CN114135258B - Indoor judging method for gas cap formation and expansion rule in top gas injection process - Google Patents
Indoor judging method for gas cap formation and expansion rule in top gas injection process Download PDFInfo
- Publication number
- CN114135258B CN114135258B CN202111442286.5A CN202111442286A CN114135258B CN 114135258 B CN114135258 B CN 114135258B CN 202111442286 A CN202111442286 A CN 202111442286A CN 114135258 B CN114135258 B CN 114135258B
- Authority
- CN
- China
- Prior art keywords
- gas
- gas cap
- stage
- cap
- recovery ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000002347 injection Methods 0.000 title claims abstract description 84
- 239000007924 injection Substances 0.000 title claims abstract description 84
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 56
- 230000008569 process Effects 0.000 title claims abstract description 31
- 238000011084 recovery Methods 0.000 claims abstract description 87
- 238000006073 displacement reaction Methods 0.000 claims abstract description 80
- 230000000007 visual effect Effects 0.000 claims abstract description 56
- 238000004519 manufacturing process Methods 0.000 claims abstract description 28
- 239000004576 sand Substances 0.000 claims abstract description 25
- 230000008859 change Effects 0.000 claims abstract description 22
- 238000002474 experimental method Methods 0.000 claims abstract description 12
- 238000004088 simulation Methods 0.000 claims abstract description 8
- 238000013508 migration Methods 0.000 claims abstract description 5
- 230000005012 migration Effects 0.000 claims abstract description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 230000005484 gravity Effects 0.000 claims description 13
- 230000035699 permeability Effects 0.000 claims description 12
- 229920006395 saturated elastomer Polymers 0.000 claims description 9
- 230000009699 differential effect Effects 0.000 claims description 6
- 239000006004 Quartz sand Substances 0.000 claims description 4
- 239000008398 formation water Substances 0.000 claims description 4
- 230000007423 decrease Effects 0.000 claims description 3
- 238000009738 saturating Methods 0.000 claims description 2
- 239000012530 fluid Substances 0.000 abstract description 4
- 239000003921 oil Substances 0.000 description 45
- 238000011160 research Methods 0.000 description 11
- 238000011161 development Methods 0.000 description 6
- 239000010779 crude oil Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009933 burial Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000000556 factor analysis Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/002—Survey of boreholes or wells by visual inspection
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/40—Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
Abstract
The invention relates to an indoor judging method for forming and expanding a gas cap in the top gas injection process, which comprises the following steps: s1, acquiring a gas cap gas drive displacement pressure difference, a recovery ratio dynamic curve and a gas cap front edge visual image, wherein the gas cap gas drive displacement pressure difference, the recovery ratio dynamic curve and the gas cap front edge visual image specifically comprise manufacturing of a high-dip angle oil reservoir visual physical model and a gas cap gas drive visual physical simulation experiment; s2, dividing stages of a gas cap front edge migration rule and an expansion rule: and (3) dividing the injected artificial gas cap into two stages of gas cap formation and gas cap expansion according to the displacement pressure difference and recovery ratio production dynamic curve obtained in the step (S1) and by combining the gas cap front edge visual change image. Based on simulating the reservoir fluid and physical conditions of an inclined oil reservoir, the method acquires a displacement pressure difference and recovery ratio change relation curve along with the gas injection amount in the top gas injection process by means of a top gas injection visual sand pipe displacement experiment, and combines a gas top front edge change characteristic image photographed by a high-definition camera in real time so as to determine the formation and expansion rule of a gas top.
Description
Technical Field
The invention relates to the technical field of inclined oil reservoir gas injection development, in particular to an indoor judging method for a gas cap forming and expanding rule in a top gas injection process.
Background
From the aspect of oil reservoir structure characteristics in China, a great part of inclined oil reservoirs belonging to anticline structures and down-the-hill structures exist, most of the oil reservoirs have the characteristics of deep burial, high closure degree, large oil reservoir dip angle, oil layer thickness and the like, and some of the oil reservoirs also have the characteristics of primary gas tops, side bottom water and the like. When developing such reservoirs, failure recovery usually forms a secondary gas cap due to separation of dissolved gas and gravity separation, and after water flooding, "attic oil" is often formed at the top of the reservoir, which affects the water flooding development effect.
How to avoid the defects caused by failure exploitation and water-flooding exploitation, reasonably utilizes oil and gas resources, and has important practical significance for improving the oil field recovery ratio. Top gas injection is considered to be one of the potential methods to effectively enhance such reservoir recovery. According to the method, the "attic oil" which cannot be used by water driving can be effectively displaced by utilizing the density difference existing between the injected gas and the crude oil through gas injection at the top of the oil reservoir and oil extraction at the bottom of the oil reservoir. The method has the characteristics of controlling the gas-oil-water interface, keeping the pressure of the oil reservoir and the like, and is an effective means for reasonably developing, utilizing and storing oil-gas resources.
