CN104122602A - Method and device for acquiring erosion thickness of sedimentary basin - Google Patents

Abstract

The invention relates to a method and device for acquiring erosion thickness of a sedimentary basin. The method comprises the following steps: acquiring information of different stratums in a researched area, wherein the information includes top-to-bottom depth of each stratum, sampling depth of each sample point of each stratum, lithology and porosity; building a fitting relationship between the corresponding porosity, depth and lithology of each stratum according to the stratum information; comparing the fitting relationships of the corresponding porosity, depth and lithology of upper and lower adjacent stratums to determine the erosion of the lower one of the two upper and lower adjacent layers; adding a stratum of which the thickness is shown as delta H and the lithology is similar to the that of the residual part to the top part of the determined erosion stratum, in order to compensate porosity difference between the upper and lower stratum interfaces; acquiring the erosion thickness H0 of the basin under initial deposition according to the compensated erosion stratum. According to the technical scheme, the method shows high applicability and effectiveness in complex geological conditions.

Description

A kind of method and device that obtains sedimentary basin erosion sediment thickness

Technical field

The present invention relates to geological exploration techniques field, particularly a kind of method and device that obtains sedimentary basin erosion sediment thickness.

Background technology

Degrade on stratum is ubiquitous phenomenon in growth course in sedimentary basin.In uplift denudation, sedimental diagenesis evolution, discharge opeing effect and Temperature Field etc. all will change, and change degree and denudation size closely related.In Basin Evolution history is analyzed, the accurate recovery of stratum erosion sediment thickness is the Focal point and difficult point of rebuilding buried history, and is inverting basin thermal history, Accumulation of Hydrocarbon row hydrocarbon history and the precondition that becomes to hide history.

For estimating that the method for stratum erosion sediment thickness has a lot, overview gets up to have following several both at home and abroad:

(1) strata antithesis: this is a kind of method of traditional recovery erosion sediment thickness, it is according to the data such as drilling well, earthquake, by closing on the thickness that does not degrade stratum, place in district, obtain zone thickness variation tendency by curve fitting method, infer and degraded regional denudation.It is less that this method is applicable to degrade area, the area that research degree is higher.But larger when degrading area, zone thickness changes larger in the horizontal, and error will be larger.

(2) rate of sedimentation method: for parallel unconformity, can study and recover erosion sediment thickness according to the rate of sedimentation on the upper and lower stratum of unconformity surface, the absolute geological age of degrading speed and stratum.Degraded if known stratum rate of sedimentation, degrade absolute age on speed and stratum, just can calculate the erosion sediment thickness on stratum.Due to the required parameter of this method, speed, stratum absolute age etc. sometimes seldom arrive exact value as degraded, so it is applicable to the more deep area of stratigraphy study.

(3) logging trace method: this is a kind of method first being proposed by Magara.He thinks the in the situation that of normal compaction, and the factor of porosity of petroclastic rock is continuous with change in depth, can obtain factor of porosity with change in depth curve with well-log information, can infer there is erosion free by the variation tendency of curve, and the size of denudation.This method is applicable to the area that denudation is larger, except factor of porosity, can also use the parameters such as density of earth formations, interval transit time, and its principle is the same.

(4) vitrinite reflectance rate: vitrinite reflectance is to apply at present very wide maturity of organic matter index.First Dow proposes a kind of method of estimating denudation with vitrinite reflectance, and this method is calculated denudation size according to the difference size of the neighbouring stratum of plane of denudation Ro value.When Ro value is with the variation of the degree of depth under normal circumstances, continuously and gradual change, still, in the time that there is plane of denudation on stratum, Ro value will produce discontinuous.Then can be in the hope of erosion sediment thickness by graphical method, the weak point of this method is to exceed while degrading layer thickness when the zone thickness of the above deposition of plane of denudation, cannot carry out denudation recovery by the method.

