CN114622889B

CN114622889B - Method for adjusting water injection well pattern of huge-thickness pore type carbonate reservoir with high permeability layer and interlayer channeling

Info

Publication number: CN114622889B
Application number: CN202011445923.XA
Authority: CN
Inventors: 杨超; 郭睿; 冯明生; 徐振永; 甘俊奇; 贾瑾; 林腾飞; 王俊文; 衣英杰
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2024-05-28
Anticipated expiration: 2040-12-11
Also published as: CN114622889A

Abstract

The invention provides a method for adjusting a water injection well pattern of a huge-thickness pore type carbonate reservoir with a high permeability layer and an interlayer cross flow. The method comprises the following steps: longitudinally dividing development layers of a target huge-thickness pore type carbonate reservoir, wherein an interlayer channeling layer and a huge thick layer are used as independent development layers; longitudinal staged successor development of the megathick layer includes: setting a first injection well pattern in the giant-layer for development, closing the first injection well pattern after development for a period of time, and setting a second injection well pattern in different longitudinal positions in the giant-layer for development, wherein the first injection well pattern and the second injection well pattern are positioned at different depths in the same area of the giant-layer; and developing a high-permeability erosion hole type high-permeability layer at the top of the huge thick layer developed by successive stages in the longitudinal direction. The method solves the problems of water channeling of the high permeability layer, interlayer channeling and the like caused by the development of the vertical well general injection well pattern of the huge thick carbonate rock, and realizes the high-efficiency utilization and water channeling control of the water injection high permeability layer of the huge thick carbonate rock oil field.

Description

Method for adjusting water injection well pattern of huge-thickness pore type carbonate reservoir with high permeability layer and interlayer channeling

Technical Field

The invention belongs to the technical field of oilfield development, and particularly relates to a method for adjusting a water injection well pattern of a huge-thickness pore type carbonate reservoir with a high-permeability layer and interlayer cross flow.

Background

Most of carbonate reservoirs in the middle east are porous carbonate reservoirs, the geologic reservoir features are complex, the reservoir has giant thickness of 200-300m and multiple layers, the pore structure of the reservoir is complex, the longitudinal and transverse heterogeneity is extremely strong, and the reservoir communication condition difference is large. In addition, several characteristics that are highly important and have a significant impact on the development effect are: (1) Hypertonic layers are ubiquitous in middle eastern pore carbonates and are of various types. The hypertonic layer is generally reformed by corrosion and is generally controlled by faults, sedimentations and beach top corrosion areas, and widely exists in Lu Maila, gu Erna, haffa subunit, ai Hadai cloth and other huge-thickness large carbonate reservoirs. (2) fluid channeling between layers is common. Unlike sandstone reservoirs, carbonate reservoirs are generally developmentally interlayer and relatively 'hidden', and although playing a certain role in blocking in development, development has great uncertainty, generally does not develop continuously, and especially in tidal channel development areas, due to frequent swinging and undercut of river channels, layers are not completely divided, and vertical fluid channeling exists. (3) Water flooding is required. The oil reservoirs in the middle east area are small in general saturation pressure difference, small in water volume, low in natural energy, good in oil product, small in oil-water fluidity and suitable for water injection development to supplement stratum energy. In the early stage of development, the geological complexity and the recognition degree of carbonate rock are considered to be low, and general water injection development is generally carried out by adopting a vertical well inverted nine-point well pattern and a vertical well linear well pattern, but due to the interlayer lithology, the physical property difference and the interlayer channeling phenomenon, injected water is rapidly propelled along a hypertonic layer after a period of development, fluid channeling exists between layers, and the overall performance is as follows: the water content of the oil well is rapidly increased, the yield is reduced, the low-efficiency and ineffective water circulation become main reasons for influencing the water flooding development effect, the original development layer system well pattern and the injection and production working system are not suitable for high-efficiency water flooding development, the water flooding and displacement efficiency is greatly influenced, the total reserve utilization degree is low, and an adjustment method of the general injection and production well pattern of the huge thick carbonate reservoir with higher adaptability and stronger operability considering the high-permeability layer and interlayer channeling is urgently needed to be established, so that the high-efficiency water flooding development of the similar reservoir in the middle east area is guided.

Well pattern deployment methods have been proposed by scholars for the world problem of carbonate reservoir waterflooding. For example, a vertical well pattern is gradually encrypted from a nine-point method point weak surface strong well pattern and an overall horizontal well (high inclination) three-dimensional well pattern into a five-point method point weak surface strong well pattern, and 2 huge carbonate reservoir typical development deployment modes are adopted, although imbalance of water flooding caused by interlayer contradiction is relieved to a certain extent, the modes are focused on spatial three-dimensional well pattern adjustment, one-time reserve control and reserve utilization are emphasized, the positive effect of a high permeability layer is not fully utilized, interlayer fluid channeling risks are not considered, and time factors of well pattern layer configuration are considered, so that the early phase comparison of the well pattern adjustment is suitable for complex heterogeneous characteristics of carbonate reservoirs, but later phase adaptability is gradually poor, and especially after water breakthrough, the flexibility of well pattern adjustment is poor, and higher recovery ratio cannot be obtained.

(1) The high permeability layer is beneficial and disadvantageous to the development of the oil field, so that the advantage of high productivity index of the high permeability layer is fully utilized to realize the rapid production of the oil field, the water channeling risk of the injected water along the high permeability layer is delayed, and the high permeability layer has great challenges in well pattern deployment.

(2) The injection and production relation of the original well pattern is disturbed due to interlayer cross flow, the injection water flow direction is difficult to control and predict, and the existing well pattern deployment mode is hardly involved or cannot fully avoid the risk.

(3) The large-scale carbonate reservoir of huge thickness is built and produced on a large scale, development investment is large, risk is high, the developed oil field already has reasonable arrangement of a large number of development wells, and the problems of orderly succession of reserves among layers and space-time conversion of new and old well pattern deployment need to be comprehensively considered so as to enhance the adaptability and the adjustment flexibility of the well pattern.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a water injection well pattern adjusting method capable of effectively improving the water drive control and the utilization degree of a well pattern of a huge-thickness pore type carbonate reservoir with a high-permeability layer and interlayer channeling. The method solves the problems of water channeling of the high permeability layer, interlayer channeling and the like caused by the development of the vertical well general injection well pattern of the huge thick carbonate rock, and realizes the high-efficiency utilization and water channeling control of the water injection high permeability layer of the huge thick carbonate rock oil field.

In order to achieve the above purpose, the invention provides a method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a high permeability layer and interlayer channeling, wherein the method comprises the following steps:

longitudinally dividing a development layer system of a target huge-thickness pore type carbonate reservoir; wherein the interlayer channeling layer is used as a separate development layer, and the giant layer (generally referred to as a reservoir layer with a thickness of not less than 100 m) is used as a separate development layer;

Carrying out longitudinal staged succession development on the giant thick layer; wherein the longitudinally phased succession development comprises: setting a first injection well pattern in the giant-layer for development, closing the first injection well pattern after development for a period of time, and setting a second injection well pattern in different longitudinal positions in the giant-layer for development, wherein the first injection well pattern and the second injection well pattern are positioned at different depths in the same area of the giant-layer; wherein, the top of the huge thick layer developed by successive stages in the longitudinal direction develops a hypertonic solution etching hole type hypertonic layer.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, the longitudinal staged successive development refers to the development of the huge-thickness layer in a certain area, the development of the water injection well pattern is carried out by arranging the huge-thickness layer in the area, the development well pattern is closed after a period of development, and the development of the new water injection well pattern is carried out by arranging the huge-thickness layer in the plane area at different longitudinal positions.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, the development layer system of the target huge-thickness pore type carbonate reservoir is preferably divided according to the characteristics of sedimentary and diagenetic. The geological oil reservoir features of the huge-thickness pore type carbonate oil reservoir are complex, the internal pore structure of the huge-thickness and multilayer features is complex, the geological oil reservoir is influenced by the deposition effect and the diagenetic reconstruction, the heterogeneity is serious, and a hidden interlayer exists between layers, so that the combination of the deposition and diagenetic features is needed to be comprehensively carried out when the development layer system is divided.

