INTELLIGENT MUD-GAS SEPARATION AND HANDLING SYSTEM
A multi-phase fluid solution measurement and gas separation system is described. The system includes a substantially vertical fluid supply pipe that introduces the multi-phase fluid solution in a steady flow having a substantially calm and steady fluid surface to a mud-gas separation unit. The mud-gas separation unit includes measurement tools such as force sensors and level sensors to allow for a rheological model of the fluid to be calculated. The system also includes components for flaring or processing gas which separates from the multi-phase solution.
This application claims priority as a divisional application of U.S. patent application Ser. No. 15/677,561, filed Aug. 15, 2017, with the same title. The application is incorporated by reference in its entirety.
BACKGROUNDMany operations in the oilfield involve extracting a multi-phase flow from a formation which can contain uncertain quantities of mud, hydrocarbons, gas, debris, and other fluids. There are tools for knowing the precise quantity of each component in the multi-phase flow, such as a VX flow meter, but many of these methods are prohibitively expensive. Knowing the precise quantity of each component in the multi-phase flow without using expensive equipment can be a challenging proposition. Another challenge is to separate gas phase components of the fluid from the liquid phase components. There is a need in the art for an inexpensive, reliable method to ascertain the characteristics of a multi-phase fluid flow and separating gas from liquid phase components.
SUMMARYVarious features of the present disclosure are described herein with reference to the accompanying figures. Embodiments of the present disclosure are directed to a multi-phase fluid flow measurement system including a fluid supply pipe oriented in an at least partially vertical orientation. The fluid supply pipe can carry a multi-phase fluid upward through the fluid supply pipe. The multi-phase fluid has an upwardly-facing fluid surface. The system can also include a transfer pipe extending laterally from the fluid supply pipe. The multi-phase fluid is pressurized sufficiently to flow through the transfer pipe while the upwardly-facing fluid surface is steady and remains steady as it enters the transfer pipe. The system also has a Weir plate positioned to at least partially impede the flow of the multi-phase fluid through the transfer pipe. The system can have a level sensor in the mud-gas separator configured to measure a level of fluid accumulated in the mud-gas separator unit, and a controller configured to release at least one of fluid or gas from the mud-gas separator in response to the level sensor determining that the fluid level has reached a predetermined level.
Other embodiments of the present disclosure are directed to a method of measuring characteristics of a fluid in a multi-phase solution. The method includes conducting a multi-phase solution in a vertical direction such that the multi-phase solution forms an upwardly-facing, steady fluid surface, and flowing the multi-phase solution laterally through a transfer pipe. The transfer pipe is at least partially blocked by a Weir plate. The method also includes flowing the multi-phase solution over one or more baffles positioned at a downwardly sloping angle, and measuring a depth of the multi-phase solution as it flows over the baffles in at least one location. The method also includes allowing gas to escape the multi-phase solution and collecting the escaped gas.
In still further embodiments the present disclosure is directed to a mud-gas separation unit including an inlet configured to receive a steady flow of a multi-phase solution and a baffle having a force sensor. The baffle is positioned so that the steady flow impinges upon the baffle on an area affected by the force sensor. The mud-gas separation unit also includes a gas collection region above the inlet configured to allow gas to escape the multi-phase solution and collect in the gas collection region, and an articulating member operatively coupled to the baffle and configured to change an angle of the baffle.
Below is a detailed description of systems and methods for analyzing and separating fluids of different phases from a multi-phase fluid flow according to embodiments of the present disclosure. Reference is made to certain example structures and techniques and it is to be understood by a person of ordinary skill in the art that these examples and illustrations are not given in a limiting manner; rather, a person of ordinary skill in the art will recognize that the scope of the present disclosure is greater than specific embodiments and illustrations.
The use of MPD and the MPD manifold 108 to control the risks and costs of drilling wells that have narrow downhole pressure limits by actively managing the wellbore pressure profile has become a common practice. The dynamic control of annular pressures enables drilling wells that might not otherwise be practical. The MPD manifold 108 delivers the multi-phase flow to the separation component 100, where it is analyzed and separated into a gas 110 and a fluid 112 outflow.
The fluid supply pipe 120 provides a multi-phase flow received from the MPD manifold 108 shown in
The vertical component of the fluid supply pipe 120 ensures establishment of a velocity profile for the fluid. The size of the supply box 130 ensures that the flow is calm and steady as it reaches the exposed fluid surface 134 and begins to flow into the MGS 124. The Weir plate 126 can be square or triangular as shown.
