Pennsylvania Rig Count from 1987 to 2011. Adapted from Baker Hughes.

There is little doubt that unconventional shale plays have gained a lot of interest in the last few years. While the Keystone State boasts the historical Drake well, generally considered the first successful oil well drilled, the state’s oil industry has remained flat for decades. Since Terry Engelder’s estimate of reserves in the Marcellus in early 2008 Pennsylvania has seen significant interest from the industry. Earlier today the U.S. Geological Survey (USGS) increased their technically recoverable Marcellus reserve estimate by an astonishing 4,100% from 2 trillion cubic feet (TCF) to 84 TCF of natural gas.

Although the USGS’s reserve increase seems unbelievable, it is only a function of an outdated and conservative estimate. As the USGS reports in the press release, “technological developments in producing unconventional resources have been significant in the last decade.” They are noting that longer horizontal wellbores and improvement in completions have increased the recovery potential in tight shales. As technology continues to improve and geological information in the play becomes more abundant, future reassessments may occur. After all, Engelder and Gary Lash conservatively estimated 168 TCF of technically recoverable natural gas.

Top 5 States by Rig Count. Adapted from Baker Hughes. *All rig counts are onshore activity only.

Pennsylvania is not the only state benefiting from shale plays. Despite the Great Recession, shale plays are growing and showing economic resilience. Since 2008 Louisiana, North Dakota and Pennsylvania have had a steady increase in drilling activity. Each of these states hold significant shale plays. By 2009 these three shale states rose into the top 5 most active by rig count.

Despite the recent rig count growth, economic factors will continue to influence growth in the industry. If the historical rig count data is any indication of the future, shale plays will continue to show strong growth for years to come, double dip or otherwise.

Matlab has special operators to perform multiplication, division and powers between the corresponding cells of two matrices. These operators are useful for simplifying and optimizing code that requires larger matrices. They can replace for loops and using them instead of for-loops saves time.


.* - Multiplication
./ - Division
.^ - Power


Example:

 

If A =

2	5
-3	7

& B =

6	1
3	2

 

Then A.*B =

12	5
-9	14

 

More Examples

Before you optimize complete the development of the code. Optimization can obfuscate code, so I recommend that a program is designed for readability until it is stable and complete. This will make debugging and changing the solution much easier during development.

Variable Declarations/Sizing

Matlab does not require the declaration of variables. However, Matlab’s variables are stored as arrays and each time the dimensions of the array change Matlab has to reallocate memory for the variable. Matrix size often changes in for-loops. To prevent this you can define the variable’s size initially and save some time. You can use the zeros or ones function to fill a variable.

Defines x as a square 3 x 3 matrix filled with zeros:

x = zeros(3);

0	0	0
0	0	0
0	0	0

Defines y as a 1 x 3 matrix filled with ones:

y = ones(1,3);

1

1

1

Eliminate For-Loops

For-loops can consume A LOT of time. Instead of for loops use matrix operators for addition, subtraction, multiplication and division. Recall from your math classes that matrix multiplication and division will not apply an element-wise multiplication of two matrices. However Matlab provides a method to perform multiplication between the corresponding cells of two matrices. To do element-element operations, use the element-wise Matlab operators. See an example here.

Element-wise operators:

.* - Multiplication
./ - Division
.^ - Power

Example of removing a for-loop:

Where a, b, t & p are arrays:

For-Loop code:

b = zeros(1000000,1);
for i=1:1000000
b(i) = a(i)*t(i)/p(i);
end

Optimized Code:

b = a.*t./p;

The reduction in speed is impressive. I ran each calculation with profiler. Lines 7-10 are pre-optimized code and line 5 is the optimized code. Each give the same answer. These are the results: (time(sec) is in red).

Functions

Functions are nice for organizing code and enhancing readability, but they come with costly overhead. The overhead comes from passing variables into a function and reassigning these values to the child function’s local variables. Placing the function’s code inline with the parent function’s code will save a significant amount of time. Built in Matlab functions can also be placed inline with your code. One large .m file will be much quicker than a number of smaller .m files.

