About Gefei Liu, PVI

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Feeling Good

Posted on June 24, 2014 by Gefei Liu, PVI

I smiled when I saw the following post the other day:

“There would be a few people who would smile at it.” I thought to myself.

We all live in an inter-connected world. We provide services to others and receive services from others as well. We feel happy or sad when triggered by outside stimulus. Meanwhile, we bring good and bad feelings to others through our interactions with them. Sometimes we are the pigeon and other times we are the statue.

Deep in our hearts, we want to create happy feelings for ourselves and others through products, services or attitudes. The interesting thing is that when we make others happy, we unintendedly make ourselves happy.

Two decades ago, when I was newly graduated from university, I came to Houston to work for Maurer Engineering, Inc. Being a newcomer in an engineering consulting firm, I was overwhelmed by the whole new world of drilling industry and software development. My initial struggles soon became enjoyment as I dived into the pool of computer programming. Dr. Maurer gave me enough encouragement and trust, which made me feel real confident. That was also my first time to see my work being used by drilling engineers in the field. “Not many things are cooler than this.” I thought at that moment and over time all the good feedback fueled my enthusiasm to pursue it further.

We will keep having joy as we develop more sophisticated models. Creating something from nothing can bring tremendous joy and this feeling is amplified when this “something” is appreciated by other people.

Buried Jewelry: Casing Centralizers

Posted on June 10, 2014 by Gefei Liu, PVI

People in ancient time had different burial customs that they believed were necessary to ensure their immortality after death. For example, the ancient Egyptians followed some rituals and protocols which included mummification, casting of magic spells and burial with specific grave goods thought to be needed in the Egyptian afterlife.

The ancient Chinese believed that the afterlife was a continuation of life on earth. Therefore, it was very important that all things they needed were buried with them in their tomb, including their jewelry.

Incidentally, in the oil well cementing business, people sometimes refer to the centralizers as “the cementing jewelry”, probably because they are installed on a casing string in a way similar to a bracelet on the wrist.

Centralizer On Casing

Casing centralizer is a mechanical device secured around the casing at various locations to keep the casing from making contact with the wall. As a result of casing centralization, a continuous annular clearance around the casing allows cement to completely seal around the casing to the borehole wall.

Because of the cementation of casing with centralizers underground, casing centralizers are literally buried jewelry.

Unlike those real jewelry buried in tombs, these centralizers provide a vital function in zonal isolation. Without centralizers, the casing touches the wellbore. In this case, cement slurry will have difficulty displacing mud in the narrow side of an eccentric annulus during a cementing job. This will lead to incomplete displacement of mud or mud channel as shown in the following picture.

Mud channel weakens the cement bond between the casing and the formation. The good news is that with a computer software like CentraDesign, it is easier than ever to choose the right centralizer type with certain properties and place them strategically along the casing for a particular well path.

Each well is different and centralizer types and properties vary. It is best to perform a standoff analysis for each casing before a cementing job. Note that the total number of centralizers required and their placement on the casing are equally important.

Attributes of Drilling Software

Posted on June 3, 2014 by Gefei Liu, PVI

Socrates once said: “The unexamined life is not worth living.” Socrates believed that the whole purpose of human life was about personal and spiritual growth. We are unable to grow toward greater understanding of our true nature unless we take the time to examine and reflect upon our life.

A company is like a living human being, who goes through various growing stages, from infant, childhood, adolescence to adulthood. Last week, 4 of our marketing people sat down and had a discussion on the core values that a drilling software company like us should have.

We agreed not to copy any of the phrases from the internet on company values. Many of these are well written, but they may not suit our particular needs. We want to look inward to see what we are cherishing and to identify the attributes that are missing in order to become a top provider of drilling software.

Each one of us listed 6 values and then we combined those 24 values until we narrowed it down to the final 6 core values for our company. Here is our thought process.

Core Values Thought Process

The selection process was simple and fun. As soon as we wrote down the final 6, we all agreed that these values should be the ones posted on our break room wall.

We did not use big words like “excellence”, because for instance, if our team members are honest, have great attitudes and take responsibilities, we will have excellent products and services. If we are passionate by default, we are diligent.

Our drilling software is “us” in digital formats. We put our knowledge into the software’s DNA. The more professional we become, the better product we produce. In other words, these 6 values are the attributes of our software in the eyes of our users.

As a team, we strive to be balanced between work and life. Our products are the results of the balance between technical brilliance and aesthetic designs.

Our graphic guru is designing the poster now. Once it is done and hung on the wall, I will post it on the blog. You will see it as soon as we see it.