Q=CdLh√{square root over (ht)}≈CdLh3/2
In the case of a triangular, or V-notch Weir, where
the calculation or flow rate, Q, can be found using the following equation:
When considering such relation for weir plates, it can be observed that the fluid density does not affect the flowrate, as the density affect in a linear way the potential energy in the supply region to the weir plate and also the kinetic energy of the flow falling through the weir plate. If the fluid contains gas bubbles which are entrained by the fluid through the weir plate opening as the same velocity, the system would so determine the total flowrate. Such two-phase flow measurement applies for gas bubble moving horizontally as the same velocity than the liquid. This is particularly applied for small bubbles and with viscous fluid. The gas which escapes from the multi-phase flow in the supply box 130 to the MGS 124 via the pipe 128 may be measured by a gas flowmeter 165. Such flowmeter may be an ultra-sonic time of flight measurement system.
Referring back to
Where:
V=average velocity
De=max depth of the flowing channel
ρ=fluid density
μ=fluid viscosity
z=vertical coordinate
x=axial coordinate along the flow channel.
The fluid level may be obtained by measurement of the layer of fluid above the baffle plate (such as 162c of
Using these calculations, the flow rate from within the transfer pipe 122 through the Weir plate 126 can provide an estimation of flow rate. The force sensor 150 (also referred to as a target sensor) can provide an estimate of fluid density ρ. The level measurement 162a above the baffle 136a can provide an estimation of apparent viscosity, where
is the slope of the baffle plate 160 which is defined by the construction of the MGS 124.
The additional feature of the articulating plate 154 provides yet another measurement, which enables use of the “two rheological model” with two parameters. For such application, the level sensor 162b can be installed above this articulating plate 154. This can be achieved using the Bingham plastic law or the power law. In some embodiments there is a second baffle having force sensors and an articulation.
The MGS 124 shown in
Furthermore, the line to flare system may be terminated by a nozzle 221. Through such nozzle, the pressure may accelerate the gas to a sonic or even super-sonic velocity. Such high velocity provides an excellent method to entrain air so that the fuel/oxygen ratio is better and allows a cleaner combustion of the gas at the flare. The compressor may be controlled by the controller 212 in relation with the measurement of a pressure gauge 223 coupled between the compressor 222 and the flare 204 and the setting on the choke (in the case of variable gas nozzle 221). With optimum setting of the nozzle 221 versus the pressure gauge 223, the fuel/oxygen can be optimized. Also, the usage of nozzle 221 operating above the sonic velocity acts as a flame arrester. This insures that the flame cannot move inside the gas supply line back to the inside of the MGS 124. Such situation may exist at start of the MGS 124, as the inside of the MGS 124 is initially filled with air. So, the initial gas flow through the compressor 222 towards the nozzle 221 is a mixture of flammable gas and air (oxygen) with the potential risk of the flame moving back from the flare towards the inside of the MGS 124 (which should be monitored for explosion).
Furthermore, the compressor 222 may also be designed and operated as partial vacuum pump. It such application, the pressure inside the MGS 124 (measured by the pressure gauge 220) may be low, helping the extraction of gas out of the supplied fluid. If the gas is not in solution (but in bubble), the bubble increases in size and float faster to surface to escape the fluid. In the gas is in solution, the low pressure may provoke some de-absorption. For such operation at low pressure in the MGS 124, the valve 210 can be coordinated with the level measurement 208 by the controller 212.
Also the gas present inside the MGS 124 and line towards the flare stack may be monitored for presence of toxic gas (such as H2S). In such case, a pilot flame may be activated (turned ON) at the flare to insure safe handling of such gas (by combustion). The MGS gas line to the flare 204 may also include a gas analyzer 225 to determine the ratio of C1, C2, C3, and C4. Such analysis may be obtain by optical absorption of specific wavelength to determine the presence (and concentration) of each type of molecules. This analysis may be useful to estimate the content of gas emitted by some down-hole formations. This information is also valuable to determine the optimum the air ration to entrain for optimum burning at the flare.
The separation component 203 includes several features generally analogous to features from
The systems and methods of the present disclosure enable a multi-phase fluid flow to be separated, gas from liquid, and measured for parameters according to Bingham's law, the power law, or another suitable calculation, without the need for an expensive VX flowmeter or another similarly expensive component.
Claims
1. A multi-phase fluid flow measurement system, comprising:
- a fluid supply pipe oriented in an at least partially vertical orientation, the fluid supply pipe being configured to carry a multi-phase fluid upward through the fluid supply pipe, wherein the multi-phase fluid has an upwardly-facing fluid surface;
- a transfer pipe extending laterally from the fluid supply pipe, wherein the multi-phase fluid is pressurized sufficiently to flow through the transfer pipe while the upwardly-facing fluid surface is steady and remains steady as it enters the transfer pipe;
- a barrier positioned to at least partially impede the flow of the multi-phase fluid through the transfer pipe; and
- a level sensor configured to measure a depth of the multi-phase fluid as it flows from the transfer pipe.
