CN111734406A - Characterization method of plane energy difference of single sand layer in front - Google Patents

Abstract

The invention relates to a method for representing the plane energy difference of a single sand layer at a front edge. Mainly solves the problem of uneven effect caused by the change of plane seepage energy in the thin-layer sand large-area mat-shaped development block. The method comprises the following steps: 1) automatically generating random phase-to-phase diagram of each deposition unit by using automatic oil reservoir drawing software; 2) analyzing lithology and logging curve difference by using a core comprehensive diagram of the coring well, establishing an energy micro-phase logging mode, counting lithology physical property parameters of a single sand layer by using a hierarchical database, making a histogram, determining distribution intervals of all energy micro-phases, and establishing an energy micro-phase classification standard by combining the energy micro-phase logging mode; 3) regenerating a random phase image diagram of the deposition unit with energy microphase change; 4) and (3) drawing a phase belt diagram of the thin-layer sand with plane energy attenuation change through human-computer interaction, and classifying the phase belt diagram into four sand body types. The characterization method improves the recognition of the planar heterogeneous characteristics of the front-edge single sand layer, and is suitable for the analysis of the connectivity relation of the reservoirs with medium and low permeability.

Description

Characterization method of plane energy difference of single sand layer in front

technical field

The invention relates to the technical field of oilfield reservoir research, in particular to a method for characterizing the plane energy difference of a single sand layer at the front.

Background technique

The single sand layer on the front edge refers to the sand layer that has been subdivided into the smallest sedimentary unit in the vertical direction, and has the characteristics of single stable layer, sheet-like distribution of flat sand bodies, and traceability. It is the main target for the secondary and tertiary infill water flooding development of the oilfield. After years of water injection development, although the overall production thickness reaches 82.4%, after entering the high water cut period, the contact relationship between the single layers is good on the surface, but the effective results The difference is large, and the sand body plane seepage law is unclear, which increases the difficulty of remaining oil analysis and adjustment of measures. Under the current requirements of precise development, it is very important to provide a characterization method that can reflect the difference in plane seepage for a single sand layer at the front.

Chinese patent CN201310517846.8 discloses a "thin single sand layer thickness prediction method", which is an effective prediction method for simple, fast and quantitative description of thin single sand layer thickness using the average reflection intensity attribute extracted by 3D seismic, including the optimization of seismic attributes, Determine the time window range of the extracted attributes, extract the average reflection intensity attribute and normalize it, establish the relationship between the average reflection intensity value and the thickness of a single sand layer, calculate the thickness of a single sand layer and correct its extreme value, and compile a thickness map of a single sand layer. The efficiency and effectiveness of the prediction of thin single sand layer are improved, and the coincidence rate of single sand layer thickness prediction is greater than 80%.

However, it is found that the related technology has at least the following problems: it mainly focuses on the combination of well-seismic and prediction of the thickness of a thin single sand layer, and solves the problem of improving the drilling rate of single sand layer sandstone by drilling. In the later stage of high water cut, due to the change of plane seepage energy, the outstanding problem of unbalanced effect has not been solved.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the problem existing in the background technology that when the thin-bed sand large-area sheet-like development block enters the later stage of high water cut due to the change of the plane seepage energy, the effect is not balanced and the contradiction is prominent, and a pre- The method for characterizing the plane energy difference of a single sand layer at the front edge improves the understanding of the plane heterogeneity characteristics of a single sand layer at the front edge, and is suitable for the analysis of the connectivity relationship of medium and low permeability reservoirs.