Ancient Memorial and Software Report

Posted on May 27, 2014 by Gefei Liu, PVI

The oldest written Chinese characters are on bronze ware, stones and mostly on bamboo or wood slips. The bamboo or wood slips allowed the Chinese to preserve their history, keep records and exchange knowledge, but one can only imagine how hard it would be to read one of these books.

The legend says that Qin Shi Huang, the first emperor of China, was very diligent in managing official businesses. He set a rule for himself that he would not go to bed until he finished reading 31kg (68lb) of bamboo slips of memorials submitted by subordinates. You can tell the amount of reading at that time was measured by weight. Back then, reading was a physical exercise as well as a brain exercise. By the way, Qin Shi Huang’s reading speed was amazing. By calculation, the memorials he read every day exceeded 300,000 words.

Later, plain silk joined the bamboo and wood slips as a material for writing and painting. Silk has advantages over the slips in that it was much lighter and could be cut into desired shapes and folded, as well as easy to be kept and carried. Due to its cost, silk was never as popular as the slips so it was later replaced by another miraculous invention: “the paper”, which we have been using till now.

One of many disadvantages of bamboo or wood slips is its excessive use of natural resources. The problem might not have been so severe at that time because the population was small and not many people read. Now, the environmental impact of paper is more significant than ever as paper becomes a cheap commodity due to highly mechanized harvesting of wood.

The next movement is to create a paperless society, which would not use paper to print texts, but would display texts on a computer screen or mobile devices.

For our drilling software users, going paperless does not have to mean they’d lose something. Digital content in the form of MS Word or PDF is not just greener but provides an unmatched convenience. This picture shows an MS Word report generated by CEMPRO, our mud displacement model.

Report from CEMPRO

Converting to a paperless practice brings many advantages such as saving on printing documents, photocopies and storage space, as well as easy email management and improved customer service. Remember that companies like Salesforce always remind us of how important and essential it is to take care of your customer service!

Today, it is tough to make great software because you have to make it environment friendly as well as user friendly.

Mud Reporting: A Piece of Cake

Posted on May 20, 2014 by Gefei Liu, PVI

Daily tasks can become heavy burdens if we do not use proper tools. These burdens cause us more stress and cost more time. Time is money, but even money cannot buy us time. On the other hand, if we are equipped with the right tools, our productivity increases. We can be happier and capable of controlling what we do.

For mud engineers, daily life starts with the preparation of mud reports in the early morning. In the old days, mud engineers used paper forms to record mud properties, usages and costs. Nowadays, most mud engineers use Excel spreadsheets or computer software like MUDPRO (drilling mud reporting) to do the same jobs. Software has become our most essential weapon to fight the daily battle of mud reporting.

But, not all weapons are created equal. Excel, while serving the purpose of electronically filing mud data, has limitations on keeping track of costs and mud volumes, because the start of each day of drilling is the continuation of the last day of drilling: we need to calculate the accumulative cost and the current inventory of chemicals. Once the drilling is done, mud engineers are required to generate end-of-well reports. At this stage, Excel’s limitations become more obvious. As the number of wells being drilled increase, the difficulties of using Excel arise exponentially.

A better approach is to use a software like MUDPRO, with a back bone of database to record and more importantly, to manage the data. Yes, it is a new piece of software we need to get familiar with, but once you use it for a few days, it can become a habit and a routine; a good one you want to keep. No matter how many days the drilling phase may take, MUDPRO keeps all the history in its database. So, daily efforts of mud reporting are almost the same and at the end of the drilling process, you can just click a couple of buttons to generate the end-of-well recaps.

If we compare the efforts in the overall performance of using Excel and mud reporting software like MUDPRO VS drilling days, we can see the divergence between the two lines.

Reporting Efforts vs Drilling Days

Managing our time is managing our lives. Using the right software saves us time and enhances our lives. MUDPRO makes mud reporting a piece of cake, which you can enjoy with a cup of morning coffee.

5 Benefits of Drilling Software Training

Posted on May 13, 2014 by Gefei Liu, PVI

These days software, in general, becomes more and more user-friendly, even as it gets more and more sophisticated. We, as users, also have more confidence in using software without being bothered to read manuals or attend training sessions. Our busy schedules do not allow us to attend software training.

The situation is the same for drilling software users. As drilling engineers, whether we work in oil companies or in service companies, we always have next wells to drill, meetings to attend and deadlines to meet. We are so busy focusing on output that sometimes we forget about taking the time to receive input and recharge ourselves.