In the foregoing method for adjusting a water injection pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlaminar channeling, preferably, the developing layer division of the target huge pore type carbonate reservoir includes:

determining the interlayer distribution of the target huge-thickness pore type carbonate reservoir;

determining the interlayer channeling layer distribution of the target huge-thickness pore type carbonate reservoir:

dividing a target huge-thickness pore type carbonate reservoir development layer system based on the target huge-thickness pore type carbonate interlayer distribution and the cross-flow layer distribution;

In one embodiment, partitioning the target ultra-thick pore carbonate reservoir development layer comprises: dividing the layers by taking each fully developed interlayer and each interlayer channeling layer as boundaries, and taking each interlayer channeling layer as an independent development layer respectively; at this time, the inside of each development layer is not a complete interlayer.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the interlayer distribution of the target huge-thickness pore type carbonate reservoir is determined comprehensively based on logging electrical response and production fluid water absorption monitoring data. More preferably, for the development and superposition of different periods tidal channel, the thickness of the single-well interlayer is counted, and the interlayer channeling characteristics are comprehensively analyzed. In order to determine the qualitative and quantitative influence of the interlayer channeling on the development effect, a tracer agent can be adopted to track the fluid migration law, and the oil quantity and the water quantity of the interlayer channeling are calculated.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer cross flow, preferably, the cross flow layer is tidal channel layers; the inventors have found that the level at which cross flow occurs between layers in a very thick pore carbonate reservoir is generally related to the developmental position of tidal channel, and that tidal channel cycle oscillations and undercutting result in incomplete barrier properties between upper and lower layers, with local vertical fluid exchange between upper and lower layers.

In the foregoing method for adjusting a water injection well pattern of a giant-thickness pore-type carbonate reservoir in which a hypertonic layer and an interlaminar fluid channeling are present, preferably, when a giant-thickness layer originally developed by taking over in stages in a longitudinal direction is already provided with a water injection well pattern, the water injection well pattern originally provided by the giant-thickness layer is plugged before the giant-thickness layer is taken over in stages in the longitudinal direction in a earlier stage of development or before the giant-thickness layer is taken over in stages in the longitudinal direction; more preferably, the old well originally provided with the longitudinally staged succession of the developed giant-layer is returned to the other developed layers except the giant-layer and the crossflow layer, and the other developed layers are mined; wherein, the developed hypertonic corrosion hole type hypertonic layer at the top of the giant thick layer developed in a longitudinal staged succession is preferably provided with a mining pattern.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the interlayer channeling layer is used in the post-stabilization period; the interlayer channeling layer has higher risk of being used, is preferably used as an interlayer in the early stage and is used in the later stage of development in order to avoid the influence on the deployment of the production well pattern on the oil field.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the first injection well pattern is a lower injection upper production injection well pattern; the second injection well pattern is a lower-injection upper-production injection well pattern.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling,

Preferably, the longitudinal staged succession development is performed by adopting a longitudinal progressive well spacing enlarging mode;

More preferably, the water injection well pattern of the second fluid injection well pattern is located below the water injection well pattern of the first fluid injection well pattern and the production well pattern of the second fluid injection well pattern is located above the production well pattern of the first fluid injection well pattern;

Further preferably, the longitudinally phased successor development comprises:

1) Setting a first injection well pattern for lower injection and upper production in the giant thick layer for development;

2) After development for a period of time, plugging a water injection well row of the first injection well pattern, and laterally drilling a water injection well of the first injection well pattern to form a new water injection well and/or drilling a new water injection well below the water injection well of the first injection well pattern, thereby forming a new water injection well row serving as a water injection well row of the second injection well pattern; thereby lengthening the waterline and delaying the propulsion of the water injection well;

3) Then plugging the production well row of the first injection well pattern, and laterally drilling the production well of the first injection well pattern to form a new production well and/or drilling a new production well above the production well of the first injection well pattern, thereby forming a new production well row serving as the production well row of the second injection well pattern;

4) Continuing development by adopting a second flooding well pattern;

in a specific embodiment, the development period in step 2) refers to 5 years of development or development to a contracted reservoir single well water content (e.g., 30%).

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, preferably, the well pattern deployed in the development process is replaced by a horizontal well pattern in a longitudinal stage by stage manner.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the high permeability layer and the interlayer channeling, preferably, the well spacing between the water injection wells of the first injection well pattern is larger than the well spacing between the water injection wells of the second injection well pattern.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar fluid channeling, preferably, the well spacing between the production wells of the first injection well pattern is larger than the well spacing between the production wells of the second injection well pattern.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, preferably, a third injection well pattern position is set for development in the longitudinal staged succession development process of the huge-thickness layer; the third injection well pattern is a middle injection and upper and lower simultaneous production well pattern;

More preferably, a dysplastic interlayer is formed between the middle water injection well row and the lower production well row of the third injection well pattern; the incomplete physical interlayer has a certain fluid shielding effect, a production well row is deployed below the physical interlayer, and water injection of the upper water injection well row is utilized to effectively displace crude oil of the lower production well row, so that rapid flooding of the production well caused by the gravity effect of injected water is avoided.

In a specific embodiment, the longitudinally phased succession development includes:

Setting a first injection well pattern inside the giant thick layer for development, wherein the first injection well pattern is a lower injection upper production horizontal well injection well pattern;

After development for a period of time, plugging a water injection well row of the first injection well pattern, laterally drilling a water injection well of the first injection well pattern downwards to form a new horizontal water injection well and/or drilling a new horizontal water injection well below the water injection well of the first injection well pattern, thereby forming a new encrypted water injection well row as a water injection well row of the second injection well pattern;

Then plugging the production well row of the first injection well pattern, and laterally drilling the production well of the first injection well pattern to form a new horizontal production well and/or drilling a new horizontal production well above the production well of the first injection well pattern, thereby forming a new encrypted production well row as the production well row of the second injection well pattern;

And after the second injection well pattern is adopted for development for a period of time, drilling a new horizontal production well pattern below the water injection well pattern of the second injection well pattern to form a third injection well pattern which takes the water injection well pattern of the original second injection well pattern as an intermediate water injection well pattern and takes the production well pattern of the original second injection well pattern and the new horizontal production well pattern below the water injection well pattern of the second injection well pattern as an upper and lower production well pattern for development.

In the foregoing method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlaminar channeling, preferably, the method further includes:

Identifying a hypertonic layer, and dividing the hypertonic layer into a particle beach type, a fault vicinity type, a tidal channel type and a hypertonic corrosion hole type;

Based on the type of the hypertonic layer, the development risk and the permeability level are combined, and reserve utilization level division is carried out on various reservoirs in the target huge-thickness pore type carbonate rock oil reservoir according to the utilization difficulty level, and is divided into:

A first type of reservoir: an unused high quality layer, an unused medium quality layer; the medium quality layer comprises a particle beach type high permeability layer, a fault nearby type high permeability layer and a medium permeability layer, wherein the permeability is less than 1000mD and not less than 10mD, the fault nearby type high permeability layer is usually a microcrack layer permeability nearby the fault and is generally hundreds of mD, and the permeability contributes to oil well productivity; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, the permeability of which is 1000mD-4000mD, and the high-permeability layer is usually an ultra-high-permeability continuously distributed high-permeability layer; such reservoirs are easy to use, reserves are easy to use, and single well productivity is high;