The present invention solves its problems and can be achieved through the following technical solutions: the method for characterizing the plane energy difference of a single sand layer on the front edge includes the following steps:

1) Collect the sedimentary unit layered boundary database, well position coordinate database, well deviation data, layered database and production well logging curve vectorization data, use the reservoir automatic drawing software, load the data, and pass the layered boundary facies type and Connectivity calculation, the software automatically generates random facies zone diagram of each sedimentary unit;

2) On the basis of the random facies zone map of the depositional unit in step (1), select the facies zone base map of the depositional unit that has a large area of thin sand on the plane with sheet-like distribution and has energy attenuation changes, and use the comprehensive core map of the coring well. , analyze the difference of lithology and logging curve, establish the energy microfacies logging mode, use the layered database in step (1) to make the effective thickness and permeability histogram, and combine the energy microfacies logging mode to establish the energy microfacies classification standard;

3) Using the energy microfacies classification standard in step (2), in the automatic reservoir mapping software, define depositional microfacies, characterize each energy microfacies with different colors, and regenerate the random facies band diagram of the deposition unit with energy microfacies changes ;

4) On the basis of the random facies zone diagram of the depositional unit with energy microfacies change in step (3), combined with the sand body distribution scale, provenance direction, and log curve shape, human-computer interaction draws the facies zone of thin-bed sand with plane energy attenuation changes. Figure, categorized into four sand body types.

The method for establishing the energy microfacies logging mode in the step (2) is to use the comprehensive core map of the coring well to analyze the lithological characteristics (including changes in grain size and shale content); value fluctuation, natural potential negative abnormal value and morphological change), according to the difference of lithology and logging curve, the energy microfacies logging mode is established.

The energy microfacies logging mode in the step (2) includes: dam core, dam main body, dam side, residual underwater distributary channel, main body type I sheet sand, main main type II sheet sand, non-main body sheet sand, There are 8 microfacies modes in the off-surface reservoirs.

The method for establishing the energy microfacies classification standard in the step (2) is to use the layered database in step (1) to count the lithological parameters of a single sand layer, namely the effective thickness, and the physical property parameters, that is, the permeability distribution range, make a histogram, and determine the distribution interval of each energy microfacies. , combined with the energy microfacies logging mode, to establish the energy microfacies classification standards for different sand body types respectively;

The four types of sand bodies with plane energy attenuation change in the step (4) include the river-controlled and residual underwater channel type, the river-controlled wave-controlled transition type, the wave-controlled remote sand bar type, and the wave-controlled coastal and outer bar type.

Compared with the above-mentioned background technology, the present invention can have the following beneficial effects:

1. The present invention establishes the energy microphase classification standard. The conventional sedimentary microfacies of a single sand layer in the front are classified into four types of sedimentary microfacies: sand bar, main sheet sand, non-main sheet sand, and off-surface reservoir according to the effective thickness. The sedimentary microfacies classification method of the present invention fully considers the sedimentary environment background, and further refines the sedimentary microfacies according to the energy change according to the curve shape, thickness and permeability parameter distribution range, and determines the classification standard. The wave-controlled sand bar is further subdivided into dam core, dam main body, and dam edge. The river-controlled main body sheet sand is further subdivided into residual underwater distributary channel microfacies, and the river-controlled wave-controlled transition main body sheet sand is subdivided. It is the first-class sheet-like sand for the main body and the second-class sheet-like sand for the main body. The classification is more precise and scientific, which fully reflects the differences in plane lithology and physical properties, and can realize the quantitative basis for judging sedimentary microfacies, with strong operability.

2. The present invention draws four types of sand body facies diagrams with plane energy attenuation changes. Compared with the conventional method, the conventional method is that the software automatically generates a random facies diagram of each sedimentary unit, without the combination of logging curve characteristics and lack of material. Source directionality, plane inhomogeneity features are not clear. In the present invention, the energy microfacies classification standard is used, each energy microfacies is represented by different colors on the plane, combined with the sand body distribution scale, provenance direction, logging curve shape, and human-computer interaction drawing, which is more conducive to identifying the advantages of water flooding The channel and variation zone, the degree of connectivity between wells is clearer.

3. According to the research results of the present invention, the types of remaining oil are summed up, and potential tapping countermeasures are formulated.

Applying the research results, it is easy to form the residual oil of differential plane seepage type for the thin layer sand body with large area sheet distribution and energy change of single sand layer in the front. direction.

