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Sunday, July 1, 2012

Importance of Choke Drill and Its Procedure

Choke drill is one of well control drills that will improve crew competency in driller's method. The advantages from the choke drill are as follows:

• Get more familiar to practice controlling the pressure via a choke on the rig

• Get more understanding about lag time

• Practice the procedure to obtain the shut-in drill pipe pressure

• Ensure the surface well control equipment as pressure gauges, choke, BOP is ready for work

• Get more practices when attempting to bring the pump up to kill speed, slow the pump down and change the pump rate

Choke Drill Steps are listed below:

1. Trip in hole above top of cement

2. Fill the pipe and circulate seawater or mud around for few minutes

3. Close annular preventer or upper rams preventer

4. Pressure up annulus to 200 psi (the pressure may be different depending on the company policy.)

5. Line up the pump

6. Pump slowly to bump the float and obtain shut in drill pipe pressure

7. Bring the pump to kill rate by holding casing pressure constant – personnel need to adjust the choke

8. Measure lag time for the drill pipe gage after the adjustment of choke is made.

9. Change circulation rate by holding casing pressure constant. Crew needs to adjust choke to achieve this.

10. Shut the pump down by holding casing pressure constant.

11. Bleed off pressure and line up for drilling operation

Emerging countries to uphold coal demand



Frost & Sullivan: Global demand for coal-fired power generation will be fuelled primarily by China and India


Over the next 25 years, the world will become significantly more dependent on electricity produced from various sources, including coal, to meet its energy needs. Global electricity generation is expected to grow from 21,224 Terawatt hours (TWh) in 2010 to 33,370 TWh in 2030.


Coal will continue to hold an increasing share in the energy mix of emerging countries since it is one of the most affordable sources of energy with abundant reserves across the world and particular concentration in the US, Russia, China, Australia and India.


New analysis from Frost & Sullivan (energy.frost.com), Global Prospects for Coal-Fired Power Generation, finds that China is expected to have unprecedented growth with about 945 GW and 1,040 GW of total coal-fired capacity in 2020 and 2030, respectively.


India, on the other hand, will have 201 GW and 267 GW of coal capacity in 2020 and 2030, respectively. Domestic power demand and capacity shortages will be the key market drivers for both countries.


"North America and the European Union will continue to be key markets for coal due to large units of capacity decommissioning, which means large MW capacity orders as replacements," noted Frost & Sullivan Analyst. "However, prospects for coal-fired power generation in Europe and North America are currently looking bleak due to the threat of tougher regulations, uncertainties over future carbon prices and the development of carbon capture and storage (CCS), rising engineering procurement and construction (EPC) costs, and low gas prices."


These factors deter investors from investing in new plants across North America and the EU. In Asia, the opposite trend can be observed, with massive investments continuing in new plants with substantial potential for major upgrades to existing plants, some of which are less than a decade old. The coal boom in Asia is projected to continue for the next decade.


"China, India, and the rest of Asia are the key focus areas for coal-fired investment in the coming decade," explained Frost & Sullivan Analyst. "Strong projected electricity demand growth and low production costs make the region attractive for both domestic and global participants."

 

Indonesia and Vietnam will emerge as major countries fuelling demand for coal-fired generation. Japan and Korea will offer limited prospects while Australia, which is rich in fossil fuel, will experience strong growth. Increasing domestic demand and need to replace ageing capacity will accelerate demand in Russia as well. However, reliance on gas and oil in the Middle East, on hydroelectric power in South America and poor infrastructure and political stability in Africa will limit the prospects for coal-fired power generation in these regions.


In Europe and North America, activity will predominantly be focused on investment in the existing base. New coal investment will be minimal until the investment climate becomes more certain.


"In general, financing issues for large coal-fired plants are likely to recede as electricity demand across emerging geographies recovers," added Frost & Sullivan Analyst. "Order levels for steam plants in Europe will pick up in a few years as capacity needs to be replaced in some countries that are affected by closures mandated by the Large Combustion Plants Directive. Order levels will increase again as the technical and commercial viability of CCS is proved."


Overall, development of environmentally friendly technologies, such as ultra-supercritical technology, CCS, and coal upgrades will contribute to the global demand for coal-fired generation.


Global Prospects for Coal-Fired Power Generation is part of the Energy & Power Growth Partnership Service programme, which also includes research in the following markets: European Power and Distribution Transformers Market, European Wind Energy Markets and Global Gas Genset Market. All research included in subscriptions provide detailed market opportunities and industry trends that have been evaluated following extensive interviews with market participants.


About Frost & Sullivan


Frost & Sullivan, the Growth Partnership Company, works in collaboration with clients to leverage visionary innovation that addresses the global challenges and related growth opportunities that will make or break today's market participants. 


Contact:

Deepshri Iyer | Executive - Corporate Communications | MENA| Frost & Sullivan

deepshrii@frost.com | P: +91-22-66072038 | C: +91-9987339129 | F: +91-22-28324713 | www.frost.com"We Accelerate Growth"   

Starting volume of original mud (weight up with Calcium Carbonate)

You know how much volume will be increased due to adding calcium carbonate into the system; however, you sometimes are limited to total volume due to limit pit volume on the rig so you need to calculate starting volume to achieve the predetermined final volume of desired mud weight.
This formula below is used to determine the staring volume of mud (for calcium carbonate system).

Starting volume in bbl  = VF x (22.5 – W2) ÷ (22.5 – W1)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

VF = final volume of mud needed in bbl

Example: Determine the barrel of starting volume of 10.0 ppg (W1) mud required to achieve final volume of 100 bbl (VF) of 13.0 ppg (W2) mud with calcium carbonate:

Starting volume in bbl = VF x (22.5 – W2) ÷ (22.5 – W1)

Starting volume in bbl = 100 x (22.5 – 13.0) ÷ (22.5 – 10.0)

Starting volume = 76 bbl

In order to achieve  final mud volume of 100 bbl of 13.0 ppg mud weight up with calcium carbonate, you must have 76.0 bbl starting volume of 10.0 ppg mud.


Please find the Excel sheet for calculating Barrel of starting volume of original mud weight required to give a predetermined final volume of desired mud weight with CALCIUM CARBONATE.

Volume of Mud Increases due to Adding Calcium Carbonate

The concept of mud volume increase due to adding calcium carbonate is as same as the mud volume increase by adding barite. The formula for calculating volume increment is just different only one factor which is 22.5 for calcium carbonate but 35 is used for barite case. Please follow the formula below for determining volume increase because of adding calcium carbonate.

Volume increase per 100 bbl of mud due to adding Calcium Carbonate = 100 x (W2 – W1) ÷ (22.5 – W2)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

Example: Determine the volume increase when increasing the density with calcium carbonate from 10.0 ppg (W1) to 13.0 ppg (W2):

Volume increase per 100 bbl of mud =100 x (13.0 – 10.0) ÷ (22.5 – 13.0)

Volume increase per 100 bbl of mud = 31.58 bbl

If you have total volume of 500 bbl of mud, the volume increase due to adding calcium carbonate will be equal to 157.9 bbl (31.58 x 500 ÷ 100).

Please find the Excel sheet for determine mud volume increase due to adding calcium carbonate.

Increase Mud Weight by Adding Calcium Carbonate

Carbonate is weighing agent mostly used in horizontal well because it does not plug up formation. We can use the same weight up concept with barite to calculate how to weight up with carbonate. Follow a topic below to learn how to weight up with calcium carbonate.

NOTE: The maximum practical mud weight attainable with calcium carbonate is 14.0 ppg.

 

This formula below is used for calculating how many sacks of calcium carbonate required per 100 bbl of drilling fluid (Mud weight increase with calcium carbonate (SG – 2.7))

Sacks of calcium carbonate per 100 bbl of mud = 945 x (W2 – W1) ÷ (22.5 – W2)

Where; W1 = current mud weight in ppg

W2 = new mud weight in ppg

Example: Determine the number of sacks of calcium carbonate per l00 bbl required to increase the density from 10.0 ppg (W1) to 13.0 ppg (W2):
Sacks of calcium carbonate per 100 bbl of mud = 945 x(13.0 – 10.0) ÷ (22.5 – 13.0)

Sacks of calcium carbonate per 100 bbl of mud = 298.4 sacks
If you have total volume of 500 bbl of mud, calcium carbonate required to increase mud weight from 10.0 ppg to 13.0 ppg is 1,492 sacks (298.4×500/100).

Please find the Excel sheet for calculating how many sacks of calcium carbonate required per 100 bbl of drilling fluid.

Thanks for visiting the site and your interest in oil and gas drilling

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