Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. The following 200 pages are in this category, out of 374 total.

Just as the compressibility of natural gas is much greater than that of oil, water, or rock, the viscosity of natural gas is usually several orders of magnitude smaller than oil or water. This makes gas much more mobile in the reservoir than either oil or water. Reliable correlation charts are available to estimate gas viscosity. Carr et al.[1] have developed charts (Figs. 1 through 4) that are the most widely used for estimating the viscosity of natural gas from the pseudoreduced critical temperature and pressure. Figure 1 gives the viscosities for individual components.

Gases have unique properties that set them apart from any other known substance. Under certain ideal pressure and temperature conditions, gases can be considered ideal gases, which can distinguish them from what we consider real gases. This page will provide a brief overview of certain fundamental gas properties. Molecules of a particular chemical species are composed of groups of atoms that always combine according to a specific formula. The chemical formula and the international atomic weight table provide us with a scale for determining the weight ratios of all atoms combined in any molecule.

Conformance is a measure of the uniformity of the flood front of the injected drive fluid during an oil recovery flooding operation and the uniformity vertically and areally of the flood front as it is being propagated through an oil reservoir. The remediation, or partial remediation, of the first conformance problem is exemplified by a mobility-control polymer flood conducted in a reservoir containing a viscous oil and/or a reservoir that is characterized as being relatively homogeneous. Successful conformance improvement treatment is dependent on correctly assessing the nature of the conformance issue. Vertical conformance problems, which are probably the most pervasive and most easily remedied conformance problems in matrix-rock (unfractured) reservoirs, are commonly manifested by geological strata of differing permeability overlying one another. In matrix-rock (unfractured) reservoirs, areal conformance problems, also referred to as "directional" high-permeability trends, can exist.

A liquid has a definite volume when compared to a gas, which tends to expand to fit its container. When unconfined, a liquid seeks the lowest possible level. Because of its fluidity, a liquid will conform to the shape of its container. The pressure existing at any point in a liquid body at rest is caused by the atmospheric pressure exerted on the surface plus the weight of the liquid above that point. This pressure is equal in all directions.

Nuclear logging has been used in some form since the late 1920s to provide information on lithology and rock characteristics. Continued technological advances have provided improved methods for analyzing the measurements of natural and induced nuclear readings. Even with better tool designs, the long-standing problem remains that logging tools do not directly measure the formation properties that engineers, geologists, and petrophysicists need to describe a reservoir. The goal of log analysis is to map out the downhole values of reservoir characteristics chiefly as porosity, fluid saturations, and permeability. Unfortunately, nuclear-logging tools only measure gamma ray or neutron count rates at cleverly positioned detectors.

Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. In the context of perforating, a WML is a wrapped metal liner.