Optical fiber measurement of pressure and temperatures

Tank temperature is ruled generally because of the reservoir’s proximity toward earth’s mantle, and also by this new relative temperature replace capacities and you will thermal conductivities away from brand new formations creating the brand new lithostatic sequence filled with the newest tank.

The new geothermal gradient resulting from the heat-change process differs from basin so you can basin, but inside a specific area new distinctions is brief. For the majority hydrocarbon-generating areas, the fresh new gradient is frequently on the list of 0.6 to 1.6°F per 100 legs from depth raise (Fig. 3). Areas where the fresh world’s crust are leaner than simply average, such as for example bristlr-datingsite eruptive and geothermal components, has actually greater gradients. Inside the slim-crust components this new gradient changes averages 4°F each 100 ft regarding breadth raise. Local temperature gradients at the breadth have been reported as much as 10°F each one hundred foot addressing singularities (elizabeth.g., major flaws, regions of tectonic movement) from the planet’s crust into the geothermal parts.

To determine a precise geothermal gradient, the fresh new chose well need to be shut in, without interference, getting an occasion enough to let conduction outcomes equilibrate the newest heat. Heat questionnaire would be presented out-of body to help you base towards the the initial lineage to the better and also at a slower rates (preferably, no more than 29 feet/minute to match the fresh new thermal inertia of sensor). This process needs given that passing of the latest thermometer alters the fresh fixed gradient. Defects present in the earliest descent-whether or not noticed or otherwise not-get drop-off with the subsequent surveys after disturbance of your own 1st thermal balance.

The virgin reservoir temperature may be determined when drilling initial exploration and appraisal wells by using the maximum temperatures recorded on successive logging runs or wireline sampling operations. The technique [1] calls for plotting T_bh vs. (t_k + ?t_c)/?t_c on a linear scale.

These data are interpreted in Horner analysis fashion by drawing a straight line through the data points and extrapolating to the reservoir temperature at (t_k + ?t_c)/?t_c = 1, which corresponds to infinite shut-in time. Even though this approach is not mathematically rigorous, it provides reliable estimates of the static temperature when short circulation times are assumed. This technique is especially applicable to regions with high geothermal gradients, where the temperatures recorded at the time of logging runs can be significantly lower than the static temperature.

Dimension of reservoir tension and heat

Many process occur having obtaining bottomhole reservoir stress and you can temperatures. A number of logging procedure can be used. Pick Getting bottomhole stress and you will temperatures research for more information. The strategy revealed below are emerging process or special factors.

Multiple assistance are increasingly being created to provide tension and heat dimensions distributed along side amount of an enthusiastic optical dietary fiber which is permanently deployed from the achievement. An advantage of dietary fiber optic technology is that the devices has no electronic portion on depth, so that they are far more legitimate. In addition, optical detectors try:

• Protected in order to amaze
• Maybe not expected to electromagnetic interference
• Operable at the high heat

Regardless if an accurate gradient is not required, pursuing the procedure continues to be suitable for powering heat surveys for the wells (shut-from inside the, inserting, or flowing)

Fibre optic technologies are based on exposing this new fiber in order to unexpected ultraviolet (UV) white activities that create good «grating» with it. Pressure and you will temperatures distinctions replace the reflection wavelength of the gratings and can getting decoded according to the fixed, incipient functioning wavelength. The machine is self-referencing.

All of the part distributed across the amount of the latest fibre has got the potential to make a special heat dimension. The pros is aspect regarding a permanent temperatures gradient along side duration of brand new soluble fiber and the power to get a hold of certain measurement points. Single-section and you can marketed heat sensors was reported to perform effortlessly in the steamflood wells as much as 575°F. In one claimed instance, temperatures measurements removed together a horizontal wellbore during the differing times showed steamchests, h2o knowledge, crossflow, and you can flow trailing pipe.