content is reduced to 80 percent, thereby achieving the purposes of controlling the fluid quantity and using a low-permeability part.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.
It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.
Claims (6)
1. A high water cut positive rhythm reservoir plugging fracturing method, which is characterized by comprising the following steps:
inquiring the proportion of a regulating material corresponding to the target permeability and the ground stress of the target stratum in the permeability curve, and preparing the regulating material according to the proportion; the permeability curve is a relation curve of permeability, ground stress and proportion, the proportion is the proportion of elastic particles and fine silt in the regulating material, the fine silt comprises 70-140 meshes of quartz sand, the elastic particles are rubber particles with the diameter of 1-2mm, the permeability of the regulating material changes along with the change of the proportion and the ground stress, and the target stratum is the positive rhythm reservoir stratum;
pumping the conditioning material into the target formation;
performing fracturing construction on the target stratum;
wherein, under the same stress, the permeability of the regulating material and the proportion of the elastic particles are in a negative correlation trend;
under the condition that the closing pressure is 15 megapascals, in an interval that the proportion of the 70-140-mesh quartz sand is 80% -100%, the permeability is reduced along with the reduction of the proportion of the 70-140-mesh quartz sand according to a first reduction speed; in the interval of 70-80% of the quartz sand proportion of 70-140 meshes, the permeability is reduced along with the reduction of the quartz sand proportion of 70-140 meshes according to a second descending speed; in the interval of 50% -70% of the quartz sand proportion of 70-140 meshes, the permeability is reduced along with the reduction of the quartz sand proportion of 70-140 meshes according to a third descending speed; in the interval of 0-50% of the quartz sand with 70-140 meshes, the permeability is 0; the second descending speed is greater than the first descending speed and greater than the third descending speed;
under the same proportion, the permeability of the regulating material and the ground stress are in a negative correlation trend;
and, in the case that the mixture ratio of the 70-140 mesh quartz sand to the elastic particles is 6, the closing pressure is in the interval of 10 megapascals to 40 megapascals, and the permeability decreases with the increase of the closing pressure; at a closure pressure of 40 megapascals, the permeability is 0;
and, in the case that the mixture ratio of the 70-140 mesh quartz sand to the elastic particles is 7, the closing pressure is in the interval of 10 megapascals to 40 megapascals, and the permeability decreases with the increase of the closing pressure; at a closure pressure of 40 megapascals, the permeability is 0.
2. The method of claim 1, further comprising:
and (3) measuring the permeability curve of the permeability of the regulating material along with the change of the proportioning and the ground stress.
3. The method of claim 1, further comprising:
measuring formation permeability of the target formation;
and determining the target permeability according to the formation permeability.
4. The method of claim 1, wherein pumping the conditioning material into the target formation comprises:
and pumping the regulating material into the target stratum by using guanidine gum.
5. The method of claim 1, wherein the method is applied to repeated fracturing, and the performing a fracturing construction on the target formation comprises:
and performing the repeated fracturing construction on the target stratum.
6. The method of claim 1, wherein the positive prosodic reservoir changes from high permeability to low permeability from bottom to top, the pumping the regulatory material into the target formation comprising:
and pumping the regulating material into the target stratum, so that the regulating material is filled into the stratum fracture and is gathered at the bottom of the stratum fracture.
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| US3682245A (en) * | 1970-09-15 | 1972-08-08 | Marathon Oil Co | Selective plugging of more permeable zones |
| US5735349A (en) * | 1996-08-16 | 1998-04-07 | Bj Services Company | Compositions and methods for modifying the permeability of subterranean formations |
| US6860147B2 (en) * | 2002-09-30 | 2005-03-01 | Alberta Research Council Inc. | Process for predicting porosity and permeability of a coal bed |
| US9120963B2 (en) * | 2006-11-08 | 2015-09-01 | Schlumberger Technology Corporation | Delayed water-swelling materials and methods of use |
| AU2008279816B2 (en) * | 2007-07-26 | 2013-02-07 | Exxonmobil Upstream Research Company | Method for controlling loss of drilling fluid |
| US10995264B2 (en) * | 2016-09-30 | 2021-05-04 | Wacker Chemie Ag | Coated proppants for fracking extraction methods |
| CN111927386B (en) * | 2020-08-14 | 2022-11-29 | 吉林省荣普达石油技术有限公司 | High-water-content oil-water well reversible deformation isotonic plugging-adjusting production-increasing technology |
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