Unlike MS Office, drilling engineering software is not general-purpose software. It requires more specific knowledge to obtain results and understand the meanings of those results. Drilling software training should always be the first step to effectively use a software. Here are the reasons why software training is necessary:

1. Understand the engineering models

All drilling engineering software is based on certain mathematical and engineering models. Understanding these models behind the graphic user interfaces helps us acknowledge the limitations of the software as well as the capabilities.

2. Interpret data meaningfully

Drilling software needs input data such as survey, BHA, wellbore and mud properties to predict hook load, pump pressure and ECD, etc. Like other software, only meaningful input data can lead to meaningful output data. It is necessary for users to know what the required input data is and to explain the meanings of the output data and charts to their colleagues or clients.

3. Increase efficiency

Training helps potential users to see the big picture as well as the tricks and features of the software. Once users know more aspects of the drilling software, they can use the software more efficiently. For example, survey data is essential to describe the well path and calculate the torque, drag and hydraulics. Survey data can be in various formats, Excel, text or PDF. All of our software can import data from these formats. The survey import feature saves tremendous time, especially when importing survey data from a PDF file.

4. Gain confidence

Software training connects the users with the developers of the software. The 2-way communication helps the users understand the ideas and structures of the software. Once users understand the inside calculations, the software is no longer a black box to them. Training removes the mysterious veil of the software. Users become more confident on explaining the results to clients.

5. Guide and influence

The software development training also provides a platform for users to influence and even guide the software development. Users, involved in field operations, can give suggestions, which can enhance the functions. This leads to better versions and win-win situations for software vendors and users.

Ancient Chinese philosopher Confucius once said:

“I hear and I forget.

I see and I remember.

I do and I understand.”

How true this is to drilling software training.

Prevention is Better than Cure

Posted on May 6, 2014 by Gefei Liu, PVI

Many of us wouldn’t go to see a doctor until we get sick. This not only costs more money, but also causes more pain. Preventive medical assessments may be seemingly unnecessary and unpleasant, but it can help identify potential health problems, save lives, and reduce medical costs.

We often hear of some famous physical doctors or medical experts, who have remedied illness, when troubles surfaced. As a matter of fact, we are all doctors ourselves, in a sense that we take care of our daily lives, command our bodies to certain tasks, and avoid certain activities. We, as doctors ourselves, play a big role every day in maintaining our health. We are all CEOs of our own way of life and happiness. If we do our best to keep up good habits, take care of our bodies regularly, we will save ourselves lots of trouble and money in medical expenses.

Prevention can be beneficial to drilling engineering as well. Our experiences gained and lessons learned help us make right decisions for our next well. Drilling engineering software also serves as a great tool to identify any potential problems in our existing drilling plan or make sound engineering designs.

Take an example of cementing job design. One of the key elements of a successful cementing job is good displacement efficiency (less mud channeling). We have known that several parameters such as casing standoff, flow rate, differentials of fluid properties and hole deviation affect the effectiveness of fluid displacement. Now, with the help of computer modeling, we can see the impacts of these parameters. The following picture shows the mud concentration in the annulus at the end of the cementing job, where casing standoff is 0% throughout the wellbore (casting touches the borehole).

Displacement Efficiency for Casing Standoff 0%

You can see that there are quite large red areas in track 3, indicating poor displacement efficiency.

Now, we change the casing standoff to 70% and keep the other parameters the same. The following picture shows the much improved mud concentration after displacement:

Displacement Efficiency for Casing Standoff 70%

Time and money (not to mention headaches) could be saved if drilling engineers undergo through all the engineering assessments before problems arise. Be sure to use your know-how, skills, experiences, lessons and available drilling software. Having a complete understanding of what will happen gives you a greater sense of control, reduces risks and saves money.

Floating Egg

Posted on April 29, 2014 by Gefei Liu, PVI

I did a simple science project with my 8-year-old daughter to show the action of buoyancy.

Step 1: Put a raw egg in a glass full of water. The egg sinks to the bottom.

Step 2: Keep adding salt and stir the water. You will feel guilty of wasting too much salt, but eventually, the egg arises.

My daughter and I were both amazed by this simple demonstration of buoyancy of salt water. Recall that Archimedes’ principle states that the upward force on a submerged object (egg) is equal to the weight of the water that it displaces. Salt water weights more than fresh water, this difference of upward force (buoyancy) makes the egg arise.

