CN101290355A - Method for determining carbonate rock hydrocarbon reservoir structure - Google Patents

Abstract

The invention relates to a seismic prospecting technology which is a method of determining a carbonate reservoir structure. The concrete steps are as follows: wave field reconstruction parameters are obtained by using a field observation system; type parameters corresponding to an underground geological structure are obtained by processing data, a discrete strata property model is established; wave field values on various discrete mesh points at each moment are reconstructed, and wave fields of the positions where a detection point is positioned at each moment are taken as a wave field reconstruction record; and sections obtained by the wave field reconstruction are compared with stacked and migrated sections obtained by processing the field acquisition data to determine the distribution, and the fracture development direction and the development degree of an underground carbonate reservoir. The technology is applicable to the wave field reconstruction of any completed structure, has the ability of determining underground oil-gas reservoir structures, and has the characteristics of high accuracy, high efficiency, low frequency dispersion and improving the calculation efficiency.

Description

A kind of method of definite carbonate rock hydrocarbon reservoir structure

Technical field

The present invention relates to seismic exploration technique, and the anisotropic elasticity wave-field reconstruction of the carbonate rock hydrocarbon reservoir of the realization of high precision, high-level efficiency and low dispersion under staggered-mesh is a kind of method of definite carbonate rock hydrocarbon reservoir structure specifically.

Background technology

In the reflection wave seismic prospecting, we utilize wave detector to accept to come from reflective information--the seismologic record of underground geologic bodies by at the ground earthquake-wave-exciting.Obtain the various attributes of Depth Domain for the reflective information that has obtained by a series of seismic data data processing and explanation, thereby determine that oil reservoir distributes.Rebuild the reflective information (process of this reconstruction underground geologic bodies reflective information also is referred to as the wave-field reconstruction process) of geologic body according to the open-air earthquake data acquisition process of the layer attribute parameters simulation that obtained, then with wave-field reconstruction to reflective information and the reflective information of the open-air actual acquisition hydrocarbon reservoir structure under being analyzed definitely.

Underground geologic bodies reflective information wave-field reconstruction and the process of descending hydrocarbon reservoir structure definitely describes for geologic interpretation, hydrocarbon reservoir structure and the hydrocarbon-bearing pool exploitation plays a very important role.The process energy true reappearance seismic event of wave-field reconstruction has very important meaning in the overall process of underground propagation to architectonic understanding.When utilizing various layer attribute parameters to rebuild seismologic record, how describing seismic event more accurately is a gordian technique of wave-field reconstruction in underground propagation, particularly seismic event in the propagation of reservoir.

At present, about under different stages and condition, having set up ACOUSTIC WAVE EQUATION, equations for elastic waves and anisotropy equation.To be that the crack is vertical be arranged in parallel the feature of carbonate rock hydrocarbon reservoir, and seismic event is propagated therein and shown as the anisotropic character that relies on the direction of propagation and fissure direction angle, and generation shear wave splitting in various degree.Can provide good description with two-dimentional three-component anisotropy equation.

At propagation of seismic wave feature in the carbonatite, Li Wenlin (" petroleum exploration ", 1995,34 (3): 51-62) provided the description of the partial differential equation of second order group of representing with displacement component:

$\mathrm{\ρ}\frac{{\∂}^{2}u}{\∂c^2}=C_{11}\frac{{\∂}^{2}u}{\∂x^2}+C_{16}\frac{{\∂}^2\mathrm{\υ}}{{\∂x}^2}+(C_{13}+C_{55})\frac{{\∂}^2\mathrm{\ω}}{\∂x\∂z}+C_{55}\frac{{\∂}^{2}u}{{\∂z}^2}+C_{45}\frac{{\∂}^2\mathrm{\υ}}{\∂z^2}$

$\mathrm{\ρ}\frac{{\∂}^2\mathrm{\υ}}{{\∂c}^2}=C_{16}\frac{{\∂}^{2}u}{{\∂x}^2}+C_{66}\frac{{\∂}^2\mathrm{\υ}}{{\∂x}^2}+(C_{36}+C_{45})\frac{{\∂}^2\mathrm{\ω}}{\∂x\∂z}+C_{45}\frac{{\∂}^{2}u}{{\∂z}^2}+C_{44}\frac{{\∂}^2\mathrm{\υ}}{{\∂z}^2}$

$\mathrm{\ρ}\frac{{\∂}^2\mathrm{\ω}}{{\∂c}^2}=C_{55}\frac{{\∂}^2\mathrm{\ω}}{{\∂x}^2}+(C_{13}+C_{55})\frac{{\∂}^{2}u}{\∂x\∂z}+(C_{45}+C_{36})\frac{{\∂}^2\mathrm{\υ}}{\∂x\∂z}+C_{33}\frac{{\∂}^2\mathrm{\ω}}{{\∂z}^2}---\left(1\right)$

