阅读说明：本技术 一种基于井震结合的含油饱和度预测方法 (Oil saturation prediction method based on well-seismic combination ) 是由 徐立恒 何英伟 梁宇 杨会东 王元波 朱权 李红星 周华建 黄勇 于 2019-09-11 设计创作，主要内容包括：本发明涉及一种基于井震结合的含油饱和度预测方法。主要解决了现有预测方法含油饱和度预测结果精度较低的问题。其特征在于：1)对目标工区进行地震采集,获取角度叠加地震数据、岩芯资料和测井数据；2)利用岩芯资料试验得到井点含油饱和度数据；3)建立与井点含油饱和度数据的关系图版；4)分别统计井点纵波速度、横波速度、密度的变差函数；5)输入纵波速度、横波速度、密度测井数据和角度叠加地震数据,建立纵波速度、横波速度、密度数据模型；6)根据含油饱和度与纵横波速度比、纵波速度×密度关系图版,将纵波速度、横波速度、密度数据模型转换生成含油饱和度模型。该井震标定方法利用高密度地震资料优势精确预测储层含油饱和度。(The invention relates to an oil saturation prediction method based on well-seismic combination. The method mainly solves the problem that the accuracy of the oil saturation prediction result is low in the existing prediction method. The method is characterized in that: 1) carrying out seismic acquisition on a target work area, and acquiring angle stack seismic data, core data and logging data; 2) obtaining well point oil saturation data by using a core data test; 3) establishing a relation chart with the oil saturation data of the well points; 4) respectively counting variation functions of longitudinal wave speed, transverse wave speed and density of well points; 5) inputting longitudinal wave velocity, transverse wave velocity, density logging data and angle stacking seismic data, and establishing longitudinal wave velocity, transverse wave velocity and density data models; 6) and converting the longitudinal wave velocity, transverse wave velocity and density data models to generate an oil saturation model according to the relation chart of the oil saturation, the longitudinal wave velocity ratio, the transverse wave velocity ratio and the longitudinal wave velocity multiplied by the density. The well seismic calibration method accurately predicts the oil saturation of the reservoir by using the advantages of high-density seismic data.)

1. A method for predicting oil saturation based on well-seismic combination comprises the following steps:

1) carrying out seismic acquisition on a target work area, acquiring angle superposition seismic data, drilling and logging in the target work area, and acquiring core data and logging data; wherein the logging data comprises longitudinal wave velocity, transverse wave velocity and density logging curves;

2) obtaining well point oil saturation data through experimental measurement by using the core data in the step (1);

3) counting the logging curves of the longitudinal wave velocity, the transverse wave velocity and the density in the step (1), calculating to obtain the longitudinal wave velocity/the transverse wave velocity and the longitudinal wave velocity multiplied by the density, and establishing a relation chart with the oil saturation data of the well point in the step (2);

4) respectively counting main, secondary and vertical variation functions of longitudinal wave velocity, transverse wave velocity and density of the well point in the step (1);

5) inputting longitudinal wave velocity, transverse wave velocity, density logging data and angle gather stacking seismic data in the step (1), and establishing a longitudinal wave velocity, transverse wave velocity and density data model by adopting a well-seismic combination method;

6) and (4) calculating to obtain a longitudinal-transverse wave velocity ratio three-dimensional model and a longitudinal wave velocity x density three-dimensional model according to the longitudinal wave velocity, the transverse wave velocity and the density three-dimensional model obtained in the step (5), and then combining the longitudinal-transverse wave velocity ratio three-dimensional model and the longitudinal wave velocity x density three-dimensional model to generate an oil saturation three-dimensional model according to a relation chart of oil saturation, longitudinal-transverse wave velocity ratio and longitudinal wave velocity x density.