Structured Arrays

I have come to enjoy the organization structured arrays offer. Unfortunately their high level of organization require additional referencing time for Matlab. Replace a structured array with a number of single arrays to cut down on this referencing time.

Unused Code

It may be surprising, but some lines of code may never be utilized in your program. Use the profile tool to determine if you have any code that is not run. Ask yourself if these lines of code exist to make you feel better, or if they actually serve a purpose and will be utilized in the future.

Tic-Toc (tic, toc) – The clock tool is a simple method for measuring run time. Insert tic to start the clock, and toc each time you want time to be printed to the command window. Each insertion of tic will restart the clock from zero, while each toc prints the current clock time.  It does not provide extensive information, but it is simple to apply and does not significantly slow down the software.

tic

for i=1:100

x = y*z;

end

toc

Each toc will print the time as: Elapsed time is 333.005251 seconds.

Profile Tool (profile) – Matlab’s profile tool provides extensive run time information for software. It takes longer to implement so if you are analyzing a short piece of code, tic-toc will do the job better. Running the tool significantly increases the overall run time of the program, but the information it provides is worth it. The profile tool reports time spent on each function and in each line of code in the program. Bottlenecks are easily identified to help focus on the most time consuming lines of code. (see the bottom of the post for a sample report).

To run the profile tool, type profile on in the command window followed by profile clear to ensure previous records are cleared. Run the code to be analyzed, then type profreport(‘function_name’) to launch the report. You should use the top function in the program’s hierarchy because the report allows you to easily view each child function in further detail.

Total time is the time spent within each function and includes time spent in that function’s child functions. Self time is time spent for operations in the function. The function EOS_fun is the bottleneck of this program. The report will also include the run time of built in Matlab functions like the roots function above. Inlining Matlab functions can increase speed by removing function overhead. Clicking a particular function gives a detailed report for the function. Below are screen shots of a detailed report for EOS_fun.

The top of the report supplies the lines where the most time was spent in the code. It is apparent that optimizing line 97 could shave a significant amount of time for this program.

The profiler also reports the time spent in children functions, this one being the Matlab function roots, however it will report on any children functions including functions defined by the user. The code analyzer will point out areas of obvious inefficiencies like output (screen printing) surpression and changing variable sizes (variable definitions). Coverage results may point out lines of code that do not run. It is useful for identifying conditional statements that are never entered. Sometimes these conditions are required for the redundency of the program, but if they are not necessary they can save a program time.

Above is a portion of the function listing. This gives a report for each line of code. Specific problem areas can be identified on a per line basis. The reported numbers on the left are: total time | total calls | line. Profile conveniently shades the most time consuming lines from pink to red based on time consumed for each line in relation to the time spent in the function.

Profile reports conveniently save in HTML format. I have uploaded the report used for the examples in this post. Take a look at this complete profile report here.

Now you have the information you need to start speeding up that code!

The Pennsylvania State University Petroleum and Natural Gas Engineering Program

By Kyle Barnoff

When an acquaintance learns about my study of Petroleum Engineering I am usually showered with questions, compliments or jeers.  More often I experience the latter, but one topic comes up most frequently.  Where does oil come from?  Seems like a simple question, but it has numerous correct answers.  I will answer all of them in this essay, including where oil is stored underground, how it gets there and where scientists believe it all came from.

Use your imagination to construct a large oil reservoir thousands of feet underneath the ground.   You probably imagine a big lake of oil trapped in a single void in bedrock.  Thanks for playing along, but this idealistic image is wrong.

When I talk about oil reservoirs with intelligent professors outside of Petroleum Engineering, this is the picture they paint for me. Realistically the earth is similar to a multi-layered hamburger from your favorite fast food chain.  Each layer, the bun, the cheese and the hamburger, are

Image 1. A sponge shares the structural properties of a reservoir rock.

different layers of rock with their own distinct properties.  None of these layers can hold oil.  But if we throw a small sponge in the middle of the sandwich we can create a potential reservoir.  This sponge best represents the type of rock that holds oil underground.

