Working in the oilfield, you need a scientific calculator to help you solve problems with complex formulas. As you learn from this website, drillingformulas.com, you really need a scientific calculator to help you.

There are different brand companies that design scientific calculators. However, the difference in brand names might not alter the similarity in functions and programming. When you are choosing a small scientific calculator, there are a number of factors that you should consider. These factors include; functionality and efficiency, portability and durability.

Functionality and Efficiency

The main reason why we buy a calculator is for faster computations. You should choose a calculator whose programming allows you to compute all the problems in your relevant discipline. Most of the calculators can help you in calculating normal mathematic problems, logarithms, fractions, statistics, probability, etc. If the calculator that you choose can handle the mathematics problems in your discipline, then it is a good calculator.

If you are in work sites as drilling rigs, you might not need a calculator with many technical buttons. You might just need a simple scientific calculator that will handle basic mathematic problems. There is no need of buying a very expensive calculator while you will not be using most of the functions indicated on the calculator. Instead, you can save on the purchase cost by buying a simple scientific calculator with the sine, cosine and tangent buttons among other important functions and you will still enjoy the functions of a scientific calculator.

This is the calculator (Casio Advanced Scientific Calculator with 2-Line Natural Textbook Display (FX-115ES)) that I used on the rig.

This calculator costs you less than 20 dollars but it will work all the hard work for you.

If you are working in the discipline that will use advanced mathematics, you really need to look into the advanced one. There is a specific scientific calculator that is programmed and designed for all math problems. The mathematics calculator is ideal for college students and engineers. It gives accurate answers with simpler decimals which enable to give more comprehensive answers. Some engineering calculators also show graphical representations. These are complex calculators that some people might not need for basic mathematics. These types of calculators are good for directional drillers, engineers (drilling, production, reservoir), geologists, etc.

The programming of the calculator determines the functions that the calculator can handle.

Texas Instruments TI-83 Plus Programmable Graphing Calculator is one of the most famous advanced scientific calculators.

Portability

Personnel especially ones working on the rig need simple scientific calculators that they can carry around easily. It is therefore important to choose a calculator that can fit in your bag or pocket. It makes it easier to hold when using and also easier to use since it has small and soft buttons. However, if you work in the office working of the complex engineering project, the advanced calculator may be suit for you.

Durability

Durability is very crucial when choosing your calculator. You need to look for a calculator that comes with a dust cover, water resistant screen and joints and buttons that are not easily unmarked after continuous use. You should choose a calculator with a clear screen too. You can ask from the store if you can use the calculator in the sun. Some screens show blurred figures when they are used outdoors.

Price should never be a determinant of the quality of calculator you want to buy. If you are guided by price you will either get a counterfeit calculator or one whose keys will fade within a couple of months making it very hard for you to use some functions on the calculator.

Find the scientific calculators at cheap price from Amazon.com.

Scientific calculators

Advanced graphing scientific calculators

I’ve got this email from my friend. The bad incident was happened in Hemphill County TX (LeNorman Ruth 87-2H Fracking Accident). I would like to share in order to raise awareness of safety in the field.

This is the detail from email that I got.

Never think your ‘Safe’ because you’ve got a good safety record; or even an excellent safety team. We sometimes tend to forget ‘what we do’ is inherently dangerous. Always think ‘at some level’ about witch way to RUN when everything goes wrong.

This was on a location where 2 wells were being worked at same time. One well a zone was being fractured, while the other well was being perforated. Hemphill county in Texas, there are two contractors involving in the operation.

They were pumping at 8,500 psig when the 7″ production casing parted, the surface casing parted above that and the Frac Head, BOP’s and all that came which landed square in the middle of the Cased Hole Truck.

Please work safe

Drill pipe elongation will occur because the higher bottom hole temperature.

Rule of Thumb

Pipe will elongate approximately 0.83 inc per 100 ft of length, per 100 degree F increase in Temperature.

We need to know the surface temperature and bottom hole temperature in order to determine pipe elongation.

The following formulas are used to determine pipe elongation.

