Monthly Archives: October 2013
Pilot Hole Directional Drilling
Pilot hole directional control is achieved by using a non-rotating drill string with an asymmetrical leading edge. The asymmetry of the leading edge creates a steering bias while the non-rotating aspect of the drill string allows the steering bias to be held in a specific position while drilling. If a change in direction is required, the drill string is rolled so that the direction of bias is the same as the desired change in direction. The direction of bias is referred to as the tool face. Straight progress may be achieved by drilling with a series of offsetting tool face positions. The drill string may also be continually rotated where directional control is not required. Leading edge asymmetry can be accomplished by several methods. Typically, the leading edge will have an angular offset created by a bent sub or bent motor housing. This is illustrated schematically in following Figure.
It is common in soft soils to achieve drilling progress by hydraulic cutting with a jet nozzle. In this case, the direction of flow from the nozzle can be offset from the central axis of the drill string thereby creating a steering bias. This may be accomplished by blocking selected nozzles on a standard roller cone bit or by custom fabricating a jet deflection bit. If hard spots are encountered, the drill string may be rotated to drill without directional control until the hard spot has been penetrated.
China scrambles to boost oil output
The mainland’s biggest state-owned oil companies, sitting on ageing fields, are scrambling to ramp up crude oil and natural gas production to meet surging domestic demand through a slew of investments that also risk pushing up their costs.
PetroChina, Sinopec and CNOOC produced more oil and gas in the first nine months of this year, they said in the past week.
That was partly in response to the government’s recent rise in domestic natural gas prices and moves to link pump prices more closely with international crude costs.
The increase, however, is far from enough to bridge the gulf between the energy consumption and production of China, which last month overtook the United States to become the world’s largest oil importer.
As domestic oilfields age, the three companies have in recent years poured billions of dollars – the biggest amount in the world so far – into the acquisition of unconventional and traditional hydrocarbon assets overseas, to boost reserves.
They have also invested heavily in risky projects such as deepwater drilling at home and abroad.
These investments, which mirror a trend in the global oil industry, will increase costs but, so far, not at the expense of profits.
PetroChina and Sinopec both reported on Tuesday net profit growth of about 20 per cent in the third quarter.
“There is a lot of incentive for China to produce as much oil as it can domestically,” said Simon Powell, the head of Asia oil and gas research at brokerage CLSA, citing the country’s soaring oil imports.
The mainland’s oil consumption last year rose 5 per cent to 10.2 million barrels a day from 2011, according to BP’s Statistical Review of World Energy, a figure that was the highest since the energy major started compiling data in 1965.
By contrast, oil production increased 2 per cent to 4.2 million barrels a day, the review shows.
China, the world’s second-largest oil user, already relies on imports for 60 per cent of its consumption and is set to double its fuel use by 2030.
PetroChina, the country’s dominant oil and gas producer, saw its output rise 4.3 per cent year on year in the first three quarters.
Crude oil production edged up 2.2 per cent to 698 million barrels, while natural gas output jumped 9 per cent, the company said on Tuesday.
But higher costs and lower realised crude prices in the period meant operating profits for its exploration and production division fell 10 per cent, it said.
Analysts said the rise in costs was partly due to PetroChina’s efforts to stem output decline at its ageing oilfields, including Daqing, the country’s largest.
PetroChina is now expected to allocate more resources to exploration and production, while cutting spending on refining, petrochemicals and businesses with lower profitability.
Sinopec posted a 4 per cent rise in oil and gas output in the January-September period.
Shale Shaker Manufacturer in China
A drilling fluid shale shaker is a vibrator used for solid/liquid separation. It is an important device in solids control system because efficient operation of other surface solids separation equipment is critically dependent on proper functioning of the shaker.
The purpose of using a shaker is to recover drilling fluid and remove large solids as most as possible. A well designed shale shaker will not only maximize use of the screen cloth to separate solids from liquid, but will also convey these solids off the screen quickly, minimizing fluid loss with the solids and clearing the screen for more feed.