Description of drawings

Accompanying drawing 1 is the random phase zone diagram of each deposition unit that software automatically generates in step (1) in the embodiment of the present invention;

Accompanying drawing 2 is the bottom map of deposition unit phase zone with energy attenuation change in step (2) in the embodiment of the present invention;

Accompanying drawing 3 is in the embodiment of the present invention, in step (2), the production well is connected with the well-connected section profile comparison diagram;

Accompanying drawing 4 is the energy microfacies logging pattern diagram in step (2) in the embodiment of the present invention;

Accompanying drawing 5 is the histogram of the distribution ratio of the effective thickness of the sand body type in the step (2) in the middle wave control coastal outer bar in the embodiment of the present invention;

Accompanying drawing 6 is the histogram of the permeability distribution ratio of the sand body type in the step (2) of the middle wave-controlled coastal outer bar in the embodiment of the present invention;

Accompanying drawing 7 is the classification standard of internal energy microfacies of sand body type with energy attenuation change in step (2) in the embodiment of the present invention;

Accompanying drawing 8 is the setting diagram of energy microphase software deposition phase type in step (3) of the embodiment of the present invention;

Accompanying drawing 9 is the four kinds of sand body type diagrams with energy variation drawn in step (4) in the embodiment of the present invention;

Fig. 10 is an analysis diagram of countermeasures taken for residual oil of plane seepage differential type formed by energy change in step (4) of the embodiment of the present invention.

Detailed ways:

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

Example 1:

Using the method for characterizing the plane energy difference of a single front sand layer according to the present invention, the implementation process of the method of the present invention is described by taking the eastern part of the pure oil area of Xingshi District, Daqing Oilfield as an example.

Step (1) Collect sedimentary unit layer boundary database, well position coordinate database, well deviation data, layer database and production well logging curve vector data, use GPTmap oil reservoir automatic drawing software, load the data, and pass the layer boundary facies type and For the calculation of the connectivity relationship, the software automatically generates a random phase diagram of each deposition unit (see Figure 1);

Step (2) On the basis of the random facies zone map of the sedimentary unit in step (1), select the bottom map of the sedimentary unit facies zone that has a large area of thin sand on the plane and is distributed in a sheet-like manner and has energy attenuation changes (see Figure 2). For example, there are 59 sedimentary units vertically developed in the eastern part of the pure oil area of Xingshi District, and 30 sedimentary units with energy attenuation changes are selected in the bottom map of the facies belt. Establish a production well connected well profile (see Figure 3), analyze the morphological changes of the logging curve, and establish an energy microphase logging mode (see Figure 4), including the dam core, the dam body, the dam side, and the residual underwater diversion There are 8 microfacies modes in river channel, main body type I sheet sand, main body type II sheet sand, non-main body sheet sand, and off-surface reservoirs. Using the layered database in step (1), count the lithological parameters of a single sand layer, namely the effective thickness, and the physical property parameters, namely the distribution range of permeability, make a histogram, determine the distribution interval of each energy microfacies, and combine the energy microfacies logging mode to establish the energy microfacies Phase classification criteria.

Taking the types of sand bodies developed by the wave-controlled coastal outer bar as an example (see Figure 5 and Figure 6), the effective thickness and permeability of the S215a sedimentary unit in 500 wells in the east of Xingshi District were calculated, and a histogram was made to see from the distribution characteristics. , the effective thickness is concentrated between 1.5m and 3.0m, and the proportion is 63.58%. Among them, the single sand layer with an effective thickness ≥ 2.5m accounts for 22.3%, the curve shape has the characteristics of the dam core, and the permeability is >= 230mD; The curve shape has the characteristics of the main body of the dam, and the permeability is between 180-230mD; the single sand layer with an effective thickness of (2.0m-1.5m) accounts for 28.9%, and the curve shape has the characteristics of the dam side, and the permeability is between 120-180mD. The main sheet sand, non-main sheet sand, and off-surface reservoirs are divided according to the thickness division standard of "Technical Specifications for the Preparation of Sedimentary Facies Belt Maps for Single Sand Layers in Daqing Oilfield", referring to the distribution range of the permeability histogram, to determine that the main sheet sand is effective. The thickness is between (1.5m-0.5m], and the permeability is <120mD; the effective thickness of non-main body sheet sand is between (0.5m-0), and the permeability is <50mD; the effective thickness of the surface reservoir is equal to 0. Through the new Compared with the old sedimentary microfacies classification methods, the original sand bar and the main sheet sand microfacies are further subdivided into the core of the bar, the main body of the bar, and the edge of the bar according to the energy microfacies logging mode, combined with the effective thickness and permeability distribution interval. Partial and main sheet sand. The classification is more precise and scientific, fully reflecting the differences in plane lithology and physical properties, and it can realize the quantitative basis for judging sedimentary microfacies, and has strong operability. Other sand body types are determined according to the above methods and so on. The block has the classification standard of internal energy microfacies of sand body types with energy attenuation changes (see Figure 7). Note: In the eastern part of Xingshi District, only the production wells of the wave-controlled coastal outer bar sand body type have large differences in permeability, while other sand bodies have large differences in permeability values. The permeability values of production wells of body type are generally low and indistinguishable, so the classification of other sand body types in this block only refers to the energy microfacies logging mode and the effective thickness distribution interval.