Average Temperature = (Bottom Hole Temperature + Surface Temperature) ÷ 2

∆ Temperature = Average Temperature – Surface Temperature

Pipe Elongation = (L ÷ 100) × (∆ Temperature ÷ 100) × 0.83

Where

Average Temperature, Bottom Hole Temperature and Surface Temperature are in F.

Pipe Elongation is in inch.

L is total length in feet.

Example

Determine pipe elongation from the following information.

Total length of pipe is 10,000 ft.

Surface temperature is 80 F.

Bottom hole temperature is 375 F.

Average Temperature = (80 + 375) ÷ 2 = 227.5 F

∆ Temperature = 227.5 – 80 = 147.5 F

Pipe Elongation = (10,000 ÷ 100) × (147.5 ÷ 100) × 0.83 = 122.43 inch

I would like to share these 3 VDO’s demonstrating how Pipe Rams, Variable Bore Rams and Shear Rams work.

This eliminate confusion when the new people in the oilfield read and try to understand about these rams.

Pipe Rams – You will see that the pipe rams will work only on size of the drill string. 

Shear Rams – Both rams will be pushed against each other resulting cutting the string of the pipe.

Variable Bore Rams (VBR) - Most of the rigs prefer to use the VBR instead of the fixed pipe rams because its flexibility to work with various pipe size in the wellbore.

You can read more details about the rams preventer via this article -> Ram Preventers as Well Control Equipment

We wish you would enjoy learning this topic.

Well control quiz ebooks here ->  http://amzn.to/WjtEvd

Reference book: Well Control Books

IADC Drilling Manual ebook version is one of the best drilling manuals.

More than 1400 pages in this ebook provide you various topics in drilling.

There are a total of 22 chapter sorted in alphabetical order from A-Z. These are the content that you can find from the IADC drilling manual.

Chapter A – Bit Classification and Grading

Chapter B – Drill String

Chapter C – Casing and Tubing

Chapter D – Drill Collars, Kellys, Subs and Heavy Weight Drill Pipe

Chapter E – Pipe Handling Equipment

Chapter F – Drawworks Brakes

Chapter G – Chains and Sprockets

Chapter H – Rotary Hose and Swivels

Chapter I – Engines

Chapter J – Pumps

Chapter K – Well Control Equipment and Procedures

Chapter L – Derricks and Masts

Chapter M – Wire Rope

Chapter N – Lubrication

Chapter O – Drilling Fluids

Chapter P – Hole Deviation and Horizontal Drilling

Chapter R – Hydraulics

Chapter T – Cementing

Chapter U – Electric Drilling Rigs

Chapter V – General Information

Chapter Y – Drilling Mud Processing

Chapter Z – Glossary

Download this ebook here -> http://bit.ly/15NpLs5

You will see the download screen like this

We would like to present some drilling knowledge in the new form. Therefore, this time we’ve created the cartoon in the topic of Types of Drilling Rigs (Both Offshore and Onshore).

Please feel free to give us any recommendation.

Ref; http://www.wikipedia.org/

https://www.google.com

www.seadrill.com

Kick tolerance is the maximum gas volume for a given degree of underbalance which the circulation can be performed without exceeding the weakest formation in the wellbore. This article is the extended version of Kick Tolerance Calculation  which will explain more on this topic. It is very critical that drilling personnel understand its importance to well design and drilling operation.

There are two important factors used for determining the kick tolerance

• Kick Intensity – It is the different between the maximum anticipated formation pressure and planned mud weight. For example, the planned mud weight is 13.0 ppg and the possible kick pressure is 13.5 ppg. Therefore, the kick intensity is 0.5 ppg (13.5 – 13.0).

A zero kick intensity (swabbed kick scenario) should be used for a know area where you have less uncertainty about an overpressure zone.

 • Kick Volume – It is a gas influx entering into the wellbore from the formation. Gas kick is always used for well control calculation because it is the worst case scenario. The kick volume should be realistic figure which personal can detect the influx on the rig. In a larger hole, it allows bigger influx volume than a small hole.