The corresponding relation that elasticity coefficient in physical parameter commonly used in the seismic prospecting and the equation is arranged again:

C ₁₁＝D ₁₁cos ⁴θ+2D ₁₃sin ²θcos ²θ+D ₃₃sin ⁴θ+D ₄₄sin ²(2θ)

C ₁₃＝D ₁₂cos ²θ+D ₁₃sin ²θ

C ₁₆＝(D ₁₃-D ₃₃)sin ³θcosθ+(D ₁₁-D ₁₃)sinθcos ³θ-D ₄₄sin2θcos2θ

C ₃₃＝D ₁₁

C ₃₆＝(D ₁₂-D ₁₃)sinθcosθ

C ₄₄＝D ₄₄cos ²θ+D ₆₆sin ²θ

C ₄₅＝(D ₆₆-D ₄₄)sinθcosθ

C ₅₅＝D ₄₄sin ²θ+D ₆₆cos ²θ

C ₆₆＝(D ₁₁-2D ₁₃+D ₃₃)sin ²θcos ²θ+D ₄₄cos ²(2θ)

$D_{11}=C_{11b}-\frac{{C_{12b}}^2}{C_{11b}}(1-1/(1+\mathrm{EN}))$

D ₁₂＝D ₁₁-2C _44b

$D_{13}=\frac{C_{12b}}{(1+\mathrm{EN})}$

$D_{33}=\frac{C_{11b}}{1+\mathrm{EN}}$

$D_{44}=\frac{C_{44b}}{1+\mathrm{ET}}$

D ₆₆＝C _44b

C _11b＝ρv _p ²

C _44b＝ρv _s ²

C _12b＝C _11b-2C _44b

To containing fluid crack: EN=0 $\mathrm{ET}=\frac{16e}{3(3-{2r}_b)-16e}$

To dry crack: $\mathrm{EN}=\frac{4e}{{3r}_b(1-r_b)-4e}$ $\mathrm{ET}=\frac{4e}{3r_b(3-{2r}_b)-16e}$

r _b＝(v _s/v _p) ²

ρ, v _p, v _sBe respectively density, velocity of longitudinal wave and the shear wave velocity of background media,

E, θ are respectively the crack density of background media, the angle of crack trend and line direction.

More than contain four blending space derivative terms in the partial differential equation of second order group represented with displacement, when difference is found the solution, need use central difference, precision is lower.And along with partial derivative launches the raising of exponent number, calculated amount becomes quadratic relationship to increase with the expansion exponent number, has increased greatly to assess the cost, and makes the wave-field reconstruction cycle elongated.The in-problem basic reason of prior art is that the displacement equation of selecting is not suitable for propagation of seismic wave feature in the carbonatite, more can not accurately determine carbonate rock hydrocarbon reservoir structure.

Summary of the invention

The object of the invention is to provide a kind of reconstruction based on seismic wave field in the carbonatite of the first-order equation of velocity of displacement and stress that realizes under staggered-mesh, and then the method for definite carbonate rock hydrocarbon reservoir structure.

The invention provides following technical scheme:

Concrete implementation step of the present invention is as follows:

(1) utilizes the field layout acquiring seismic data, obtain the wave-field reconstruction parameter;

(2) data is handled the angle and the gapfiller type parameter of the velocity of longitudinal wave that obtains subsurface geologic structures and conform to, shear wave velocity, density, fracture density, crack trend and line direction, adopted conventional method to set up discrete stratum attribute model;

(3) the following formula of utilization is rebuild the wave field value on each each discrete grid block point of the moment, and with the wave-field reconstruction record of each moment geophone station position wave field as this moment;

$\mathrm{\ρ}\frac{{\∂v}_x}{\∂t}=\frac{{\∂\mathrm{\σ}}_{\mathrm{xx}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{xz}}}{\∂z}$

$\mathrm{\ρ}\frac{{\∂v}_y}{\∂t}=\frac{{\∂\mathrm{\σ}}_{\mathrm{xy}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{yz}}}{\∂z}$

$\mathrm{\ρ}\frac{{\∂v}_z}{\∂t}=\frac{{\∂\mathrm{\σ}}_{\mathrm{xz}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{zz}}}{\∂z}$

$\frac{{\∂\mathrm{\σ}}_{\mathrm{xx}}}{\∂t}=c_{11}\frac{{\∂v}_x}{\∂x}{+c}_{13}\frac{{\∂v}_z}{\∂z}+c_{16}\frac{{\∂v}_y}{\∂x}$

