Evaluation of true horizontal plane under natural head position as a basis for cephalometric analysis;

Objective: To probe into the studying method of natural head posture(NHP) and to analyze the reproducibilityof NHP by means of cephalometric technique.

It can provide perfect formation water resisitivity in argillaceous sand- stone by using SP(spontaneous potential)data.

On the basis of the theory of sequence stratigraphy,identifying sequence stratigraphy boundaries using well logging of SP(spontaneous potential),AC(acoustic time),RA(apparent resistivity),electric conductivity were comprehensively analyzed.

Two-dimensional forward of spontaneous potential in interlayer oxidation zone sandstone type uranium deposits

Strata physical nature is good for geophysical prospecting in lqe coalfield,there are less interference in the area, while the spontaneous potential curve anomalies are clearly reflected.

The traditional model used to describe the distribution of natural electric field in open hole is interfacial potential that shows spontaneous potential distributes on the interface between formation and mud.

The text building up the return equation with natural potential data of well tests and analyses coal sulphur content in labo- ratories,expanses the application that the natural potential data of the well tests in actual work.

According to the relation of natural potential logging data and reservoir water salinity,based on the layer thickness emendation,slime emendation,temperature emendation and oil & gas effect emendation of natural potential,formation water electrical resistivity can be confirmed accurately.

Variation of natural potentials, cathodic polarization curves and variation of stable current density with time for carbon steels in flowing fresh water with different velocities and in three different surface states are tested.