Effective Oil and Gas Separator and Heater Treater Measurements

Going back to 1980s when I worked on offshore oil & gas production projects, it seemed that well test measurements could be a tricky business. Even with today’s technologies, the increase in unconventional oil & gas production continues to make well test measurements a challenge.

Michael Machuca Upstream O&G Industry Marketing Manager

Michael Machuca
Upstream O&G Industry Marketing Manager

EP-Mag-Measurement-PracticeIn an E&P magazine article, Benefits of best practice maximize production and profits, Emerson’s Michael Machuca explores some of the measurement technologies and associated diagnostics to help drive sound decisions in well optimization, reservoir life sustainability and long-term profitability.

Michael highlights these unconventional oil & gas production challenges:

Operators are moving toward larger well pads with longer laterals that may have multiple lease holders per pad and tank. Larger facilities are now requiring commingling of production into a single tank or pipeline. As a result, it is necessary to measure production at the separator or heater treater to ensure proper allocation of royalties to the land owner and to fully understand how each well is producing.

Specifically, a separator and a heater treater are: Continue Reading

Adjusting Model Predictive Controller Response

Knowledge sharing need not be limited to one week conferences like the recent Emerson Exchange conference. I mention this to highlight an excellent discussion thread in Emerson Experts Forum in the Emerson Exchange 365 community. The thread, MPC [Model Predictive Control Penalties opens with this question:

What should I understand for “Penalty on Move” and “Penalty on Error”? Is there a way to calculate these?

Emerson’s Lou Heavner, whom you may recall from numerous advanced control-related posts responded:

Lou Heavner Systems/Project Engineering Consultant

Lou Heavner
Systems/Project Engineering Consultant

The Penalty on Move is calculated based on the dynamics of the problem and is usually a good first guess. The Penalty on Error is initially set to a default value of 1. They both work to improve the performance of the controller, especially in the face of imperfect models.

Increasing the POM of an MV will make the action of that MV less aggressive. If an MV seems to be cycling or moving to aggressively, then increase the POM. I find that it is best to make changes larger or smaller by a factor of 2. Occasionally the POM will be too large and the MV seems almost dead. In that case reduce the POM, always observe after making a change.

I have rarely seen the need to adjust the POE of a Process Output. My colleague and fellow contributor to this forum James Beall has seen some benefits with changing POE. It works on a single Process Output rather than an MV. Increasing the POE will make it try harder to reach its constraint target. Decreasing POE will allow it to give up more easily. Think in terms of relative importance and increase the POE on variables that are not achieving the control objective and reduce it on those that are not as important such as level in a surge tank. For Process Outputs that are not being optimized, it doesn’t make much sense to me to worry about it.

Before MPC Plus, POM and POE required a download to change. In MPC Plus they can be modified on-line.

Let me know if this is not what you were seeking.

Seeing the thread, Emerson’s James Beall, also highlighted here on the blog numerous times, added [hyperlinks inserted by Jim]: Continue Reading

Solids Level Measurement in Mining—A New Way

Douglas Morris Director of Marketing, Mining & Power Industries

Douglas Morris
Director of Marketing, Mining & Power Industries

Author: Douglas Morris

When it comes to mining there are a number of measurement applications that are unique to the industry. Accurately measuring the density of slurry and the level of an ore pile are two that come to mind. Although measuring level throughout the mining process is very common, getting an accurate solids level reading can be downright frustrating.

Radar, ultrasonic, and laser are single point measurements and the combination of irregularly shaped ore piles and dust most often cause these technologies to provide very inaccurate levels because they miss things like material buildups or cavities. Whether selling finished goods or running a concentration plant, getting a complete level picture is important in both instances and in order to do so, a three dimensional view is needed.

A new technology is available that addresses this need and uses sound to create a 3D surface image of the solids storage area. Examples of where this works are storage silos, bins, and stockpiles, regardless of the ore or mineral.

A caveat is that the sensor(s) has to be mounted to a fixed structure for reference/calibration purposes. The best way to see how this technology works is through a video. Continue Reading

How to Videos on Installing DP Flowmeters

3051SFA Annubar FlowmeterDifferential pressure (DP) is one of the most used and proven technologies for flow measurement. With averaging pitot tube (APT) technology, the impact pressure is sensed on the front of the device as the flow initially approaches the obstruction or bluff body which creates the pressure difference. For the most accurate measurement possible, it is essential to accurately measure the changing characteristics of the velocity flow profile. An integrated reading of the flow velocity profile samples across the full diameter of the pipe and produces a more accurate representation of the average velocity.

Rosemount Annubar flowmeters minimize this pressure drop to save energy and perform real-time mass and energy flow measurements with integral temperature design. The team managing the Rosemount measurement brand put together a series of “how to” videos on the installation process—tool requirements, device orientation guidelines, installation via Pak-Lok mounting, and Flo-Tap flowmeter installation.

In the first video, Tool Requirements and Receiving Guide (4:15 runtime), Emerson’s Mike Montgomery explains the tools required to install an Annubar Averaging Pitot Tube, as well as Inspection process recommendations upon receiving a new flowmeter. Continue Reading

Safety Instrumented System Solenoid-Operated Valve Approaches

Last week at the Emerson Exchange conference, I caught up with Emerson’s Riyaz Ali. You may recall Riyaz from many safety instrumented system-related posts. We discussed some of the trends in integrated positioners + solenoid valves + limit switches + valve position transmitters.

Riyaz Ali Senior Business Development Manager

Riyaz Ali
Senior Business Development Manager

Riyaz felt that this approach not in line with the safety instrumented system (SIS) general philosophy for several reasons.

For these devices with an integral solenoid-operated valve (SOV), the pneumatic path is only a single path and the requirement for a redundant path will not be met.

This will affect the PFDavg calculations as per ISA TR84.00.02-2002 part 2 using the simplified equation for a one-out-of-one (1oo1) arrangement:

λdu x T /2 (Note: λdu is dangerous undetected failure rate of equipment under control (EUC) and T is test interval.)

For solutions with external SOVs in series with smart positioners, this 1oo2 approach has a PFDavg:

λdu x T2 /3

A 1oo2 arrangement provides an improved PFDavg over a 1oo1 single box arrangement.

Riyaz notes that going to external SOV will improve safety reliability, which means either the SOV or smart positioner are capable of taking a valve to safe state. With integral SOVs with smart positioners, only one pneumatic path is available, which means there is no redundancy. Project teams may have to re-visit the HAZOP analysis to evaluate new safety integrity level (SIL) conditions. Continue Reading