2. The method for predicting oil saturation based on well-seismic combination according to claim 1, wherein the method comprises the following steps: the three-dimensional model in the step (5) is specifically realized by the following steps:

1) based on the data of the longitudinal wave velocity, the transverse wave velocity and the density curve of the well point, obtaining an initial three-dimensional model of the longitudinal wave velocity, the transverse wave velocity and the density by adopting a sequence inertia Gaussian simulation algorithm with a variation function as a core;

2) obtaining 3 reflection coefficient models of near, medium and far angles by using a Richards formula according to the initial three-dimensional model of the longitudinal wave velocity, the transverse wave velocity and the density;

3) performing convolution calculation on the near, medium and far angle reflection coefficient models and the wavelets to obtain near, medium and far angle synthetic seismic models, and performing difference calculation on the near, medium and far angle synthetic seismic models and the near, medium and far angle seismic models obtained through actual acquisition to obtain near, medium and far seismic residual values;

4) when the seismic residual value is smaller than a set value (generally 1%), the initial three-dimensional models of the longitudinal wave velocity, the transverse wave velocity and the density are determined as final results to be output, otherwise, the initial three-dimensional models of the longitudinal wave velocity, the transverse wave velocity and the density are recalculated until the set value requirement is met.

3. The method for predicting oil saturation based on well-seismic combination according to claim 2, wherein: the formula of Richards in the step (2):

theta is the angle of incidence, v_sVelocity of longitudinal wave, v_pTransverse wave velocity, rho is density, density difference between upper and lower mediums of delta rho, delta v_pIs the difference of longitudinal wave velocities of upper and lower media, Δ v_sThe difference of the transverse wave speeds of the upper medium and the lower medium is shown.

4. The method for predicting oil saturation based on well-seismic combination according to claim 2, wherein: the formula of the seismic residual value in the step (3) is as follows: q_θ(synthetic record)_θ-actual earthquake_θ) Actual earthquake_θ。

5. The method for predicting oil saturation based on well-seismic combination according to claim 1, wherein the method comprises the following steps: and (4) setting the seismic residual value to be 1%.

Technical Field

The invention relates to the technical field of oilfield development, in particular to an oil saturation prediction method based on well-seismic combination.

Background

At present, most of domestic onshore oil fields are in a high-water-content development stage, the well pattern density is high, the residual oil is dispersed, and how to accurately predict the oil saturation of a reservoir stratum is significant for the stable production and the efficiency improvement of the oil fields. The high-density seismic data has the advantage of transverse high-density sampling, and the accuracy of saturation prediction can be improved.

The method for predicting the saturation related to earthquake in the currently published documents and patents has the following defects: (1) quantitative characteristic charts of oil and water explanations are not established, so that uncertainty of a prediction result is enhanced, and deviation exists between the prediction result and actual residual oil characteristics; (2) the conventional method generally selects means such as fluid factors, amplitude, seismic low-frequency information and the like to simulate the distribution of residual oil, and does not fully exert the advantages of high longitudinal resolution of well data and intensive transverse sampling of seismic data, so that the accuracy of the saturation prediction result is low. Therefore, how to realize the fine prediction of the residual oil through the combination of well and earthquake is an urgent problem to be solved.

Disclosure of Invention

The invention provides an oil saturation prediction method based on well-seismic combination, aiming at overcoming the problem of low accuracy of the oil saturation prediction result of the existing prediction method in the background art. The oil saturation prediction method based on well-seismic combination fully utilizes the advantages of high-density seismic data, can accurately predict the oil saturation of the reservoir, and has important significance for oil field yield stabilization and efficiency improvement.

The invention can solve the problems by the following technical scheme: a method for predicting oil saturation based on well-seismic combination comprises the following steps:

a method for predicting oil saturation based on well-seismic combination comprises the following steps:

1) carrying out seismic acquisition on a target work area, acquiring angle superposition seismic data, drilling and logging in the target work area, and acquiring core data and logging data; wherein the logging data comprises longitudinal wave velocity, transverse wave velocity and density logging curves;

2) obtaining well point oil saturation data through experimental measurement by using the core data in the step (1);

3) counting the logging curves of the longitudinal wave velocity, the transverse wave velocity and the density in the step (1), calculating to obtain the longitudinal wave velocity/the transverse wave velocity and the longitudinal wave velocity multiplied by the density, and establishing a relation chart with the oil saturation data of the well point in the step (2);

