Rheonics Support

What products are involved?
DVM HPHT ultra-high accuracy all-in-one density meter and viscometer.

What is the purpose of this article?
To give an overview of how to build or use the Rheonics DVM in a high-pressure loop.

Overview

The DVM is an in-line sensor capable of measuring Viscosity, Density, and Temperature simultaneously. This sensor is designed to work in high-pressure (up to 30,000 psi, 2100 bar) and high-temperature (up to 200°C, 400°F) applications with ultra-high accuracy. This sensor requires less than 0.7 cc fluid sample to measure and its wetted parts are made of Titanium Gr. 5 (3.7165).

Figure 1. Rheonics DVM

Use Cases

PVT and Reservoir Fluid Analysis:

Figure 2.  Example of a PVT study using Rheonics DVM

Viscosity and density of fluids in oil and gas applications are variable and critical. When you’re pumping drilling mud, fracking fluid, or crude oil through several kilometers of pipe, small changes in viscosity have huge consequences for the pressure balance, energy efficiency, and costs of the system. While traditional oilfield measurements come back from labs after a few hours, an in-line solution to measuring the changing viscosity and density such as the DVM can allow operators to adjust temperature and diluent flows on the fly. 

In PVT studies, high-quality density and viscosity data are crucial for determining accurate EOS (Equation of State) models, thermodynamic properties, and transport equations. Integrated models using actual measurements from field (downhole GOR, viscosity, density) and lab (PVT: Formation volume factors, solution gas-oil ratio, viscosity, density) are used to predict crude oil flow properties and production rates, determine reservoir evaluations, and determine pump type and sizes for land-based operations. 

New reservoirs are increasingly ultra-deep with very high-pressure conditions (>25000 psi) and high temperature (>400 °F). It is very expensive to acquire sample fluids from ultra-deep wells so it is important that density and viscosity measurements be carried out with minimal volume of the reservoir fluid. 

In PVT analysis, operators use either an offline or an inline instrument to measure density and another instrument to measure viscosity (mostly offline) meanwhile Rheonics’ DVM is a single instrument combining HTHP density meter and viscometer that delivers simultaneous density, viscosity, and temperature measurement in the harshest of conditions.

Integration of a Rheonics DVM in PVT systems allows evaluation of fluid changes rapidly onsite with large pressure and temperature ranges applicable to downhole, pipeline, and other oil and gas processing conditions. Downhole conditions are challenging to work with and the DVM easily reaches these conditions for the PVT lab. See more information here:

• Density Viscosity for PVT Studies.
• New approaches to density and viscosity measurement across the spectrum of oil and gas application.

Equipment required for the High-Pressure Pump Setup

Item	Name	Qty	Part Number/ Manufacturer	Specifications	Material	T. [°C] Range	Pressure Rating	Referral Image	Link
1	High-Pressure Manual Valve (Two ways)	5	30-11HF4 / HiP	1/4” OD tubing. HF4 connection. 3/32” orifice.	Stainless steel	0°C to 427 °C	2068 bar		Link
2	High-Pressure Cross	3	60-24HF4 / HiP	1/4” OD tubing. HF4 connection. 1/16” orifice.	Stainless steel	0°C to 427 °C	4136 bar		Link
3	3 Way ball valve	1	SS-43GXS4 / Swagelok	1/4” ports	Stainless steel	-198 °C to 648 °C	207 bar		Link
4	Manual Valve NC (Normally Closed)	1	HE-2-QS-8 / Festo	-	Polyoxyme thylene (POM)	0°C to 60°C	10 bar		Link
5	Pressure Transducer	1	TJE 060-1108-02TJG / Honeywell	0.1 % accuracy 4 mA to 20 mA, 0 Vdc to 5 Vdc, or 0 Vdc to 10 Vdc output. Intrinsically safe available option.	Stainless steel	-54 °C to 121 °C	4136 bar		Link
6	Pressure Indicator	1	Additel 681 7 Additel	Up to 0.02% accuracy. IP67. Data logging option. Ex certified. RS232 connection	Case Material: Aluminium alloy Wetted parts: Stainless Steel	-10 °C to 50 °C	4200 bar		Link
7	Vacuum Pump	1	VE 115N / RAT HVAC	1/4 HP 1/4” inlet port	Metal	T. room (10 °C to 40°C)	vacuum until 150 microns		Link
8	Syringe Pump - 65D	1	60-1249-024 / Teledyne ISCO	1/4” ports size. 0.1% pressure accuracy. Cylinder capacity 67.97 ml.	Stainless steel	T. room (5 °C to 40°C)	1400 bar		Link
9	Manual pressure pump generator	1	37-6-30 / HiP	Manual pressure generator for 3/8” lines	Stainless steel	-29 °C to 204 °C	2068 bar		Link
10	Condensate Trap	1	777902 / Eurovacuum	G3/4" Ports	Polypropy lene	5 °C to 50°C	Atm.		Link
11	Fluid Basin	1	-	-	Stainless steel	-200 °C to 800 °C	2 bar		-
12	Over-pressure Rupture disk	1	-	-	Stainless steel	Custom for this case 200 °C	Custom for this case 2100 bar		Link

