CN101963056A - Method for predicting carbonate formation pore pressure by using log information - Google Patents

Abstract

The invention discloses a method for predicting carbonate formation pore pressure by using log information. The method for predicting the carbonate formation pore pressure by using the log information is based on the effective stress theorem; and by establishing a framework longitudinal wave velocity and pore fluid longitudinal wave velocity equation, a carbonate formation pore pressure equation is established, so that the carbonate formation pore pressure is detected according to the measured log information, scientific evidences are provided for determining safety drilling fluid density during drilling design, and carbonate formation underground complex accidents in the construction process are effectively prevented.

Description

A kind of method of utilizing well-log information Predicting Carbonate Formation pore pressure

Technical field

The present invention relates to a kind of method of utilizing well-log information Predicting Carbonate Formation pore pressure, more particularly, relate to a kind ofly, consider skeleton and pore-fluid velocity of longitudinal wave, utilize well-log information to come the method for Predicting Carbonate Formation pore pressure based on the effective stress theorem.

Background technology

A large amount of undeveloped oil gas are arranged in the hill carbonate stratum, and this is the new exploratory area of the following stable yields in oil field.The carbonate rock distribution is extensive, and oil fields such as huge port, Tarim Basin, Jiang-Han Area, Sichuan, triumph, Central Plains, North China, Xinjiang, Qinghai, long celebrating are all at the exploitation carbonate rock hydrocarbon reservoir.The interstitial space complex structure that carbonate formation has, as crack and hole, and factors such as its anisotropy, non-homogeneity have been aggravated the complexity of carbonate rock deposition process, cause can not accurately determining the formation mechanism of carbonate formation abnormal pore high pressure, thereby be difficult to find the proper explanations model.Bore to meet carbonate formation, because abnormal pressure prediction difficulty, regular meeting causes cave-in, leakage, even down-hole complex accident such as blowout.If accurately the Predicting Carbonate Formation pore pressure just can be and determines that safety drilling liquid density window provides scientific basis, with the generation of effective prevention carbonate formation down-hole complex accident.

Creator among the present invention relies on it to be engaged in the experience and the practice of relevant industries for many years for this reason, and through concentrating on studies and developing, creates the method that a kind of utilization utilizes well-log information Predicting Carbonate Formation pore pressure finally.

Summary of the invention

The object of the present invention is to provide a kind of method of utilizing well-log information Predicting Carbonate Formation pore pressure; utilize this method can the Predicting Carbonate Formation pore pressure; so that when drilling design, provide scientific basis for definite safety drilling liquid density; the protection carbonate rock hydrocarbon reservoir is with the generation of effective prevention carbonate rock down-hole complex accident.

Utilize the method for well-log information Predicting Carbonate Formation pore pressure among the present invention, include the following step:

1) in the drilling process, utilizes sieve residue log to determine the carbonate rock interval, get core and test the effective stress p of rock sample _e, coefficient of cubical compressibility C _Ma, confined pressure p and SVEL v _Ma, obtain the rock mechanics parameter attribute DS { C of rock sample _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾;

2) in the formation testing process, composition x, saturation state y, temperature T, pressure p, the density p of record oil sample, the SVEL v of measurement oil sample _f, obtain the characteristic series { x of oil sample ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾, v _f ⁽ⁱ⁾;

3), by multiple nonlinear regression method, set up skeleton velocity of longitudinal wave equation and be: v according to the characteristic series of rock sample _Ma=f (C _Ma, P _e);

4) according to the characteristic series of oil sample, by multiple nonlinear regression method, the velocity of longitudinal wave equation of setting up formation pore fluid is: v _f=f (ρ, p, T);

5) by empirical formula, the SVEL equation of setting up carbonate formation is: v=f (v _f, v _Ma, φ);

6),, set up the formation pore pressure predictive equation, p with the velocity of longitudinal wave equation substitution SVEL equation of skeleton velocity of longitudinal wave and formation pore fluid according to the effective stress theorem _p=f (ρ _f, T, C _Ma, v, p ₀, φ);

7) pore pressure detects:

(A) stratum is a carbonate rock,

(B) set up skeleton velocity of longitudinal wave equation,

(C) set up formation pore fluid velocity of longitudinal wave equation,

(D) set up the formation pore pressure predictive equation,

(E) with carbonate rock SVEL, coefficient of cubical compressibility, overburden pressure, the temperature of oil sample, pressure, density, the degree of porosity substitution p at different depth place _p=f (ρ _f, T, C _Ma, v, p ₀, φ), obtain the formation pore pressure at different depth place.

