A method for drawing logging-while-drilling curves

Abstract

The invention provides a method for drawing logging-while-drilling curves, which belongs to the field of oil and gas development and exploration. The method includes: the first step, establishing a vertical stratigraphic profile; the second step, projecting the borehole trajectory data onto the longitudinal stratigraphic profile; the third step, constructing a two-dimensional vertical depth-logging response data pair along the borehole trajectory sequence; the fourth step is to construct a two-dimensional vertical depth-horizontal displacement pair sequence along the borehole trajectory; the fifth step is to establish a curve drawing coordinate drawing track, and draw the two-dimensional vertical depth-logging response data pair sequence The first point N0; the sixth step, along the wellbore trajectory, based on the points in the sequence of M consecutive two-dimensional vertical depth-horizontal displacement pairs after the current drawing point, the cubic spline algorithm is used to form a regression equation; the seventh The first step is to conduct second-order derivation of the regression equation, and then search for the inflection point, and draw the logging curve from the inflection point; the eighth step is to end. The method of the invention realizes clearer vertical formation feature display.

Description

technical field [0001] The invention belongs to the field of oil and gas development and exploration, and in particular relates to a method for drawing logging-while-drilling curves to realize clearer vertical formation feature display. Background technique [0002] Petroleum logging curves are the main means to visually analyze formation lithology, physical properties and fluid properties. Logging data has always been displayed in the form of a curve according to the vertical depth; that is, the position of the wellhead is specified as the zero point, and the vertical depth and the amplitude of the logging physical quantity at a certain depth point are the Cartesian coordinates. The above position, and connect point by point to form the logging curve. In a vertical well, this display method can truly reflect the change of a certain physical parameter of the formation according to the amplitude change of the logging curve. [0003] At present, in the field of drilling expl...

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Problems solved by technology

[0004] The object of the present invention is to solve the above-mentioned difficult problems in the prior art, and provide a method for drawing logging-while-drilling curves, so as to overcome the problem that the projected curves are repetitive when the logging trajectory is repeatedly traversed back and forth in the upper and lower formations. However, the characteristics of the formation cannot be distinguished, and the vertical projection method loses its function, so as to guide the drilling personnel to quickly and accurately adjust the dip angle of the drilling trajectory, prevent the target layer from being penetrated, and ensure that the trajectory passes through the target layer

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