At present, research on improving recovery ratio by top gas injection mainly takes practical application, and research on aspects of oil reservoir influence factor analysis, oil well productivity evaluation, development mode optimization, development strategy adjustment and the like is carried out from a macroscopic level mostly based on development requirements and targets of practical oil reservoirs, and the adopted research methods mainly comprise theoretical deduction and numerical simulation. The research of the related mechanism aiming at top gas injection is mostly concentrated on the aspects of local stress analysis, oil-gas interface migration and the like, the research method is still limited to theoretical deduction and numerical simulation, and the research of the related work carried out by adopting a physical simulation means is freshly reported. In recent years, with the continuous improvement of research means and the continuous and deep research degree, research aspects begin to gradually relate to internal mechanism explanation, and physical research means are increasingly applied. However, in general, the existing research work is far from sufficient, especially how the gas cap is formed and further expanded in the whole process of top gas injection, and the effect of the gas cap on the exploitation effect is influenced, so that the system knowledge in the aspect is still lacking, and a related rule judging method is further lacking.
Disclosure of Invention
The invention aims to solve the technical problems that: in order to overcome the defects in the prior art, the invention provides an indoor judging method for a gas cap forming and expanding rule in a top gas injection process, which is used for acquiring a displacement pressure difference and recovery ratio changing relation curve along with gas injection quantity in the top gas injection process by means of a top gas injection visual long sand pipe displacement experiment on the basis of simulating the fluid and physical property conditions of an inclined oil reservoir, and determining the forming and expanding rule of the gas cap by combining a gas cap front edge changing characteristic image photographed by a high-definition camera in real time.
The technical scheme adopted for solving the technical problems is as follows: an indoor judging method for forming and expanding rule of gas cap in top gas injection process comprises the following steps:
s1, acquiring a gas cap gas drive displacement differential pressure, a recovery ratio dynamic curve and a gas cap front edge visual image:
s1-1, manufacturing a high-dip angle oil reservoir visual physical model: according to the porosity, permeability and stratum dip angle reservoir conditions of the target block reservoir, adopting quartz sand to fill and manufacture a visual sand filling pipe model, setting the included angle between the sand filling pipe model and the horizontal direction as the stratum dip angle, and simulating the dip reservoir; saturating formation oil in the model based on the saturated formation water to produce a irreducible water saturation and an initial oil saturation;
s2-2, a gas cap gas drive visual physical simulation experiment: continuously injecting gas into the model at a certain flow rate to develop a top gas injection visual long sand pipe displacement experiment; recording experimental data of displacement pressure difference and oil recovery at intervals in the experimental process, and shooting the change characteristics of the gas cap front edge in the visual model in real time by adopting a high-definition camera; after the experiment is finished, calculating the gas cap gas drive recovery ratio, and drawing a change relation curve of displacement pressure difference and recovery ratio along with the gas injection amount; according to the obtained displacement pressure difference and recovery ratio production dynamic curve, the formation and expansion rule of the gas cap is comprehensively determined by combining the visual change characteristics of the front edge of the gas cap;
s2, dividing stages of a gas cap front edge migration rule and an expansion rule:
according to the displacement pressure difference and the recovery ratio production dynamic curve obtained in the step S1, the injected artificial gas cap is divided into two stages of gas cap formation and gas cap expansion by combining a gas cap front edge visual change image;
gas cap formation stage: in the stage, the artificial gas cap is gradually formed, no gas is seen at the outlet end, namely the injected gas is not broken through, the displacement pressure difference is rapidly increased, the recovery ratio is gradually increased, and the contribution of the whole device to the final recovery ratio is smaller;
stage of gas cap expansion: the artificial gas cap formed during this stage is gradually enlarged, the injected gas has broken through, the displacement pressure differential is gradually reduced and tends to be smooth, the recovery rate is gradually increased and tends to be smooth, and the final recovery rate contributes mostly to this stage.
Preferably, in the step S1, the permeability of the sand filling pipe used for the visual sand filling pipe model is 100-10000×10 -3 μm 2 The length is 30-100 cm, the diameter is 2-5 cm, and the stratum dip angle is 0-90 degrees.
Further, in the step S2, the gas cap formation stage may be subdivided into an early gas cap formation stage a and a late gas cap formation stage B;
stage a-early stage of gas cap formation: the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front edge is integrally pushed forward in a slug mode, and piston type displacement characteristics are presented;
stage B-advanced gas cap formation: the displacement pressure difference continues to increase to the highest point, and the recovery ratio is rapidly increased; the periphery of the gas cap front edge is unchanged temporarily, but is influenced by the non-uniformity of the model, fingering occurs in the model inside the gas cap front edge, a dominant channel is gradually formed, and injected gas presents a non-piston displacement characteristic.
