Method for measuring porosity and permeability of stratum by using rock debris

Abstract

The invention relates to a method for measuring formation porosity and permeability by using rock debris, which comprises the following steps: S1, acquiring drilling rock debris, and cleaning the rock debris to remove a fluid medium in the rock debris; s2, preparing the rock debris into spherical particles, and drying the spherical particles; and S3, measuring the porosity and pore size distribution of the dried spherical particle rock debris, and calculating the permeability. The method provided by the invention solves the problems of high cost and low efficiency of a traditional measurement method, can accurately and quickly obtain parameters such as the porosity and the permeability of the stratum, and provides a quick, economical and effective technical means for oil and gas reservoir evaluation.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and natural gas exploration and development, and in particular to a method for measuring stratum porosity and permeability by using rock cuttings. Background Art

[0002] During oil and gas exploration and development, accurately measuring formation porosity and permeability is crucial for assessing reservoir properties and development potential. Traditional porosity and permeability determination methods typically require large, regular cores, which must first be obtained through specialized coring operations and then tested in the laboratory, resulting in high costs and a long time-consuming process. With the advancement of oil and gas exploration technology, the demand for rapid, economical, and accurate determination of formation porosity and permeability is growing. Against this backdrop, rock cuttings generated during drilling have begun to attract attention as a potential alternative sample. Therefore, developing a method that can effectively process rock cuttings samples and accurately determine their porosity and permeability is of great practical significance in the field of oil and gas exploration and development. Summary of the Invention

[0003] The object of the present invention is to provide a method for rapidly, economically and accurately measuring the porosity and permeability of a formation.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions: A method for measuring formation porosity and permeability using rock cuttings comprises the following steps: S1. Obtain drilling cuttings and clean the cuttings to remove fluid medium from the cuttings; S2, preparing the rock cuttings into spherical particles and drying them; S3. Measure the porosity and pore size distribution of the dried spherical rock fragments and calculate the permeability.

[0005] In a preferred embodiment, in step S1, the rock cuttings are cleaned with three-stage solvents, wherein the first-stage solvent is toluene, acetone or petroleum ether, the second-stage solvent is chloroform, and the third-stage solvent is methanol.

[0006] In a preferred embodiment, the rock cuttings are prepared into spherical particles in step S2, comprising: Cutting the rock cuttings into a cube shape with the thickness of the thinnest part of the rock cuttings as the side length; The cube-shaped rock cuttings are processed into spherical particles using a beading machine.

[0007] In a preferred embodiment, the diameter of the spherical particles in step S2 is 0.5-5 mm, and the sphericity is greater than 0.9.

[0008] In a preferred embodiment, the diameter of the spherical particles in step S2 is 1-2 mm.

[0009] In a preferred embodiment, a vacuum oven or a supercritical fluid is used in step S2. The drying method is to dry the rock chips into spherical particles.

[0010] In a preferred embodiment, the permeability calculation method in step S3 is: ; in, K is the permeability, mD; φ is the porosity, decimal; r 50 The capillary radius corresponding to 50% mercury intrusion in the mercury injection experiment, μm.

[0011] The beneficial effects of the present invention are as follows: the present invention provides a method for measuring the porosity and permeability of formations using rock cuttings, directly using drilling rock cuttings as measurement samples, avoiding the coring operation in traditional measurements and reducing the coring cost; the method provided by the present invention can complete relevant tests at the well site after the rock cuttings are cleaned and processed, and obtain the physical properties of the formation, which can timely support drilling decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the method flow of the present invention; Figure 2 These are regular spherical particles in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0013] The following describes the embodiments of the present disclosure through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0014] During oil and gas exploration and development, drilling cuttings are readily available, but due to their irregular shape and tiny size (typically <10 mm), they cannot be directly used in conventional permeability analysis. Existing cuttings analysis methods (such as microscopic observation and elemental scanning) can only qualitatively assess mineral composition but cannot quantitatively determine key physical properties.

[0015] When determining formation porosity and permeability parameters, conventional laboratory core analysis methods are not only costly but also require weeks of coring time, significantly lagging behind drilling decisions and making real-time reservoir evaluation difficult. Based on this, this application provides a low-cost, rapid, and highly accurate method for determining formation porosity and permeability using rock cuttings, providing data support for drilling decisions, reservoir economic assessments, and development plan formulation.

[0016] like Figure 1 A flow chart of a method for measuring formation porosity and permeability using drilling cuttings provided in an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method includes the following steps: S1. Obtain drilling cuttings and clean the cuttings to remove fluid medium from the cuttings; In step S1, the directly obtained drilling cuttings must first be cleaned. During this cleaning process, a three-stage solvent can be used to remove fluid media such as drilling fluid, oil, and formation water from the cuttings, thereby ensuring that the cleaned cuttings retain the rock skeleton structure, facilitating subsequent physical property parameter measurement. In a specific embodiment, the first-stage solvent in the three-stage solvent is toluene, acetone, or petroleum ether, the second-stage solvent is chloroform, and the third-stage solvent is methanol.

[0017] S2, preparing the rock cuttings into spherical particles and drying them; In step S2, the irregular rock chips are first cut into cubes with the thickness of the thinnest part of the rock chips as the side length. The cube-shaped rock chips are then ground into regular small balls using a ball mill, ensuring that the diameter of the small balls is 0.5–5 mm and the sphericity is greater than 0.9. Finally, the regular small spherical rock chips need to be dried, which can be done in a vacuum oven or supercritical fluid. The drying method is used to dry the cuttings. Through the cleaning and drying steps, it can be ensured that the drilling fluid, oil, gas and water in the pores of the cuttings have been completely removed.

[0018] Preferably, the pellets are 1–2 mm in diameter.

[0019] S3. Measure the porosity and pore size distribution of the dried spherical rock fragments and calculate the permeability.

[0020] For dried, regularly spherical rock cuttings, physical property parameters can be directly measured. Specifically, nuclear magnetic resonance (T2 spectroscopy), mercury intrusion porosimetry, low-pressure nitrogen adsorption (BET), or helium porosimetry can be used to determine the pore size distribution and porosity of the rock cuttings. The porosity parameters measured in this step can be used as porosity for formation evaluation.

[0021] The permeability is calculated using the porosity measured by mercury injection, the 50% mercury intrusion and the improved Kozeny model: ; in, K is the permeability, mD; φ is the porosity, decimal; r 50 The capillary radius corresponding to 50% mercury intrusion in the mercury injection experiment, μm.

[0022] In a specific embodiment of the present invention, the permeability of a regular core is measured and the gas permeability of the core is 3.05 mD. The core is then processed and the processed regular spherical particles are as follows Figure 2 As shown in FIG, using the method provided in this application, the permeability of the spherical particles is calculated to be 1.97 mD. This shows that the permeability results of the two are relatively close and can meet engineering applications.

[0023] It can be seen that the present invention provides a method for measuring formation porosity and permeability using drilling cuttings. By processing irregular cuttings into small spherical cuttings with regular shapes to eliminate morphological errors, the permeability is determined through multi-parameter coupling (porosity + capillary radius distribution corresponding to different mercury intrusion amounts). This method can accurately and quickly obtain formation physical properties, providing a cost-effective technical means for oil and gas reservoir evaluation.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for measuring formation porosity and permeability using rock cuttings, comprising the following steps: S1. Obtain drilling cuttings and clean the cuttings to remove fluid medium from the cuttings; S2, preparing the rock cuttings into spherical particles and drying them; S3. Measure the porosity and pore size distribution of the dried spherical rock fragments and calculate the permeability.

2. The method for measuring formation porosity and permeability using rock cuttings as claimed in claim 1, wherein in step S1, the rock cuttings are cleaned using a tertiary solvent, wherein the first-stage solvent is toluene, acetone or petroleum ether, the second-stage solvent is chloroform, and the third-stage solvent is methanol.

3. The method for measuring formation porosity and permeability using rock cuttings according to claim 1, wherein the rock cuttings are prepared into spherical particles in step S2, comprising: Cutting the rock cuttings into a cube shape with the thickness of the thinnest part of the rock cuttings as the side length; The cube-shaped rock cuttings are processed into spherical particles using a beading machine.

4. The method for measuring formation porosity and permeability using rock cuttings as claimed in claim 1, wherein the diameter of the spherical particles in step S2 is 0.5-5 mm and the sphericity is greater than 0.

9.

5. The method for measuring formation porosity and permeability using rock cuttings as claimed in claim 4, wherein the diameter of the spherical rock cuttings in step S2 is 1-2 mm.

6. The method for measuring formation porosity and permeability using rock cuttings according to claim 1, wherein in step S2, a vacuum oven or a supercritical fluid is used. The drying method is to dry the rock chips into spherical particles.

7. The method for measuring formation porosity and permeability using rock cuttings according to claim 1, wherein the permeability calculation method in step S3 is: ； in, K is the permeability, mD; φ is the porosity, decimal; r 50 The capillary radius corresponding to 50% mercury intrusion in the mercury injection experiment, μm.

8. A computer-readable storage medium comprising instructions, which, when executed on a computer, enable the computer to execute the method according to any one of claims 1 to 7.

9. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method according to any one of claims 1 to 7 when executing the program.

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