How to build the High-Pressure setup?

Figure 3. DVM in a High-Pressure System Setup

Considerations: 

• Use High-pressure connections and equipment (Valve, Tee, Cross, etc).
• The schematic above shows two pumps, a 1400 bar pressure syringe pump, and a 2100 bar manual pressure generator. Users select pumps or generators with specifications as needed for their application. Ensure the DVM ordered is rated for the highest pressure that you expect in the system. 
  
• Operating above-rated pressure for DVM will cause irreversible damage to the sensor. Always check the pressure rating of the components used and ensure there is a suitable safety factor. 
  
• Use pressure protection rupture discs to protect the DVM and the HPHT loop against overpressure.

How to use the DVM in the HPHT Loop?

To configure the high-pressure system and test the Rheonics DVM correctly follow these steps:

Fill DVM and HPHT Loop with test fluid:

1. Close all valves in the system.

2. Open V2, V3, and V4.

3. Turn the vacuum pump (G3) on and wait until the pressure stops dropping.

4. Once pressure stabilizes (observed on pressure indicator P2), close V4.

5. Turn the vacuum pump (G3) off.

6. Open V6 to break the vacuum in the pump.

7. Open V1 to allow fluid (S1) into the system.

8. Fill the loop with the fluid.

9. Finally, Close V1.

Pressurizing the system:

Once the system is filled with the testing fluid follow these steps:

1. Pressurize the system by ‘closing’ the manual pressure generator G2 (if manual operation is desired) or operating the automatic syringe pump (G1).

2. Check the pressure on the manometer (P2).

How to Clean and Dry the DVM and HPHT Loop?

Cleaning the system:

For the case of the manual pump and the Rheonics DVM, they need to be manually cleaned. 

The rest of the system can be flushed with solvent in a way that each branch of the system gets flushed separately. To clean the system by flushing follow these steps: 

1. Close all valves in the system and make sure that the electronic syringe pump (G1) is as empty as possible.
2. Connect a pump to the system instead of the fluid basin and choose a solvent that matches the original fluid.
3. Open V1, V2 and V3;
4. Pump the solvent through V3 branch by repeatedly filling and emptying the manual pressure generator (G3).
5. Once the previous step is complete, empty the manual pressure generator (G2).
6. Close V3;
7. Open V4.
8. Change the 3-way valve V7 to discharge the fluid into the Condensate trap S2.
9. Pump the solvent through V4 and into the Condensate trap S2.

Drying the system:

To dry the whole system repeat the cleaning steps shown before, but instead of using solvent connect compressed air to the high-pressure system. Ensure compressed air is dry and clean to avoid any deposits in the system that can affect measurement accuracy in DVM.

References:

[1] Density Viscosity for PVT Studies.

[2] New approaches to density and viscosity measurement across the spectrum of oil and gas application.

[3] DVM Demo | Density viscosity HPHT Pressure test.

[4] DVM Introduction | Ultra High accuracy HPHT Density & Viscosity.