In drilling mud situations, saltwater drilling fluids can be formulated with high-density brines, such as calcium chloride, calcium bromide, etc. The mud weight is dependent upon the specific gravity (SG) of salts added and concentration of these salts. The heavier the mud, the higher the bottom hole pressure is. Note that one of the main functions of drilling fluids is to provide hydrostatic pressure to prevent formation fluids from entering into the well. Heavy mud brings some advantages and some disadvantages to other aspects of drilling operations because of the buoyancy it creates.

Buoyancy makes drill string appear light. This reduces the side force, which pushes drill string against wellbore. Therefore, there is less torque and drag for a heavier drilling fluid system, but what helps also causes problems in this case: too much buoyancy revokes the effectiveness of transferring the pipe weight to the bit.

When cementing a casing, due to the large size of the casing and the big difference of fluid densities in the annulus and inside the pipe, the buoyancy could be so great that the casing could be pushed out of the hole if it is not chained down.

Let’s use Dr.DE (drilling engineering tool box software) to show a couple of examples.

Consider an 11.75” OD casing with weight of 47lb/ft. The casing shoe is at 12,345 ft in a vertical well. The annulus is full of cement slurry of 16ppg. We assume mud weight of 8.33 ppg. With the help of Dr.DE the calculation shows that the casing will be lifted up.

Casing Will Be Lifited Up

Now, change the mud weight to 9 ppg, due to this change, the hydraulic pressure inside the casing increases and the casing will not be lifted up by the buoyancy.

Casing will NOT be lifited up

Wooden Barrel Theory

Posted on April 22, 2014 by Gefei Liu, PVI

Have you ever seen those old-fashioned wooden barrels? I recently ordered one, Of course, my intention is not to study the theory indicated in the title, but use it as my foot SPA.

Because of the way wooden barrels are made, people have derived a theory: the capacity of a barrel is determined not by the longest wooden bars, but by the shortest, as you can see illustrated below.

The theory can apply to numerous situations. A chain is only as strong as its weakest link. The durability of a product depends on the part that fails first. In military situations, sometimes all it takes to win a battle is to find the weakest point of the enemy and attack it. The performance of a team is severely limited by the least capable member. A fleet will only move as fast as its slowest ship. In plant or crop growth situations, increasing the amount of plentiful nutrients did not increase a plant’s growth. Only by increasing the amount of the limiting nutrient was the growth of a plant improved.

For a software product, we need to ensure the robustness of major functions. Ironically, the overall quality of a piece of software does not depend on the maximum number of fancy features, but on the minimum number of bugs or errors.

Fancy features in a software package may be eye-catching, but bugs are the killers of its usability. As we expand a computer program by adding more features, the chances of having more bugs grow at the same rate, if not a greater rate. It is up to our software development team to look at the balance of features and bugs.

We may have the best idea or architecture of a software package; however, if our implementation process creates fatal shortcomings, the success of the product will not exceed the size of the fatal mistakes.

Same rules apply to the drilling software development, including the levels of developers and qualities of programs. Needless to say, we strive to have more comprehensive programs (with minimum bugs). We also heavily invest in the usability of software by eliminating as many bugs as possible. After all, if there is just one short wooden bar on the barrel, all the other bars that are longer than the short one are actually wasted, right?

Imagination, Prediction and Reality

Posted on April 15, 2014 by Gefei Liu, PVI

There is a joke about the human brain and it goes like this: our brain has two parts. One is the left brain and the other is in the right. The right one has nothing left and the left one has nothing right.

According to the theory of left-brain or right-brain dominance, a person who is “left-brained” is often said to be more logical, analytical, and objective, while a person who is” right-brained” is said to be more intuitive, thoughtful, and subjective.

Artists may use the right side of their brains more to maximize creativity, but if they exhaust their imagination, their art works lose their appeal.

Sometimes, we, as viewers, participate in the creative process when we enjoy a good piece of art. This can be demonstrated in our appreciation of the statue of Venus de Milo. The statue is widely renowned for the mystery of her missing arms. The missing arms do not stop people from appreciating this marvelous work of ancient Greek. People are fascinated by the missing parts and are creating their own interpretations of the possible positions of the missing arms. By imagination, everyone creates a Venus statue in their mind. Maybe that is the everlasting beauty of Venus: the incompleteness of an original work of art.

However, in the world of engineering, we strive to remove any uncertainties as much as possible. Drilling software is a tool for drilling engineers to help them predict what will happen on the rig floor and downhole.

The following graph shows the hook load prediction using TADPRO (torque and drag model).

Hook Load Prediction Using TADPRO (torque and drag model).

Charts like these give drilling engineers guidelines as to what to expect during drilling operations. This way, we can see the upcoming reality with little imagination.

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