Porosity and fluid saturations essay

Porosity is the best known physical characteristic of your oil water tank. It

decides the volume of oil or perhaps gas present, and all recovery computations must

be based on knowledge of their value. Porosity of a material is defined as that

fraction of the bulk volume of this fabric that is not busy by the sound

framework with the material. In oil reservoirs, the porosity represents the

percentage from the total space that is available for occupancy simply by eighter fluids

or smells. It establishes the memory space of the yellow sand and is generally

expressed on the percentage basis or being a fraction or a decimal. You can

distinguish two styles of porosity, namely, absolute and powerful: Absolute

porosity is the percentage of total void space with respect to the volume volume

regardless of interconnection in the pore voids. Effective porosity is the

percentage of connected with each other void space with respect to the large volume.

Successful Porosity Measurements: Grain volume methods: In these methods the

consolidated test is solvent extracted and dried, most volume is determined

eighter by displacement of a liquid which in turn does not penetrate the sample or

simply by saturating the sample and volumetrically displacing a suitable the liquid with

the saturated sample. The materials volume, or perhaps volume of the solid construction of the

test, maybe assessed by the volumetric displacement of a gas or maybe a liquid, although

the ouverture volume can be measured simply by determining the quantity of liguid neccesary to

fill the sample. It is clear that the percentage of porosity may be

calculated from this sort of data by simply use of eighter of the two following human relationships:

Per cent porosity=100x(bulk volume feed volume/bulk volume) OR Per cent

porosity=100x(pore volume/bulk volume) Large volume willpower: The bulk quantity

of the removed and dried out samples might be determined by volumetric displacement

of mercury. Ouverture gas expansion method: The measurements of porosity may also be

made by the pore-gas expansion method, or perhaps so-called Washburn-Bunting

method. (1922). This method utilizes a revised Toepler pump so much being used in

high-vacuum techniques in order to produce the barometric vacuum and take out air

via a dried up core. The bulk volume of the core should be known from all other tests.

Mercury-injection method: When a rock contains a very small small percentage of void space, that

is diffucult to measure it by simply methods previously discussed. You can then resort

to pushing a noncompressible liquid in to the sample under very high pressure. The

unique idea appears to have been that of Horner(1944). Loss of excess weight

method: The measurement with the grain volume of a primary sample can also be

determined by the loss in excess weight of a over loaded sample stepped in a liquid.

Liquid vividness Method: Measurements of ouverture volume are often achieved by

liquefied saturation. Porosity of large main samples: A technique is recommended by

Locke and Bliss(1950) for the measurement of porosity in large cores, i. e, cores

as recovered from drilling businesses without further reduction in size by

testing of tiny plugs. Overall Porosity Way of measuring: In the dedication of

complete porosity, it truly is required that most nonconnecting along with

interconnecting pores be accounted for. FLUID SATURATIONS: Methods for the

determination of reservoir liquid saturations in place consist in analyzing

reservoir core selections for drinking water and essential oil, the saturation in gas being obtained by

big difference since the quantity of the saturations in the 3 fluids is usually equal to

unity. As a general practice an easy procedure should be to determine this particular

saturation of your sample by a suitable approach and then to measure the total

loss of fat of the test on removal and blow drying. The quantity of petrol

present is then calculated by simply subtracting the weight of water located from the

total loss in weight. The techniques which may be recommended for this willpower

will be talked about briefly. Handiwork method: Water saturation may be

determined by handiwork methods such as the ASTM approach and the Leader and

Abgefahren method. Crucial solution heat method: A fluid saturation method

whick makes use of the critical solutoin tempereture has been described by

Taylor(1938). Titration technique: Another process of saturation perseverance

makes use of the titration method. Retort method: the procedures mentioned above

happen to be nearly all mixtures or changes of methoads previously described in

the availble books which have been identified satisfoctory in handling a superb

variety of primary samples with assorted requirements of rapididty and accuracy.

Different methods have been completely tested and found to be fewer desirable, like the

retort method( Yuster and Levine, 1938). The main doubt to the retort

method, nonetheless in common employ, is the cracking of the essential oil with the resluting

production of gases plus the possibility of traveling out normal water of crystallization.

Capillary pressure method: Consideringg the difficulties involved with fluid

vividness determinations via cores, Thornton and Marshall (1947) include proposed

the usage of capillary pressure curves (capillary suction vs . brine saturation) as

a substitute for the direct measurments of connate water. The process involves

the determination of air-water capillary pressure curves on selected core

examples, the perseverance of the range above water-oil contact where the

trials were properly secured, and the putting on a modification in order to decrease the

air-water capillary presuure competition to an oil-water capillary pressure.

Summarizing, fluid saturation determinations are probably the least reliable of

the measurements performed about reservoir rock and roll samples. Perhaps the best strategy

to a true solution with the problem is simply by correlation of quantitative information

from several independent calculating means, to of which have been completely reviewed just before

namely, by direct measurments of main samples through indirect measurments

through the use of capillary pressure curves.