A second type of reservoir: a used high quality layer and a used medium quality layer; the medium quality layer comprises a particle beach type high permeability layer, a fault nearby type high permeability layer and a medium permeability layer, wherein the permeability is less than 1000mD and not less than 10mD, the fault nearby type high permeability layer is usually a microcrack layer permeability nearby the fault and is generally hundreds of mD, and the permeability contributes to oil well productivity; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, the permeability of which is 1000mD-4000mD, and the high-permeability layer is usually an ultra-high-permeability continuously distributed high-permeability layer; the second reservoir is easy to use, the reserve is easy to use, and the single well productivity is high;

Third class of reservoirs: a hypotonic tight reservoir having a permeability of less than 10mD and not less than 1 mD; the third easy-to-use small layer of the reservoir is the penultimate easy-to-use, the vertical well is difficult to use, the natural productivity is low, and the acidizing production is generally performed through the horizontal well;

A fourth type of reservoir: a difficult extremely dense layer with permeability lower than 1mD and a tidal channel type high-permeability layer, namely an interlayer channeling layer; the fourth easy-to-use method is the most difficult-to-use method, the reserve of the ultra-compact layer is difficult to use, natural energy production is generally avoided, and the production can be put into production by means of horizontal well acid fracturing or even multistage fracturing yield increasing measures; the tidal channel type hypertonic layer is usually an interlayer channeling layer with higher use risk, and is used as an interlayer in the early stage and in the later stage of development in order to avoid the influence on the deployment of a well pattern on an oil field;

More preferably, the reserve utilization level of various reservoirs in the target huge-thickness pore type carbonate reservoir is divided according to the utilization difficulty, and the reserve utilization level is divided into:

A first type of reservoir: an unused particulate beach type high permeability layer, a near fault type high permeability layer, and a medium permeability layer, the permeability of which is less than 1000mD and not less than 10mD;

a second type of reservoir: the permeability of the used hypertonic corrosion hole type hypertonic layer is 1000mD-4000mD;

third class of reservoirs: a hypotonic tight reservoir having a permeability of less than 10mD and not less than 1 mD;

A fourth type of reservoir: a difficult extremely dense layer with permeability lower than 1mD and a tidal channel type high-permeability layer, namely an interlayer channeling layer;

in a specific embodiment, the identifying the hypertonic layer and classifying the hypertonic layer into a particle beach type, a fault vicinity type, a tidal channel type and a hypertonic solution etching hole type comprises:

Comprehensively identifying the hypertonic layer according to three-dimensional seismic interpretation, logging interpretation, coring well observation and PLT, MDT, PNL dynamic monitoring data, and analyzing the type, physical property and plane longitudinal spreading characteristics of the hypertonic layer;

Wherein, granule beach type, near fault type, tidal channel type and hypertonic solution etching hole type possess following characteristics:

Particle beach type, near fault type: the hillside body forms a high-permeability layer near the fault, and the oil yield and the water content of nearby oil wells are higher;

tidal channel type: isolated hillocks have poor connectivity, large physical differences between tidal channel and tidal channel, and serious heterogeneity;

High-permeability etching hole type: compared with tidal channel, the product has better physical properties, is distributed in a continuous piece, and has the permeability as high as Darcy grade (easy to cause rapid sudden injection of water).

In the method for adjusting the water injection well pattern of the huge thick pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the huge thick layer is divided into a first class of small layers, a second class of small layers, a third class of small layers and a fourth class of small layers; wherein the first type of small layer is a small layer mainly comprising a first type of reservoir; the second class of small layers are small layers mainly comprising the second class of reservoir; the third class of small layers are small layers mainly comprising a third class of reservoir; the fourth class of small layers are small layers mainly comprising fourth class of reservoir layers;

the giant thick layer developed by successive stages in the longitudinal direction comprises a second type of small layer, a first type of small layer and a third type of small layer from top to bottom; the first injection well pattern is arranged in a first type small layer; the water injection well row of the second oil injection well pattern is arranged at the upper part of the second class of small layers, and the production well row of the second oil injection well pattern is arranged at the upper part of the third class of small layers;

more preferably, the lower production well row of the third pattern is disposed in the middle or bottom of the third class of small layers;

This preferred embodiment is shown in fig. 1.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the water injection well pattern adjusting process of the huge-thickness pore type carbonate reservoir divides different development stages: a transitional development period, a main development period and a succession development period;

Wherein, carry out including in the transition development period: returning the old well originally arranged in the huge thick pore type carbonate rock oil reservoir to other developed layers except the huge thick layer and the crossflow layer, and carrying out single-layer exploitation by using the returned old well; setting a first injection well pattern in a first type of small layer of the giant thick layer developed in a longitudinal staged succession for development;

the development period of the subject comprises the following steps: setting a second type of well pattern in the giant thick layer developed in a longitudinal staged succession mode for development; setting a third type of injection well pattern in the giant thick layer developed in a longitudinal staged succession mode for development;

the following steps are carried out in the succession development period: developing a development layer based on the fourth type of reservoir and/or a small layer based on the fourth type of reservoir in the huge thick layer;

In this preferred mode, the development period is transitioned: as a transitional production stage before the oilfield production reaches the peak production target; and the transitional development period fully utilizes the high-permeability layer to rapidly produce new well pattern deployment, and compensates the yield loss caused by old well adjustment. Main development period: after the transitional development period, the method mainly comprises an ascending phase and a stable production phase of the oil reservoir production reaching the final peak production target. Successor development period: after the main development period, the reservoir stable period is ended, the maintenance period of peak yield and the subsequent yield decrement period.

In the foregoing method for adjusting a water injection pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlaminar fluid channeling, preferably, the step of returning the old well originally set in the huge pore type carbonate reservoir to other developed layers except the huge layer and the fluid channeling layer and using the returned old well for single-layer mining includes:

firstly, carrying out upward return of an old well originally arranged in a giant thick layer developed by successive stages in the longitudinal direction, and carrying out single-layer exploitation by using the old well after the upward return; firstly, performing uphole return in the layer, and then performing uphole return of other old wells in the layer; firstly, old well adjustment originally arranged in a giant thick layer developed by longitudinal staged succession is convenient for well pattern adjustment of the giant thick layer developed by longitudinal staged succession in later period;

Then, carrying out upward returning on the old wells of other development layers except the giant thick layer developed in succession by stages, and carrying out single-layer exploitation by using the upward returning old wells; wherein, the lying well in the layers is returned firstly, and then the other old wells in the layers are returned;

more preferably, the old well is plugged by adopting the following operation construction mode:

Setting the high-yield reservoir by adopting an oil pipe bridge plug, pouring 3 meters of cement;

plugging the low-permeability tight reservoir by adopting a workover rig lower bridge plug, pouring 3 meters of cement, and performing acid fracturing after plugging;

after the plugging operation is completed, the cable is used for probing the bottom, so that the plugging success is ensured.

The cost of the two plugging operation modes is low; even if the extreme mode of adopting a workover rig to plug a low-permeability tight reservoir, pouring 3 meters of cement and carrying out acid fracturing after plugging is adopted, single-well operation is approximately equivalent to 10-15% of the cost of horizontal well drilling and completion in the same area, if a development well uses clean water to kill a well, the conditions of great loss of completion fluid and difficulty in killing the well cannot occur in the operation process, the construction operation difficulty is low, and the practicability is strong.

In the foregoing method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlayer fluid channeling, preferably, the step of returning an old well originally set in the huge pore type carbonate reservoir to other developed layers except the huge layer and the fluid channeling layer and performing single-layer mining by using the adjusted old well further includes: the old well originally arranged in the huge thick pore type carbonate reservoir is returned to other used development layers except the huge thick layer and the fluid channeling layer, and the well injection pattern encryption is carried out to form a new well injection pattern after adjustment so as to mine the development layer;

More preferably, the encryption forms a new after-adjustment injection well pattern by selecting one or more than two modes of nine-point well pattern, five-point well pattern, upper horizontal well production by injecting lower vertical well, upper vertical well production by injecting lower horizontal well, upper and lower horizontal well production by injecting middle vertical well, and upper and lower horizontal well production by injecting middle horizontal well.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlayer channeling, preferably, the method further comprises the following steps of: well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a first type of reservoir; well patterns are deployed in the megathick layer where no phased succession development occurs in the machine direction to develop the first class of small layers.