4) respectively counting main, secondary and vertical variation functions of longitudinal wave velocity, transverse wave velocity and density of the well point in the step (1);

5) inputting longitudinal wave velocity, transverse wave velocity, density logging data and angle gather stacking seismic data in the step (1), and establishing a longitudinal wave velocity, transverse wave velocity and density data model by adopting a well-seismic combination method;

6) and (4) calculating to obtain a longitudinal-transverse wave velocity ratio three-dimensional model and a longitudinal wave velocity x density three-dimensional model according to the longitudinal wave velocity, the transverse wave velocity and the density three-dimensional model obtained in the step (5), and then combining the longitudinal-transverse wave velocity ratio three-dimensional model and the longitudinal wave velocity x density three-dimensional model to generate an oil saturation three-dimensional model according to a relation chart of oil saturation, longitudinal-transverse wave velocity ratio and longitudinal wave velocity x density.

The three-dimensional model in the step (5) is specifically realized by the following steps:

1) based on the data of the longitudinal wave velocity, the transverse wave velocity and the density curve of the well point, obtaining an initial three-dimensional model of the longitudinal wave velocity, the transverse wave velocity and the density by adopting a sequence inertia Gaussian simulation algorithm with a variation function as a core;

2) obtaining 3 reflection coefficient models of near, medium and far angles by using a Richards formula according to the initial three-dimensional model of the longitudinal wave velocity, the transverse wave velocity and the density;

3) performing convolution calculation on the near, medium and far angle reflection coefficient models and the wavelets to obtain near, medium and far angle synthetic seismic models, and performing difference calculation on the near, medium and far angle synthetic seismic models and the near, medium and far angle seismic models obtained through actual acquisition to obtain near, medium and far seismic residual values;

4) when the seismic residual value is smaller than a set value (generally 1%), the initial three-dimensional models of the longitudinal wave velocity, the transverse wave velocity and the density are determined as final results to be output, otherwise, the initial three-dimensional models of the longitudinal wave velocity, the transverse wave velocity and the density are recalculated until the set value requirement is met.

Richards formula:

theta is the angle of incidence, v_sVelocity of longitudinal wave, v_pTransverse wave velocity, rho is density, density difference between upper and lower mediums of delta rho, delta v_pIs the difference of longitudinal wave velocities of upper and lower media, Δ v_sThe difference of the transverse wave speeds of the upper medium and the lower medium is shown.

Seismic residual value formula: q_θ(synthetic record)_θ-actual earthquake_θ) Actual earthquake_θ。

Compared with the background technology, the invention has the following beneficial effects: the invention provides an oil saturation prediction method based on well-seismic combination, which can give full play to the advantages of high longitudinal resolution of well data and intensive transverse sampling of seismic data, has a more precise oil saturation prediction result, can quantitatively predict the oil saturation information of a reservoir, improves the potential excavation effect of residual oil, is beneficial to high efficiency and stable yield of an oil field, and has a higher application value for development of the oil field in China.

Description of the drawings:

FIG. 1 is a flow chart of a well-seismic and oil saturation prediction method of the invention;

FIG. 2 is a graph of the relationship between oil saturation and the velocity ratio of longitudinal and transverse waves, and the velocity of longitudinal waves multiplied by density;

FIG. 3 is a main direction variation function of the velocity of longitudinal waves, the velocity of transverse waves and the density in an embodiment of the present invention;

FIG. 4 is a function of variation of the secondary direction of the longitudinal wave velocity, the transverse wave velocity and the density in an embodiment of the present invention;

FIG. 5 is a vertical variation function of the longitudinal wave velocity, the transverse wave velocity and the density in an embodiment of the present invention;

FIG. 6 is a three-dimensional model diagram of the longitudinal-transverse wave velocity ratio in an embodiment of the present invention;

FIG. 7 is a diagram of a longitudinal wave velocity x density three-dimensional model according to an embodiment of the present invention;

FIG. 8 is a three-dimensional model diagram of oil saturation in an embodiment of the present invention.

The specific implementation mode is as follows:

the invention will be further described with reference to the following drawings and specific embodiments: