Natural Gas to the Rescue

It has often been said that even a broken clock has the correct time twice a day. So, my recent predictions for a reversal of the price of natural gas shouldn't draw too many accolades, as this was a fairly easy analysis. I guess the key in the energy prediction business is keeping your focus on the future price trends. Technical Data used in the field explained in diploma in petroleum technology.

It has also been said that the past is history and the future is a mystery... our greatest gift is the present. Currently natural gas is beginning to fall into favor among elites and pundits alike as I am receiving a greater number of articles every day from government and industry experts who are beginning to realize that our access to cheap and easy oil is going the way of the Model T. Of course, as we have laboriously detailed for many years on our website, this is old news for those of us in the know.

The Cantarell Field in Mexico, the largest single discovery of oil and natural gas in North American history (far exceeding Alaska's Prudoe Bay) is now reportedly on a 25%+ decline curve as this aging elephant field of energy labors through its declining breaths of production. Some whisper that we may soon begin to see the last vestiges of crude oil. Some more details of diploma in petroleum technology are as under.

Replace it with Brazil's new oil discovery, called the Tupi field, you say? As we have indicated, the world is not running out of oil, it is running out of cheap, easily accessible oil, and the Tupi field is a great example. Located 15,000 feet beneath the ocean surface, this field of oil does not even have the production architecture yet available to bring the crude to market. The Brazilians need to develop a massive series of cooling loops in order to extract crude oil at ultra-high temperatures, from deep in the earth, into a production facility without eviscerating rubber seals, gaskets, collars and pipelines. Let's just say we have a ways to go with these new discoveries. It is obvious that production will be very expensive. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join diploma in petroleum engineering.

Positive-Displacement Meters

The installation of SCADA systems with automatic well testing generated a need for gas measurement over a wide flow range with direct readout capability. The “rotary” positive-displacement gas meter is similar to the liquid “lobed-impeller” or gear-type meter. Technical Data used in the field explained in diploma in petroleum technology.   The rotary gas meter has the capability to measure gas accurately over a range of about 15 to 1 compared with about 4 to 1 for an orifice meter with a fixed orifice plate size. The rotary meter can be equipped with mechanical compensation on indicated volume for static pressure and flowing temperature corrections. The rotary meter needs to be protected from over-range and liquid accumulation within the measuring elements. These meters are usually applied to low-pressure gas measurement service.

Gas-flow computers were developed to use existing orifice-meter runs and to provide a direct readout of gas volume that was compatible with SCADA. These devices use static and differential pressure electrical transducers on a standard orifice meter as a basis for gas measurement. The computer integrates the signals from the transducers and combines with fixed data on meter run size, plate size, etc. to develop a gas volume. The volume readout will be in the form of a switch closure that will register on an internal counter and provide input to electronic counter in an RTU. Some more details of diploma in petroleum technology  are as under.

Some gas-flow computers can accept a temperature transducer input to measure temperature of flowing gas stream for improved accuracy of volume measurement. Computers also may have capability to use two differential pressure transducers (e.g., 0 to 20 and 0 to 200 in.) and to select input from the unit providing most accurate instantaneous reading for integration. Early gas-flow computers were analog devices. Many current designs are digital units based on a microcomputer. The flow computer integration function also is being done by the microcomputer-based RTU. All designs have integration accuracy compatible with the basic measurement capability of the orifice meter. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for  Pakistani Students who wants to join diploma in petroleum engineering.

Inferential Meters.

The turbine meter and the orifice meter are commonly used inferential meters for liquid measurement. Technical Data used in the field explained in diploma in petroleum technology. These meters indirectly determine volume by sensing some property of the moving stream that can be related to volume. For example, the rotation of the turbine blades in the turbine meter and the differential pressure developed across the orifice plate in an orifice meter can be used as basis of volume determination.

Turbine meters became important in volume measurement when electronics were accepted as an element of a measuring device. The rotation of the turbine blades can be sensed electronically without need for any mechanical connection to the turbine rotor. This provides a simple arrangement that is inherently reliable and particularly suitable for high-pressure service. Thus, turbine meters initially were applied to measure injection water volumes. However, high-viscosity fluids drastically reduce the range of turbine meters.

Turbine meters are being used for well testing and wetoil lease production measurements when   combined with net-oil computers. These meters tend to be more tolerant of short over-range periods and sandy fluid than are positive volume meters. Turbine meters also arc being used for ACT, particularly for high-volume and/or high-pressure service. Some more details of diploma in petroleum technology are as under.