In the step S2, the gas cap expansion stage may be divided into an early gas cap expansion stage C and an late gas cap expansion stage D;
stage C-early stage of gas cap expansion: after the injected gas breaks through, the displacement pressure difference gradually decreases, and the recovery ratio is rapidly increased; the gravity differential action is gradually developed, the air dome begins to float upwards, and the upper part of the periphery of the front edge is gradually enlarged; meanwhile, the dominant channel in the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased;
stage D-advanced gas cap expansion: the gas is suddenly fed along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is slowly increased and the recovery ratio is stable; in this stage, gravity difference plays a dominant role, the whole air cap is pushed forward horizontally, and the air cap range is further enlarged.
The beneficial effects of the invention are as follows: according to the invention, on the basis of simulating the reservoir fluid and physical conditions of an inclined oil reservoir, a displacement pressure difference and recovery ratio along with the gas injection amount change relation curve in the top gas injection process is obtained by means of a top gas injection visualization long sand pipe displacement experiment, and the formation and expansion rule of a gas roof is determined by combining a gas roof front edge change characteristic image photographed by a high-definition camera in real time.
Drawings
The invention will be further described with reference to the drawings and examples.
FIG. 1 is a schematic illustration of the gas cap formation and expansion stage division in the present invention.
Fig. 2 is a schematic diagram of formation and expansion rule of the air cap in embodiment 1 of the present invention.
Fig. 3 is a schematic diagram of formation and expansion rule of the air cap in embodiment 2 of the present invention.
Fig. 4 is a schematic diagram of formation and expansion rule of the air cap in embodiment 3 of the present invention.
Detailed Description
The invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic representations which merely illustrate the basic structure of the invention and therefore show only the structures which are relevant to the invention.
An indoor judgment method for forming and expanding a gas cap in a top gas injection process as shown in fig. 1 comprises the following steps:
s1, acquiring a gas cap gas drive displacement differential pressure, a recovery ratio dynamic curve and a gas cap front edge visual image:
s1-1, manufacturing a high-dip angle oil reservoir visual physical model: according to reservoir conditions such as porosity, permeability, stratum inclination and the like of a target block oil reservoir, adopting quartz sand to fill and manufacture a visual sand filling pipe model (the permeability of the sand filling pipe is 100-10000 multiplied by 10) -3 μm 2 The length is 30-100 cm, the diameter is 2-5 cm), and the included angle between the sand filling pipe model and the horizontal direction is the stratum dip angle (0-90 degrees) for simulating an inclined oil reservoir; saturated formation oil is added to the model on the basis of saturated formation water to produce irreducible water saturation and initial oil saturation.
S1-2, a gas cap gas drive visual physical simulation experiment: continuously injecting gas (the gas contains N) into the model at a certain flow rate 2 、CO 2 And gas waiting), and carrying out a top gas injection visual long sand pipe displacement experiment. Record at intervals during the experimentDisplacement pressure difference, oil recovery and other experimental data, and adopting a high-definition camera to shoot the change characteristics of the gas cap front edge in the visual model in real time; and after the experiment is finished, calculating the gas cap gas drive recovery ratio, and drawing a change relation curve of the displacement pressure difference and the recovery ratio along with the gas injection amount. And comprehensively determining the formation and expansion rule of the gas cap according to the obtained displacement pressure difference and the recovery ratio production dynamic curve and by combining the visual change characteristics of the front edge of the gas cap.
S2, dividing stages of a gas cap front edge migration rule and an expansion rule:
according to displacement pressure difference and recovery ratio production dynamic curves, the injected artificial gas cap can be divided into two stages of gas cap formation and gas cap expansion by combining a gas cap front edge visual change image, wherein the gas cap formation stage can be subdivided into a gas cap formation early stage and a gas cap formation late stage, and the gas cap formation early stage and the gas cap formation late stage are respectively recorded as a stage A and a stage B; the gas cap expansion stage can be subdivided into early gas cap expansion and late gas cap expansion, denoted stage C and stage D, respectively.
S2-1, a gas cap forming stage: in this stage, the artificial gas cap is gradually formed, no gas is seen at the outlet end, namely the injected gas is not broken through, the displacement pressure difference is rapidly increased, the recovery ratio is gradually increased, and the contribution of the whole device to the final recovery ratio is smaller. Wherein:
stage a-early stage of gas cap formation: the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front is pushed forward in a slug form as a whole, presenting a piston-type displacement feature.
Stage B-advanced gas cap formation: the displacement pressure difference continues to increase to the highest point, and the recovery ratio is rapidly increased; the periphery of the gas cap front (close to the wall of the sand filling pipe and can be directly observed by a visual image) has no change, but is influenced by the non-uniformity of the model, the inside of the gas cap front is fingered in the model, a dominant channel is gradually formed (can be confirmed by the visual image), and the injected gas presents a non-piston displacement characteristic.
