Process 66 is first performed, in which the appropriate well log data is retrieved from disk storage 34 by system computer 24 to determine the normal compaction trend line at the location of existing well 2. The change of the gradient slope is contingent on the formation's fluid density and the vertical subsurface Exploration risk and drilling challenges are greatly impacted by the subsurface geopressure gradients changeability. Accordingly, closely spaced interval transit times can be used to produce acoustic velocity logs at specific CDP locations. Accordingly, low pressure zones that are vulnerable to such fracturing must be detected, and the appropriate precautions taken, so that such fracturing and loss of mud circulation does not occur. As is well known in the art, a density log of a wellbore is conventionally obtained by directing a beam of gamma rays from the logging tool into the surrounding formation and, using a gamma ray detector in the logging tool at a specified distance from the source, detecting changes in the radiation intensity, as the intensity of detected radiation varies inversely with the density of the formation. All rights reserved.
Video: Values of geopressure gradient generator Pressure Gradient Example
values of geopressure gradient Geopressure Gradient is the measure of the This geopressuregradient model was used to generate a series of maps that. Given the pore pressure and fracture gradients of Table and the values ofabscissa of point with data used to generate the “Differential Sticking” curve . Abnormal formation pore pressure (geo-pressure): This type exists in regions.
Series of Five Maps Characterizing Geopressure Gradients Based on Mud Weight generate ten regional-scale maps (Burke et al., a): five contour maps.
methods which allow for calculating values between known data points.
The method of claim 6, further comprising: after the step of generating a normal compaction trend line for the well log data, generating a pore pressure gradient at the well location from the normal compaction trend line for the well location. If additional existing logged wells are present in the area, the overburden gradient cross section may be produced by system computer 24 performing the correlation of process 44 at each of the logged well locations, and then producing the overburden gradient in process 46 using a weighted average of the correlation relationships from the differing wells.
As discussed hereinabove, the normal compaction trend line corresponds to the expected increase in density of shale formations as a function of depth, due solely to increasing hydrostatic pressure i. As is well known in the art, the overburden gradient is generally calculated by establishing an average trend line through the bulk density data acquired in the density log data retrieved in process It is contemplated that disk storage devices 30, 32, 34 are implemented by way of a local area network or by remote access.
The model was used to generate ten maps: five contour maps press [a]; in press [b]) define the geopressure-gradient model. A summary of methods which allow for calculating values between known data points. The model was used to generate contour maps that characterize the depth and In this paper, we focus on the de- tails of the geopressure-gradient model and. c1 = psi/ft/ppg and c1 -gradient value above and below the value.
Values of geopressure gradient combeautio
The model was used to generate contour maps that characterize the depth and tails of the geopressure-gradient model and the creation of the psi/ft pressure-gradient. -gradient value above and below the value closest to psi/ft.
Process 72 is now preferably performed by system computer 24 to retrieve, from disk storage 32, drilling parameters pertaining to the drilling of well 2. In this embodiment of the invention, system computer 24 is able to retrieve seismic survey data from disk storage 30, drilling measurement and parameter data from disk storage 32, and well log data from disk storage As is well known in the art, hydrostatic pressure increases with depth from the surface.
Referring back to FIG.
As is evident in the example of FIG. Alternatively or in addition to an automated regression, manual placement of the normal compaction trend line by a human user may be performed via mouse 25 or keyboard 26, either to set the line originally or to edit the placement made by the automated linear regression.