Orifice meters are used more commonly for gas measurement but they have some applications in liquid measurement. Compressible liquids that require pressure correction for volume determination frequently are measured with orifice meters.

The primary device for lease gas volume measurement has been and continues to be the orifice meter, which initially measured gas volume by using a mercury manometer before development of the bellows-type chart recorder. Orifice meters have these advantages: (1) no moving parts in the gas stream, (2) the ability to handle wide range of flow rates (long term) by means of plate size changes, (3) reliable and no external powered recorder, and (4) a reliable sensor (bellows). The chart recorder is not compatible with automatic data acquisition; other types of gas measurement devices are used with SCADA. These gas measurement devices include positive-displacement meters, gas-flow computers, turbine meters, and vortex meters. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join diploma in petroleum engineering.

Positive-Displacement Meters.

A positive displacement meter, regardless of specific type, consists of two primary elements: a stationary case and a mobile element, which acts to isolate within the case fixed volume of fluid each cycle of operation. Technical Data used in the field explained in diploma in petroleum technology.   The mobile element may be a rotor with sliding vanes, rotatable vanes, or rotatable buckets. It may be two rotors that mesh somewhat similarly to two helical or cycloid gears as they rotate. The mobile element may be a disk that notates about a carlike follower in three-dimensional motion or a cylinder that oscillates about a cam follower in two-dimensional motion. Or, finally, the mobile element could be a conventional piston such as that found in a power pump.

Most positive-displacement meters are, in fact, closely akin to positive-displacement pumps. Positive-displacement meters rapidly became the standard for ACT use. The positive-displacement meter provided a less costly and less complex facility than the positive-volume meter. In addition, the positive displacement meter provides a means to drive samplers and/or net oil computers with signals on a small increment of volume that is more compatible with automatic qualitative measurement requirements. Some more details of diploma in petroleum technology are as under.

Care must be exercised in the installation design for a  positive-displacement meter. All free gas must be removed upstream to avoid spinning the meter, which would cause erroneous readings and, possibly, damage to the meter. For greatest accuracy, a constant flow rate should be maintained through the meter and at a rate at least 15% or greater of the rated capacity of the meter. Standards for calibration frequency, methods, etc., are set forth in API Std. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join diploma in petroleum technology

Automatic Quantitative Measurement

Gross volumes frequently must be adjusted by quantitative measurements such as water content, temperature, pressure, and density before net volumes at standard conditions can be determined. Technical Data used in the field explained in diploma in petroleum technology.  Several of these quantitative ammeters are necessary for automation of lease operations.

There are three types of quantitative (volume) devices commonly used for automatic liquid measurement on the lease: positive-volume meters, positive-displacement meters, and inferential meters. Positive-volume meters are essentially extensions of tank measurement with automatic “filling” and “running” functions. Positive displacement meters “trap” a fixed volume of liquid within moving elements of the meter. Inferential meters measure liquid by detecting some property of the moving stream that is a basis for determining volume indirectly. Some more details of diploma in petroleum technology are as under.

Positive-Volume Meters. Positive-volume meters operate on a “fill” and “dump” cycle rather than being a continuous operation. This type meter is essentially the automatic gauging of a tank by using level controls to move a fixed volume through the tank on each complete cycle. The volume that is “dumped” or measured is related to the displacement volume in the meter between the high “fill” point and the low “dump” point in the meter. Various types of level controls are used to control the fluid levels in the meter. Each complete “fill” and “dump” cycle is registered on a counter as a basis for total volume determination. Since the positive-volume meter is cyclic with a separate “fill” and “dump” period, allowance for handling produced volumes while the meter is in the “dump” cycle must be made. Continuous operation is possible by having a pair of meters that are sequenced to have alternating cycles. This essentially requires duplication of facilities and some increased complexity in the controls. A more common arrangement is to provide surge volume capacity upstream of a single meter.

Volume-type dump tanks or meters have been built in a variety of shapes and volumes. Capacities per dump have ranged from less than V bbl to several hundred barrels.

The metering chamber may be in a stand-alone vessel or it may be an integral portion of a vessel such as a separator or heater treater. The positive-volume meter is not as compatible with qualitative measurement as the positive-displacement and inferential meters since the volume measurement cannot be separated easily into smaller increments to drive sampling and other qualitative measurement devices. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join diploma in petroleum engineering,