Maximum Allowable Annular Surface Pressure (MAASP) and Kick Tolerance

Weakest formation point in the open hole is assumed to be at the shoe depth of the previous casing. The well bore will be fractured if a summation of hydrostatic and surface pressure exceeds the weakest pressure (Leak Off Test pressure). The maximum surface pressure before breaking the formation is called “Maximum Allowable Shut In Casing Pressure” (MASICP).

Make it simpler for your understanding. MASICP is the total of kick tolerance budget. It consists of pressure from kick intensity and hydrostatic pressure loss due to gas.

Kick Tolerance Example Calculation

Previous casing shoe (9-5/8” casing) at 6,000’ MD/ 6,000’ TVD

Predicted formation pressure at TD (10,000’MD/10,000’TVD) = 14.0 ppg

Pore pressure uncertainty = 1.0 ppg

Planned mud weight = 14.5 ppg (0.754 psi/ft)

Gas gradient = 0.1 psi/ft

LOT = 16.0 ppg

Hole size = 8-1/2”

Drill Pipe = 5”

BHA + Drill Collar = 7”

Length of BHA+Drill Collar = 400 ft

Annular capacity between open hole and BHA = 0.0226 bbl/ft

Annular capacity between open hole and 5” DP = 0.0459 bbl/ft

Calculation Steps

Maximum anticipated pressure = 14.0 + 1 = 15.0 ppg

Maximum Allowable Shut In Casing Pressure (MASICP) = (LOT – MW) x 0.052 x Shoe TVD

Maximum Allowable Shut In Casing Pressure (MASICP) = (16 – 14.5) x 0.052 x 6,000 = 468 psi

Kick Intensity = 15.0 – 14.5 = 0.5 ppg

Underbalance due to kick intensity = 0.5 x 0.052 x 10,000 = 260 psi

As you can see, when the well is in underbalance condition (260 psi), the shoe will not be broken because the MASICP is more than underbalance pressure (468 > 260).

We know that 0.5 ppg kick intensity we will have 208 psi (468 – 260 = 208 psi) before shoe broken.

It means that gas bubble can replace mud in equivalent to 208 psi before fracturing the shoe. With this relationship, we can determine height of gas kick by the following equation.

Height of gas kick = remaining pressure, psi ÷ (mud gradient, psi/ft – gas gradient, psi/ft)

Height of gas kick = 208 ÷ (0.754 – 0.1) = 318 ft.

Determine gas kick volume base on height of gas kick

We need to separate into two cases and compare the smallest volume.

1st case – Gas at the bottom

Volume of gas kick = Annular capacity between open hole and BHA x Height of gas kick

Volume of gas kick (bbl) = 0.0226 bbl/ft x 318 ft = 7.2 bbl

2nd case – Gas right below casing shoe

For this case, we need to convert gas at the shoe to the bottom condition by applying Boyle’s Laws.

Volume of gas kick = Annular capacity between open hole and 5” DP x Height of gas kick

Volume of gas kick (bbl) = 0.0459 bbl/ft x 318 ft = 14.6 bbl

Convert to the bottom hole condition

Volume at the bottom = (volume of gas kick at shoe x Leak off test) ÷ formation pressure

Leak off test = 0.052 x 16 x 6,000 = 4,992 psi

Formation pressure (gas kick condition) = 0.052 x 15 x 10,000 = 7,800 psi

Volume at the bottom = (14.6 x 4992) ÷ 7800 = 9.3 bbl

We can compare the kick volume from two cases like this.

1 st case : kick volume = 3.9 bbl

2nd case : kick volume = 7.2 bbl

The smallest number must be selected to represent maximum kick volume therefore kick volume is 7.2 bbl.

We wish this article could help you get more understanding about Kick Tolerance.

Ref book:  Formulas and Calculations for Drilling, Production and Workover, Second Edition

These are some footage showing some oil drilling rigs were blown out and got fired. I would like to share these VDO clips to raise awareness of well control.

