Geotek MINI-PCATS comprehensive testing system for pressure retaining rock cores

Geotek Company Introduction:

Geotek, a British company, is the designer and manufacturer of the world's best-selling core equipment MSCL (Multi Sensor Core Logger Core Comprehensive Testing System, also known as Multi Parameter Core Scanner). Almost every laboratory engaged in core research work in the world (scientific research, engineering exploration, oil drilling, etc.) has installed MSCL, with over 220 users. MSCL has very stable, reliable, and durable performance, suitable for both laboratory and field use. It has been widely used in core libraries, geological key laboratories, temporary field laboratories, offshore survey ships, deep-sea drilling ships, and engineering ships around the world. Geotek is the most commonly used core analysis equipment by scientists. Wherever there are rock cores on Earth, there are Geotek products.

If a core is worth taking, it's worth logging... Core is precious, data is priceless.

MINI-PCATS comprehensive testing of pressure retaining rock cores

Pressure retaining core is a core sample that maintains the pressure level at the collection site even after core collection, and contains important physical, chemical, and biological components. The most common reason for collecting pressure retaining rock cores is to maintain the original structure of natural gas hydrates and sediments inside. The natural gas hydrates in core samples will decompose with the decrease of external pressure and the increase of temperature, thus producing a large amount of gas. These gases will continuously expand inside the sample and destroy its original structure before reaching the water surface. Therefore, maintaining the original pressure and temperature at the sample collection site is crucial for analyzing the original sediment structure.

MINI-PCATS installed in the Geological Laboratory of the University of Texas, with a multi screen software display interface

Processing and analysis of rock cores under pressure holding conditions

To measure the pressure retaining core samples, a core processing and analysis system capable of operating in the same high-pressure environment is required. Geotek can provide such equipment, model MINI-PCATS, which integrates pressure core analysis and transmission system. The MINI-PCATS system provides a mechanical transfer device that can transfer pressure maintaining rock core samples from high-pressure coring tools to measurement chambers for non-destructive analysis. It provides simple geophysical data and X-ray images, and can segment and cut rock core samples. The cut samples are then transferred to customized pressure maintaining chambers for transportation and further analysis. For example, quantitative analysis of natural gas hydrates through depressurization and exhaust.

Real time core evaluation

After the pressurized core is transferred from the high-pressure storage compartment compatible with the PCATS system, the X-ray system measures the length, quality, and composition of the core. Initial evaluation of the rock core can be conducted immediately based on the output X-ray images

a. Which part of the core needs to be preserved for subsequent analysis;

b. Which parts of the sample require immediate release of pressure for visual inspection or storage in liquid nitrogen;

c. Which parts require slow release of pressure for quantitative analysis of natural gas hydrates, and rapid core assessment can also help users check whether the collected core meets their needs and whether it needs to be collected again.

non-destructive measurement

The pressure type multi parameter core scanner MSCL-P is integrated into the MINI-PCATS system, which can automatically, high-resolution, and non-destructive in-situ measurement of pressure holding samples. Gamma and X-rays can penetrate aluminum alloy pressure shells for gamma density and X-ray imaging, and P-wave velocity is measured using ultrasonic pulse emission technology. The P-wave transducer is located inside the pressure measurement chamber. The transfer and rotation of the entire pressure retaining core can be controlled through a computer, and data from different positions of each core sample can be collected, including a video image obtained by rotating a position under an X-ray beam. And it can provide X-ray tomographic images of the entire sample. These data can be collected immediately on the survey vessel, providing users with quantitative information on structures and qualitative information on sediments.

MINI-PCATS Laboratory

Transported pressure retaining rock core+MiniPCATS to onshore laboratory

Mini PCATS can be used in the laboratory to transport and perform non-destructive analysis on pressure retaining rock cores, followed by secondary cutting and storage in a pressure retaining chamber. Mini PCATS can transport a maximum length of 1.2m for pressure holding rock cores. It can directly measure the permeability of K0 and is suitable for PCTB pressure holding core, with a length of 25-30mm.

On site secondary sampling (cutting)

The new feature of the MINI-PCATS system is the ability to cut and segment pressure retaining rock cores on-site. After all non-destructive scanning analyses are completed, users can cut the core samples based on the scanning results and actual needs. Each small section of the sample can be transferred to a customized pressure storage chamber.

In order to achieve high-quality cutting of pressure retaining rock core samples, the PCATS system first uses a rotating cutting disc to cut the plastic casing without debris, and then a reciprocating saw cutting blade to cut open the sediment rock core.

The cut small core samples are then pushed toSample pressure storage compartmentInternally, the pressure chamber is sealed and isolated using large ball valves.

Pressure chamber

Samples of various specifications stored in the pressure chamber (with a maximum length of 1.2m and a pressure of 35MPa)

MINI-PCATS System Technical Specifications

1. Length, width, and height

2. Pressure rating: Maximum working pressure 350bar (35MPa)

3. Working temperature: 0~50 ℃ (expandable)

4. Maximum core length: 1.2m

5. Maximum core diameter: 63mm, maximum casing wall thickness: 4mm

6. Compatible with Geotek pressurized core storage tool

MINI-PCATS system functions

1. Conveying of pressure retaining rock cores

2. Rock core analysis under pressure:

(1) Gamma density

(2) P-wave velocity

(3) X-ray imaging and CT

(4) Third party analysis system

3. Cutting of pressure retaining rock cores and transferring them to pressure retaining tanks for storage, with a maximum length of up to 1.2m

4. Liquid nitrogen cooled transfer chamber for rock core under pressure, freezing samples under pressure

Liquid nitrogen freezer

Geotek has developed a new technology to preserve sediment samples containing gas hydrates in liquid nitrogen LN2, ensuring minimal damage to all natural gas hydrates and the physical structure of the samples. This freezing technology can preserve sub samples cut twice, suitable samples (12-20cm) cut from PCATS, and transport them to the pressure chamber. Before connecting to the freezer, replace the water around the sample with high-pressure liquid nitrogen. The freezer is pre filled with liquid nitrogen and then pressurized to the same pressure range as the pressure chamber. When the ball valve between the two pressure chambers is fully opened, the sample falls into liquid nitrogen under high pressure. After 2 minutes, the sample will be completely frozen, the pressure will be released, and then the frozen sample will be taken out of the freezer and transferred to a liquid nitrogen Dewar flask for storage. It can be transported in dry bulk to the final destination.

Liquid nitrogen freezer+frozen samples+liquid nitrogen storage tank

5. The production test of pressure retaining rock core can simultaneously conduct pressure relief experiments on four samples. Sample and analyze the escaping gas, or store it for further isotope analysis experiments. Any length of sample cut can be subjected to a slow pressure drop test for quantitative analysis of natural gas hydrates.

6. Secondary cutting of pressure retaining rock core, transported to the analysis room:

(1) PCATS Triaxial Geotechnical Testing

PCAT Triaxial Testing Equipment

Small stress resonance column test (shear modulus and shear wave velocity)

Penetration testing

Triaxial strength test

Productive experiment

(2) PCATS K0 permeameter: permeability test under soil pressure

(3) Third party analysis and measurement laboratory

7. PCATS Over pack Secondary Packaging System

Transport certified pressure retaining rock cores to Geotek and third-party laboratories. It can store pressure chambers up to 1.2m in length. Up to 10 pressure compartments can be transported in a 20 foot refrigerated container.

Over pack secondary packaging system

With the demand for more precise testing of pressure retaining rock cores, it has become very important to transport undisturbed samples to specific laboratories. In the past few years, a large number of pressure retaining rock cores that require post-processing analysis have been stored in pressure retaining warehouses and then transported to local laboratories. However, most of the rock cores previously transported in the ballast tank were transported domestically. The rock cores in the pressure vessel have not been transported internationally yet due to some restrictions on the transportation of dangerous goods regulations. Natural gas hydrates contain a large amount of methane, which is highly flammable and can explode when mixed with air at a certain concentration.

To overcome the aforementioned challenges, Geotek has developed a comprehensive transportation solution that enables the safe transportation of up to 1.2m pressure retaining rock cores to any location in the world, while maintaining in-situ temperature and pressure. By sea or land transportation. Once the pressure chamber leaks or ruptures during transportation, the cylindrical bottle of secondary packaging can provide sufficient volume space inside to accommodate all methane gas releases, although this probability is very small.

The Geotek pressure vessel is installed safely and earthquake resistant in all directions through mechanical support structures, so there is no risk of damage to the secondary packaging cylindrical bottles during transportation. After the pressure chamber is installed in the bottle, the free volume inside the bottle is purified with nitrogen to avoid the possibility of explosive mixing inside the cylindrical bottle. Any leaked methane in the bottle will only mix with nitrogen gas. When the preservation system was first used in Japan, 5 pressure retaining rock cores were preserved for 1 year before being transported to the United States.

Secondary packaging cylindrical bottles, installed in refrigerated transport boxes for safe and shock resistant pressure holding compartments

Pressure holding transportation to onshore laboratory