$\frac{{\∂\mathrm{\σ}}_{\mathrm{zz}}}{\∂t}=c_{13}\frac{\∂v_x}{\∂x}+c_{33}\frac{{\∂v}_z}{\∂z}+c_{36}\frac{{\∂v}_y}{\∂x}$

$\frac{{\∂\mathrm{\σ}}_{\mathrm{yz}}}{\∂t}=c_{44}\frac{{\∂v}_y}{\∂z}+c_{45}(\frac{{\∂v}_x}{\∂z}+\frac{\∂v_z}{\∂x})$

$\frac{{\∂\mathrm{\σ}}_{\mathrm{xz}}}{\∂t}=c_{45}\frac{{\∂v}_y}{\∂z}+c_{55}(\frac{{\∂v}_x}{\∂z}+\frac{{\∂v}_z}{\∂x})$

$\frac{{\∂\mathrm{\σ}}_{\mathrm{xy}}}{\∂t}=c_{16}\frac{{\∂v}_x}{\∂x}+c_{36}\frac{{\∂v}_z}{\∂z}+c_{66}\frac{{\∂v}_y}{\∂x}$

In the formula:

ρ is a Media density, c _IjBe elasticity coefficient (with same meaning in the equation (1))

σ _Xx, σ _Zz, σ _Yz, σ _Xz, σ _XtBe respectively normal stress and shearing stress, v _x, v _y, v _zBe respectively line direction, horizontal vertical line direction and the particle displacement speed of line direction downward vertically;

(4) record that will obtain is done and the identical processing of step (2), obtains stack and migrated section;

(5) section that wave-field reconstruction is obtained and field data collection are handled stack and the migrated section contrast that obtains, and descend distribution, fracture development direction and the development degree of carbonate rock hydrocarbon reservoir definitely.

The present invention also provides following technical scheme:

Step (1) obtains the wave-field reconstruction parameter and comprises shot interval, track pitch, big gun number, road number, sampling interval, road length, cautious X, the Y coordinate of big gun.

Step (2) data is handled the single shot record that comprises collecting and is carried out static correction, normal moveout correction, velocity analysis, stack and migration processing.

The present invention has wave-field reconstruction that is applicable to any complex structure and the ability of descending hydrocarbon reservoir structure definitely, and the characteristics that precision height, efficient height, frequency dispersion are low, improve counting yield are arranged.The present invention has comprised shear wave splitting information in the record that wave-field reconstruction obtains, it is the characteristic feature of hydrocarbon-bearing pool reflection seismic waves, is the important evidence of descending carbonate rock hydrocarbon reservoir definitely.

The linear relationship of calculated amount and difference order had reduced calculated amount when the present invention will guarantee to utilize higher difference to find the solution wave equation, can also obtain the stress wave field data simultaneously.

Description of drawings

Fig. 1 is a carbonatite of the present invention crack reservoir model;

Reconstruction record (X component, Y component, Z component) figure when Fig. 2 spends for angle 0 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 3 spends for angle 15 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 4 spends for angle 30 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 5 spends for angle 45 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 6 spends for angle 60 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 7 spends for angle 75 of the present invention;

Reconstruction record (X component, Y component, Z component) figure when Fig. 8 spends for angle 90 of the present invention;

Fig. 9 is angle 45 of the present invention reconstruction wave field (X component, Y component, Z component) figure 500 milliseconds time the when spending.

Embodiment

The present invention finds the solution two-dimentional three-component anisotropic elasticity wave-field reconstruction formula (2) under the single order staggered-mesh, to rebuild three-component wave field record.Adopt the staggered-mesh method to find the solution in the process of wave-field reconstruction, promptly find the solution three velocity of displacements earlier, find the solution the partial derivative equation of five stress again the time to the partial derivative equation of time.Iterate these two steps solution procedure and export each constantly the velocity of displacement of geophone station position promptly obtain three-component wave field record.

The specific embodiment of the present invention is:

(1) the open-air actual recording geometry acquisition parameter of foundation is determined the reconstruction parameter in the wave-field reconstruction process, (comprising shot interval, track pitch, big gun number, road number, sampling interval, road length, cautious X, the Y coordinate of big gun).

(2) read the P-wave interval velocity, S-wave interval velocity, density, fracture density and the gapfiller type parameter that conform to this area's subsurface geologic structures (Fig. 1) that obtains through seismic data data processing in early stage (comprising that the single shot record to collecting carries out a series of processing such as static correction, normal moveout correction, velocity analysis, stack and skew), set up discrete stratum attribute model.

(3), utilize formula (2) to rebuild each wave field value (Fig. 9) on each discrete grid block point constantly, and each geophone station position wave field output is constantly recorded as this reconstructing wave script holder constantly according to recording geometry parameter and discrete stratum attribute model.Fig. 2-Fig. 8 is a crack trend and the angle of line direction is respectively 0 degree, 15 degree, 30 degree, 45 degree, 60 degree, reconstructing wave script holder record when 75 degree and 90 are spent.