Oil Rig Blowout

Chesapeake Energy Nomac Rig 17 Blowout Fire

Workover Rig Blows Out Tubing

BWD Rig 136 Blowout , Rawdatain, north Kuwait

Actinia Oil Rig Blowout – shallow gas blowout

Camera captured the shallow blowout to the rig floor

Drilling rig Accident: Blowout, Rig Burns down (Ensign #59)

BBC Stephen Fry And The Great American Oil Spill

If you are interested in well control articles, please check out our link -> http://www.drillingformulas.com/category/well-control/

A drill pipe float valve is a check valve installed in the drill stem that allows mud to be pumped down but prevents flow back up. There are two types of float valves which are flapper type and plunger type.

The following VDO will demonstrate you the mechanism of each type of drilling float valve.

Drill collar provides weight to the bit for drilling and keep the drill string from buckling. Additionally, drill pipe should not run in compression because it can get seriously damaged therefore we need to know weight of drill collar that is enough to provide weight to the bit.

Drill pipe buckle due to insufficient of drill collar

Drill pipe straight because of sufficient drill collar weight

Drill collar weight in a vertical well

The following formula is used to determine required drill collar weight to obtain a desired weight on bit for a vertical well.

W_DC = (WOB x SF) ÷ BF

Where

W_DC is drill collar weight in air, lb.

WOB is a required weight on bit, lb.

SF is a safety factor.

BF is mud buoyancy factor.

Drill collar weight in a deviated well

In a deviated well, the drill collar weight will not directly transfer to the bit because of well inclination which has direct affect on weight on bit.

The following formula is used to determine required drill collar weight to obtain a desired weight on bit for a deviated well.

W_DC = (WOB x SF) ÷ (BF x COS (θ))

Where

W_DC is drill collar weight in air, lb.

WOB is a required weight on bit, lb.

SF is a safety factor.

BF is mud buoyancy factor.

θ  is inclination of the well.

Example: The deviated well has inclination of 30 degree in tangent section and planned mud weight is 12.0 ppg. Safety factor for this case is 25%.

What is the drill collar weight to obtain the desired WOB of 50 Klb?

Buoyancy Factor = (65.5 – 12.0) ÷ 65.5 = 0.817

SF @ 25 % = 1.25

W_DC = (50,000 x 1.25) ÷ (0.817 x COS (30))

W_DC = 88,333 Klb

In this case, drill collar weight in the air should be 88.3 Klb. In reality, the BHA does not only have the drill collar so you need to adapt this figure. For instant, the BHA consists of mud motor, stabilizer, LWD and HWDP which have a total weight of 30 Klb. Therefore, the actual drill collar weight is just only 58.3 Klb (88.3 – 30).

 Ref Book: Formulas and Calculations for Drilling, Production and Workover, Second Edition

Margin of overpull is additional tension to be applied when pulling the stuck drill string without breaking the tensile limit of the drill string. This is the difference between maximum allowable tensile load of drill string and hook load.

The formula for margin of overpull is described below;

Margin of Overpull = Ta – Th

Where;

Ta is the maximum allowable tensile strength, lb.

Th is the hook load (excluding top drive weight), lb.

The ratio between Ta and Th is safety factor (SF).

SF =Ta ÷ Th

Example: The drill string consists of the following equipment:

5” DP S-135, 4-1/2” IF connection, adjusted weight of 23.5 ppf = 8,000 ft

5” HWDP S-135, 4-1/2” IF connection, adjusted weight of 58 ppf = 900 ft

Mud motor and MWD, weight 20 Klb, = 100 ft

Expected hook load at TD = 270 Klb

Tensile strength of 5” DP S-135 (premium class) = 436 Klb

Tensile strength of 5” HWDP S-135 (premium class) = 1,100 Klb

90% of tensile strength is allowed to pull without permission from town.

Determine the margin of overpull from the information above.