S2-2, a gas cap expansion stage: the artificial gas cap formed during this stage is gradually enlarged, the injected gas has broken through, the displacement pressure differential is gradually reduced and tends to be smooth, the recovery rate is gradually increased and tends to be smooth, and the final recovery rate contributes mostly to this stage. Wherein:
stage C-early stage of gas cap expansion: after the injected gas breaks through, the displacement pressure difference gradually decreases, and the recovery ratio is rapidly increased; the gravity differential action is gradually developed, the air dome begins to float upwards, and the upper part of the periphery of the front edge is gradually enlarged; meanwhile, the dominant channel inside the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased.
Stage D-advanced gas cap expansion: the gas is suddenly fed along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is slowly increased and the recovery ratio is stable; in this stage, gravity difference plays a dominant role, the whole air cap is pushed forward horizontally, and the air cap range is further enlarged.
Example 1
In the embodiment, a visual sand filling pipe model is designed and manufactured according to reservoir conditions such as porosity, permeability and stratum inclination angle of a target block reservoir; saturated formation water and dehydrated de-aerated crude oil are introduced into the model to produce irreducible water saturation and initial oil saturation; adopts high-purity N 2 As injected gas, carrying out a top gas injection visual oil displacement experiment, recording production data such as displacement pressure difference, oil production and the like in the experimental process, and monitoring the change characteristics of the front edge of the gas cap in real time by using a high-definition camera; and after the experiment is finished, calculating the top gas injection recovery ratio, drawing a production dynamic curve of displacement pressure difference and recovery ratio along with gas injection quantity, dividing the formation and expansion stages of the gas cap by combining the gas cap front edge visual image, and finally determining the formation and expansion rule of the gas cap in the top gas injection process.
An indoor determination method for forming and expanding rule of gas cap in top gas injection driving process specifically comprises the following steps:
(1) Selecting a visual sand filling pipe with the length of 40cm and the diameter of 4cm, filling mixed quartz sand with the fineness of 100 meshes into the visual sand filling pipe, manufacturing a visual sand filling pipe experimental model, and calculating the apparent volume of the model;
(2) Vacuumizing the manufactured visual sand filling pipe model for 8 hours;
(3) Saturated stratum water is filled into the model, the pore volume of the model is measured, and the porosity of the model is calculated; in this example, the porosity of the model was 31.05%;
(4) Measuring the permeability of the model by adopting stratum water, setting the injection speed to be 0.2mL/min, recording the injection pressure when the injection pressure is stable for more than 30 minutes, and calculating the water measured permeability of the model according to a Darcy formula; in this example, the water permeability of the model was 448.60 ×10 -3 μm 2 ；
(5) Saturated crude oil in the model is injected at the injection speed of 0.08mL/min, when the outlet end of the model is not discharged any more and the oil is discharged constantly, the saturated oil process is finished, the saturated oil volume is recorded, and the initial oil saturation is calculated; in this example, the viscosity of the dehydrated and degassed crude oil was 5 mPas and the initial oil saturation of the model was 66.67%;
(6) Setting an included angle between the model and the horizontal plane, namely, setting the stratum inclination angle to be 20 degrees, and simulating an inclined oil reservoir;
(7) Adopting N 2 As an injection gas (purity: 99.9%), gas injection was started at the top of the model, the injection rate was set to 0.01PV/min, and N was constantly injected 2 Until the air content of the outlet end of the model reaches 95%; recording displacement pressure difference and oil production at intervals in the experimental process, monitoring the change characteristics of the front edge of the gas cap in the visual model in real time by using a high-definition camera, and calculating the recovery ratio of the gas cap gas drive after the experimental process is finished;
(8) Drawing a production dynamic curve of displacement pressure difference, recovery ratio and gas injection quantity, dividing the formation and expansion stages of the gas cap by combining a gas cap front edge visual image in the displacement process, and determining the formation and expansion rule of the gas cap in the gas cap gas drive process, as shown in figure 2.
As can be seen from FIG. 2, the 20 dip reservoir is at N 2 N under the condition of injection speed of 0.01PV/min 2 The gas cap can be divided into two major stages of gas cap formation and gas cap expansion, wherein the gas cap formation stage can be further divided into an early stage of gas cap formation (stage a) and a late stage of gas cap formation (stage B), and the gas cap expansion stage can be further divided into an early stage of gas cap expansion (stage C) and a late stage of gas cap expansion (stage D).
(1) Gas cap formation stage: n (N) 2 The injection amount is 0-0.10 PV, the artificial gas cap is gradually formed in the stage, and the injected gas does not protrude yetBreaking; the displacement pressure difference is rapidly increased to 36kPa, the recovery rate gradually increases to 7.11%, and the contribution to the final recovery rate is only 23.38%. Wherein:
stage a-early stage of gas cap formation: n (N) 2 The injection quantity is 0-0.01 PV, the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front was pushed forward all the way to 4cm (10% of the well spacing) in the form of a slug, and the gas exhibited a piston displacement characteristic.