The shale shaker, in various forms, has played prominent role in oilfield solids control schemes for several decades. Shakers have evolved from small, relatively simple devices capable of running only the coarsest screens to the models of today. Modern, high-performance shakers of today are able to use 10 mesh and finer screens at the flow-line in most applications.
With rapid development of drilling new technology, the demand for drilling fluid solids control is getting higher and higher. The research for solids control equipments especially for the shale shaker is paid closer attention by world drilling engineers.
DC Machinery is a professional manufacturer of solids control equipments. Shale shakers designed and manufactured by DC Machinery include three types: Linear Motion Shale Shaker, Balanced Elliptical Motion Shale Shake, and Circular Motion Shale Shaker.
The History Of Horizontal Directional Drilling
Martin Cherrington first conceived horizontal directional drilling in the 1960’s. He first realized the value of underground drilling when he and another contractor were given the same job: lay down telephone lines in Los Angeles. The only difference was that Cherrington was using an open trench method while the other contractor was using drilling to lay down cables. That contractor arrived two weeks after Cherrington yet managed to finish two weeks before him. This led Cherrington to believe there was merit in looking at underground drilling methods.
In 1964 Cherrington founded Titan Contractors, which specialized in utility road boring. It was an opportune time for the company’s formation because of a building boom in Sacramento and a recent “beautification” decree from the First Lady, Lady Bird Johnson. The decree was instated to clean up America by getting rid of utility lines which were an eyesore and hazardous during seismic and extreme weather events. As a solution, Sacramento proposed placing all utilities underground. Despite a favorable environment and HDD’s merits, however, other, more familiar, tunneling technologies like jack and bore and auger boring were usually preferred.
One of the main problems was the lack of control when drilling. It was often very difficult to make a straight bore, and the drill bit would resurface in unexpected places (like the middle of the road). Cherrington realized a solution when an engineer from P G& E invited him to consider a project for placing a gas line underneath the Pajaro River. The project would require drilling underneath the river, and the variability of the drill bit’s direction would make it challenging. To find a solution, Cherrington experimented with angled bores on a similar river, trying several different angles. He observed that the steeper the angle of the bore, the greater the achieved distance. This relationship between angle and distance helped prove that with “optimum entry angle, proper drilling techniques and the right downhole tool assembly” (Cherrington) HDD could be used to cross a river. Since then, familiarity with HDD has increased, and it has become a much more routine method for projects requiring a non-evasive boring solution.
3D technology helping find new oil wells in Southwest Nebraska
McCOOK, Nebraska — Oil officials in Nebraska are crediting advancements in a technology called 3D seismic surveys for increased — and highly successful — oil drilling in southern Hitchcock and Dundy counties.
While there’s been drilling and exploration for oil in the two counties for many years — drillers found oil at Dry Creek northwest of Swanson Lake in 1963 — this new drilling frenzy is unheard of in this area of Southwest Nebraska.
“What’s changed, over the past four or five years, is the application of 3D seismic,” Bill Sydow, director of the Nebraska Oil and Gas Conservation Commission in Sidney, said. Jim Gohl of Culbertson, a commissioner for NOGCC, said that 3D seismic is “a great tool” to help locate favorable drilling locations.
Gohl could name six companies that are drilling holes in the two counties in Nebraska, and on locations directly across the state line south in Kansas. Some of the resulting wells have been “very lucrative,” he said, although he couldn’t confirm rumors of individual wells pumping 700 to 800 barrels a day.
Sydow gets excited about the capabilities of and enhancements in seismic testing. He said that when seismic started, one dynamite charge (buried beneath the surface of the ground) sent vibrations down, they bounced off subsurface formations of rocks and up again, and a sensor called a ‘geophone’ made a single trace.
Sydow said that 2D seismic employed a line of geophones.
Now, Sydow said, 3D seismic means that a dense array of geophones records a subsurface “cube of data” from a grid pattern on the surface, and produces — in conjunction with improved computer processing — a much more detailed set of seismic information, including the “subtle highs” of stored oil and gas rather than just the indication of structural elements that may indicate oil/gas.
Horizontal Directional Drilling Process
The tools and techniques used in the horizontal directional drilling (HDD) process are an outgrowth of the oil well drilling industry. The components of a horizontal drilling rig used for pipeline construction are similar to those of an oil well drilling rig with the major exception being that a horizontal drilling rig is equipped with an inclined ramp as opposed to a vertical mast. HDD pilot hole operations are not unlike those involved in drilling a directional oil well. Drill pipe and downhole tools are generally interchangeable and drilling fluid is used throughout the operation to transport drilled spoil, reduce friction, stabilize the hole, etc. Because of these similarities, the process is generally referred to as drilling as opposed to boring.
Installation of a pipeline by HDD is generally accomplished in three stages as illustrated in Figure 1. The first stage consists of directionally drilling a small diameter pilot hole along a designed directional path. The second stage involves enlarging this pilot hole to a diameter suitable for installation of the pipeline. The third stage consists of pulling the pipeline back into the enlarged hole.
Vacuum degasser working principle
As the second stage purification equipment for oilfield drilling fluid, Vacuum degasser actually is used to remove little invaded gas in drilling mud. It will be set between shale shaker and mud cleaner/desander.
The vacuum degasser can be used in many fields, such as commercial uses, agricultural uses and oilfield uses. In oilfield drilling fluid system, there are two types of degassers. One is poor boy degasser separate large quantity invaded gas, the other is the vacuum degasser, we also call it gas buster.
Vacuum degasser is vertical type degasser. It consists of vessel, base, vacuum pump, gear box, internal blade. Basic principle is degasser adopts water circle vacuum pump. Based on vacuum gas or negative pressure the gas buster will remove harmful air rapidly. It is very necessary device in oil and gas drilling, explore well or unbalance drilling. Adaptable for various well drilling fluid purification system.
The vacuum degasser uses the suction function of the vacuum pump to form the negative pressure in the vacuum tank. Under the pressure of atmosphere, the drilling fluid enters into hollow shaft from suction line, and then to be gathered by the umbrella slices around of the hollow shaft to toss to tank skin in spurting. With the impact of vacuum and bubble centrifuge, the bubble will be broken in the drilling fluid, the gas will escape and suction out by the vacuum pump and vent to the safety zone.
BHP gives up nine oil & gas exploration blocks in India
(Reuters) – Global miner BHP Billiton said on Monday it has given up nine oil and gas exploration blocks in India due to its inability to carry out exploration operations there.
The company is withdrawing from those blocks because of delays in clearances, according to local media, but BHP would not confirm the reason for its decision to relinquish its interest.
“The decision to relinquish these blocks is the result of an exploration portfolio review … there have been regular discussions and communications over the last 12 months with the Ministry of Petroleum and Natural Gas,” BHP said in a statement.
BHP gave up its interest in six blocks awarded in India’s NELP VII bid round, in which it held 26 percent interest and GVK held 74 percent interest as well as three blocks awarded in the NELP VIII bid round in which it held 100 percent interest.
BHP Billiton will keep its 50 percent interest in its NELP IX block, operated by BG Group.
MONGOOSE dual-motion shale shaker
Shale shakers come in a variety of shapes and sizes, and today’s designs are fundamentally the same as those produced 50 years ago, consisting of a metal basket that vibrates from forces generated by multiple electric motors. This vibration accelerates the natural settling of solids in the drilling fluid as the fluid passes over and through the shaker.
The vibration function has evolved over the years into a combination of elliptical and linear motion, called dual-motion shale shaker.
M-I SWACO groundbreaking MONGOOSE PT shale shaker is a such unit capable of adjusting on-the-fly as solids characteristics change. It gives you the ability to change the shaker motion as the characteristics and volume of the cuttings change. It can go from linear to elliptical motion with the simple flip of a switch.
The MONGOOSE PT shaker allows you to use linear motion while drilling top-hole sections where heavy, high- volume solids usually are encountered. These intervals require shakers to generate high G-forces to effectively move dense solids across the screens. As the drilling volume and solids characteristics, the MONGOOSE PT can be changed to the gentler elliptical mode, reducing the G-forces. This, in turn, extends screen life, while delivering drier solids, increasing fluid recovery and overall reduced operating costs.
The MONGOOSE PT shaker replaces the typical flow line trap or possum belly with an innovative distribution box. The unique design of the box redirects flow evenly across the entire width of the screen, increasing fluid handling capacity. It also dampens the velocity of the fluid in the flow line for more effective solids separation.
ONGC finds rich reserves of oil in KG Basin block
Oil and Natural Gas Corporation (ONGC), facing a prolonged stagnancy in oil production, has got a shot in the arm with one of its blocks in the Krishna-Godavari basin off the Andhra Pradesh coast, close to Reliance Industries’ much-touted KG-D6 field, having been found to hold reserves four times the previous estimate, at 100 million tonnes (mt). The PSU has stumbled upon rich in-place reserves of oil in block KG-DWN-98/2, earlier believed to hold predominantly gas.
ONGC has consistently missed its production targets over the last five years despite a healthy reserve replacement ratio (1.84 in FY13) due to project delays and most new finds being in difficult terrain.
Confirming the find of oil reserves to the tune of 100 mt (700 million barrels) in the block, ONGC’s director (exploration) Narendra Verma told FE that oil was struck in three out of six appraisal wells drilled in the block. “With two more appraisal wells remaining to be drilled, a further upside to oil reserves is possible and the estimate is subject to (upward) revision,” Verma said.
ONGC has lined up a massive capital expenditure plan of around R51,500 crore or close to $9 billion for the block by 2030. The block was awarded to Cairn in the NELP round in 2000, which offloaded a 90% stake to ONGC in 2005 before selling out completely.
The public sector company had earlier made seven discoveries (mostly gas) in the block that has been divided into northern and southern discovery areas.
The declarations of commerciality (DoC) of these were submitted in 2010 and 2009, respectively. ONGC was subsequently granted an extension to its exploration period in the block up to December 2013 for drilling eight appraisal wells.
As the recovery factor for oil ranges between 25% and 30%, if the current oil estimates hold ONGC might be able to recover around 30 mt or around 200 million barrels of oil from the block. “We are now planning to set up a floating production, storage and offloading unit to store the oil as well,” Verma said.
The oil find at 98/2 is in addition to the 4.85 trillion cubic feet of natural gas reserves the block is said to hold. The commencement of natural gas production from the block is targeted by 2017-18, with an estimated peak output of 22 million metric standard cubic metres per day (mmscmd). ONGC chairman Sudhir Vasudeva had said that the company was pinning its hopes on the block to contribute significantly to the incremental 35 mmscmd of gas ONGC will produce by 2017-18.
ONGC is now working on submitting a revised DoC to the Directorate General of Hydrocarbons (DGH) by December after accounting for the oil finds. In January it also plans to submit a revised field development plan (FDP).
Due to ONGC’s relative inexperience in developing deepwater blocks, it has sought foreign partners to invest and share technology. While ConocoPhilips has not shown interest in investing in the 98/2 block, ONGC is still awaiting a response from Shell. ONGC’s KG block has received interest from international players in the past as well but delays in approving their participation stymied their entry. Though the farm-out agreements for giving 15% to Brazil’s Petrobras and 10% to Norway’s Statoil were signed in 2007, a joint operating agreement could not be signed.
It has been close to 60 years since ONGC was set up and has just one marginal field, G-1, that is a producing asset, which commenced production just a couple of months ago. So far ONGC has made 35 deepwater discoveries (seven oil & gas and 28 gas discoveries) and has drilled 104 deepwater wells as on March 31. In FY13 alone, 14 wells have been drilled, of which seven were found to bear hydrocarbons.