Maximum tension will happen at the surface so 5”DP will get the most tension when pulling and since only 90% of tensile strength is allowed. The allowable tensile (Ta) is as follows;

Ta = 0.9 x 436 = 392 Klb

Th = 270 Klb at TD

Margin of over pull = 392 – 270 = 122 Klb

Safety Factor = 392 ÷ 270 = 1.45

 Ref Book: Formulas and Calculations for Drilling, Production and Workover, Second Edition

Sometimes drillpipe is accidentally dropped into the well and you need to fish it out of the well. One easy option that may be feasible to perform is to use a drill string to screw into the drill pipe in the well.

Before going into a detailed procedure, you may need to check the following conditions.

• Tight clearance between hole and tool joint

• Tool joint at the top of fish is in a good condition

Data that you need to know before going to fish the drill string

• Fish length

• Top of fish

• Weight of fish in the mud

• Actual turn to fully engage when screw in

Detailed procedure for fishing drill pipe by screwing into the fish

Fish length = xxx ft

Expected TOF = xxx ft

Weight of the fish (BHA + DP) = xx Klb

1. Trip in hole 1 stand

2. Count the actual turn of drill pipe

3. Run in hole to xxx MD (200 ft above the Top Of Fish)

4. Make up top drive

5. Break circulate with 160 GPM using current drilling fluid in the well

• Record pressure

6. Record pick up and slack off weight without rotation

7. Record pick up and slack off weight with 20 RPM

8. Record torque with 20 RPM

- In the steps 5-8, you will get the base line values when the drill string does not engage with another part.

9. Slowly run in hole without rotation

10. Tag top of fish while pumping with 160 GPM

11. Pick up 5 ft

12. Slowly run in hole with 20 RPM

13. Attempt to screw into the top of fish (tool joint)

14. Indicators if the fish is engaged.

- Increase in pumping pressure, torque, weight on bit and pick up weight.

- When picking up drill string, increment of pick up weight should close to buoyed weight of the fish (dropped drill string).

15. Flow check

16. Pull out of hole to surface.

 Note: This is the generic guideline. You may need to adapt some parameters/steps to match with your rig operation.

Mechanical blind back off is the procedure to intentionally break out stuck drill string by applying left hand torque and transmitting down hole. This is the last method to recover drill string because back-off position cannot exactly determine. One situation that I used to do the blind back of is when the perforating gun cannot be run into tubing string.

Procedure to Perform Blind Back Off Operation

1. Determine drilling parameters prior to get stuck if possible.

Pick up weight __ lb

Slack off weight __ lb

Rotating weight __ lb

2. Pick up drill string at 10% over the rotating weight. Apply 50% of make-up torque with left hand turn and lock TDS. Record how many turns. Slowly work string down for 5-10 minutes to transmit surface torque to the bottom. Weight while working should be between pick-up and slack off weight.

3. Repeat step#2 with 70%, 90%, 100%, 110% make up torque

4. The string should be back off while working down.

Note: The concept is to have overpull tension applied at each connection while left hand torque is transmitted into the drillstring. Once the drill string is worked, the torque will be transferred to the bottom connection of the well.

We would like to have a free download promotion for our Kindle well control book “Kick Detection (Warning Sign) and Shut In” which is the interactive quiz book running on kindle.

This promotion will be only 5 days from 15-Jul-13 to 19-Jul-13.  This promotion will be end at 11:59 PM Pacific Standard Time on 19-Jul-13.

Please click this link to see the download page

http://amzn.to/OSQTxO

Once you open the page in Amazon, you will see the screen like this. You will see that the price is “$ 0.00” for this promotion period.

Click at the “Buy now with 1-Click” button“ to download the book.

This Kindle book “Well Control Quiz Book: Basic Pressure In Well Control” will be automatically transferred to your kindle device / account. You don’t need to have the kindle device. You can have the tablet like as Kindle tablets, Ipad, Sumsung Galaxy Tab, etc. This is the kindle book that I download into my Ipad.

If you don’t have the kindle device, you still can download the kindle program. Read this article “How To Read the Kindle Books on Your Personal Computer” for more information.

Please leave us a good feedback if you like our book.

Riser margin in the mud weight increase below mud line to compensate bottom hole pressure in case of an accident disconnect or a failure marine riser close to the BOP stack at sea bed.

The riser margin is described by a following equation:

Where;

ρ_rm is riser margin, ppg

ρ_df is drilling fluid density equivalent to formation pressure, ppg

ρ_sw is sea water density, ppg

L is riser length from sub sea BOP to rig floor, ft

D is true vertical depth of the well, ft

DW is water depth, ft

Note: When you consider adding the riser margin, you need to make sure that formation strength is sufficient. Additionally, you must not add trip margin and riser margin to the system because it is way over safety factor. If trip margin is higher than the riser margin, you must use the trip margin.

Example: Determine riser margin for this case.

Drilling fluid weight equivalent to formation pressure = 9.2 ppg.

Sea water weight = 8.6 ppg

Length of riser to the rig = 8000 ft

Well TVD = 13,000 ft

Water depth = 8,000 ft

ρ_rm = 1.2 ppg

Riser margin for this case is 1.2 ppg.

Reference book: Well Control Books

This is very bad news “ Hercules Jackup Rig 265 Blows Out In Gulf Of Mexico and 44 People Evaculated”. The details that I gather from several sources on the internet. This is the reason why well control is very important to us.

July 23rd, 2013

Forty-four workers were evacuated from a natural gas platform in the Gulf of Mexico on Tuesday after a blowout occurred, according to officials.
Crew members aboard the Hercules 265 were preparing the well for production when they hit an unexpected pocket of gas.
No injuries were reported.

Officials had said earlier that 44 workers were evacuated.

While gas is flowing from the well, “no oil is being released,” according to the Bureau of Safety and Environmental Enforcement.
The platform, about 60 miles southwest of Grand Isle, Louisiana, is leased by Houston-based Walter Oil & Gas Corporation. The company did not respond to CNN’s requests for comment Tuesday.

A light sheen about a half-mile wide was spotted by environmental inspectors, but was “dissipating almost immediately,” the safety bureau said.
Source: CNN http://www.cnn.com/2013/07/23/us/gulf-rig-evacuation/index.html?hpt=us_c2

UPDATE: July 24th, 2013

Hercules 265 is now on fire.

The fire started about 10:50 p.m. local time yesterday.

Experts from Wild Well Control Inc. were to assess the well site overnight and develop a plan to shut down the flow of gas, said Jim Noe, executive vice president of Hercules Offshore Inc., owner of the drilling rig where the blowout occurred.

Noe stressed that gas, not oil, was flowing from the well. He said it is an important distinction because gas wells in relatively shallow areas — this one was in 154 feet (47 meters) of water — sometimes tend to clog with sand, effectively snuffing themselves out. “That is a distinct possibility at this point,” he said. “But until we have our Wild Well Control personnel on the rig, we won’t know much more.”

Tuesday’s blowout occurred near an unmanned offshore gas platform that was not currently producing natural gas, said Eileen Angelico, spokeswoman for the bureau. The workers were aboard a portable drilling rig known as a jackup rig, owned by Hercules, which was a contractor for exploration and production company Walter Oil & Gas Corp.

Walter Oil & Gas reported to the BSEE that the rig was completing a “sidetrack well” — a means of re-entering the original well bore, Angelico said.

The purpose of the sidetrack well in this instance was not immediately clear. A spokesman for the corporation didn’t have the information Tuesday night. Industry websites say sidetrack wells are sometimes drilled to remedy a problem with the existing well bore.

“It’s a way to overcome an engineering problem with the original well,” Ken Medlock, an energy expert at Rice University’s Baker Institute said. “They’re not drilled all the time, but it’s not new.”

Walter Oil & Gas Corp., the owner of the well, initially said it appeared that some of the shear rams on the rig’s blowout preventer failed to close and seal off the well. The company later said it is still investigating the incident and wouldn’t know the cause of the blowout, or why the well continues to flow, for some time.