2. The multi-phase fluid flow measurement system of claim 1 wherein the barrier is a Weir plate.
3. The multi-phase fluid flow measurement system of claim 1, further comprising a mud-gas separator (MGS) unit coupled to the transfer pipe and configured to receive the multi-phase fluid.
4. The multi-phase fluid flow measurement system of claim 3, further comprising a gas transfer conduit between the fluid supply pipe and the mud-gas separator unit.
5. The multi-phase fluid flow measurement system of claim 1, further comprising a plurality of baffles in the mud-gas separator, wherein at least one of the baffles has a force sensor configured to measure kinetic energy within the multi-phase fluid.
6. The multi-phase fluid flow measurement system of claim 5 wherein the level sensor is configured to measure the height of the flowing fluid above one or more of the baffles.
7. The multi-phase flow measurement system of claim 6 wherein the multi-phase fluid flow measurement system is configured to determine the apparent viscosity of the multi-phase fluid.
8. The multi-phase fluid flow measurement system of claim 5, wherein at least one of the baffles comprises an articulating member configured to articulate to change an angle of the baffle.
9. The multi-phase fluid flow measurement system of claim 8, and associated with the claim 3c to determine the apparent viscosity of the fluid at different flow conditions.
10. The multi-phase fluid flow system of claim 9, wherein the multi-phase fluid flow measurement system is configured to determine the rheological model of the multi-phase fluid.
11. The multi-phase fluid flow measurement system of claim 5, wherein the level sensor comprises at least two level sensors, each on a different baffle, wherein the level sensors are configured to measure a change of at least one of density and rheology due to extraction of gas.
12. The multi-phase fluid flow measurement system of claim 11, wherein the difference of fluid properties may be measured on the first and last baffle plate, the multi-phase fluid flow measurement system is configured to determine the flow rate of gas extracted from the multi-phase fluid.
13. The multi-phase fluid flow measurement system of claim 1 wherein the multi-phase solution includes at least one of mud and hydrocarbons.
14. The multi-phase fluid flow measurement system of claim 3, further comprising a controller configured to release at least one of fluid or gas from the mud-gas separator in response to the level sensor determining that the fluid level has reached a predetermined level.
15. The multi-phase fluid flow measurement system of claim 3, further comprising a gas line configured to carry gas out of the MGS unit released from the multi-phase fluid.
16. The multi-phase fluid flow system of claim 15, further comprising a sensor configured to enable a determination of a type and amount of gas flowing through the gas line.
17. The multi-phase fluid flow measurement system of claim 15, further comprising a compressor in the gas line.
18. The multi-phase fluid flow system of claim 17, wherein the compressor is configured to feed a flare stack trough a variable choke orifice, the multi-phase fluid flow system further comprising a pressure gauge in the gas line, and means for controlling a choke orifice at least in part in response to a pressure measured by the pressure gauge.
19. The multi-phase fluid flow system of claim 18, wherein the compressor, the variable choke orifice, the pressure gauge, and the means for controlling the choke orifice are configured to entrain adequate air flow versus the ejected gas flow at the nozzle.
20. A mud-gas separation unit, comprising:
- an inlet configured to receive a steady flow of a multi-phase solution;
- a baffle having a force sensor, wherein the baffle is positioned so that the steady flow impinges upon the baffle on an area affected by the force sensor;
- a gas collection region above the inlet configured to allow gas to escape the multi-phase solution and collect in the gas collection region; and
- an articulating member operatively coupled to the baffle and configured to change an angle of the baffle.
21. The mud-gas separation unit of claim 20, further comprising a gas outlet and a fluid outlet, the fluid outlet being positioned at a lower portion of the mud-gas separation unit.
22. The mud-gas separation unit of claim 20, further comprising a force sensor on one or more of the baffles to determine a fluid density of the fluid.
23. The mud-gas separation unit of claim 22, wherein the force sensors are configured to measure the density of the multi-phase flow at 2 different baffles of the gas separator and determining the difference of fluid density from a first baffle and a second baffle, wherein the quantity of gas is associated with a flow rate from the inlet.
24. The mud-gas separation unit of claim 20, further comprising a heater configured to apply heat to the multi-phase fluid as it enters the mud-gas separation unit.
25. The mud-gas separation unit of claim 24, further comprising a temperature sensor configured to monitor a temperature within the mud-gas separation unit to prevent overheating.
26. The mud-gas separation unit of claim 20, further comprising:
- a compressor;
- an associated controller associated with the compressor, the controller being configured to influence the compressor; and
- a glycol tower configured to receive fluid from the mug-gas separation unit to remove the water from the gas.
Type: Application
Filed: Oct 21, 2019
Publication Date: Feb 13, 2020
Inventors: Ashley Johnson (Cambridge), Jacques Orban (Katy, TX)
Application Number: 16/658,944