Stage B-advanced gas cap formation: n (N) 2 The injection amount is 0.01-0.10 PV, the displacement pressure difference is continuously increased to the highest point of 36kPa, and the recovery ratio is rapidly increased to 7.11%; the periphery of the gas cap front was unchanged temporarily (still at 4 cm), but was affected by the model inhomogeneity, fingering occurred inside the gas cap front in the model, and a dominant channel was developed (as evidenced by the visual image), and the injected gas exhibited a non-piston displacement characteristic.
(2) Stage of gas cap expansion: n (N) 2 The injection amount is 0.10-1.25 PV, during the stage, the formed artificial gas cap is gradually enlarged, the injected gas is broken through, the displacement pressure difference is gradually reduced, the area is stable, the recovery ratio is gradually increased to 30.58%, and the contribution of the stage to the final recovery ratio is 76.62%. Wherein:
stage C-early stage of gas cap expansion: n (N) 2 The injection quantity is 0.10-0.55 PV, after the injection gas breaks through, the displacement pressure difference gradually drops to 19kPa, and the recovery ratio is rapidly increased; gravity differential action is gradually developed, the air dome starts to float upwards, and the upper part of the periphery of the front edge is gradually enlarged (which can be confirmed by a visual image); meanwhile, the dominant channel inside the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased.
Stage D-advanced gas cap expansion: n (N) 2 The injection quantity is 0.55-1.25 PV, the gas is extruded along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is slowly increased and is stable; in this stage, gravity difference plays a dominant role, the whole gas cap is pushed forward to a position of 6cm (accounting for 15% of well spacing), and the gas cap range is further expanded.
Example two
Indoor determination of gas cap formation and expansion rule in top gas injection driving processIn the present embodiment, N is 2 The injection rate of (2) was set to 0.05PV/min, the experimental visual sand filling pipe model size (length 40cm, diameter 4 cm), porosity (31.05%), permeability (448.60 ×10) -3 μm 2 ) Parameters such as initial oil saturation (66.67%), formation dip (20 °) and the like are the same as those of the first embodiment; the materials and specific steps of the experimental water, oil, gas and the like are basically the same as those of the first embodiment, the production dynamic curves of displacement pressure difference, recovery ratio and gas injection amount are obtained, the gas top forming and expanding stages are divided by combining the gas top front edge visual image result in the displacement process, and the gas top forming and expanding rule in the gas top gas driving process is determined, as shown in fig. 3.
As can be seen from FIG. 3, the 20 dip reservoir is at N 2 N under the condition of injection speed of 0.05PV/min 2 The gas cap can be divided into two major stages of gas cap formation and gas cap expansion, wherein the gas cap formation stage can be further divided into an early stage of gas cap formation (stage a) and a late stage of gas cap formation (stage B), and the gas cap expansion stage can be further divided into an early stage of gas cap expansion (stage C) and a late stage of gas cap expansion (stage D).
(1) Gas cap formation stage: n (N) 2 The injection amount is 0-0.025 PV, the artificial gas cap is gradually formed in the stage, and the injected gas is not broken through yet; the displacement pressure difference is rapidly increased to 86kPa, the recovery rate gradually increases to 1.29%, and the contribution to the final recovery rate is only 6.77%. Wherein:
stage a-early stage of gas cap formation: n (N) 2 The injection quantity is 0-0.005 PV, the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front was pushed forward all the way to 3.5cm (8.75% of the well spacing) in the form of a slug, and the gas exhibited a piston displacement characteristic.
Stage B-advanced gas cap formation: n (N) 2 The injection amount is 0.005-0.025 PV, the displacement pressure difference is continuously increased to 86kPa at the highest point, and the recovery ratio is gradually increased to 1.25%; the periphery of the gas cap front was unchanged temporarily (still at 3.5 cm), but was affected by the model inhomogeneity, fingering inside the gas cap front in the model and gradually forming a dominant channel (as evidenced by the visual image), the injected gas exhibited a non-piston displacement characteristic.
(2) Gas cap expansionThe large stage: n (N) 2 The injection amount is 0.025-1.17 PV, the artificial gas cap is gradually enlarged in the stage, the injected gas breaks through, the displacement pressure difference is gradually reduced and the area is stable, the recovery ratio is gradually increased to 19.04%, and the contribution of the stage to the final recovery ratio is 92.23%. Wherein:
stage C-early stage of gas cap expansion: n (N) 2 The injection amount is 0.025-0.50 PV, after the injection gas breaks through, the displacement pressure difference gradually drops to 65kPa, and the recovery ratio is rapidly increased; gravity differential action is gradually developed, the air dome starts to float upwards, and the upper part of the periphery of the front edge is gradually enlarged (which can be confirmed by a visual image); meanwhile, the dominant channel inside the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased.