Step (3) Using the energy microphase classification standard in step (2), in the GPTmap software, define the deposition microphase, and characterize each energy microphase with different colors. Taking the eastern block of Xingshi District as an example, the sedimentary facies is firstly set according to the classification criteria. In GPTmap software, select "Settings" - "Sedimentary Facies Settings" - "Sedimentary Facies Type" in the menu bar, and set nine types of energy microfacies - dam core A, dam main body B, dam side C, residual water Lower distributary channel D, main body type I sheet sand E, main body type II sheet sand F, non-main body sheet sand G, off-surface reservoir H, pinch-out J, set the color of each energy microfacies (see Figure 8). ) to regenerate the random phase band diagram of the deposition unit with energy microphase changes.

Step (4) On the basis of the random facies zone diagram of the depositional unit of the energy microfacies change in step (3), first, according to the energy microfacies logging mode, the energy microfacies generated by the software is subjected to single-well phase judgment correction, and then combined with the distribution scale and provenance direction. , combine the same microfacies according to the provenance direction, delineate the facies zone boundaries of different microfacies types, and draw the facies zone diagrams of thin-bed sand with plane energy attenuation changes through human-computer interaction, which are classified into four types of sand bodies, Including the river-controlled and residual underwater channel type, the river-controlled wave-controlled transition type, the wave-controlled far sand bar type, and the wave-controlled coastal and outer bar type (see Figure 9).

Because the previous conventional methods did not study the energy change, the sand body that appears to be relatively homogeneous on the surface has complex heterogeneity in reality, and the dynamic effect is not balanced and the contradiction is prominent. In the eastern block of Xingshi District, the method of plane energy difference characterization of a single sand layer in the front is applied, and for the residual oil of the plane seepage difference type due to the large-scale development of a single sand body and a plane seepage difference formed by energy changes, countermeasures such as water plugging, fracturing and plane adjustment are adopted. Optimize the seepage direction and improve the development effect.

Taking the Sa _II15a sedimentary unit in the eastern part of the pure oil area in the Xing 10 area as an example (see Figure 10), this unit belongs to the wave-controlled coastal outer bar type sand body. Distribution, on the surface, there is no difference in connectivity, and injection and production are perfect, but there are differences in terms of water cut in connected oil wells. Using the plane energy difference characterization method of a single sand layer at the front, after redrawing the energy change facies zone diagram, the provenance direction of the sand body is along the northwest-southeast direction, along the northwest direction of the provenance, with good connectivity, with dominant channels and vertical provenance. There are sand body variation parts between oil and water wells, and the plane seepage difference is obvious. Well Xing 10-3-Gengbing 43 with high water-cut in the dominant direction of water flooding in this layer was implemented to plug water and adjust the parameters of Xing 10-5-Bing43 to reduce the production pressure difference. After the implementation, the wells Xing 10-5-Bing 43 and Xing 10-5-Bing 44, which were shielded by the sand body variation between the wells, were significantly effective, the seepage direction was improved, the inefficient circulation direction was controlled, and the water cut decreased by 0.3 percentage point.