A sponge holds liquid like a “reservoir rock” holds oil.  Little holes and cavities inside rocks allow oil to be stored.  These rocks are usually sandstones, limestone or dolomites. Oil can be extracted because like a sponge, the rock’s small cavities have interconnecting tunnels allowing oil to flow from thousands of feet away to a small cylindrically shaped hole drilled into the rock.

Many underground rocks have small cavities, but only a minority become reservoir rocks.  A reservoir rock always lies underneath a cap rock.  Like the cloth of a hot air balloon prevents air from escaping, a cap rock keeps oil in the underlying reservoir rock.  Within the reservoir rock gas may exist above the oil, and water below the oil. The layering is similar to the separation seen in oil based salad dressings, and it occurs for the same reason.  Finding new cap rocks and new reservoir rocks in hopes of discovering new oil fields is the job of a Petroleum Geologist.

Image 2. A simple drawing of an oil and gas reservoir. Gas and oil, being lighter than water, rise above the water but are prevented from escaping by a cap rock. Like a sponge, the reservoir rock contains each liquid in very small cavities.

Now that we know oil is stored in sponge-like rocks below the earths surface, and held in place by cap rocks, we can think about how it got there.  According to Norman Hyne, Ph.D of The University of Tulsa, the oil and gas come from a rock called a Black Shale, which is composed of old organic matter that once collected on the sea floor.

Image 3. Methane escapes from the La Brea Tar Pit in Los Angeles, California.

Over time the bottom of the sea floor is compressed and heated by additional layers of organic matter.  The organic material is heated and pressurized.  Temperatures and pressures increase over millions of years until the organic carbon molecules break down into much smaller particles that begin to rise out of the black shale.  These particles rise because they are lighter than water.  On some occasions these smaller organic molecules are trapped by a cap rock and an oil reservoir forms. Otherwise the oil makes its way to the surface of the earth and forms tar pits and/or releases methane gas into the atmosphere.  Thus from creation to storage, the story of petroleum is complete.

The nature of oil storage sheds light on the challenges and inefficiencies of oil extraction. Even though billions of barrels of oil have been extracted from reservoir rocks, billions of barrels remain. From decomposed sea creatures to broken down macromolecules in ancient rocks, the history of petroleum is old.

Works Referenced

Hyne, N., (2001). Nontechnical Guide to Petroleum Geology, Exploration, Drilling, and Production. Tulsa: Penn Well Corp.

http://laist.com/attachments/la_henry/labrea_tarbubble.jpg

Sorry to anyone who follows my RSS and does not know Cory.

Driving his Boat.

I have heard second hand that my good friend Cory Wincek has suffered from a common complication of paralysis and as a result, passed away earlier today.  He was a very good friend of mine throughout High School and into College, I am sad to hear that he is gone.  This post is for the people that knew Cory.  If there is enough interest, I will continue to update any new information as it becomes available to me.

The shirt is blue and white, the colors of the sky, with a blue line running down the middle of the shirt, and the words Penn State completing the cross across the chest. The back of the shirt says “dont be intimidated… it is just me and 110,000 of my friends” which refers to the many gatherings of Paterno’s die hard followers each year in Beaver Stadium. The white represents the percentage of cloudy days in Happy Valley, while the blue represents the percentage of sunny days in Happy Valley. The shirt has sold well to Paterno’s devout followers.  However, the shirt has sparked some controversy.

Some students and alumni think that the shirt excludes followers that do not attend the mass gatherings.

“Some of us cannot make the gatherings because of work or popularity of the event.  Others come with friends only to wait outside Beaver Stadium and worship his statue.  There are more than 110,000 friends of Joe Paterno.”