In the foregoing method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlaminar channeling, preferably, the method further comprises the following steps: well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a third type of reservoir; well patterns are arranged in the huge thick layer which is not subjected to longitudinal staged succession development to develop the second type of small layers and the third type of small layers.

In the foregoing method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a hypertonic layer and an interlaminar channeling, preferably, the following steps are further performed in a succession development period: well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a fourth type of reservoir; well patterns are placed in the giant-layer to develop a fourth class of small layers.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar fluid channeling, preferably, the development layer which is not the huge thick layer and mainly comprises a first type reservoir, a second type reservoir and a third type reservoir is selected from one or more than two modes of nine-point well pattern, five-point well pattern, upper horizontal well production of lower vertical well injection, upper vertical well production of lower horizontal well injection, upper and lower horizontal well production of middle vertical well injection and upper and lower horizontal well production of middle horizontal well injection; more preferably, a reverse nine-point well pattern is used.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the high permeability layer and interlayer cross flow, preferably, the cross flow layer development layer is developed by selecting a vertical well pattern. The inventor finds through simulation that: and a vertical well is deployed in tidal channel, when the well spacing is equal to that of the existing old well, the boundary distance between the vertical well and the tidal channel is at least half of that, so that a good development effect can be achieved.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar fluid channeling, preferably, in the development layer of the non-huge-thickness layer, the development layer mainly comprising a fourth type of reservoir of the non-channeling layer is selected from one or more than two modes of nine-point well pattern, five-point well pattern, upper horizontal well pattern of lower vertical well injection, upper vertical well pattern of lower horizontal well injection, upper and lower horizontal well pattern of middle vertical well injection, upper and lower horizontal well pattern of middle horizontal well injection and upper and lower horizontal well pattern.

In the method for adjusting the water injection well pattern of the huge thick pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, preferably, staggered linear horizontal well injection well patterns are adopted in the huge thick layer developed by successive stages in the longitudinal direction.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, preferably, the deployment position of the horizontal well is adjusted according to the fault plane distribution diagram obtained by the structural fracture analysis, so that the distance between the horizontal well and the fault is larger than half well distance.

In the method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir with the hypertonic layer and the interlaminar channeling, preferably, the target huge-thickness pore type carbonate reservoir is used for comprehensively dividing the reserve plane utilization sequence by taking the ground facility as a unit according to a reservoir plane physical distribution map and a ground treatment facility distribution map of porosity, permeability and the like controlled by lithofacies constraint. And according to the sequence from good to bad and from difficult to easy, the longitudinal reserve utilization sequence and the difficulty of implementation of ground supporting facilities are combined, and comprehensive deployment adjustment of the well pattern is implemented. In general, the transition development period and the main development period are mainly the reserves with good physical properties, and take over the thin poor reserve with difficult use in the development period.

In the method for adjusting the water injection well pattern of the huge pore type carbonate reservoir with the hypertonic layer and the interlaminar fluid channeling, the deployment position of the newly drilled well in the transition development period process can be selected by preferentially selecting the residual oil enrichment area with lower flooding degree according to the residual oil saturation distribution map of the hypertonic layer of the fine history fitting model.

The inventor determines a staged reserve utilization strategy for high permeability layer utilization and interlayer fluid channeling risk avoidance based on geological development characteristic analysis of the huge thick carbonate rock with high permeability layers and interlayer fluid channeling as typical characteristics and the like. Based on the method, the technical scheme provided by the invention is provided, specifically, an efficient well pattern deployment method is provided for the high-permeability water channeling caused by the development of the vertical well general injection well pattern of the huge thick carbonate rock and the oil reservoirs with fluid channeling between different layers of the reservoir, so that the high-efficiency utilization and water channeling management of the huge thick carbonate rock and the risk avoidance of interlayer channeling (the reasonable utilization of a large number of drilled old wells is further realized in a preferred embodiment) are realized, the water driving control and the utilization degree of an oil field well pattern are improved, and the problem of the water injection development well pattern deployment of the huge thick carbonate rock oil field is solved; provides technical support for the high-efficiency water injection development of the ultra-thick carbonate reservoir and the later well pattern adjustment.

The technical scheme provided by the invention has certain universality and popularization and application value, and particularly has obvious effects of water injection development, high-efficiency reserve utilization and well pattern adjustment on the huge-thickness pore carbonate reservoir in the middle east area with the reserve and the petroleum yield accounting for more than half of the world.

Drawings

FIG. 1 is a schematic illustration of the development of a longitudinally staged succession of a megalayer in accordance with a preferred embodiment of the invention.

Fig. 2 is a flow chart of a method for adjusting a water injection well pattern of a huge pore type carbonate reservoir with a high permeability layer and an interlayer channeling, which is provided in embodiment 1 of the present invention.

FIG. 3 is a graph showing a cross-sectional view of several representative well fluids for a target reservoir in accordance with example 1 of the present invention.

FIG. 4A shows the interlayer channeling between the K2 layer and the upper K1 layer in example 1 of the present invention.

FIG. 4B shows the interlayer channeling between the K2 layer and the lower K31 layer in example 1 of the present invention.

Fig. 5A is a schematic diagram of a vertical well general flooding pattern.

Fig. 5B is a schematic diagram of a vertical well zonal injection pattern.

Fig. 5C is a schematic diagram of an overall horizontal well pattern.

Fig. 5D is a schematic diagram of a vertical well horizontal well pattern for zonal injection.

FIG. 6A is a graph of the production of different patterns as a function of water content for example 1 of the present invention.

Fig. 6B is a diagram showing the end of contract period index for different extraction levels in embodiment 1 of the present invention.

Fig. 7A is a schematic diagram of a staged reserve utilization strategy for high permeability layer utilization and interlaminar cross-flow risk avoidance in example 1 of the present invention.

Fig. 7B is a schematic diagram of a staged reserve strategy according to embodiment 1 of the present invention.

FIG. 8 is a schematic diagram of a plan zoned old well plan and new well deployment in accordance with example 1 of the present invention.

Fig. 9A is a sequence diagram of the implementation of 13 areas of a single production K1 layer of a general injection production old well in example 1 of the present invention.

Fig. 9B is a schematic diagram of the number of annual construction wells for blocking single production K1 layer of a general injection production old well in example 1 of the present invention.

Fig. 10A is a schematic diagram of a general vertical well pattern in accordance with example 1 of the present invention.

FIG. 10B is a schematic diagram of a transitional development phase fluid-injection well pattern deployment in accordance with example 1 of the present invention.

FIG. 10C is a schematic representation of a main development phase fluid injection well pattern deployment in accordance with example 1 of the present invention.

FIG. 10D is a schematic representation of a subsequent development phase injection well pattern deployment in example 1 of the present invention.

Fig. 10E is a schematic diagram illustrating fig. 10A, 10B, 10C, and 10D.

FIG. 11 is a schematic diagram of a primary horizontal well injection and recovery pattern according to example 1 of the present invention.

FIG. 12 is a graph showing the compensation of the yield loss and the contribution of the K31 layer to the oil reservoir production in example 1 of the present invention.

FIG. 13 is a schematic diagram showing the overall effect of embodiment 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

Example 1

The embodiment provides a method for adjusting a water injection well pattern of a huge-thickness pore type carbonate reservoir with a hypertonic layer and interlayer channeling, which is used for adjusting the water injection well pattern of a certain typical huge-thickness pore type carbonate reservoir.