Stage D-advanced gas cap expansion: n (N) 2 The injection quantity is 0.50-1.17 PV, the gas is extruded along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is slowly increased and is stable; in this stage, gravity difference plays the dominant role, the whole air cap is pushed forward to 4cm (accounting for 10% of well spacing), and the air cap is slightly enlarged.
Example III
Indoor determination method for gas cap formation and expansion rule in top gas injection driving process, N in this embodiment 2 Is set at 0.01PV/min, the visual model inclination is set at 40 DEG, the model size (length 40cm, diameter 4 cm), the porosity (31.05%), the permeability (448.60X 10) -3 μm 2 ) Parameters such as initial oil saturation (66.67%) are the same as in example one; the materials and specific steps of the experimental water, oil, gas and the like are basically the same as those of the first embodiment, the production dynamic curves of displacement pressure difference, recovery ratio and gas injection amount are obtained, the gas top forming and expanding stages are divided by combining the gas top front edge visual image result in the displacement process, and the gas top forming and expanding rule in the gas top gas driving process is determined, as shown in fig. 4.
As can be seen from FIG. 4, the 40 dip reservoir is at N 2 N under the condition of injection speed of 0.01PV/min 2 The gas cap can be divided into two stages of gas cap formation and gas cap expansion, wherein the gas cap formation stage can be subdivided into early gas cap formation stageStage (stage a) and late gas cap formation (stage B), the gas cap expansion stage can be subdivided into early gas cap expansion (stage C) and late gas cap expansion (stage D).
(1) Gas cap formation stage: n (N) 2 The injection amount is 0-0.11 PV, the artificial gas cap is gradually formed in the stage, and the injected gas is not broken through yet; the displacement pressure difference is rapidly increased to 31kPa, the recovery rate gradually increases to 5.77%, and the contribution to the final recovery rate is only 16.67%. Wherein:
stage a-early stage of gas cap formation: n (N) 2 The injection quantity is 0-0.01 PV, the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front was pushed forward all the way to 4.5cm (11.25% of the well spacing) in the form of a slug, and the gas exhibited a piston displacement characteristic.
Stage B-advanced gas cap formation: n (N) 2 The injection amount is 0.01-0.11 PV, the displacement pressure difference is continuously increased to the highest point of 31kPa, and the recovery ratio is gradually increased to 5.77%; the periphery of the gas cap front was unchanged temporarily (still at 4.5 cm), but was affected by the model inhomogeneity, fingering inside the gas cap front in the model and gradually forming a dominant channel (as evidenced by the visual image), the injected gas exhibited a non-piston displacement characteristic.
(2) Stage of gas cap expansion: n (N) 2 The injection amount is 0.11-1.73 PV, during the stage, the formed artificial gas cap is gradually enlarged, the injected gas is broken through, the displacement pressure difference is gradually reduced, the area is stable, the recovery ratio is gradually increased to 34.62%, and the contribution of the stage to the final recovery ratio is 83.33%. Wherein:
stage C-early stage of gas cap expansion: n (N) 2 The injection quantity is 0.11-1.06 PV, after the injection gas breaks through, the displacement pressure difference gradually drops to 17kPa, and the recovery ratio is rapidly increased; gravity differential action is gradually developed, the air dome starts to float upwards, and the upper part of the periphery of the front edge is gradually enlarged (which can be confirmed by a visual image); meanwhile, the dominant channel inside the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased.
Stage D-advanced gas cap expansion: n (N) 2 The injection quantity is 1.06-1.73 PV, the gas is suddenly introduced along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is increased slowly andthe stability is achieved; in this stage, gravity difference plays the dominant role, the whole air cap is pushed forward to 9cm (accounting for 22.5% of well spacing), and the air cap is slightly enlarged.
According to the invention, a visual physical simulation model is utilized, on the basis of simulating the reservoir fluid and physical conditions of an inclined oil reservoir, a displacement pressure difference and recovery ratio along with the change relation curve of gas injection quantity in the top gas injection process are obtained by means of a top gas injection visual long sand pipe displacement experiment, and the formation and expansion rule of a gas roof is determined by combining with a gas roof front edge change characteristic image photographed by a high-definition camera in real time, so that a basis is provided for accurately identifying and judging the formation and expansion of the gas roof. The formation of the judging method can deeply recognize the action mechanism of improving the recovery ratio by top gas injection on one hand, and provide theoretical support for formulating reasonable development programs and strategies for the inclined oil reservoirs on the other hand.
With the above-described preferred embodiments according to the present invention as an illustration, the above-described descriptions can be used by persons skilled in the relevant art to make various changes and modifications without departing from the scope of the technical idea of the present invention. The technical scope of the present invention is not limited to the description, but must be determined according to the scope of claims.
