The application of high-precision downhole temperature sensors has resulted in pressure-transient analysis (PTA) being complemented or replaced by temperature-transient analysis (TTA). However, the derivation and use of TTA solutions is challenging because of the small value of the measured temperature change and the more-complex nature of the governing physics and equations. In particular, analysis work flows for wells producing gas or gas/liquid mixtures are still lacking because most published liquid TTA solutions cannot be applied in the presence of gas. The complete paper addresses a work flow for a dry-gas-producing well.
Applications of downhole temperature measurements can be divided into two broad classes based on the type of temperature models used and the reservoir-flow regimes analyzed. The first class uses semisteady-state models, usually in conjunction with measurements made at a single point in time by distributed-temperature sensors (DTSs). The second class of models uses TTA with both point and distributed measurements made over a period of time.
TTA is relatively tolerant to measurement accuracy. It essentially requires data on the rate of temperature change, which is normally measured one or two orders of magnitude better than the absolute values (i.e., the difference between the sensor’s resolution and the sensor accuracy)....
Novel Solutions for Transient Sandface Temperature in Dry-Gas-Producing Wells
01 February 2017