The main force reservoir lithology of the target area is biological clastic limestone, and 3 treatment stations are sequentially built on the plane from north to south: f8, F7 and F6. The thickness of the oil reservoir is about 200m, the average porosity is 11-35%, the average permeability is 2.0-52.5mD, and the fine stratum is compared with the longitudinal development of 5 layers: k1, K2, K3, K4, K3 comprises 2 layers: the K31 hypertonic layer is mainly and K32 hypotonic but thicker and has larger reserves. The overall longitudinal heterogeneity of the oil reservoir is very serious, the high-permeability strips and the interlayers in the oil reservoir develop, the spatial distribution of the interlayers is complex and changeable, and 3 types of high-permeability layers develop: k1 is a typical particle beach hypertonic layer, a fault is arranged at a high position of the structure to cause microcrack hypertonic layer, K2 is tidal channel, K31 is a hypertonic etching hole, the permeability reaches Darcy level (1000-4000 mD), K32 and K4 are low-permeability compact layers which are not used yet, the permeability is several mD, and the reserve accounts for 1/3 of the total reserve. In the early stage, K1, K2 and K31 are developed by adopting a 900m inverted nine-point vertical well injection and production net system, the sweep degree of a water injection plane and a longitudinal direction is uneven, the water drive reserve utilization degree is low, the water drive recovery ratio is low, the water injection projects into part of high permeable layers, part of oil wells have shorter anhydrous oil recovery period, the water content of the oil wells rises faster after water is taken in the oil wells, the injection ratio of part of well groups is too high, the invalid water circulation problem is gradually developed, the water injection utilization rate is reduced, and the water treatment cost is greatly increased. Dynamic characteristics show that the interlayer channeling and the hypertonic layer have great influence on the water injection development effect, the conventional injection well pattern is not suitable for the special geological characteristics, and a high-efficiency well pattern deployment method aiming at the huge-thickness pore type carbonate rock general injection high-permeability layer channeling and the interlayer channeling is urgently needed to be researched.

As shown in fig. 2, the method specifically comprises the following steps:

1. geological and development characteristic analysis of the huge-thickness pore type carbonate reservoir:

1.1 identification and classification of hypertonic layer: comprehensively identifying a hypertonic layer according to three-dimensional seismic interpretation, logging interpretation, coring well observation and PLT, MDT, PNL dynamic monitoring data, and analyzing the type (divided into a particle beach type, a fault vicinity type, a tidal channel type and a hypertonic solution etching hole type), physical properties and plane longitudinal spreading characteristics;

1.2 Interlayer crossflow layer identification and crossflow calculation: the layer position where the interlayer cross flow occurs is generally related to the development position of tidal channel, tidal channel periodic swing and undercut cause incomplete shielding of the interlayer layers of the upper layer and the lower layer, and local vertical fluid exchange exists between the upper layer and the lower layer;

determining different development units through fine geological small layer comparison analysis; comprehensively determining the distribution position of the interlayer according to the electrical response of logging and the monitoring data of water absorption of production fluid, particularly the development and superposition conditions of tidal channel in different periods, counting the thickness of the single-well interlayer, and comprehensively analyzing the characteristics of interlayer channeling; tracking the fluid migration law by adopting the tracer, calculating the oil quantity and the water quantity of the interlayer fluid channeling, and determining the qualitative and quantitative influence of the interlayer fluid channeling on the development effect.

Analysis shows that the target oil reservoir develops 3 types of hypertonic layers: k1 is mainly deposited on a hillside body on an inner gentle slope background; k2 is tidal channel deposition on the lagoon background; k31 is a hypertonic layer, mainly a granular beach deposit; k32 is the outer gentle slope deposition. Between K1 and K2 there is a stable interlayer C2 distributed throughout the oil field. K31 thief layers and K2 some local hypertonic layers develop solution holes, causing severe longitudinal heterogeneity. The thickness and average permeability of the different layers are shown in table 1.

TABLE 1

The target oil reservoir only uses K1, K2 and K31 layers, the use degree of the reservoir layer is greatly different, and as shown in a few typical well liquid profile tests of fig. 3, the yield of K1, K2 and K31 accounts for about 22%, 36% and 42% of the total production yield, and the water absorption contribution of the K31 layers is close to 2/3. The method shows that the current injected water mainly bursts along the K31 hypertonic layer, so that the longitudinal utilization degree of the total reserve is low, only 43% is generated at present, and the gradual descending trend is generated along with the pushing of water injection.

The interlayer channeling of the target oil reservoir is serious and is mainly characterized in that the K2 tidal channel and the K31 hypertonic solution etching hole layer are bonded, as shown by interlayer thickness statistics in Table 2: k2 and K31 no matter the old well and the new well have no interlayer, the communication rate reaches 60 percent, and if the interlayer of 1 meter is considered to be unable to be separated, the communication rate reaches about 90 percent. The overall K2 and K3 are basically communicated, but a small amount of interlayer exists on the upper part, the middle part and the lower part of the K2 tidal channel, so that a certain beneficial space is provided for tidal channel to develop the water channeling prevention.

TABLE 2

Sandwich thickness (Rice)	0	1	2	3	≥4
						Well number (mouth)	76	36	6	4	3
Percentage (%)	61％	29％	5％	3％	2％
						Cumulative percentage (%)	61％	90％	94％	98％	100％

The tracer is used for marking the K2 oil-water phase, the amount of the marker is found on the upper layer and the lower layer of the K2 through numerical simulation, and as shown in figures 4A-4B, the result shows that the K2 and the upper layer and the lower layer have flow, the oil channeling ratio is 5-8%, and the water channeling ratio is 10-19%.

K1 to K2 crossflow: the oil amount is 5% of the total accumulated oil production, the water amount is 19% of the total water production, and the total water injection is 7%.

K2 to K31 crossflow: the oil amount is 8% of total accumulated oil, the water amount is 10% of total produced water, and the total injected water is 4%.

2. Reserve usage classification based on hypertonic layer characteristics, reservoir physical properties, and development risk:

based on the type of the high permeability layer and the interlayer channeling layer, the permeability rate is combined, and reserve utilization level division is carried out on various reservoirs in the target huge-thickness pore type carbonate reservoir according to the utilization difficulty, and is divided into:

A first type of reservoir: an unused high quality layer, an unused medium quality layer; wherein the medium quality layer comprises a granule beach type high permeability layer, a fault vicinity type high permeability layer and a medium permeability layer, and the permeability is less than 1000mD and not less than 10mD; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, and the permeability of the high-quality layer is 1000mD-4000mD; such reservoirs are easy to use, reserves are easy to use, and single well productivity is high;

A second type of reservoir: a used high quality layer and a used medium quality layer; wherein the medium quality layer comprises a granule beach type high permeability layer, a fault vicinity type high permeability layer and a medium permeability layer, and the permeability is less than 1000mD and not less than 10mD; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, and the permeability of the high-quality layer is 1000mD-4000mD; the second reservoir is easy to use, the reserve is easy to use, and the single well productivity is high;

Third class of reservoirs: a hypotonic tight reservoir comprising a permeability of less than 10mD and not less than 1 mD; the third easy-to-use small layer of the reservoir is the penultimate easy-to-use, the vertical well is difficult to use, the natural productivity is low, and the acidizing production is generally performed through the horizontal well;

a fourth type of reservoir: comprises a difficult extremely compact layer with permeability lower than 1mD and a tidal channel high-permeability layer; the fourth easy-to-use method is the most difficult-to-use method, the reserve of the ultra-compact layer is difficult to use, natural energy production is generally avoided, and the production can be put into production by means of horizontal well acid fracturing or even multistage fracturing yield increasing measures; the tidal channel type hypertonic layer is usually an interlayer channeling layer with higher utilization risk, and is used as an interlayer in the early stage and in the later stage of development in order to avoid the influence on the deployment of a well pattern on an oil field.

The results of the target reservoir type partitioning are shown in table 1.

