CN105956938A - Fracture-vug type oil reservoir dynamic reserve calculation method - Google Patents

Abstract

A fracture-vug type oil reservoir dynamic reserve calculation method provided by the present invention relates to a method for calculation aiming at the oil reservoir reserves of the elastic drive stages, and aims to realize the effects that the needed calculation parameters are less, the parameter values are all measured at an oil recovery site and are objective and accurate, and the calculation results are more credible. The fracture-vug type oil reservoir dynamic reserve calculation method of the present invention comprises the following steps of S01 measuring the bottom hole crude oil density rho 1 for the first time by a manometry method; S02 exploiting an oil well for a period of time, and recording the cumulative oil production as Np; S03, measuring the bottom hole crude oil density rho 2 for the second time by the manometry method; S04 substituting the measured rho 1, rho 2 and the Np into a formula to obtain the fracture-vug type oil reservoir dynamic reserves.

Description

The method that fracture-pore reservoir dynamic holdup calculates

Technical field

The present invention relates to a kind of reservoir reserve computational methods, particularly relate to a kind of drive the reservoir reserve in stage for elasticity and enter The method that row calculates.

Background technology

Harrar Ha Tang oil field, Tarim Basin ORDOVICIAN CARBONATE oil reservoir belongs to typical fracture-pore reservoir, reservoir space Based on crack and solution cavity, having anisotropism strong, fluid properties is changeable, fluid distrbution and the feature such as oil water relation is complicated.Shadow The factor of sound oil reservoir development feature is in addition to reservoir space type and architectural feature, well pattern and technical policy, and key exists In the scale of fracture-cavity units, the most accurately calculating fracture-cavity units dynamic holdup becomes a difficult problem.

Reservoir behavior reserves calculate and mostly use falloff curve method, pressure drop recovery curve method, water driver front, successively decrease at present Curve method, material balance method and well testing method etc., wherein, well testing method is only applicable to the sealed elastic of oil reservoir development constant volume in early days Drive, and its well-test curve obtained according to well test data matching and then to obtain dynamic holdup computing formula complicated, all can lead Activate state reserves computational accuracy relatively low；Material balance method divides in detail not according to the reservoir space of oil reservoir to be developed, because of Matter balance equation often quality after this simplification is coarse and does not meets practical situation, causes dynamic holdup computational accuracy low, inclined Difference is big；In addition same, falloff curve method, pressure drop recovery curve method, water driver front and decline curve method etc. are according to all kinds of songs Line and then obtain dynamic holdup computing formula, method is complicated, calculates process loaded down with trivial details, adds owing to artificially calculating the error caused The error gathering oil reservoir actual development data easily causes dynamic holdup computational accuracy low, and poor accuracy, to oil reservoir development and tune Whole bringing is slipped up and unnecessary time and economic loss.

Summary of the invention

It is less that the technical problem to be solved in the present invention is to provide one required calculating parameter, and parameter value is oil recovery now The field First Astronautic Research Institute for Measurement and Test obtains, objective and accurate, the method that result of calculation more believable fracture-pore reservoir dynamic holdup calculates.

The method that the present invention a kind of fracture-pore reservoir dynamic holdup calculates, comprises the steps:

S01: oil density ρ at the bottom of piezometric well for the first time₁；

S02: to oil development a period of time, period tires out oil production and is designated as N_p；

S03: oil density ρ at the bottom of piezometric well for the second time₂；

S04: the ρ that will record₁、ρ₂And N_pSubstitute into formula

$N=\frac{{\mathrm{\ρ}}_2}{{\mathrm{\ρ}}_1-{\mathrm{\ρ}}_2}{N}_p$

Ask for fracture-pore reservoir dynamic holdup.

The method that the present invention a kind of fracture-pore reservoir dynamic holdup calculates, wherein oil density computing formula in shaft bottom is:

Wherein, P_{The end}For shaft bottom crude oil pressure, P_rFor reference point crude oil pressure, H_{The end}For bottom depth, H_rFor the reference point degree of depth.

The method that the present invention a kind of fracture-pore reservoir dynamic holdup calculates, wherein H_{The end}-H_r=50, i.e. reference point be chosen as away from The position of shaft bottom 50m.

The method that the present invention a kind of fracture-pore reservoir dynamic holdup calculates is compared to the advantage of material balance method: 1. count Calculate the ρ that dynamic holdup required calculating parameter is less and required₁、ρ₂And N_pThree parameters all accurately can be asked by oil recovery scene Take, it is to avoid do not survey the uncertain parameter of PVT well, oil volume factor, the oil compressibility impact on result of calculation；Cause This, it is higher that the method that the present invention provides calculates dynamic holdup accuracy than material balance method.2. fracture-cavity type carbonate has been avoided The particularity of oil reservoir, complexity, the calculating for fractured-cavernous carbonate reservoir dynamic holdup provides a kind of new method, is more as the criterion Really have rated Reservoir Size, the reasonable Efficient Development for oil field is laid a good foundation.

Detailed description of the invention

The method that the present invention a kind of fracture-pore reservoir dynamic holdup calculates, comprises the steps:

S01: oil density ρ at the bottom of piezometric well for the first time₁；

S02: to oil development a period of time, period tires out oil production and is designated as N_p；

S03: oil density ρ at the bottom of piezometric well for the second time₂；

S04: the ρ that will record₁、ρ₂And N_p(1) formula of substitution asks for fracture-pore reservoir dynamic holdup.