Method in the described step 1) is to carry out the experiment of rock mechanics parameter, sets up effective stress p _e, coefficient of cubical compressibility C _Ma, confined pressure p and SVEL v _MaDS { C _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾.

Described step 2) method in is on-the-spot record oil sample data, and laboratory experiment in addition, sets up composition x, saturation state y, temperature T, pressure p, the density p of oil sample, SVEL v _fDS { x ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾, v _f ⁽ⁱ⁾.

Method in the described step 3) is by to ordered sequence { C _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾Carry out nonlinear multivariable and return, obtain the relation between coefficient of cubical compressibility and confined pressure, effective stress and skeleton SVEL, set up skeleton velocity of longitudinal wave equation and be: v _Ma=f (C _Ma, P _e).

Method in the described step 4) is by to ordered sequence { v _f ⁽ⁱ⁾, x ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾Carry out the nonlinear multivariable recurrence, and obtaining the relation between oil sample SVEL and temperature, pressure and density, the velocity of longitudinal wave equation of setting up formation pore fluid is: v _f=f (ρ, p, T).

Method in the described step 5) is to utilize the characteristic of carbonate formation, considers degree of porosity, sets up the equation v=f (v between carbonate rock SVEL and matrix velocity and pore-fluid speed _f, v _Ma, φ).

Method in the described step 6) is according to the effective stress theorem, sets up the formation pore pressure predictive equation, p _p=f (ρ _f, T, C _Ma, v, p ₀, φ).

Method in the described step 7) is at first to confirm the carbonate rock feature, by non-linear regression method, sets up skeleton velocity of longitudinal wave equation v _Ma=f (C _Ma, P _e) and formation pore fluid velocity of longitudinal wave equation v _f(ρ, p T), according to the effective stress theorem, set up formation pore pressure predictive equation p to=f _p=f (ρ _f, T, C _Ma, v, p ₀, φ),, obtain the formation pore pressure at different depth place with carbonate rock SVEL, coefficient of cubical compressibility, overburden pressure, the temperature of oil sample, pressure, density, the degree of porosity substitution formation pore pressure predictive equation at different depth place.

Utilize the method for well-log information Predicting Carbonate Formation pore pressure to be based on the effective stress theorem among the present invention, by setting up skeleton velocity of longitudinal wave and pore-fluid velocity of longitudinal wave equation, set up carbonate formation pore pressure equation with this, thereby detect the carbonate formation pore pressure according to the log data that records, so that when drilling design for determining that safety drilling liquid density provides scientific basis, with the generation of carbonate formation down-hole complex accident in effective prevention work progress.

Description of drawings

Fig. 1 is a carbonate formation log response characteristic pattern;

Fig. 2 utilizes carbonate formation pore pressure that well-log information detects figure as a result.

The specific embodiment

Below in conjunction with accompanying drawing the instantiation among the present invention is described in further detail.

According to the effective stress theorem, overburden pressure is born jointly by frame stress and pore fluid pressure, and rock porosity diminishes with total stress (overburden pressure) increase in the normal discharging consolidation process.The sedimentation mechanism of carbonate formation is different from the clastic stratum.According to ^ THE THEORY OF ELASTIC WAVE, sound wave is propagated in the stratum, will inevitably be by rock matrix and pore-fluid, the velocity of sound can reflect rock matrix and pore-fluid composition situation, and think that the velocity of sound is dimerous by matrix velocity and pore-fluid speed, the velocity of sound is relevant with factors such as effective stress, bulk modulus, pore-fluid density, formation pore pressure, pore-fluid temperature.Therefore utilize the well-log information response characteristic can Predicting Carbonate Formation pore pressure situation.

Utilize the method for well-log information Predicting Carbonate Formation pore pressure to comprise the following steps: among the present invention

1. determine the carbonate rock interval

Determine the carbonate rock interval by the sieve residue log data, and core at carbonate formation; In the laboratory, carry out rock sample and core, be processed into the standard rock core, carry out rock mechanics parameter testing experiment, obtain the rock mechanics characteristic series { C of rock sample _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾, as follows:

$\left\{\begin{array}{cc}{C}_{\mathrm{ma}}& P_e\\ 0& 0.000184\\ 10& 0.000452\\ 15& 0.000393\\ 20& 0.000376\\ 30& 0.00034\\ 40& 0.000304\\ 50& 0.000299\\ 60& 0.000285\\ 70& 0.000271\\ 80& 0.00025\end{array}\right\}$ $\left\{\begin{array}{cc}{P}_e& v_{\mathrm{ma}}\\ 10& 5.62\\ 20& 5.68\\ 30& 5.74\\ 40& 5.79\\ 50& 5.84\\ 60& 5.86\\ 70& 5.88\\ 80& 5.91\end{array}\right\}$

2. in the formation testing process, write down composition x, saturation state y, temperature T, pressure p, the density p of oil sample, measure the velocity of longitudinal wave v of oil sample _f, and the chamber of experimentizing experiment obtains the characteristic of oil sample.

3. return by the rock mechanics characteristic of rock sample being carried out nonlinear multivariable, obtaining coefficient of cubical compressibility and confined pressure is that index concerns, confined pressure can represent with effective stress, then thinks coefficient of cubical compressibility and effective stress exponent function relation; Effective stress and velocity of longitudinal wave are linear.The velocity of longitudinal wave equation that can set up the rock sample skeleton thus is

4. pass through ordered sequence { v _f ⁽ⁱ⁾, x ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾Carry out nonlinear multivariable and return, it is linear that the velocity of longitudinal wave that obtains oil sample and density, temperature and pressure are distinguished, linear with the product of temperature and pressure.The velocity of longitudinal wave equation of setting up oil sample is υ _f=b ₁ρ _f-b ₂T+b ₃P _p+ b ₄Tp _p

5. formula rule of thumb, the velocity of longitudinal wave equation of setting up carbonate formation is $\frac{1}{v_p}={\left(\frac{1}{v_f}\right)}^{\mathrm{\φ}}\·{\left(\frac{1}{v_{\mathrm{ma}}}\right)}^{(1-\mathrm{\φ})}.$

6. have based on the effective stress theorem:

P _On=P _p+ P _e

With the velocity of longitudinal wave equation substitution SVEL equation of skeleton velocity of longitudinal wave and formation pore fluid, set up the formation pore pressure predictive equation, have:

$\frac{1}{v_p}={\left(\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="HSA00000235290900011.png"\; state="\{\{state\}\}">b</figure-callout>}}_1{\mathrm{\&rho;}}_f-{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000235290900011.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\&CenterDot;T+b_3\&CenterDot;p_p+b_4\&CenterDot;T\&CenterDot;p_p}\right)}^{\mathrm{\&phi;}}\&CenterDot;{\left(\frac{1}{a_1+a_2{e}^{C_{\mathrm{ma}}}+a_3{p}_e}\right)}^{(1-\mathrm{\&phi;})}.$

7. utilize the acoustic logging data, the formation pore pressure data according to actual measurement return out model parameter in the formation pore pressure predictive equation, that is:

a ₁＝0.14387，a ₂＝2.51628，a ₃＝0.15674

b ₁＝0.25146，b ₂＝0.04715，b ₃＝0.02843，b ₄＝0.10913

Can utilize this model prediction carbonate formation pore pressure thus.

Claims (8)

1. method of utilizing well-log information Predicting Carbonate Formation pore pressure includes the following step:

1) in the drilling process, utilizes sieve residue log to determine the carbonate rock interval, get core and test the effective stress p of rock sample _e, coefficient of cubical compressibility C _Ma, confined pressure p and SVEL v _Ma, obtain the rock mechanics parameter attribute DS { C of rock sample _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾;

2) in the formation testing process, composition x, saturation state y, temperature T, pressure p, the density p of record oil sample, the SVEL v of measurement oil sample _f, obtain the characteristic series { x of oil sample ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾, v _f ⁽ⁱ⁾;

3), by multiple nonlinear regression method, set up skeleton velocity of longitudinal wave equation and be: v according to the characteristic series of rock sample _Ma=f (C _Ma, P _e);

4) according to the characteristic series of oil sample, by multiple nonlinear regression method, the velocity of longitudinal wave equation of setting up formation pore fluid is: v _f=f (ρ, p, T);

5) by empirical formula, the SVEL equation of setting up carbonate formation is: v=f (v _f, v _Ma, φ);

6),, set up the formation pore pressure predictive equation, p with the velocity of longitudinal wave equation substitution SVEL equation of skeleton velocity of longitudinal wave and formation pore fluid according to the effective stress theorem _p=f (ρ _f, T, C _Ma, v, p ₀, φ);

7) pore pressure detects:

(A) stratum is a carbonate rock,

(B) set up skeleton velocity of longitudinal wave equation,

(C) set up formation pore fluid velocity of longitudinal wave equation,

(D) set up the formation pore pressure predictive equation,

(E) with carbonate rock SVEL, coefficient of cubical compressibility, overburden pressure, the temperature of oil sample, pressure, density, the degree of porosity substitution p at different depth place _p=f (ρ _f, T, C _Ma, v, p ₀, φ), obtain the formation pore pressure at different depth place.

2. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method in the described step 1) is to carry out rock mechanics parameter testing experiment, sets up effective stress p _e, coefficient of cubical compressibility C _Ma, confined pressure p and SVEL v _MaDS { C _Ma ⁽ⁱ⁾, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾.

3. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method described step 2) is on-the-spot record oil sample data, and laboratory experiment in addition, set up composition x, saturation state y, temperature T, pressure p, the density p of oil sample, SVEL v _fDS { x ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾, v _f ⁽ⁱ⁾.

4. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method in the described step 3) is by to ordered sequence { C ^{Ma (i)}, p ⁽ⁱ⁾, { p _e ⁽ⁱ⁾, v _Ma ⁽ⁱ⁾Carry out nonlinear multivariable and return, obtain the relation between coefficient of cubical compressibility and confined pressure, effective stress and skeleton SVEL, set up skeleton velocity of longitudinal wave equation and be: v _Ma=f (C _Ma, P _e).

5. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method in the described step 4) is by to ordered sequence { v _f ⁽ⁱ⁾, x ⁽ⁱ⁾, y ⁽ⁱ⁾, T ⁽ⁱ⁾, p ⁽ⁱ⁾, ρ ⁽ⁱ⁾Carry out the nonlinear multivariable recurrence, and obtaining the relation between oil sample SVEL and temperature, density, pressure, the velocity of longitudinal wave equation of setting up formation pore fluid is: v _f=f (ρ, p, T).

6. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method in the described step 5) is to utilize the characteristic of carbonate formation, consider degree of porosity, set up the equation v=f (v between carbonate rock SVEL and matrix velocity and pore-fluid speed _f, v _Ma, φ).

7. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, the method in the described step 6) is according to the effective stress theorem, sets up the formation pore pressure predictive equation, p _p=f (ρ _f, T, C _Ma, v, p ₀, φ).

8. according to the method for utilizing well-log information Predicting Carbonate Formation pore pressure described in the claim 1, it is characterized in that: the method in the described step 7) is at first to confirm the carbonate rock feature, by non-linear regression method, sets up skeleton velocity of longitudinal wave equation v _Ma=f (C _Ma, P _e) and formation pore fluid velocity of longitudinal wave equation v _f(ρ, p T), according to the effective stress theorem, set up formation pore pressure predictive equation p to=f _p=f (ρ _f, T, C _Ma, v, p ₀, φ),, obtain the formation pore pressure at different depth place with carbonate rock SVEL, coefficient of cubical compressibility, overburden pressure, the temperature of oil sample, pressure, density, the degree of porosity substitution formation pore pressure predictive equation at different depth place.

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