“The crew was concerned for their safety, so once gas was detected and they felt like they did all they could do to shut in the well, they evacuated,” Mr. Noe said.

The form below is for calculating hydrostatic pressure in metric unit.

Basic information for hydrostatic pressure

Hydrostatic pressure calculation

Any comments are welcome.

I’ve collected several sources of Hercules 265 Blows Out. You can read the update here.

CIMB: Fire subsides after gulf rig partially collapses

A Gulf of Mexico drilling rig partially collapsed off the coast of Louisiana after catching fire because of a ruptured natural gas well, U.S. regulators said on Wednesday.

The blaze broke out after a blowout on the Hercules 265 natural gas platform at around 10:45 p.m. local time Monday.

Eileen Angelico, a spokeswoman for the Bureau of Safety and Environmental Enforcement, said no one was on board when the fire started and it was not known what sparked it. She said an investigation into the cause of incident was “well under way.”

http://usnews.nbcnews.com/_news/2013/07/24/19652537-fire-subsides-after-gulf-rig-partially-collapses?lite

Yahoo NEWS: Gulf rig partially collapses in fire off Louisiana: U.S. government.

HOUSTON (Reuters) – A shallow-water Gulf of Mexico drilling rig has partially collapsed off the coast of Louisiana after catching fire because of a ruptured natural gas well, U.S. regulators said on Wednesday.

The U.S. Bureau of Safety and Environmental Enforcement said beams supporting the derrick and rig floor on the Hercules Offshore jackup rig had crumpled over the rig structure.

A third firefighting vessel was en route to the scene, though no sheen was seen on the water’s surface during overflights conducted on Wednesday morning, the regulator said.

More details => http://news.yahoo.com/gulf-rig-fire-natural-gas-flows-ruptured-well-145808123.html

Rig Zone: Natural Gas Well Bridged; Hercules Rig Fire Continues

 The flow of natural gas has been contained at a natural gas well located in 154 feet of water 55 miles offshore of Louisiana at South Timbalier, Block 220, the Bureau of Safety and Environmental Enforcement (BSEE) said in a statement to the press July 25

More details here => http://www.rigzone.com/news/oil_gas/a/127991/Natural_Gas_Well_Bridged_Hercules_Rig_Fire_Continues

Rig Zone: Fire Out on Hercules Rig and Natural Gas Well, Gas Flow Halted

The natural gas well blowout and fire earlier in the week that spread to a jackup, causing part it to collapse, has gone out. The well owner and governmental organizations have set up a Unified Command to secure the well, the Bureau of Safety and Environmental Enforcement (BSEE) said in a release Friday.

Firefighting vessels remain on the scene, working with the well owner, the rig owner, the U.S. Coast Guard, Wild Well Control, and other relevant parties, BSEE said.

More details here => http://www.rigzone.com/news/oil_gas/a/128040/Fire_Out_on_Hercules_Rig_and_Natural_Gas_Well_Gas_Flow_Halted

When a tensile load is applied into a drillstring, it results in elongation of the drillstring.

The formula to determine pipe elongation is listed below;

Oilfield unit

e = (L x T) ÷ (735,000 x W)

Where;

e = elongation, inch

L = length of drill string, ft

T = tensile load, lb

W = drill string weight, lb/ft

Metric (SI) unit

e = (L x T) ÷ (26.7 x W)

Where;

e = elongation, mm

L = length of drill string, metres

T = tensile load, kN

W = drill string weight, kg/m

Note: The equations are taken from API RP 7G 16^th Edition, August 1998.

Determine the pipe elongation from the following data (this example will use “oilfield unit” for calculation.

5” DP, S-135, 4-1/2” IF Connection. The pipe specification is listed below.

W = 23.52 ppf

Length = 8,500 ft

Pick up weight = 300 Klb

Block weight without drill string = 70 Klb

Tensile load applied into the drill string is equal to pick up weight minus block weight.

T = 300 – 70 = 230 Klb

e = (8,500 x 230,00) ÷ (735,000 x 23.52)

e = 113.1  inch

Ref books: Drilling engineering books