Claims (4)
1. An indoor judging method for forming and expanding rule of gas cap in top gas injection process is characterized in that: the method comprises the following steps:
s1, acquiring a gas cap gas drive displacement differential pressure, a recovery ratio dynamic curve and a gas cap front edge visual image:
s1-1, manufacturing a high-dip angle oil reservoir visual physical model: according to the porosity, permeability and stratum dip angle reservoir conditions of the target block reservoir, adopting quartz sand to fill and manufacture a visual sand filling pipe model, setting the included angle between the sand filling pipe model and the horizontal direction as the stratum dip angle, and simulating the dip reservoir; saturating formation oil in the model based on the saturated formation water to produce a irreducible water saturation and an initial oil saturation;
s2-2, a gas cap gas drive visual physical simulation experiment: continuously injecting gas into the model at a certain flow rate to develop a top gas injection visual long sand pipe displacement experiment; recording experimental data of displacement pressure difference and oil recovery at intervals in the experimental process, and shooting the change characteristics of the gas cap front edge in the visual model in real time by adopting a high-definition camera; after the experiment is finished, calculating the gas cap gas drive recovery ratio, and drawing a change relation curve of displacement pressure difference and recovery ratio along with the gas injection amount; according to the obtained displacement pressure difference and recovery ratio production dynamic curve, the formation and expansion rule of the gas cap is comprehensively determined by combining the visual change characteristics of the front edge of the gas cap;
s2, dividing stages of a gas cap front edge migration rule and an expansion rule:
according to the displacement pressure difference and the recovery ratio production dynamic curve obtained in the step S1, the injected artificial gas cap is divided into two stages of gas cap formation and gas cap expansion by combining a gas cap front edge visual change image;
gas cap formation stage: in the stage, the artificial gas cap is gradually formed, no gas is seen at the outlet end, namely the injected gas is not broken through, the displacement pressure difference is rapidly increased, the recovery ratio is gradually increased, and the contribution of the whole device to the final recovery ratio is smaller;
stage of gas cap expansion: the artificial gas cap formed during this stage is gradually enlarged, the injected gas has broken through, the displacement pressure differential is gradually reduced and tends to be smooth, the recovery rate is gradually increased and tends to be smooth, and the final recovery rate contributes mostly to this stage.
2. The indoor judgment method for gas cap formation and expansion rules in the top gas injection process of claim 1, wherein the method comprises the following steps: in the step S1, the permeability of the sand filling pipe used for the visual sand filling pipe model is 100-10000 multiplied by 10 -3 μm 2 The length is 30-100 cm, the diameter is 2-5 cm, and the stratum dip angle is 0-90 degrees.
3. The indoor judgment method for gas cap formation and expansion rules in the top gas injection process of claim 1, wherein the method comprises the following steps: in the step S2, the gas cap formation stage may be subdivided into an early gas cap formation stage a and a late gas cap formation stage B;
stage a-early stage of gas cap formation: the displacement pressure difference is rapidly increased, and the recovery ratio is gradually increased; the gas cap front edge is integrally pushed forward in a slug mode, and piston type displacement characteristics are presented;
stage B-advanced gas cap formation: the displacement pressure difference continues to increase to the highest point, and the recovery ratio is rapidly increased; the periphery of the gas cap front edge is unchanged temporarily, but is influenced by the non-uniformity of the model, fingering occurs in the model inside the gas cap front edge, a dominant channel is gradually formed, and injected gas presents a non-piston displacement characteristic.