$N=\frac{{\mathrm{\ρ}}_2}{{\mathrm{\ρ}}_1-{\mathrm{\ρ}}_2}{N}_p---\left(1\right)$

Wherein involved in (1) formula shaft bottom oil density parameter ρ₁、ρ₂Derived by (2) formula respectively and ask for

Wherein, P_{The end}For shaft bottom crude oil pressure, P_rFor reference point crude oil pressure, H_{The end}For bottom depth, H_rFor the reference point degree of depth. Reference point distance the nearlyest (the i.e. H of bottom hole spacing chosen_{The end}-H_rValue the least), then the final shaft bottom oil density calculated gets over convergence In shaft bottom crude oil actual density, if but reference point distance shaft bottom is too near, reference point crude oil pressure and shaft bottom crude oil pressure can be recorded The most essentially identical (i.e. P_{The end}-P_r=0), thus can cause to shaft bottom crude oil calculate failure.In order to draw shaft bottom successfully, accurately Oil density, the reference point in the present invention chooses a point between the 50-300m scope of shaft bottom.

In order to ensure that disclosure of the invention is abundant, the existing derivation to (1) formula illustrates:

If V is ρ₁It is the shaft bottom quality of crude oil under original state, V ρ₂For the shaft bottom residual crude oil well after exploitation a period of time Substrate amount, N_PB_oρ₂/ ρ is then for the shaft bottom quality of extraction crude oil.Can be obtained by shaft bottom crude quality conservation

Vρ₁=V ρ₂+N_PB_oρ₂/ρ (3)

Wherein, V subsurface deposit volume ρ₁Oil density at the bottom of piezometric well for the first time

ρ₂Oil density N at the bottom of piezometric well for the second time_PAccumulative product crude oil amount during twice pressure measurement

B_oOil volume factor ρ crude oil density in stock tank at present

Further:

V=NB_oi/ρ (4)

Wherein, N oil in place B_oiOriginal crude oil volume factor

(3) formula of (4) formula being brought into obtains following formula:

$N=\frac{{\mathrm{\ρ}}_2{N}_p}{{\mathrm{\ρ}}_1-{\mathrm{\ρ}}_2}\·\frac{B_o}{B_{oi}}---\left(5\right)$

Fractured-cavernous carbonate reservoir is at initial stage of development, and the oil well of more than 90% has the Development characteristics of " well one is hidden ", Between well, fluid properties differs greatly, and causes oil volume factor between well to differ greatly, and owing to the restriction of development cost is impossible Every mouthful of well all carries out PVT (pressure, volume, temperature) sample analysis.Standard empirical equation is asked for oil volume factor and is generally deposited In bigger error, it is contemplated that the change that the volume factor of crude oil drives the stage in elasticity is less, and for ignore volume factor ask for time The error the existed impact on result of calculation, B_o/B_oiCan approximate and be considered as 1, thus (5) formula can be reduced to:

$N=\frac{{\mathrm{\ρ}}_2}{{\mathrm{\ρ}}_1-{\mathrm{\ρ}}_2}{N}_p.---\left(6\right)$

By (6) formula it can be seen that ask for the dynamic holdup of fractured-cavernous carbonate reservoir, it is only necessary to 3 calculate parameter, i.e. Elasticity drives at the bottom of oil density, for the second time piezometric well at the bottom of the first time piezometric well in stage accumulative oil-producing between oil density and twice pressure measurement Amount.

In order to verify the present invention accuracy to fracture-pore reservoir dynamic holdup measurement result, applicant have chosen Harrar and breathes out 20 mouthfuls of oil field, pool oil well uses material balance method and method described in the invention to carry out contrast test, wherein result of the test respectively As shown in the table:

As can be seen from the above table, use result that fracture-pore reservoir dynamic holdup records by method described in the invention with Using the result measured by material balance method to compare, absolute error is only 0.0 × 10⁴T～3.7 × 10⁴t.As can be seen here, shaft bottom It is the most credible that oil density difference method calculates dynamic holdup.Shaft bottom oil density difference method calculates dynamic holdup and need not PVT test number According to, thus the method may apply to not carry out the oil reservoir of PVT sample analysis.

Embodiment described above is only to be described the preferred embodiment of the present invention, the not model to the present invention Enclose and be defined, on the premise of designing spirit without departing from the present invention, the those of ordinary skill in the art technical side to the present invention Various deformation that case is made and improvement, all should fall in the protection domain that claims of the present invention determines.

Claims (3)

1. the method that fracture-pore reservoir dynamic holdup calculates, comprises the steps:

S01: oil density ρ at the bottom of piezometric well for the first time₁；

S02: to oil development a period of time, period tires out oil production and is designated as N_p；

S03: oil density ρ at the bottom of piezometric well for the second time₂；

S04: the ρ that will record₁、ρ₂And N_pSubstitute into formula

$N=\frac{{\mathrm{\ρ}}_2}{{\mathrm{\ρ}}_1-{\mathrm{\ρ}}_2}{N}_p$

Ask for fracture-pore reservoir dynamic holdup.

The method that a kind of fracture-pore reservoir dynamic holdup the most according to claim 1 calculates, it is characterised in that: step S01, In S02 step, shaft bottom oil density computing formula is:

Wherein, P_{The end}For shaft bottom crude oil pressure, P_rFor reference point crude oil pressure, H_{The end}For bottom depth, H_rFor the reference point degree of depth.

The method that a kind of fracture-pore reservoir dynamic holdup the most according to claim 2 calculates, it is characterised in that: H_{The end}-H_r= 50, i.e. reference point is chosen as the position away from shaft bottom 50m.