Characterization of Gas Shale Pore Systems by Analyzing Low Pressure Nitrogen Adsorption

Transcription

1 Characterization of Gas Shale Pore Systems by Analyzing Low Pressure Nitrogen Adsorption Presented by: Mehdi Labani PhD student in Petroleum Engineering Supervisor: Reza Rezaee September 212

2 Objective Quantitative analysis of the gas shale pore systems in Perth and Canning basins. Determining the shale samples with the higher potential for methane sorption. Limitation: High heterogeneity of the potential gas shale layers Small sample size Our results only will show nature and variability in pore structure

3 Used Techniques for Porosity Analysis Gas Adsorption Mercury Porosimetry Techniques Helium Porosimetery

4 Used Techniques for Porosity Analysis Gas Adsorption Can measure only open pores Pore size > 1 nm Can determine PSD Micro & Mesopores Mercury Porosimetry Techniques Helium Porosimetery

5 Used Techniques for Porosity Analysis Similar to gas adsorption Can measure only open pores Pore size > 3 nm Can determine PSD Meso & Macropores Gas Adsorption Mercury Porosimetry Techniques Helium Porosimetery

6 Used Techniques for Porosity Analysis Gas Adsorption Can measure only open pores Easy & Established technique Mercury Porosimetry Techniques Helium Porosimetery

7 Theory: Porosity Measurement,, Porosity Pore size and its distribution or,,

8 Theory: Size of Pores (IUPAC Standard) Micropores Mesopores Macropores 2 nm 5 nm

9 Theory: Adsorption Process 1. Diffusion to adsorbent surface 2. Migration into pores of adsorbent 3. Monolayer builds up of adsorbate

10 Theory: Isotherm Isotherm is a measure of the volume of gas adsorbed at a constant temperature as a function of gas pressure. Desorption isotherm V a Adsorption isotherm P/P o 1

11 Theory: Hysteresis Hysteresis: Dependence of a system to its history. Hysteresis gives information regarding pore shapes. V a P/P o 1

12 Theory: Hysteresis Type A Type B Type C Type D Type E V a P/P o 1 1 P/P o 1 P/P o P/P o 1 P/P o 1 Cylindrical Slits Funnel shaped Bottle neck

13 Steps for Measurement 1. Sample Preparation Crushing shale samples Sieve analysis Proper samples: less than 25 µm Heating shale samples for 8 hours at 11 o C under vacuum condition 2. Adsorption Analysis 3. Interpretation

14 Interpretation Pore size & distribution Points P/P o Volume adsorbed 1 2 Pore shape Results Pore volume 3 Weight of sample Specific surface area

15 Sample Name Results He Porosity (%pu) TOC Content (wt%) T max ( o C) BET Surface Area(m 2 /gr) Perth Samples Total Pore Vol.(cm 3 /1gr) at maximum pressure Micropore Vol.(cm 3 /1gr) Mesopore Vol.(cm 3 /1gr) Macropore Vol.(cm 3 /1gr) AS2-S AS2-S AS2-S AS2-S RB2-S RB2-S RB2-S RB2-S RB2-S Sample Name He Porosity (%pu) BET Surface Area(m 2 /gr) Total Pore Vol.(cm 3 /1gr) at maximum pressure Canning Samples Micropore Vol.(cm 3 /1gr) Mesopore Vol.(cm 3 /1gr) Macropore Vol.(cm 3 /1gr) GW ML PE S1-DD S2-DD WL Adsorption Average pore width(4v/a)(nm) Adsorption Average pore width (4V/A)(nm)

16 Results adsorption AS2 S1 desorption AS2 S4 adsorption desoprtion RB2 S1 adsorption desoprtion RB2 S3 Adsoprtion Desorption Perth Samples AS2 S2 adsorption desorption AS2 S6 adsorption desorption RB2 S2 Adsoprtion Desorption RB2 S5 Adsoprtion Desorption RB2 S4 Adsorption Desorption

17 Canning Samples GW1 Adsorption Desorption ML1 Adsorption Desorption PE1 Adsorption Desorption S1 DD1 Adsorption Desorption S2 DD1 Adsorption Desorption WL1 Adsorption Desorption

18 Pore Size Distribution (PSD) Perth samples.3 Incremental PA(m 2 /gr) Micropore Mesopore Macropore Pore width(nm) AS2 S1 AS2 S2 AS2 S4 AS2 S6 RB2 S1 RB2 S2 RB2 S3 RB2 S4 RB2 S5 AS2: Avg. SA 5 m 2 /gr Incremental PV(ml/gr) Micropore Mesopore Macropore AS2 S1 AS2 S2 AS2 S4 AS2 S6 RB2 S1 RB2 S2 RB2 S3 RB2 S4 RB2 S5 RB2: Avg. SA 8.2 m 2 /gr Pore width(nm)

19 Pore Size Distribution (PSD) Canning samples-goldwyer Formation.5 Incremental PA(m 2 /gr) Micropore Mesopore Macropore GW1 ML1 PE1 S1 DD1 S2 DD1 WL Pore width(nm) Goldwyer Formation: Avg. SA m 2 /gr Incremental PV(ml/gr) Micropore Mesopore Macropore GW1 ML1 PE1 S1 DD1 S2 DD2 WL Pore width(nm)

20 Pore Size Distribution (PSD)-MICP vs. Gas Adsorption 12 1 Mesopore AS2 S1 Macropore 12 1 Mesopore AS2 S4 Macropore Incremental PV(%pu) Micropore MICP data Gas Ads. data Incremental PV(%pu) Micropore MICP data Gas Ads. Data Pore width(nm) Pore width(nm) Incremental PV(%pu) Micropore Mesopore RB2 S1 Macropore MICP Data Gas Ads. Data Incremental PV(%pu) Micropore Mesopore RB2 S2 Macropore MICP data Gas Ads. Data Pore width(nm) Pore width(nm)

21 Pore Size Distribution (PSD)-MICP vs. Gas Adsorption 1. Different sample preparation 2. Compressibility of grains at high mercury intrusion pressure

22 Conclusions Pore Size vs. Pore Volume: Micropore Vol. Avg. Pore Diameter Macropore Vol. 2 2 Avg. Pore Diameter(nm) Micropore Vol. (ml/1gr) Avg. Pore Diameter(nm) Macropore Vol. (ml/1gr) 1. All samples show an increase in Micropore vol. and decrease in Macropore vol. with decreasing pore diameter.

23 Conclusions Pore Size vs. Surface Area : Avg. Pore Diameter Surface Area Micropore Vol. Surface Area Macropore Vol. Surface Area Avg. Pore Diameter(nm) Surface Area(m 2 /gr) Micropore Vol. (ml/1gr) Surface Area(m 2 /gr) Macropore Vol.(ml/1gr) Surface Area(m 2 /gr) 2. Micropore Vol. has an important role on adsorbed gas storage.

24 Conclusions GA results vs. He porosity: 4 Total PV GA(ml/1gr) He Porosity(%pu) 3.5 Sum of Meso&Macropore(ml/1gr) He Porosity(%pu) Micropore Vol.(ml/1gr) He Porosity(%pu) 3. Micropore vol. has not any positive effect on free gas storage.

25 Conclusions Perth Samples Surface Area(m 2 /gr) TOC Content(wt%) Micropore Vol.(ml/1gr) TOC Content(wt%) 4. TOC content is not a controlling factor for high SA. Surface Area(m 2 /gr) Tmax ( o C) Micropore Vol. (ml/1gr) Tmax ( o C) 5. Perth samples with higher thermal maturity has a higher potential for gas adsorption.

26 Future Work High Pressure Volumetric Adsorption Measurement

27 Thank you for Your Attention