(5) seismic stratigraphy method: this is a kind of based on seismic stratigraphy principle, and comprehensive geology, drilling data calculate the method for erosion sediment thickness.Its ultimate principle is: according to Seismic Stratigraphic Interpretation, divide sedimentation sequence, analyze and whether have residual thickness and the zone thickness horizontal change rule of degrading and being degraded stratum, demarcate the age of sequence of sedimentation with drilling data, determine the sedimentary environment by the controllable certain limit of well, provide near the bound of the erosion sediment thickness in position, well point as near erosion sediment thickness this point; Finally utilize the loose point processing of geometrograph to obtain erosion sediment thickness.The erosion sediment thickness that this method is calculated is subject to the impact of seismic data quality larger, and the impact of human factor is very important.

(6) rock gas equilibrium concentration method: Li Mingcheng, Li Wei propose a kind of method of utilizing rock gas equilibrium concentration estimation erosion sediment thickness.According to rock gas diffusion mechanism, as long as the rock gas in stratum exists concentration difference, gas diffusion will occur.Its ultimate principle is: be continuous the diffusion time of rock gas, but may be discontinuous (having plane of denudation) corresponding to the diffusion stratum of this time; If the equilibrium concentration value going out according to geology Time Calculation is less than the equilibrium concentration value that base area layer thickness calculates, this difference may be relevant with the disappearance on stratum.At this moment, at the thickness of known source rock and overlying strata, volume, amount of coalbed methane generated and start, on the diffusion time of isoparametric basis, can estimate erosion sediment thickness.If study area does not have rock gas to generate or amount of coalbed methane generated is little, can not be in this way.

By finding out the brief introduction of above-mentioned erosion sediment thickness method, the method of renwing stratum erosion sediment thickness has certain limitation at present, as strata antithesis and the higher area of the applicable stratigraphy study degree of rate of sedimentation method, the area that the suitable erosion sediment thickness of logging trace method is larger, vitrinite reflectance rate applicable elements is that the zone thickness of the above deposition of plane of denudation is no more than and degrades layer thickness, it is larger that seismic stratigraphy method is subject to human factor impact, and rock gas equilibrium concentration rule can only be used for the area that has rock gas to generate.The limitation problem of being badly in need of solving prior art scheme, finds the better scheme of a kind of applicability and validity.

Summary of the invention

In order to solve the limitation problem of prior art, the present invention proposes a kind of method and device that obtains sedimentary basin erosion sediment thickness.The required basic data of method of recovery sedimentary basin erosion sediment thickness proposed by the invention easily obtains, and has better applicability and validity.

For achieving the above object, the invention provides a kind of method of obtaining sedimentary basin erosion sediment thickness, the method comprises:

Obtain the formation information of study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

According to described formation information, set up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

More neighbouring stratum is the matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether the sub-surface on these two neighbouring stratum was subject to degrade;

Adding a thickness at the top of degrading stratum of judging is Δ H, lithology and residual fraction one section of stratum roughly the same, and the porosity difference between bed interface is up and down made up; Described Δ H is:

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

According to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

Preferably, described basis makes up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀concrete steps comprise:

According to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})---\left(7\right)$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

Preferably, described set up each stratum accordingly the step of the matching relation of factor of porosity and the degree of depth, lithology comprise:

Obtain each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Obtain each stratum relational expression that sandstone porosity changes with buried depth accordingly;

The relational expression that the relational expression, described sandstone porosity changing with buried depth according to described mudstone porosity changes with buried depth obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.

Preferably, the relational expression that described mudstone porosity changes with buried depth is:

${\mathrm{\φ}}_{\mathrm{sh}}\left(Z\right)={\mathrm{\φ}}_{0\mathrm{sh}}{e}^{(-C_{\mathrm{sh}}*Z)}$

Wherein, φ _sh(Z) be the factor of porosity that mud stone changes along with buried depth, φ _0shfor mud stone original porosity, C _shfor mudstone compacting coefficient, Z is sediment buried depth.

Preferably, the relational expression that described sandstone porosity changes with buried depth is:

${\mathrm{\φ}}_s\left(Z\right)={\mathrm{\φ}}_{0s}{e}^{(-C_s*Z)}$

Wherein, φ _s(Z) be the factor of porosity that sandstone changes along with buried depth, φ _0sfor sandstone original porosity, C _sfor sandstone compaction coefficient, Z is sediment buried depth.

Preferably, described each stratum accordingly the expression formula of the matching relation of factor of porosity and the degree of depth, lithology be:

$\mathrm{\φ}(Z,\mathrm{Rn})=r_{\mathrm{sh}}{\mathrm{\φ}}_{0\mathrm{sh}}{e}^{-C_{\mathrm{sh}}*Z}+(1-r_{\mathrm{sh}}){\mathrm{\φ}}_{0s}{e}^{-C_s*Z}$

Wherein, φ (Z, Rn) is expressed as the factor of porosity with buried depth and lithological change, r _shbe expressed as the shared ratio of mud stone, φ _0shand φ _0soriginal porosity while being expressed as mud stone and sandstone deposition, C _shand C _sbe expressed as mud stone and sandstone compaction coefficient, Z is expressed as sediment buried depth.

Preferably, describedly judge whether underlying formation comprised by the step of degrading:

Utilize the factor of porosity function of every one deck to ask for respectively the factor of porosity size of neighbouring stratum in the same degree of depth and identical lithology situation;

According to the contact relation on the neighbouring stratum after judgment expression judgement correction; Wherein, described judgment expression is:

Wherein, φ _a(Z ₁, R ₁) and φ _b(Z ₁, R ₁) represent that respectively upper and lower stratum is corrected to the same buried depth Z of contact point ₁, same lithology R ₁on factor of porosity; ε is expressed as formation contact and differentiates the random deviation allowing.

For achieving the above object, the present invention also provides a kind of device that obtains sedimentary basin erosion sediment thickness, and this device comprises:

Formation information acquiring unit, for obtaining the formation information of study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

Matching Relation acquisition unit, for according to described formation information, sets up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

Judging unit, for the more neighbouring stratum matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether the sub-surface on these two neighbouring stratum was subject to degrade;

Making up processing unit, is Δ H, lithology and residual fraction one section of stratum roughly the same for add a thickness at the top of degrading stratum of judging, and the porosity difference between bed interface is up and down made up; Described Δ H is:

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

Erosion sediment thickness acquiring unit when embryo deposit, for according to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

Preferably, when described embryo deposit erosion sediment thickness acquiring unit specifically for according to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

Preferably, described matching Relation acquisition unit comprises the first relational expression acquisition module, the second relational expression acquisition module and the 3rd relational expression acquisition module; Wherein,

Described the first relational expression acquisition module, for obtaining each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Described the second relational expression acquisition module, for obtaining each stratum relational expression that sandstone porosity changes with buried depth accordingly;

Described the 3rd relational expression acquisition module, the relational expression changing with buried depth for the relational expression, described sandstone porosity that change with buried depth according to described mudstone porosity obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.

Technique scheme has following beneficial effect: geologic information required for the present invention comprises strata division, lithological information and the factor of porosity information along with change in depth, these data are the geologic informations on basis in basin research, easily obtain, can be applied to the basin that research degree is high and can be applied to again the basin that research degree is low, the method that the present invention proposes has better applicability and validity.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is a kind of method flow diagram that obtains sedimentary basin erosion sediment thickness that the present invention proposes;

Fig. 2 is a kind of device block diagram that obtains sedimentary basin erosion sediment thickness that the present invention proposes;

Fig. 3 is the method flow diagram that obtains sedimentary basin erosion sediment thickness that the present embodiment adopts;

Fig. 4 is that in the present embodiment, theoretical model schematic diagram is recovered to calculate by erosion sediment thickness in stratum.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, the data of the embodiment of the present invention are from the noble fort of Nanpu Sag of Bohai Bay Basin structural belt.Obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

Principle of work of the present invention is: according to study area Different Strata top at the bottom of the degree of depth, and sampling depth, the lithology of each sample point in each stratum, erosion sediment thickness when factor of porosity size waits formation information to obtain embryo deposit, makes to recover sedimentary basin erosion sediment thickness and has better applicability and validity.

As shown in Figure 1, a kind of method flow diagram that obtains sedimentary basin erosion sediment thickness proposing for the present invention.The method comprises:

Step 101): the formation information that obtains study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

Step 102): according to described formation information, set up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

Step 103): more neighbouring stratum is the matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether sub-surface was subject to degrade;

Step 104): adding a thickness at the top of degrading stratum of judging is Δ H, lithology and residual fraction one section of stratum roughly the same, and the porosity difference between bed interface is up and down made up; Wherein,

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

Step 105): according to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

The zone thickness of every one deck is along with the time changes, degrade on the stratum that we observe is now to form before N, Δ H be the stratum of being degraded In the view of now by erosion sediment thickness, but the erosion sediment thickness that we need to ask refers to the thickness of stratum before N, i.e. erosion sediment thickness when embryo deposit.

Preferably, described step 105 specifically comprises:

According to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

Preferably, described set up each stratum accordingly the step of the matching relation of factor of porosity and the degree of depth, lithology comprise:

Obtain each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Obtain each stratum relational expression that sandstone porosity changes with buried depth accordingly;

The relational expression that the relational expression, described sandstone porosity changing with buried depth according to described mudstone porosity changes with buried depth obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.

Preferably, the relational expression that described mudstone porosity changes with buried depth is:

${\mathrm{\φ}}_{\mathrm{sh}}\left(Z\right)={\mathrm{\φ}}_{0\mathrm{sh}}{e}^{(-C_{\mathrm{sh}}*Z)}$

Wherein, φ _sh(Z) be the factor of porosity that mud stone changes along with buried depth, φ _0shfor mud stone original porosity, C _shfor mudstone compacting coefficient, Z is sediment buried depth.

Preferably, the relational expression that described sandstone porosity changes with buried depth is:

${\mathrm{\φ}}_s\left(Z\right)={\mathrm{\φ}}_{0s}{e}^{(-C_s*Z)}$

Wherein, φ _s(Z) be the factor of porosity that sandstone changes along with buried depth, φ _0sfor sandstone original porosity, C _sfor sandstone compaction coefficient, Z is sediment buried depth.

Preferably, described each stratum accordingly the expression formula of the matching relation of factor of porosity and the degree of depth, lithology be:

$\mathrm{\φ}(Z,\mathrm{Rn})=r_{\mathrm{sh}}{\mathrm{\φ}}_{0\mathrm{sh}}{e}^{-C_{\mathrm{sh}}*Z}+(1-r_{\mathrm{sh}}){\mathrm{\φ}}_{0s}{e}^{-C_s*Z}$

Wherein, φ (Z, Rn) is expressed as the factor of porosity with buried depth and lithological change, r _shbe expressed as the shared ratio of mud stone, φ _0shand φ _0soriginal porosity while being expressed as mud stone and sandstone deposition, C _shand C _sbe expressed as mud stone and sandstone compaction coefficient, Z is expressed as sediment buried depth.

Preferably, describedly judge whether underlying formation comprised by the step of degrading:

Utilize the factor of porosity function of every one deck to ask for respectively the factor of porosity size in the same degree of depth and identical lithology situation in neighbouring stratum.

According to the contact relation on the neighbouring stratum after judgment expression judgement correction; Wherein, described judgment expression is:

Wherein, φ _a(Z ₁, R ₁) and φ _b(Z ₁, R ₁) represent that respectively upper and lower stratum is corrected to the same buried depth Z of contact point ₁, same lithology R ₁on factor of porosity; ε is expressed as formation contact and differentiates the random deviation allowing.

As shown in Figure 2, a kind of device block diagram that obtains sedimentary basin erosion sediment thickness proposing for the present invention.This device comprises:

Formation information acquiring unit 201, for obtaining the formation information of study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

Matching Relation acquisition unit 202, for according to described formation information, sets up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

Judging unit 203, for the more neighbouring stratum matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether sub-surface was subject to degrade;

Making up processing unit 204, is Δ H, lithology and residual fraction one section of stratum roughly the same for add a thickness at the top of degrading stratum of judging, and the porosity difference between bed interface is up and down made up; Wherein,

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

Erosion sediment thickness acquiring unit 205 when embryo deposit, for according to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

The zone thickness of every one deck is along with the time changes, degrade on the stratum that we observe is now to form before N, Δ H be the stratum of being degraded In the view of now by erosion sediment thickness, but the erosion sediment thickness that we need to ask refers to the thickness of stratum before N, i.e. erosion sediment thickness when embryo deposit.

Preferably, when described embryo deposit erosion sediment thickness acquiring unit 205 specifically for according to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

Preferably, described matching Relation acquisition unit 202 comprises the first relational expression acquisition module, the second relational expression acquisition module and the 3rd relational expression acquisition module; Wherein,

Described the first relational expression acquisition module, for obtaining each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Described the second relational expression acquisition module, for obtaining each stratum relational expression that sandstone porosity changes with buried depth accordingly;

Described the 3rd relational expression acquisition module, the relational expression changing with buried depth for the relational expression, described sandstone porosity that change with buried depth according to described mudstone porosity obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.

In order to understand the present invention in depth, below in conjunction with accompanying drawing and application example, embodiments of the invention are described in further detail.

The embodiment of the present invention is taking a bite well of the noble fort of Nanpu Sag of Bohai Bay Basin structural belt as research object, Nan Bao depression is Cenozoic depression, and north, according to Yanshan folding zone, reaches Bohai Offshore in the south, West Depression the north, fort, south is taking southwestern village tomography as boundary, and Yu Laowang village projection, southwestern village projection are separated by; The Yi Baige village, northeast tomography is that Jie Yubaige village projection, head of the horse battalion projection are connected; South is disconnected super formula with Shaleitian uplift and contacts.Nan Bao depression be a Ge Zhong Neozoic group superimposed, be deposited as the super single formula dustpan shape that breaks in disconnected south, main north with Neozoic group and cave in.The Nan Bao main second-order structure zone that caves in comprises southern fort structural belt, noble fort structural belt, Liu Zan structural belt, master mausoleum structural belt, fracture shirt rim, the Ji Baige village, southwestern village structural belt etc.Noble fort structure is a draping anticlinal structure of buried hills, the core portion of anticline is between high willow tomography and high northern tomography, be large-scale compound oil gas accumulation zones stacked, many oil water relation taking structure layered pool as polymorphic type, the multilayer of main Types, exploration area 210km ².Find altogether Liao Minghua town group, Guantao group, one section, east, two sections, east, three sections, east, Sha Yiduan, the oily series of strata such as husky three sections, accumulative total reports verifies oil-bearing area 34.76km ², verify petroleum-in-place 14917.60 × 10 ⁴t.

" recessed in grand " of noble fort structural belt between northern two oil generation of Nan Bao depression time low-lying area, taking husky three sections of coating anticlines as structure main body, at an upper portion thereof, combine the Tibetan that becomes of composition " from being conigenous storage " and " lower raw upper storage " for Lower Tertiary Source Rock onlap or coating.According to structure development feature, noble fort structural belt can be further divided into three local structures, i.e. the south brokeback of height on the south high willow tomography is (disconnected nose) structural belt, noble fort coating anticline structure to the north of high willow tomography and the disconnected nose structure in height north of high northern tomography uplifted wall tiltedly.

The cave in erosion sediment thickness maximum of area, noble fort Dongying Formation of Nan Bao, take second place in master mausoleum, area, northern fort, central concave area is minimum, to the north of high willow tomography, the erosion sediment thickness that serious region is degraded in area, noble fort reaches more than 1000 meters, and on the south high willow tomography, erosion sediment thickness obviously diminishes, and is generally 200-600 rice, fort area, south Dongying Formation erosion sediment thickness is that Beijing University south is little, the large feature of the little surrounding in center generally, and this is by Nan Bao depression deposition and structural evolution decision.The concrete data of the present embodiment are from high 62 wells of noble fort structural belt.

As shown in Figure 3, the method flow diagram that obtains sedimentary basin erosion sediment thickness adopting for the present embodiment.Described method comprises:

Step 1) obtain the formation information of study area different layers;

Concrete, described formation information comprises: the degree of depth at the bottom of the top on each stratum, the sampling depth of each sample point in every one deck, lithology, factor of porosity size.The formation information that following table 1 is the present embodiment;

Table 1

Step 2) set up the matching relation of every one deck mesoporosity degree and the degree of depth and lithology;

Concrete, can first set up respectively the relational expression that mudstone porosity changes with buried depth, sandstone porosity is with the relational expression of buried depth, then sets up the matching relation of factor of porosity and the degree of depth and lithology.

Set up the matching relation of mudstone porosity and buried depth variation according to formula (1);

${\mathrm{\φ}}_{\mathrm{sh}}\left(Z\right)={\mathrm{\φ}}_{0\mathrm{sh}}{e}^{(-C_{\mathrm{sh}}*Z)}---\left(1\right)$

Wherein, φ _sh(Z) be the factor of porosity that mud stone changes along with buried depth, φ _0shfor mud stone original porosity, C _shfor mudstone compacting coefficient, Z is sediment buried depth.

Set up the matching relation of sandstone porosity and buried depth variation according to formula (2);

${\mathrm{\φ}}_s\left(Z\right)={\mathrm{\φ}}_{0s}{e}^{(-C_s*Z)}---\left(2\right)$

Wherein, φ _s(Z) be the factor of porosity that sandstone changes along with buried depth, φ _0sfor sandstone original porosity, C _sfor sandstone compaction coefficient, Z is sediment buried depth.

Set up the matching relation of every one deck mesoporosity degree and the degree of depth, lithology according to formula (3);

$\mathrm{\φ}(Z,\mathrm{Rn})=r_{\mathrm{sh}}{\mathrm{\φ}}_{0\mathrm{sh}}{e}^{-C_{\mathrm{sh}}*Z}+(1-r_{\mathrm{sh}}){\mathrm{\φ}}_{0s}{e}^{-C_s*Z}---\left(3\right)$

Wherein: φ (Z, Rn) is the factor of porosity with buried depth and lithological change, r _shfor the shared ratio of mud stone, φ _0shand φ _0soriginal porosity while being respectively mud stone and sandstone deposition, C _shand C _sfor mud stone and sandstone compaction coefficient, Z sediment buried depth.

Step 3) factor of porosity on neighbouring stratum is compared having proofreaied and correct after the impact of buried depth, rock character, judge the deposition contact relation on stratum according to the size of the two difference;

Judge formation contact according to formula (4);

Wherein, φ _a(Z ₁, R ₁) and φ _b(Z ₁, R ₁) represent that respectively upper and lower stratum is corrected to contact point and unifies buried depth (Z ₁), unified lithology (R ₁) on factor of porosity; ε differentiates for formation contact the random deviation allowing, and its numerical values recited is looked the precision (measured value and theoretical fitting value deviation) of study area data and determined.

Step 4) when being greater than formation contact, the two difference differentiates the random deviation allowing, judge that abtragung occurred the sub-surface on these two adjacent stratum;

According to formula (4), as Δ φ _abwhen >+ ε, can judge that abtragung occurred on this stratum, otherwise be undercompaction and normally contact, be not the situation that the present embodiment will be discussed.

Calculate Δ H according to formula (5);

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}---\left(5\right)$

Wherein, Δ H is the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, the porosity difference between bed interface is up and down made up, Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface, ρ ' _a(Z), ρ ' _b(Z) respectively time overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface, as shown in Figure 4.

Set up the matching relation of density of earth formations and the degree of depth in every one deck according to formula (6);

$\mathrm{\ρ}=K*Z^{D_0}---\left(6\right)$

Wherein, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature.

Step 5) add a thickness at the top of being degraded stratum be Δ H, lithology and residual fraction one section of stratum roughly the same, and the porosity difference between bed interface is up and down made up;

Step 6) method erosion sediment thickness while obtaining embryo deposit of using back stripping.

Erosion sediment thickness while obtaining embryo deposit according to formula (7);

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})---\left(7\right)$

Wherein, H ₀erosion sediment thickness during for embryo deposit, ρ ₀, ρ is respectively the density function on the stratigraphic section of deposition compacting front and back, φ ₀, φ is respectively factor of porosity function on the stratigraphic section of deposition compacting front and back, Z ₁for plane of denudation buried depth now, Δ H is degraded stratum erosion sediment thickness now, and the present invention supposes that the stratum presedimentary weight of rock pillar body equals post-depositional weight and discharge currents body weight sum.If formula (7) the equation left side is the weight of initially degrading stratum, the right is weight and the discharge currents body weight sum of being degraded stratum after deposition.

It is 576 meters that the embodiment of the present invention calculates the cave in erosion sediment thickness of high 62 wellblocks of structural belt, noble fort of Nan Bao, obtain be calculated as 600 meters of the erosion sediment thickness of forefathers to this study area by investigation, can think that result of calculation of the present invention is rational, with respect to the method for other research erosion sediment thickness, the basic data of wanting required for the present invention more easily obtains, for the relatively low area of research degree, the present invention has better applicability and validity.

In the above-described embodiments, provide a kind of new method that obtains sedimentary basin erosion sediment thickness, first, obtained the formation information of study area different layers; Formation information comprises: the degree of depth at the bottom of the top on each stratum, the sampling depth of each sample point in every one deck, lithology, factor of porosity size; Set up the matching relation of every one deck mesoporosity degree and the degree of depth and lithology; The factor of porosity on neighbouring stratum is compared having proofreaied and correct after the impact of buried depth, rock character, judge the deposition contact relation on stratum according to the size of the two difference; Differentiate when the two difference is greater than formation contact the random deviation allowing, judge that abtragung occurred the sub-surface on these two adjacent stratum; Adding a thickness at the top of being degraded stratum is Δ H, lithology and residual fraction one section of stratum roughly the same, and the porosity difference between bed interface is up and down made up; Erosion sediment thickness while obtaining embryo deposit by the method for returning stripping.The present embodiment has verified that the technical program can, for complicated geologic condition, have better applicability and validity.

Above-described embodiment; object of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only the specific embodiment of the present invention; the protection domain being not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (10)

1. a method of obtaining sedimentary basin erosion sediment thickness, is characterized in that, the method comprises:

Obtain the formation information of study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

According to described formation information, set up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

More neighbouring stratum is the matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether the sub-surface on these two neighbouring stratum was subject to degrade;

Adding a thickness at the top of degrading stratum of judging is Δ H, lithology and residual fraction one section of stratum roughly the same, and the porosity difference between bed interface is up and down made up; Described Δ H is:

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

According to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

2. the method for claim 1, is characterized in that, described basis makes up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀concrete steps comprise:

According to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})---\left(7\right)$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

3. method as claimed in claim 1 or 2, is characterized in that, described set up each stratum accordingly the step of the matching relation of factor of porosity and the degree of depth, lithology comprise:

Obtain each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Obtain each stratum relational expression that sandstone porosity changes with buried depth accordingly;

The relational expression that the relational expression, described sandstone porosity changing with buried depth according to described mudstone porosity changes with buried depth obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.

4. method as claimed in claim 3, is characterized in that, the relational expression that described mudstone porosity changes with buried depth is:

${\mathrm{\φ}}_{\mathrm{sh}}\left(Z\right)={\mathrm{\φ}}_{0\mathrm{sh}}{e}^{(-C_{\mathrm{sh}}*Z)}$

Wherein, φ _sh(Z) be the factor of porosity that mud stone changes along with buried depth, φ _0shfor mud stone original porosity, C _shfor mudstone compacting coefficient, Z is sediment buried depth.

5. method as claimed in claim 3, is characterized in that, the relational expression that described sandstone porosity changes with buried depth is:

${\mathrm{\φ}}_s\left(Z\right)={\mathrm{\φ}}_{0s}{e}^{(-C_s*Z)}$

Wherein, φ _s(Z) be the factor of porosity that sandstone changes along with buried depth, φ _0sfor sandstone original porosity, C _sfor sandstone compaction coefficient, Z is sediment buried depth.

6. method as claimed in claim 3, is characterized in that, described each stratum accordingly expression formula of the matching relation of factor of porosity and the degree of depth, lithology is:

$\mathrm{\φ}(Z,\mathrm{Rn})=r_{\mathrm{sh}}{\mathrm{\φ}}_{0\mathrm{sh}}{e}^{-C_{\mathrm{sh}}*Z}+(1-r_{\mathrm{sh}}){\mathrm{\φ}}_{0s}{e}^{-C_s*Z}$

Wherein, φ (Z, Rn) is expressed as the factor of porosity with buried depth and lithological change, r _shbe expressed as the shared ratio of mud stone, φ _0shand φ _0soriginal porosity while being expressed as mud stone and sandstone deposition, C _shand C _sbe expressed as mud stone and sandstone compaction coefficient, Z is expressed as sediment buried depth.

7. the method for claim 1, is characterized in that, describedly judges whether underlying formation comprised by the step of degrading:

Utilize the factor of porosity function of every one deck to ask for respectively the factor of porosity size of neighbouring stratum in the same degree of depth and identical lithology situation;

According to the contact relation on the neighbouring stratum after judgment expression judgement correction; Wherein, described judgment expression is:

Wherein, φ _a(Z ₁, R ₁) and φ _b(Z ₁, R ₁) represent that respectively upper and lower stratum is corrected to the same buried depth Z of contact point ₁, same lithology R ₁on factor of porosity; ε is expressed as formation contact and differentiates the random deviation allowing.

8. a device that obtains sedimentary basin erosion sediment thickness, is characterized in that, this device comprises:

Formation information acquiring unit, for obtaining the formation information of study area different layers; Wherein, described formation information comprises: the sampling depth of each sample point, lithology and factor of porosity size in the degree of depth, each stratum at the bottom of the top on each stratum;

Matching Relation acquisition unit, for according to described formation information, sets up each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly;

Judging unit, for the more neighbouring stratum matching relation of factor of porosity and the degree of depth, lithology accordingly, judges whether the sub-surface on these two neighbouring stratum was subject to degrade;

Making up processing unit, is Δ H, lithology and residual fraction one section of stratum roughly the same for add a thickness at the top of degrading stratum of judging, and the porosity difference between bed interface is up and down made up; Described Δ H is:

$\mathrm{\ΔH}=\frac{\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_A^{\′}}=\frac{2*\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{ab}}}{{\mathrm{\ρ}}_a^{\′}\left(Z\right)+{\mathrm{\ρ}}_b^{\′}\left(\text{Z}\right)}$

Wherein, Δ H is the thickness on one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up; Δ ρ _abthe density difference of neighbouring stratum on the contact point of interface; ρ ' _a(Z), ρ ' _b(Z) be respectively overlying strata and under cover the first order derivative of density of earth formations function at contact point place, interface;

Erosion sediment thickness acquiring unit when embryo deposit, for according to making up the stratum erosion sediment thickness H while obtaining basin embryo deposit that degrades after treatment ₀.

9. device as claimed in claim 8, is characterized in that, when described embryo deposit erosion sediment thickness acquiring unit specifically for according to Δ H, erosion sediment thickness H while utilizing back strip to obtain basin embryo deposit ₀; Wherein, described time strip is expressed as by following formula:

${\∫}_0^{H_0}{{\mathrm{\ρ}}_0}^{\mathrm{dZ}}={\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\ρdZ}+({\∫}_0^{H_0}{{\mathrm{\φ}}_0}^{\mathrm{dZ}}-{\∫}_{Z_1}^{Z_1+\mathrm{\ΔH}}\mathrm{\φdZ})$

Wherein, H ₀erosion sediment thickness during for embryo deposit; ρ ₀be expressed as the density function on the front stratigraphic section of deposition compacting; ρ is expressed as the density function on stratigraphic section after deposition compacting, ρ is the density function changing along with depth of stratum Z, and K is the parameter relevant with lithology, D ₀for the parameter relevant with study area deposition compacting feature; φ ₀be expressed as factor of porosity function on the front stratigraphic section of deposition compacting; φ is expressed as after deposition compacting factor of porosity function on stratigraphic section; Z ₁represent plane of denudation buried depth now; Δ H is expressed as the thickness on the one section of stratum adding at the top of being degraded stratum, and the lithology on this section of stratum is identical with residual fraction, and the porosity difference between bed interface is up and down made up.

10. install as claimed in claim 8 or 9, it is characterized in that, described matching Relation acquisition unit comprises the first relational expression acquisition module, the second relational expression acquisition module and the 3rd relational expression acquisition module; Wherein,

Described the first relational expression acquisition module, for obtaining each stratum relational expression that mudstone porosity changes with buried depth accordingly;

Described the second relational expression acquisition module, for obtaining each stratum relational expression that sandstone porosity changes with buried depth accordingly;

Described the 3rd relational expression acquisition module, the relational expression changing with buried depth for the relational expression, described sandstone porosity that change with buried depth according to described mudstone porosity obtains each stratum matching relation of factor of porosity and the degree of depth, lithology accordingly.