- Ira Nintou, class of 2004

Nintou is referring to the statement of ’110,000 friends’ on the rear of the shirt.  A friend of Paterno is slang for follower.  While 110,000 is the capacity of the stadium, many others adore the gatherings through television and radio.  Even others may be working and are forced to watch via tivo or rely on periodical coverage.

A select few still question the legitimacy of Paterno’s title, but his devout followers are quick to defend it. From the most bowl wins of any NCAA football coach, to a $34 million dollar library in his name, Paterno holds all the accomplishments of deity.  He has been glorified on Wheaties boxes and Italian Bread packaging.  The Football God will also add another Sports Illustrated article to his name in the near future.  Joe Telme also supports the father of football.

“It is only appropriate.  No other man could run the exact same offense for 45 years and be so successful.  It is a miracle and can only be the work of almighty Paterno.”

- Joe Telme, Sophomore, Journalism

Recently, Paterno was also honored with another shirt that states ”Joe Paterno is God”.  This shirt uses less symbolism, it gets straight to the point.  The almighty’s opinion on the new shirt is unknown.  Paterno was unavailable for comment on Saturday, his secretary reported he was overloaded with prayers regrading the Michigan Wolverines.

Already this semester, drinking is at an all time low. Never before has a school lost its Princeton Review #1 party school ranking so quickly. Students used to rely on Red Bull as their mixer, chaser and all around pregame drink. As Venessea Wighetton explains, the low supply of free Red Bull has ruined the party experience at Penn State.

I cannot drink vodka without it(Red Bull). Every time I do go out, everyone is so depressed and numb. No one has any energy. And it is so expensive that no one can afford it.
-Venessa Wighetton, Junior – Education

Partying is not the only victim of the lack of Red Bull. Without free drinks high in sugar and caffeine students are having trouble staying awake to study. Students are finding it more difficult to pull those important all nighters. Test grades have slumped and so has the amount of competed homework. At this rate, giant curves will be assigned even for art classes.

Some students like Russel Vick have gone to great lengths to get their fix.

I could not stay awake to study and my grades were slipping, so I got a job at Uni-Mart to help pay for Red Bull. It went well until I was fired when a bunch of kids raided the cooler for all the Red Bull… I had fallen asleep on the counter.

- Russel Vick, Sophomore – Kinesiology

With every sad story, there is often a glimmer of hope… this time it is coffee. Coffee sales have been on the rise however, many students have yet to switch over to coffee. When asked why they don’t supplement their diets with coffee instead of Red Bull, most claim the lack of professional athletes that ride for coffee.

Penn State officials have recognized the problem but have declined to give further comments. It is rumored that Penn State has even considered subsidizing the famous drink. Their plan of action is unknown, but the longer they wait, the more the students will suffer.

*This article is an exaggeration about the abandonment of the Red Bull Marketing Program in State College. Its place in time is the middle of the Fall semester 2009.*

This past weekend I traveled down to Ligonier/Latrobe, Pennsylvania to visit my friend Kyle Tennant. Along with @little_lauren and @brittanyjoy, we experienced the ‘Pond Jump’. Tennant had explained the ‘Pond Jump’ earlier in the summer. On a farm outside of Ligonier, a bike is ridden off of a jump at the end of a dock. After watching a short video from 2008, I was stoked to give it a try.

The man made pond is only about 10 feet deep and is located in the middle of the farm. The shallowness kept me from trying anything too gnarly, but I ended up feeling too comfortable by my 5th jump. We also sessioned Tennant’s back yard set up before jumping in the pond. Enjoy the photos of the ‘Pond Jump’ and Tennant’s backyard jibs. Gallery (click here).

He knew how to ride a bike.

Kyle Tennant giving the jump a try

A 360 on a bike! I always had wanted to try one.

My 3rd 360. After 2 successful attempts I decided to go bigger. Poor decision.

Great Shot!

Tennant gets artistic with the camera. (Nice bang huh?)

Set up for a blind 270 off... nice shot!

Hey Good Lookin'

Oh hey, nice paint job.

The rainbow rail and I got along well!