3. Staged reserve utilization strategy

3.1 Development period partitioning based on yield targets: according to the set yield target of the oil field, dividing different development stages in the water injection well pattern adjustment process of the huge-thickness pore type carbonate reservoir: the DP1 transitional development period, the DP2 main development period and the DP3 take over the development period as the adjustment basis of the staged well pattern, different strategy and development well patterns are adopted in different development stages, the well patterns of the horizontal wells with different strategies are distributed longitudinally in a staggered manner, so that the water breakthrough time of the horizontal wells is delayed, and the reserve utilization degree is improved;

stage DP 1: a transition development period, which is used as a transition output period before the output of the oil field reaches a peak output target;

Stage DP 2: after the main development period and DP1, the main development period mainly comprises an ascending phase and a stable production phase, wherein the oil reservoir yield reaches the final peak yield target;

Stage DP 3: following the development period, DP2, the reservoir stable period, the maintenance of peak production, and the subsequent production decline.

3.2 Longitudinal reserve utilization order

DP1 phase (transitional development phase): the high-permeability layer is preferentially used as a reserve foundation for quick production, and along with development and promotion, the injection and production well of the high-permeability layer is gradually plugged according to the established oilfield water content standard, so that water breakthrough of a large-scale oil well is avoided; and meanwhile, the adjustment of the existing well pattern is also considered. The deployment of the stage not only ensures the requirement of quick production in the oil field, but also avoids large-area flooding caused by water channeling of injected water along a hypertonic layer.

DP2 stage (subject development period): sidetrack drilling and new well drilling are carried out on the high permeability layer development well to form a scale development well pattern, and main reserves accounting for most of the oil deposit geological reserves are used as main substance foundations for stable upper oil deposit production;

DP3 phase (successor development phase): the reserve of the interlayer channeling layer with larger uncertainty and other difficult low-permeability tight reserves are used, the stable production period is properly prolonged, adverse effects caused by interlayer channeling are reduced as much as possible, the yield progressive rate is reduced, and the total recovery degree in the same period is increased.

The reserves of the interlayer channeling layers (generally referred to as tidal channel layers) for delay use. For a reservoir of the type tidal channel, the physical properties of tidal channel and tidal channel are very different, the permeability is very poor exceeding 50, the reserves of tidal channel are generally difficult to use, the contribution of tidal channel is very small for the simulation result of a preferred model, the recovery is only 5%, and the recovery of tidal channel is as high as 24%. Thus, in tidal channel sedimentary type reservoirs, only tidal channel was determined as the main development goal, with no effort between tidal channel.

3.3 Planar reserve order: according to reservoir plane physical property distribution diagrams and ground treatment facility distribution diagrams of lithofacies constraint control on porosity, permeability and the like, a ground facility is taken as a unit, and a reserve plane utilization sequence is comprehensively divided. And according to the sequence from good to bad and from difficult to easy, the longitudinal reserve utilization sequence and the difficulty of implementation of ground supporting facilities are combined, and comprehensive deployment adjustment of the well pattern is implemented. In general, the DP1 and DP2 phases are mainly the reserve with good physical properties, and the DP3 phase is the reserve with a thin difference layer.

The formulated phased reserve usage strategy is:

1) Dividing the production stages of the up-production and stable-production to gradually build the production according to the set peak production target of 110 ten thousand barrels per day of the up-production of the oil reservoir: a transitional development period, a main development period and a succession development period. The transitional development period is 2020-2024, and the transitional yield is 70 ten thousand barrels per day; the main development period is 2025-2033 well pattern deployment, and the upper production of 2028 to 110 thousand barrels per day and stable production of 2037 are ensured; the succession development period is 2034-2036, the reserve is continued to prolong the stable production period, the yield is stabilized at 110 ten thousand barrels per day, and the yield is reduced in 2038. Different well pattern strategies are formulated at different stages, as shown in fig. 7A, 7B and 8.

2) And 3 area units are divided according to physical property distribution of reservoirs in different areas on a plane according to treatment stations: north, middle and south areas, each having a processing station. The overall physical properties tend to be progressively inferior in the south-to-south direction, with the best middle region and the inferior north region.

4. Development well pattern and selection

4.1 General injection and production old well pattern selection

To release the lower interval potential and reduce inter-layer interference, the old well is plugged with K1 alone in stages. According to the physical property distribution and the treatment station distribution of the plane, the old well operation sequence is sequentially carried out according to 13 areas of the plane, namely the sequence of firstly distinguishing the area, secondly distinguishing the area and then distinguishing the area from the north area and finally distinguishing the area from the south area. The method is implemented gradually from the date of production, and the single production operation 388 wells are plugged within 5 years, and all old wells are single-produced in K1 layers, as shown in figures 9A-9B.

4.2 Development of patterns and well demonstration

And establishing a typical mechanism model capable of reflecting the distribution characteristics of the hypertonic layer according to the history fitting actual model, researching and developing the influence of well pattern adjustment on the water injection development effect, and guiding later-stage layer-system well pattern adjustment. Comprehensively comparing the development effects of the vertical well anti-nine point general injection and production, the vertical well anti-nine point encryption into a five-point general injection and production well pattern, the vertical well anti-nine point layered injection and horizontal well pattern layered development, and the vertical well + horizontal well layered development well pattern 5-layer system well pattern scheme, quantitatively determining the influence of a high permeability layer on layer system well pattern adjustment, and guiding the well pattern deployment of a high permeability layer oil reservoir. The relationship between water content and production degree of different well patterns is shown in fig. 6A, and the end-of-contract index is shown in fig. 6B. Simulation results show that the basic well pattern (vertical well reverse nine-point general injection production) of the scheme 1 has low water content production speed and low water content, and the final recovery degree of the contract period is the lowest and only 11%; scheme 2 the vertical well is inverted to nine-point encryption, five-point general injection and production is converted into a point weak surface strong well pattern, the injection and production perfection degree is improved, the water injection amount and the water content are both increased, and the production degree is increased by 12.5%; scheme 3 vertical well separate layer water injection solves the interlayer contradiction, and the extraction degree is increased to 18.1%; the overall horizontal well pattern layering development of the scheme 4 is that the water content is greatly reduced under the condition that the extraction degree of the scheme 3 is equivalent; the maximum exploitation and extraction degree of the vertical well and horizontal well pattern layered development in scheme 5 is 24%, the water content is 57.6%, and is slightly lower than the water content of 58.1% in scheme 5, so that the method is the optimal scheme. In a carbonate oil reservoir with a high-permeability layer, even if a vertical well adopts separated-layer water injection, the high-permeability layer in the vertical well can cause rapid breakthrough of injected water, so that the extraction degree is influenced; and better development effect can be obtained by comprehensively utilizing staggered linear horizontal well patterns and vertical well reverse nine-point well pattern layering system development.

Thus, the determined development patterns are:

old well pattern adjustments have been developed: the existing development well and the single-production K1 layer are plugged and still kept as the vertical well injection and production well pattern, the encryption well is deployed in the northwest part and the northeast part, the injection and production relation is perfected, and the relatively perfect anti-nine-point vertical well injection and production well pattern is formed.

New well pattern with unused reserves: unused K32 and K42 account for more than 1/3 of the total reserve and are important potential for future production. And 2km horizontal well development is adopted, and the horizontal well development is bottom injection top production and staggered horizontal well injection well patterns.

Postpone the well pattern developed: the K2 layer tidal channel has a large periodic oscillation, and is stacked longitudinally to form a multi-stage tidal channel composite, and the tidal channel undercut results in vertical fluid exchange with the lower K31 layer. Tidal channel is 2-3km in width, and the irregular anti-five-point well pattern with weak points and weak planes is formed through newly drilling a straight well.