(4) processing identical with real data (comprising a series of processing such as static correction, normal moveout correction, velocity analysis, stack and skew) done in the record that previous step is obtained, and obtains corresponding section (comprising stack and migrated section).

(5) section that wave-field reconstruction is obtained (stack and migrated section) is analyzed with the section (stack and migrated section) that the field data collection processing obtains, and determines crack trend and crack density, and then definite hydrocarbon occurrence, oil and gas reserves and development plan.

When the present invention launches when partial derivative Xiang Zuoshi rank, space, same model is carried out numerical simulation with identical parameters, it is about 60% that the equation (1) that the equation that the present invention provides (2) provides than Li Wenlin computing time has shortened, and improved the precision of rebuilding wave field, rebuild the stress field data simultaneously.

Claims (3)

1, a kind of method of definite carbonate rock hydrocarbon reservoir structure is characterized in that: concrete implementation step is as follows:

(1) utilizes the field layout acquiring seismic data, obtain the wave-field reconstruction parameter;

(2) data is handled the angle and the gapfiller type parameter of the velocity of longitudinal wave that obtains subsurface geologic structures and conform to, shear wave velocity, density, fracture density, crack trend and line direction, adopted conventional method to set up discrete stratum attribute model;

(3) the following formula of utilization is rebuild the wave field value on each each discrete grid block point of the moment, and with the wave-field reconstruction record of each moment geophone station position wave field as this moment;

$\mathrm{\ρ}\frac{\∂v_x}{\∂t}=\frac{{\∂\mathrm{\σ}}_{\mathrm{xx}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{xz}}}{\∂z}$

$\mathrm{\ρ}\frac{\∂v_y}{\∂t}\frac{\∂{\mathrm{\σ}}_{\mathrm{xy}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{yz}}}{\∂z}$

$\mathrm{\ρ}\frac{\∂v_z}{\∂t}\frac{\∂{\mathrm{\σ}}_{\mathrm{xz}}}{\∂x}+\frac{{\∂\mathrm{\σ}}_{\mathrm{zz}}}{\∂z}$

$\frac{\∂{\mathrm{\σ}}_{\mathrm{xx}}}{\∂t}=c_{11}\frac{\∂v_x}{\∂x}+c_{13}\frac{\∂v_z}{\∂z}+c_{16}\frac{{\∂v}_y}{\∂x}$

$\frac{\∂{\mathrm{\σ}}_{\mathrm{zz}}}{\∂t}=c_{13}\frac{\∂v_x}{\∂x}+c_{33}\frac{\∂v_z}{\∂z}+c_{36}\frac{{\∂v}_y}{\∂x}$

$\frac{\∂{\mathrm{\σ}}_{\mathrm{yz}}}{\∂t}=c_{44}\frac{\∂v_y}{\∂z}+c_{45}(\frac{\∂v_x}{\∂z}+\frac{{\∂v}_z}{\∂x})$

$\frac{\∂{\mathrm{\σ}}_{\mathrm{xz}}}{\∂t}=c_{45}\frac{\∂v_y}{\∂z}+c_{55}(\frac{\∂v_x}{\∂z}+\frac{{\∂v}_z}{\∂x})$

$\frac{\∂{\mathrm{\σ}}_{\mathrm{xy}}}{\∂t}=c_{16}\frac{\∂v_x}{\∂x}+c_{36}\frac{\∂v_z}{\∂z}+c_{66}\frac{{\∂v}_y}{\∂x}$

In the formula:

ρ is a Media density, c _IjBe elasticity coefficient (with same meaning in the equation (1)) σ _Xx, σ _Zz, σ _Yz, σ _Xz, σ _XyBe respectively normal stress and shearing stress, v _x, v _y, v _zBe respectively line direction, horizontal vertical line direction and the particle displacement speed of line direction downward vertically;

(4) record that will obtain is done and the identical processing of step (2), obtains stack and migrated section;

(5) section that wave-field reconstruction is obtained and field data collection are handled stack and the migrated section contrast that obtains, and descend distribution, fracture development direction and the development degree of carbonate rock hydrocarbon reservoir definitely.

2, the method for a kind of definite carbonate rock hydrocarbon reservoir structure according to claim 1 is characterized in that: step (1) obtains the wave-field reconstruction parameter and comprises shot interval, track pitch, big gun number, road number, sampling interval, road length, cautious X, the Y coordinate of big gun.

3, the method for a kind of definite carbonate rock hydrocarbon reservoir structure according to claim 1 is characterized in that: step (2) data is handled the single shot record that comprises collecting and is carried out static correction, normal moveout correction, velocity analysis, stack and migration processing.

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