DD282592A7 - METHOD FOR TEMPERATURE MEASUREMENT OF POROESEN EARTH INFORMATION - Google Patents

Abstract

The invention relates to a method for measuring the temperature of a porous earth formation in a well, wherein during the continuous measurement of the temperature, which is still below the initial temperature and whose course allows extrapolation to the initial value, a fluid from the porous earth formation is conveyed with a volume flow , Fig. 1 {earth formation, poroes; Temperature; Cooling; Warming; Temperature increase, initial; Flow}

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a method for measuring the temperature of a porous earth formation in a bore.

Characteristic of the known state of the art

Fluidsaturated porous earth formations are opened up by drilling. At this time, flushed during the drilling for discharge of the drill cuttings dio bore with liquid having a temperature of about 1O ⁰ C. This purging process causes the earth formation in the well environment to cool at the well-drilled interval.

After pervading the relevant earth formation, it is examined, whereby it is necessary to determine the initial undisturbed temperature. In the known methods, the temperature must be continuously measured until the cooled borehole environment has reheated and the initial temperature is reached. For this measurement, a depth thermometer is installed in the area of the earth formation and the bore is provided with a pump. This re-heating process caused by heat conduction requires very long waiting times and thus causes high costs. Due to the long waiting times, the measuring process is often aborted prematurely, so that too small values for the initial temperature are determined and thus false statements are made.

Object of the invention

The aim of the invention is to carry out the determination of the initial undisturbed temperature of earth formations in boreholes after the drilling process in a drastic reduction of the measuring time and thereby to save costs and to provide accurate initial temperatures.

Explanation of the essence of the invention

The invention has for its object to achieve the rapid increase in temperature in the bore until reaching the initial undisturbed temperature of the earth formation by an accelerated heat conduction. This is achieved in that, according to the invention, during the continuous measurement of the temperature, which is still below the initial temperature, of the porous earth formation, a fluid having a volumetric flow which allows extrapolation of the measured temperature profile to the initial temperature is conveyed.

embodiment

The invention will be explained with reference to a drawing. The figure shows the porous earth formation 2 which is to be connected across the open area 5 7 Dr 1 hole to ensure an unobstructed flow over a selective section. In the vicinity of the entrance of the layer medium, the depth thermometer 4, which records the course of the change in temperature to install.

The bore 1 is to be equipped with the pump 7, which promotes an approximately constant volume flow 6. The constant flow 6 provides favorable starting conditions for extrapolation of ^r emperaturverlaufes.

As a result of spilling the well 1 to discharge the cuttings, fluid-saturated earth formations 2 are cooled during the drilling process in the well environment.

After plowing, these earth formations 2 are investigated, one of the main goals being to determine the initial undisturbed temperature as accurately as possible. For this purpose, the borehole environment must heat up again until the initial temperature is reached. To accelerate this process 2 fluid 3 is to be conveyed from the open area 5 through the hole from the respective earth formation and to measure the temperature continuously with the depth thermometer 4.

In this case, the highest possible volume flow 6 is to be selected in order to transport fluid at an initial temperature from the thermally undisturbed remote borehole environment into the nearer cooled borehole environment in a very short time, so that it heats up. Minimal is to promote a volume of V = M η r ² π

 To this mean

V - fluid volume ³

M - thickness of the fluid - saturated porous layer in m η - porosity of the fluid - saturated porous layer in 1 r - radius of the cooled zone in m.

With normal penetration of the layer, the radius of the cooled zone is <3m.

If the temperature increase after the promotion of this minimum fluid volume has not yet been completed, the initial undisturbed temperature is to be determined by extrapolation of the registered measured value profile. For extrapolation, the measured temperature profile is to be displayed as a function of the modified measuring time. The resulting curve is to coincide with a typical curve from a flock and to extrapolate to the desired initial temperature. If it has been conveyed until the high temperature no longer changes, but has a constant course, then the initial temperature has been reached and need not be determined by extrapolation.

Claims (4)

A method of temperature measurement of a porous earth formation in a well, wherein a depth thermometer is disposed in the region of the porous earth formation and the well is provided with a pump, characterized in that during the continuous measurement of the temperature which is still below the initial temperature, from the porous earth formation, a fluid with a volume flow, which allows the extrapolation of the measured temperature profile to the initial temperature, is promoted. 2. The method according to claim 1, characterized in that the fluid is conveyed with a large volume flow. 3. The method according to claim 1, characterized in that the fluid with a minimum fluid volume V = M · η · r ² · π is promoted. 4. The method according to claim 1, characterized in that the fluid is conveyed from the earth formation until the measured temperature does not change.