5. Oil-water well deployment location under phased reserve utilization strategy

The method for adjusting the water injection well pattern of the huge-thickness pore type carbonate reservoir based on the analysis of the steps 1-4 comprises the following specific steps:

4.1 development layer division: based on the distribution of the interlayer of the target huge-thickness pore carbonate and the distribution of the channeling layers, longitudinally dividing the development layer system of the target huge-thickness pore carbonate reservoir (dividing the development layer system by taking each interlayer with complete development and each interlayer channeling layer as boundaries, and taking each interlayer channeling layer as an independent development layer system respectively); wherein the interlayer channeling layer is used as an independent development layer, and the giant layer is used as an independent development layer;

from this, it can be seen that: k1 is a development layer, K2 is a development layer (the development layer is an interlayer channeling layer), and K31-K4 is a development layer (the development layer is a giant layer);

Dividing the giant thick layer into a first class of small layers, a second class of small layers, a third class of small layers and a fourth class of small layers; the first type of small layer is a small layer mainly comprising a first type of reservoir; the second class of small layers are small layers mainly comprising the second class of reservoir; the third class of small layers are small layers mainly comprising a third class of reservoir; the fourth class of small layers are small layers mainly comprising fourth class of reservoir layers;

from this, it can be seen that: the middle region and the north region K31-K4 giant thick layers are divided into a second class of small layers (K31 layers), a first class of small layers (middle upper part of a K32 layer) and a third class of small layers (middle lower part of the K32 layer and the K4 layer) from top to bottom in the longitudinal direction of the giant thick layers developed by stages; the longitudinal direction of the south area K31-K4 giant thick layer is divided into a third class of small layers (the upper part of the K31 layer and the upper part of the K32 layer) and a fourth class of small layers (the middle lower part of the K32 layer and the K4 layer) from top to bottom;

Taking into consideration the space configuration of longitudinal different types of hypertonic layers, interlayer channeling layers, 13 planar areas and different well patterns, the phased three-dimensional well pattern adjustment is carried out according to the transitional development period, the main development period and the succession development period. The general method is that 1 set of vertical well pattern is changed into 3 sets of well patterns: k1, K2 and K3-K4, wherein K1 and K2 are developed by adopting a vertical well and K3-K4 are developed by adopting a horizontal well, the physical properties of reservoir fluid are taken into consideration to set the development well spacing, the water breakthrough time of the horizontal well of the lower reservoir is delayed, the yield of dry oil is increased, and the overall utilization degree is improved.

4.2 Water injection well pattern adjustment in stages

(1) Transitional development period:

① Old well plugging single production: the existing nine-point well pattern vertical well combined production and combined injection well workover operation is carried out, K2 and K31 are plugged in the whole area, K1 is singly produced, and the original 900m vertical well nine-point well pattern is maintained; the old well adopts K1 layer singly, which not only can obtain higher extraction degree, but also is easy to adjust and saves investment.

And (3) drilling a straight well at the northwest and northeast parts without well control in K1, drilling a new well 36, perfecting the injection and production relation, forming a perfect inverted nine-point straight well injection and production well network, and improving the water drive reserve control degree.

② Unused lower reservoirs K3, K4 new well deployment:

And (3) deploying a first injection and production well pattern of the bottom injection and top production staggered linear horizontal well on a first small layer developed in the middle region K32 layer, wherein the well pitch of an upper production well is 900m, and the well pitch of a lower injection well is 900m.

And (3) deploying a first injection and production well pattern of the bottom injection and top production staggered linear horizontal well on a first small layer developed in the K32 layer of the north region, wherein the well spacing of the upper production well is 900m, and the well spacing of the lower injection well is 900m.

Before deployment of new wells in the middle zone K32 layer and the north zone K32 layer, a pilot test zone can be opened up to test production capacity and injection capacity, and risks of comprehensive deployment and development of new wells in the middle zone K32 layer and the north zone K32 layer are reduced.

(2) Main development period:

For the middle region: plugging a water injection well row of a first injection well pattern deployed in a first small layer developed in a middle K32 layer, drilling a water injection well of the first injection well pattern downwards and sideways at the bottom of a third type of reservoir developed in the middle K32 layer to form a new horizontal water injection well, and drilling a new horizontal water injection well at the bottom of the third type of reservoir developed in the middle K32 layer to form a new encrypted water injection well row as a water injection well row of a second injection well pattern; plugging a production well row of a first injection well pattern deployed in a first small layer developed in a middle K32 layer, drilling the production well of the first injection well pattern to the upper side to form a new horizontal production well at the top of a second type reservoir developed in the middle K31 layer, and drilling the new horizontal production well at the top of the second type reservoir developed in the middle K31 layer, thereby forming a new encrypted production well row as the production well row of the second injection well pattern; using a second injection well pattern to perform middle zone K3 layer mining; wherein the production well spacing of the second fluid injection well pattern is 450m and the production well spacing of the second fluid injection well pattern is 450m.

For the north region: plugging a water injection well row of a first injection well pattern deployed in the north of a first small layer developed in the north region K32, drilling a water injection well of the first injection well pattern downwards at the bottom of a third type of reservoir developed in the north region K32 to form a new horizontal water injection well, and drilling a new horizontal water injection well at the bottom of a third type of reservoir developed in the north region K32 to form a new encrypted water injection well row serving as a water injection well row of a second injection well pattern; plugging a production well row of a first injection well pattern deployed in the north of a first small layer developed in the north region K32, drilling the production well of the first injection well pattern upwards to form a new horizontal production well at the top of a second type of reservoir developed in the north region K31, and drilling a new horizontal production well at the top of a second type of reservoir developed in the north region K31, thereby forming a new encrypted production well row as the production well row of the second injection well pattern; carrying out K3 layer mining in the north region by using a second flooding well pattern; wherein the production well spacing of the second fluid injection well pattern is 300m and the production well spacing of the second fluid injection well pattern is 450m.

For the south region: 2km horizontal production wells are drilled in the middle of the K31 layer in the north area, and the well spacing is 900m; 2km horizontal water injection wells are drilled on the dense layer in the middle of the north region K32, and because of the low-permeability compactness of the south region K32 and poor injection capability, the well spacing of the water injection wells is reduced to 300m, so that continuous water injection lines are formed for uniformly displacing crude oil from bottom to top.

For middle and south regions: a horizontal production well row with a well spacing of 300m is deployed below a K4 reservoir lithology interlayer of the middle zone and the north zone, and a third injection well pattern with middle injection and up-down production is formed with the water injection well row and the production well row of the original second injection well pattern; the displacement energy is used for maintaining the peak output and stable output by means of the water injection well row at the bottom of the K32.

(3) Successor development period:

end-of-labor stabilization with K2 tidal channel reserves: the K32 layer which is rich in unused reserves and produces dry oil is preferentially developed, and then the K2 layer which has good physical properties but is not flooded is developed. Considering the existence of adhesion between K2 tidal channel and K31 hypertonic layers, the development scheme considers K2 as a barrier layer between K1 and K3-K4 layers in 2020-2030, and no production well is deployed. In 2031, 98 vertical wells are deployed in K2 tidal channel to form a 900m irregular five-point well pattern, and after production, the peak yield is prolonged by 1-2 years, so that the risk of interlayer channeling is avoided in the main development period, the static and dynamic characteristics of tidal channel are fully known, and the deployment method is a reliable and reliable deployment method.

In the later development stage 2032-2034, a multistage fracturing horizontal production well and a water injection well are arranged in the lower hypotonic compact layer in the south K32, the well spacing is 300m, the stable production period is prolonged, and the yield decline is slowed down.

TABLE 3 Table 3

In summary, through 3 development periods, the whole area can be divided into 13 areas based on the horizontal well position, and 13 types of horizontal wells are shared according to the horizons and the areas. The 2020-2034 years drill 320 horizontal production wells and 321 horizontal water injection wells altogether. As shown in table 3 and fig. 10A-11.