4. The indoor judgment method for gas cap formation and expansion rules in the top gas injection process of claim 3, wherein the method comprises the following steps: in the step S2, the gas cap expansion stage may be divided into an early gas cap expansion stage C and an late gas cap expansion stage D;
stage C-early stage of gas cap expansion: after the injected gas breaks through, the displacement pressure difference gradually decreases, and the recovery ratio is rapidly increased; the gravity differential action is gradually developed, the air dome begins to float upwards, and the upper part of the periphery of the front edge is gradually enlarged; meanwhile, the dominant channel in the model is rapidly enlarged, and the swept volume of the injected gas is gradually increased;
stage D-advanced gas cap expansion: the gas is suddenly fed along the dominant channel, the swept volume is not increased any more, the injection and production pressure difference is stable, the recovery ratio is slowly increased and the recovery ratio is stable; in this stage, gravity difference plays a dominant role, the whole air cap is pushed forward horizontally, and the air cap range is further enlarged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111442286.5A CN114135258B (en) | 2021-11-30 | 2021-11-30 | Indoor judging method for gas cap formation and expansion rule in top gas injection process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111442286.5A CN114135258B (en) | 2021-11-30 | 2021-11-30 | Indoor judging method for gas cap formation and expansion rule in top gas injection process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114135258A CN114135258A (en) | 2022-03-04 |
| CN114135258B true CN114135258B (en) | 2023-10-20 |
Family
ID=80389881
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111442286.5A Active CN114135258B (en) | 2021-11-30 | 2021-11-30 | Indoor judging method for gas cap formation and expansion rule in top gas injection process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114135258B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108229051A (en) * | 2018-01-18 | 2018-06-29 | 陕西延长石油(集团)有限责任公司研究院 | A kind of method of oil reservoir prediction air foam flooding shaft recovery ratio |
| CN108361008A (en) * | 2018-03-20 | 2018-08-03 | 中国石油大学(华东) | A kind of method of tilted fault block oil reservoir different development phases gas injection body volume increase |
| CN113250659A (en) * | 2020-02-13 | 2021-08-13 | 中国石油天然气股份有限公司 | Gas injection experiment simulation method and device for improving displacement efficiency |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110514754B (en) * | 2019-08-06 | 2020-09-04 | 北京科技大学 | Condensate gas reservoir circulating gas injection development injected gas overlap determination device and method |
-
2021
- 2021-11-30 CN CN202111442286.5A patent/CN114135258B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108229051A (en) * | 2018-01-18 | 2018-06-29 | 陕西延长石油(集团)有限责任公司研究院 | A kind of method of oil reservoir prediction air foam flooding shaft recovery ratio |
| CN108361008A (en) * | 2018-03-20 | 2018-08-03 | 中国石油大学(华东) | A kind of method of tilted fault block oil reservoir different development phases gas injection body volume increase |
| CN113250659A (en) * | 2020-02-13 | 2021-08-13 | 中国石油天然气股份有限公司 | Gas injection experiment simulation method and device for improving displacement efficiency |
Non-Patent Citations (2)
| Title |
|---|
| 人工气顶形成评价理论方法与参数界限研究;刘维霞;;石油钻采工艺(第02期);第86-92页 * |
| 带气顶油藏油气同采条件下流体界面移动规律;范子菲;程林松;宋珩;吴学林;张安刚;;石油勘探与开发;第42卷(第05期);第624-630页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114135258A (en) | 2022-03-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110905472B (en) | Method for determining real-time steering fracturing parameters based on composite temporary plugging system | |
| CN110863806B (en) | Carbon dioxide flooding gas front dynamic change prediction method | |
| CN101190743A (en) | Carbon dioxide geological sequestration method based on mixed fluid self-detaching | |
| CN103541705A (en) | High-temperature blocking and adjusting device and method for super-heavy oil reservoir steam flooding | |
| CN110541693B (en) | Low permeability thick sandstone reservoir CO2Driving and drainage composite development method | |
| CN114135258B (en) | Indoor judging method for gas cap formation and expansion rule in top gas injection process | |
| CN104405350B (en) | A kind of horizontal well chemical profile control method | |
| RU2351752C1 (en) | Method of developing oil deposits in fractured reservoirs | |
| CN1834403A (en) | Hot air filling balance oil recovery technique 'zhanqian' mountain oil reservoir | |
| CN107727527A (en) | A kind of system for determining the critical pressure gradient of foam generation at permeability mutation | |
| CN109858177A (en) | A kind of horizontal well with bottom water reservoir water drive method for numerical simulation based on quasi- streamline method | |
| CN103225495A (en) | Displacement method in sections from near to distant | |
| CN113338915B (en) | Method for judging whether gas well accumulates liquid and predicting liquid accumulation height | |
| CN108316891A (en) | A kind of method of the brine vapor content of natural gas in control salt hole air reserved storeroom | |
| US20160047231A1 (en) | Gas well inflow detection method | |
| CN102364041B (en) | Oil extraction method for establishing oil permeable water stop sieve by filling fusheng sand in horizontal well fracture | |
| CN110397436B (en) | Oil reservoir plugging adjustment feasibility analysis method and system | |
| CN113803029B (en) | Method and device for adjusting coalbed methane well pattern and computer readable storage medium | |
| 刘逸盛 et al. | Large-scale physical simulation experimental study on thick carbonate reservoirs | |
| Liu et al. | The Control Theory and Application for Well Pattern Optimization of Heterogeneous Sandstone Reservoirs | |
| CN110939430B (en) | Method for determining shale gas fracturing fluid flowback model | |
| CN110412204B (en) | Visualization method for simulating influence of multi-stage oil filling on carbonate cementation | |
| CN112989528A (en) | Calculation method for predicting plane utilization coefficient of shallow layer horizontal seam oil reservoir inverse nine-point well pattern | |
| CN114592838B (en) | Layered super heavy oil reservoir steam flooding potential evaluation method and system | |
| Mirazimi et al. | Comparison of Co2 and Hydrocarbon Gas Injection in a Low-Permeable Chalk Reservoir |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |