CN106096858A - A kind of Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods - Google Patents

Abstract

The present invention relates to a kind of Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods, comprise the following steps: 1) fluid information of multiple producing wells that utilizes actual oil field to be taken, set up shallow layer thick oil crude oil viscosity respectively with temperature, pressure and the relational expression of dissolved gas oil ratio change；2) according to step 1) in three relational expressions, obtain the quantitatively characterizing formula of shallow layer thick oil oil field viscosity of crude under the conditions of different temperatures, pressure and dissolved gas oil ratio；4) a certain position viscosity of crude is calculated.

Description

A kind of Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods

Technical field

The present invention relates to a kind of Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods, belong to oil and gas exploitation technology Field.

Background technology

Crude oil in reservoir is hydrocarbon source rock after hydrocarbon, freight index future and cross-mixing change during thermal evolution, finally Form complicated hydrocarbon fluid system, then the transformation of postmenstruation and degraded changing of grade, make existing fluid present difference Physicochemical characteristic.Therefore, the crude oil property feature in oil-gas reservoir is oil-gas migration, assembles, preserves shape or even oil gas The concentrated expression scattered and disappeared, destroy, the viscous crude field based on fluvial facies deposit, the change of reservoir properties, fluid properties acutely, changes Rule is complicated, and the regularity of distribution of its oil viscosity of dissimilar oil field is different, and the regularity of distribution of oil viscosity is closed The oil field very important decision problems such as the deployment being tied to the design of oilfield development program, Adjusted Option, its effect of different development schemes Difference is huge, therefore, accurately recognizes the regularity of distribution of oil viscosity and affects the factor of oil viscosity change, right The Efficient Development of viscous crude field is especially of great significance by subject oil field, and have puts to make the tap production potential in oil field accomplish Vow, be to increase the technical guarantee of recoverable reserves.

Research about the viscosity of crude regularity of distribution at present is only limitted to single factors qualitative analysis, the most only considers a certain stratum The condition such as temperature affecting laws to viscosity of crude, does not considers the shadow of the multiple factors such as temperature, pressure, dissolved gas oil ratio Ring, especially biodegradation for Shallow Heavy Oil Reservoir viscosity of crude impact clearly, and current research does not gives Consider.Meanwhile, the identification existence sampling to formation fluid is relatively costly, and quantity of sampling quantity and sample position all cannot represent whole oil The problem of the fluid properties hidden.Therefore, set up one and be applicable to shallow layer thick oil oil field multi-factor comprehensive quantitative forecast in-place oil Exploitation Shallow Heavy Oil Reservoir is had great importance by the method for the regularity of distribution of viscosity.

Summary of the invention

For the problems referred to above, it is an object of the invention to provide one, to consider temperature, pressure, dissolved gas oil ratio etc. multiple The Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods of the impact of factor.

For achieving the above object, the present invention is by the following technical solutions: a kind of Shallow Heavy Oil Reservoir underground viscosity of crude obtains Access method, comprises the following steps:

1) fluid information of multiple producing wells that the actual oil field of utilization is taken, sets up shallow layer thick oil crude oil viscosity respectively The relational expression changed with temperature, pressure and dissolved gas oil ratio, three relational expressions are as follows:

$ln\mathrm{\η}\left(T\right)\≈\mathrm{\α}\·\[\frac{1}{T-170}+0.0024\]---\left(1\right)$

In formula, η represents viscosity of crude, cp；T represents absolute temperature, K；α is the parameter relevant with fluid, different fluids Corresponding different α value；

η (P) ≈ η (P=0)+0.51P (2)

In formula, P represents pressure, bar；η (P=0) represents that pressure is extrapolated for the viscosity of crude under conditions of zero, and cp (assumes Whole process does not has gas evolution)；

$ln\mathrm{\η}\left(RS\right)\≈\frac{ln\mathrm{\η}(RS=0)}{0.013RS+1}---\left(3\right)$

In formula, RS represents dissolved gas oil ratio, vol/vol；Ln η (RS=0) represents that dissolved gas oil ratio is that crude oil when zero glues The natural logrithm of degree, cp；

2) according to step 1) in three relational expressions, obtain shallow layer thick oil oil field at different temperatures, pressure and dissolving gas and oil The quantitatively characterizing formula of the viscosity of crude under the conditions of Bi:

$ln\mathrm{\η}(T,P,RS)\≈\[\frac{1}{T-170}+0.0024\]\·\[\frac{\mathrm{\α}}{0.013\·RS+1}+0.51\·P\]---\left(4\right)$

Wherein, by the viscosity of crude of a known sample point and formation condition (η₀, T₀, P₀, RS₀), calculate the side of α Method is as follows:

$\mathrm{\α}\≈\[\frac{{\mathrm{ln\η}}_0}{\frac{1}{T_0-170}+0.0024}-0.51\·P_0\]\·(0.013\·{\mathrm{RS}}_0+1)---\left(5\right)$

3) utilize the fluid information of multiple producing wells in multiple actual oil field, and choose T_r=50 DEG C, P_r=50bar, RS_r =15vol/vol as reference conditions, set up under reference conditions the viscosity of crude of the shallow layer thick oil of a certain position with away from profit circle Distance d in face_WOCRelational expression as follows:

lnη(d_WOC)=ln η_r(0)-S·d_WOC (6)

In formula, η_rRepresent the viscosity of crude under reference conditions, cp；η_r(0) crude oil at oil-water interfaces under reference conditions is represented Viscosity, cp；S represents empirical coefficient, the value of the corresponding S of a set of oil-water system；

4) a certain position viscosity of crude is calculated, specific as follows:

1. in destination layer position, two sample points, the viscosity of crude of sample point and formation condition are taken for it is known that take two Data (the η of sampling point₁,T₁,P₁,RS₁) and (η₂,T₂,P₂,RS₂) substitute into formula (5) respectively, obtain the fluid institute at two sample points right The α answered₁And α₂Value；

2. by α₁And α₂Value respectively together with reference conditions T_r=50 DEG C, P_r=50bar, RS_r=15vol/vol, substitutes into formula (4) the viscosity of crude η under reference conditions of the oil sample at two sample spot, it is calculated_r1、η_r2；

3. by (η_r1,T_r,P_r,RS_r,d_WOC1) and (η_r2,T_r,P_r,RS_r,d_WOC2) substitute into formula (6), reference bar can be calculated Viscosity of crude η at oil-water interfaces under part_rAnd the value of S (0)；

4. according to η_r(0) and S, formula (6) is utilized can be calculated under reference conditions, at oil-water interfaces any position Viscosity of crude η_r(d_WOC)；

5. by (η_r(d_WOC), T_r,P_r,RS_r), and utilize formula (5) that the α that the oil sample of this position is corresponding can be calculated (d_WOC) value；

6. by α (d_WOC) substitute into formula (4), and combine the actual formation condition (T (d of this position_WOC), P (d_WOC), RS (d_WOC)) Viscosity of crude η (d herein can be calculated_WOC)。

Due to the fact that and take above technical scheme, it has the advantage that 1, the present invention by multiple linear regression, build Vertical viscosity of crude combines relational expression with temperature, pressure and dissolved gas oil ratio, thus makes the present invention finally be calculated the former of acquisition Oil viscosity has considered the impact of temperature, pressure and dissolved gas oil ratio, and its result of calculation is closer to truth.2, this Bright by viscosity of crude is corrected to same temperature, pressure and gas-oil ratio under the conditions of, set up viscosity of crude with distance table Far and near relation, it is achieved the biodegradation quantitative analysis to viscosity of crude.

Detailed description of the invention

Below in conjunction with embodiment, the present invention is described in detail.

The present invention proposes a kind of Shallow Heavy Oil Reservoir underground viscosity of crude computational methods, comprises the following steps:

1) fluid information of multiple producing wells that the actual oil field of utilization is taken, sets up shallow layer thick oil crude oil viscosity respectively The relational expression changed with temperature, pressure and dissolved gas oil ratio, three relational expressions are as follows:

$ln\mathrm{\η}\left(T\right)\≈\mathrm{\α}\·\[\frac{1}{T-170}+0.0024\]---\left(1\right)$

In formula, η represents viscosity of crude, cp；T represents absolute temperature, K；α is the parameter relevant with fluid, different fluids Corresponding different α value；

η (P) ≈ η (P=0)+0.51P (2)

In formula, P represents pressure, bar；η (P=0) represents that pressure is extrapolated for the viscosity of crude under conditions of zero, and cp (assumes Whole process does not has gas evolution)；

$ln\mathrm{\η}\left(RS\right)\≈\frac{ln\mathrm{\η}(RS=0)}{0.013RS+1}---\left(3\right)$

In formula, RS represents dissolved gas oil ratio, vol/vol；Ln η (RS=0) represents that dissolved gas oil ratio is that crude oil when zero glues The natural logrithm of degree, cp；

2) according to step 1) in three relational expressions, obtain shallow layer thick oil oil field at different temperatures, pressure and dissolving gas and oil The quantitatively characterizing formula of the viscosity of crude under the conditions of Bi:

$ln\mathrm{\η}(T,P,RS)\≈\[\frac{1}{T-170}+0.0024\]\·\[\frac{\mathrm{\α}}{0.013\·RS+1}+0.51\·P\]---\left(4\right)$

Wherein, by the viscosity of crude of a known sample point and formation condition (η₀, T₀, P₀, RS₀), calculate the side of α Method is as follows:

$\mathrm{\α}\≈\[\frac{{\mathrm{ln\η}}_0}{\frac{1}{T_0-170}+0.0024}-0.51\·P_0\]\·(0.013\·{\mathrm{RS}}_0+1)---\left(5\right)$

3) viscosity of crude and distance d away from oil-water interfaces_WOCThere are obvious relation, and distance d away from oil-water interfaces_WOCIt is the most remote, Biodegradation degree is the lowest, and viscosity of crude is the least, therefore, utilizes the fluid money of multiple producing wells in multiple actual oil field Material, and choose T_r=50 DEG C, P_r=50bar, RS_r=15vol/vol, as reference conditions, sets up a certain position under reference conditions Shallow layer thick oil viscosity and distance d away from oil-water interfaces_WOCRelational expression as follows:

lnη(d_WOC)=ln η_r(0)-S·d_WOC (6)

In formula, η_rRepresent the viscosity of crude under reference conditions, cp；η_r(0) crude oil at oil-water interfaces under reference conditions is represented Viscosity, cp；S represents empirical coefficient, the value of the corresponding S of a set of oil-water system.

4) a certain position viscosity of crude is calculated, specific as follows:

1. in destination layer position, two sample points, the viscosity of crude of sample point and formation condition are taken for it is known that take two Data (the η of sampling point₁,T₁,P₁,RS₁) and (η₂,T₂,P₂,RS₂) substitute into formula (5) respectively, obtain the fluid institute at two sample points right The α answered₁And α₂Value；

2. by α₁And α₂Value respectively together with reference conditions T_r=50 DEG C, P_r=50bar, RS_r=15vol/vol, substitutes into formula (4) the viscosity of crude η under reference conditions of the oil sample at two sample spot, it is calculated_r1、η_r2；

3. by (η_r1,T_r,P_r,RS_r,d_WOC1) and (η_r2,T_r,P_r,RS_r,d_WOC2) substitute into formula (6), reference bar can be calculated Viscosity of crude η at oil-water interfaces under part_rAnd the value of S (0)；

4. according to η_r(0) and S, formula (6) is utilized can be calculated under reference conditions, at oil-water interfaces any position Viscosity of crude η_r(d_WOC)；

5. by (η_r(d_WOC), T_r,P_r,RS_r), and utilize formula (5) that the α that the oil sample of this position is corresponding can be calculated (d_WOC) value；

6. by α (d_WOC) substitute into formula (4), and combine the actual formation condition (T (d of this position_WOC), P (d_WOC), RS (d_WOC)) Viscosity of crude η (d herein can be calculated_WOC)。

With reference to the method for the viscosity of crude of a certain position of above-mentioned calculating, the reality that can obtain this series of strata viscosity of crude is divided Cloth rule.In enforcement step 4) time, if destination layer position only has a sample point, S value can use the S value of adjacent layers position； If do not have sample point in destination layer position, formula S value can use the S value of adjacent layers position, η simultaneously_r(0) can also use and close on The η of layer position_r(0) value, subsequent calculations step is identical with preceding method.

In above-described embodiment, step 1) in set up shallow layer thick oil crude oil viscosity respectively with temperature, pressure and solution gas Oil is as follows than the detailed process of the relational expression of change:

1. use the most conventional Vogel viscous temperature evaluation methodology, i.e. ln η (T)=A+B/ (T+C), utilize actual oil field The fluid information of multiple producing wells determines three undetermined coefficients A, B and C in formula by Multiple Non Linear Regression, finally gives:

$ln\mathrm{\η}\left(T\right)\≈\mathrm{\α}\·\[\frac{1}{T-170}+0.0024\]$

2. with stratum original saturation pressure for boundary, pressure can be divided into two parts to the impact of oil viscosity, i.e. When pressure is less than original saturation pressure, the lower general who has surrendered of pressure causes the precipitation of former oil dissolved gas, during higher than crude oil saturation pressure, The change of pressure causes the single-phase expansion of crude oil or compression.Here ensure that pressure is consistently higher than saturation pressure, simultaneously temperature, solution gas Oil sums up the shallow layer thick oil pressure-dependent rule of crude oil viscosity in the case of constant, utilizes fluid information and combines many The method of unit's linear regression, determines the shallow layer thick oil pressure-dependent functional relation of crude oil viscosity:

η (P) ≈ η (P=0)+0.51P

3. dissolved gas oil ratio is the biggest, and viscosity of crude is the least.Keep pressure, temperature-resistant in the case of, measure different oil The viscosity of sample is with the Changing Pattern of dissolved gas oil ratio, on the basis of correlation analysis, by the means of Multiple Non Linear Regression Determine the functional relationship of viscosity of crude and dissolved gas oil ratio:

$ln\mathrm{\η}\left(RS\right)\≈\frac{ln\mathrm{\η}(RS=0)}{0.013RS+1}$

The various embodiments described above are merely to illustrate the present invention, and wherein the enforcement step etc. of method all can be varied from, Every equivalents carried out on the basis of technical solution of the present invention and improvement, the most should not get rid of in protection scope of the present invention Outside.

Claims (1)

1. a Shallow Heavy Oil Reservoir underground viscosity of crude acquisition methods, comprises the following steps:

1) fluid information of multiple producing wells that the actual oil field of utilization is taken, sets up shallow layer thick oil crude oil viscosity respectively with temperature Degree, pressure and the relational expression of dissolved gas oil ratio change, three relational expressions are as follows:

$ln\mathrm{\η}\left(T\right)\≈\mathrm{\α}\·\[\frac{1}{T-170}+0.0024\]---\left(1\right)$

In formula, η represents viscosity of crude, cp；T represents absolute temperature, K；α is the parameter relevant with fluid, and different fluids is corresponding Different α values；

In η (P) ≈ η (P=0)+0.51P (2) formula, P represents pressure, bar；η (P=0) represents that pressure is extrapolated for zero Under the conditions of viscosity of crude, cp (assumes that whole process does not has gas evolution)；

$ln\mathrm{\η}\left(RS\right)\≈\frac{ln\mathrm{\η}(RS=0)}{0.013RS+1}---\left(3\right)$

In formula, RS represents dissolved gas oil ratio, vol/vol；Ln η (RS=0) represents that dissolved gas oil ratio is viscosity of crude when zero Natural logrithm, cp；

2) according to step 1) in three relational expressions, obtain shallow layer thick oil oil field at different temperatures, pressure and dissolved gas oil ratio bar The quantitatively characterizing formula of the viscosity of crude under part:

$ln\mathrm{\η}(T,P,RS)\≈\[\frac{1}{T-170}+0.0024\]\·\[\frac{\mathrm{\α}}{0.013\·RS+1}+0.51\·P\]---\left(4\right)$

Wherein, by the viscosity of crude of a known sample point and formation condition (η₀, T₀, P₀, RS₀), calculate the method for α such as Under:

$\mathrm{\α}\≈\[\frac{{\mathrm{ln\η}}_0}{\frac{1}{T_0-170}+0.0024}-0.51\·P_0\]\·(0.013\·{\mathrm{RS}}_0+1)---\left(5\right)$

3) utilize the fluid information of multiple producing wells in multiple actual oil field, and choose T_r=50 DEG C, P_r=50bar, RS_r= 15vol/vol as reference conditions, set up under reference conditions the viscosity of crude of the shallow layer thick oil of a certain position with away from oil-water interfaces Distance d_WOCRelational expression as follows:

lnη(d_WOC)=ln η_r(0)-S·d_WOC(6) in formula, η_rRepresent the viscosity of crude under reference conditions, cp；η_r(0) Represent the viscosity of crude at oil-water interfaces, cp under reference conditions；S represents empirical coefficient, the corresponding S's of a set of oil-water system Value；

4) a certain position viscosity of crude is calculated, specific as follows:

1. taking two sample points, the viscosity of crude of sample point and formation condition in destination layer position is it is known that by two sample points Data (η₁,T₁,P₁,RS₁) and (η₂,T₂,P₂,RS₂) substitute into formula (5) respectively, obtain corresponding to the fluid at two sample points α₁And α₂Value；

2. by α₁And α₂Value respectively together with reference conditions T_r=50 DEG C, P_r=50bar, RS_r=15vol/vol, substitutes into formula (4), It is calculated the viscosity of crude η under reference conditions of the oil sample at two sample spot_r1、η_r2；

3. by (η_r1,T_r,P_r,RS_r,d_WOC1) and (η_r2,T_r,P_r,RS_r,d_WOC2) substituting into formula (6), can calculate under reference conditions Viscosity of crude η at oil-water interfaces_rAnd the value of S (0)；

4. according to η_r(0) and S, formula (6) is utilized can be calculated under reference conditions, the crude oil at oil-water interfaces any position Viscosities il_r(d_WOC)；

5. by (η_r(d_WOC), T_r,P_r,RS_r), and utilize formula (5) that the α (d that the oil sample of this position is corresponding can be calculated_WOC) Value；

6. by α (d_WOC) substitute into formula (4), and combine the actual formation condition (T (d of this position_WOC), P (d_WOC), RS (d_WOC)) permissible It is calculated viscosity of crude η (d herein_WOC)。