The invention has obvious effect of controlling water in the research area. Through the adjustment of the general development well pattern, 641 horizontal wells and 134 vertical wells are drilled together, the number of drilling machines reaches 2,3, 4, 5 and 6 in 5 years of production, and 60 wells are drilled every year at most, so that the practical and feasible layered water injection well pattern deployment of the vertical wells and the horizontal wells is formed, the risk of interlayer channeling is effectively utilized, and the development problems of rapid water rise, low reserve and serious interlayer interference caused by the water channeling of the general injection and production high-permeability layer are effectively avoided.

The production target of 70 ten thousand barrels per day in the transitional period is built in 4 years, the peak production target of 110 ten thousand barrels per day is built in 8 years, and compared with the corresponding time of the original scheme, the full utilization of the transitional period hypertonic layer is advanced by 3 years and 2 years, so that the production reduction caused by the plugging single production of the old well is compensated, and the deployed horizontal well pattern becomes an important contribution to the production of the oil reservoir, as shown in fig. 12. After adjustment, the new well count is decremented 388. The average single well production is improved by a factor of 3.

The water channeling of the general injection and production hypertonic layer causes the rapid rise of water content and the whole reserve utilization degree to be only 43 percent, and the multi-layer injection and production span is large, so that the backward flow and the interlayer interference are serious after the well is closed. From the water-extraction degree before and after adjustment, the water-containing rising rule is obviously changed after the well pattern adjustment of the high permeability layer and the interlaminar channeling is considered, and the S-shaped faster rising curve caused by the water channeling of the high permeability layer of the early injection water of the general injection well pattern is changed into a slowly rising concave curve; the 900m reverse nine points of the general flooding well pattern in the later development stage are changed into 636m five-point method weak-face strong well pattern through corner well transfer, side well transfer and oil well encryption, then the oil well encryption and encryption well transfer forms a 450m five-point method dense well pattern, the water content is lowered to some extent, the water content is raised, and the well pattern is always in a slow rising trend after adjustment. After the adjustment, the comprehensive water content at the end of the contract period is reduced from 73% to 67%, the longitudinal reserve utilization degree is improved from 43% to more than 85%, the geological reserve extraction degree is improved from 24.3% to 28.1%, and the development effect is greatly improved, as shown in fig. 13.

Claims

1. A method for adjusting a water injection well pattern of a huge-thickness pore type carbonate reservoir with a hypertonic layer and interlayer channeling, wherein the method comprises the following steps:

Longitudinally dividing a development layer system of a target huge-thickness pore type carbonate reservoir; wherein the interlayer channeling layer is used as an independent development layer, and the giant layer is used as an independent development layer;

Carrying out longitudinal staged succession development on the giant thick layer; wherein the longitudinally phased succession development comprises: setting a first injection well pattern in the giant-layer for development, closing the first injection well pattern after development for a period of time, and setting a second injection well pattern in different longitudinal positions in the giant-layer for development, wherein the first injection well pattern and the second injection well pattern are positioned at different depths in the same area of the giant-layer; wherein, the top of the huge thick layer developed by successive stages in the longitudinal direction develops a high-permeability erosion hole type high-permeability layer;

wherein, the development of the longitudinal staged succession is specifically as follows:

4) Development continues with the second fluid-filled well pattern.

2. The method of claim 1, wherein developing a stratigraphic division of a target giant-thickness pore carbonate reservoir comprises:

the target huge-thickness pore carbonate reservoir development layer system is divided based on the target huge-thickness pore carbonate interlayer distribution and the cross-flow layer distribution.

3. The method of claim 2, wherein partitioning the target ultra-thick pore carbonate reservoir development layer system comprises: dividing the layers by taking each fully developed interlayer and each interlayer channeling layer as boundaries, and taking each interlayer channeling layer as an independent development layer respectively; at this time, the inside of each development layer is not a complete interlayer.

4. A method according to any one of claims 1-3, wherein the channeling layer is tidal channel layers.

5. The method of claim 1, wherein when the longitudinally staged take over development of the megathick layer has been provided with the pattern, the pattern provided by the megathick layer is plugged prior to or prior to longitudinally staged take over development of the megathick layer.

6. The method of claim 1, wherein the old well in which the longitudinally staged succession of developed megalayers was originally placed is returned to other deployed development layers other than the megalayers, the crossflow layers, and the other deployed development layers are mined.

7. The method of any of claims 1-6, wherein the phased succession development in the machine direction is performed with a progressive increase in the well spacing in the machine direction.

8. The method of claim 1, wherein a spacing between water injection wells of the first injection well pattern is greater than a spacing between water injection wells of the second injection well pattern; the interval between production wells of the first fluid injection well pattern is greater than the interval between production wells of the second fluid injection well pattern.

9. The method of claim 1, wherein a third fluid injection pattern is set for development during the longitudinal staged succession of development of the megalayer; and the third injection well pattern is a middle injection and upper and lower simultaneous production well pattern.

10. The method of claim 9, wherein the method further comprises:

A first type of reservoir: an unused high quality layer, an unused medium quality layer; wherein the medium quality layer comprises a granule beach type high permeability layer, a fault vicinity type high permeability layer and a medium permeability layer, and the permeability is less than 1000mD and not less than 10mD; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, and the permeability of the high-quality layer is 1000mD-4000mD;

a second type of reservoir: a used high quality layer and a used medium quality layer; wherein the medium quality layer comprises a granule beach type high permeability layer, a fault vicinity type high permeability layer and a medium permeability layer, and the permeability is less than 1000mD and not less than 10mD; the high-quality layer comprises a high-permeability corrosion hole type high-permeability layer, and the permeability of the high-quality layer is 1000mD-4000mD;

A fourth type of reservoir: a difficult extremely dense layer with permeability lower than 1mD and tidal channel type hypertonic layer, i.e. an interlayer channeling layer.

11. The method of claim 9, wherein the method further comprises:

12. The method of claim 10 or 11, wherein the giant-layer is sub-divided into a first class of sub-layers, a second class of sub-layers, a third class of sub-layers, and a fourth class of sub-layers; wherein the first type of small layer is a small layer mainly comprising a first type of reservoir; the second class of small layers are small layers mainly comprising the second class of reservoir; the third class of small layers are small layers mainly comprising a third class of reservoir; the fourth class of small layers are small layers mainly comprising fourth class of reservoir layers;

the lower production well row of the third injection well pattern is arranged at the middle or bottom of the third class of small layers.

13. The method of claim 12, wherein the ultra-thick pore carbonate reservoir water injection pattern adjustment process divides the different development phases: a transitional development period, a main development period and a succession development period;

The following steps are carried out in the succession development period: the development layer based on the fourth type of reservoir and/or the small layer based on the fourth type of reservoir in the giant-thick layer.

14. The method of claim 13, wherein the uphole returning old wells originally disposed in the giant-thickness pore carbonate reservoir to other activated development layers other than the giant-thickness, fluid-channeling layer and single-layer production using the uphole old wells comprises:

Then, carrying out upward returning on the old wells of other development layers except the giant thick layer developed in succession by stages, and carrying out single-layer exploitation by using the upward returning old wells; wherein, the lying well in the layers is returned first, and then the other old wells in the layers are returned.

15. The method of claim 13, wherein the transition development phase is further performed:

Well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a first type of reservoir; well patterns are deployed in the megathick layer where no phased succession development occurs in the machine direction to develop the first class of small layers.

16. The method of claim 13, wherein the further performing during the subject development period:

Well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a third type of reservoir; well patterns are arranged in the huge thick layer which is not subjected to longitudinal staged succession development to develop the second type of small layers and the third type of small layers.

17. The method of claim 13, wherein the succession development period is further performed:

well pattern layout and development are carried out in a development layer system which is not a giant thick layer and mainly comprises a fourth type of reservoir; well patterns are placed in the giant-layer to develop a fourth class of small layers.

18. The method of claim 13, wherein,

The channeling layer development layer is developed by selecting a vertical well pattern;

staggered linear horizontal well injection and production patterns are adopted in the giant thick layer developed by successive stages in the longitudinal direction.