Using the method of plane energy difference characterization method of single sand layer on the front, the single sand layer on the front has a sheet-like distribution in a large area and has a thin layer of sand body with energy change. It is easy to form residual oil of plane seepage difference type. and plane adjustment and other countermeasures to optimize the seepage direction, the block has expanded potential for 67 wells, formulated 33 wells, implemented 11 water injection plans, 1 water plugged well, and implemented 4 well-controlled fracturing corresponding to a single sand body in thin and poor layers. . After the implementation, 0.38×104 tons of effective oil has been accumulated ^. Calculated according to the technical contribution rate of 80%, the economic benefit of 4.1481 million yuan has been directly obtained, and a good development effect has been achieved.

Claims (7)

1. a front edge single sand layer plane energy difference characterization method, is characterized in that: comprise the following steps: 1) Collect sedimentary unit layered boundary database, well position coordinate database, well deviation data, layered database and production well logging curve vectorization data, use reservoir automatic drawing software to load data, and use layered boundary facies type and production well to load data. Connectivity calculation, the software automatically generates random facies zone diagram of each sedimentary unit; 2) On the basis of the random facies zone map of the depositional unit in step (1), select the facies zone base map of the depositional unit that has a large area of thin sand on the plane with sheet-like distribution and has energy attenuation changes, and use the comprehensive core map of the coring well. , analyze the difference of lithology and logging curve, establish the energy microfacies logging mode, use the layered database in step (1) to make the effective thickness and permeability histogram, and combine the energy microfacies logging mode to establish the energy microfacies classification standard; 3) Using the classification standard of energy microfacies in step (2), in the automatic reservoir drawing software, define depositional microfacies, characterize each energy microfacies with different colors, and regenerate the random facies band diagram of the deposition unit with energy microfacies changes ; 4) On the basis of the random facies zone diagram of the sedimentary unit with energy microfacies change in step (3), combined with the sand body distribution scale, provenance direction, and the shape of the logging curve, the facies zone of thin-bed sand with plane energy attenuation changes is drawn by human-computer interaction. Figure, categorized into four sand body types. 2. The method for characterizing the plane energy difference of outer front facies thin layer sand according to claim 1, characterized in that: the method for establishing the energy microfacies logging mode in the step (2) is to utilize the core comprehensive map of the coring well to analyze the rock formation. The characteristics of the well logging curve are analyzed, and the energy microfacies logging mode is established according to the lithology and the difference of the logging curve. 3 . The method for characterizing the plane energy difference of thin sand layers of outer front facies according to claim 2 , wherein the types of energy microfacies logging modes include: dam core, dam main body, dam edge, residual water There are 8 microfacies patterns in the lower distributary channel, the main body type 1 sheet sand, the main body type 2 sheet sand, the non-main body sheet sand, and the off-surface reservoir. 4. The method for characterizing the plane energy difference of outer front facies thin layer sand according to claim 2, characterized in that: the lithology features include changes in particle size and shale content; the logging curve features include micro-electrode curve amplitude difference and Amplitude fluctuations, negative outliers of spontaneous potential and morphological changes. 5. The method for characterizing the plane energy difference of outer front facies thin layer sand according to claim 1, characterized in that: establishing the energy microfacies classification standard method in the step (2) is to use the layered database in the step (1) to count the single sand layer. Lithological parameters are the effective thickness, and physical parameters are the permeability distribution range. Make a histogram to determine the distribution interval of each energy microfacies, and combine the energy microfacies logging mode to establish energy microfacies classification standards for different sand body types. 6. The method for characterizing the plane energy difference of outer front facies thin-bed sand according to claim 1, wherein the four types of sand bodies with plane energy attenuation change in the step (4) include river-controlled and residual underwater channels. type, river-controlled and wave-controlled transition type, wave-controlled far sand bar type, and wave-controlled coastal and outer bar type. 7 . The method for characterizing the plane energy difference of thin sand layer of outer front facies according to claim 1 , wherein the automatic drawing software of the oil reservoir is GPTmap software. 8 .

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