Non-Linear Formation Temperature Profile in Mahakam Fields

Abstrak

Formation temperature data is commonly calculated by linear interpolation data anchored by bottom hole temperature (normally from LWD tool). LWD temperature is affected by wellbore dynamic such as mud circulation. Surface temperature which used in interpolation is usually over simplified by using fixed value for all field. The method of linear interpolation itself is also not always proper, because formation temperature is not always linear.

The surface temperature is varied by location, land and river has lower temperature than sea surface. The formation temperature measurement which likely not affected by wellbore dynamic are coming from stationary measurement such as wireline pressure test and fluid analysis (PT/FA) and drill stem test (DST). Formation temperature profile of Mahakam field is non-linear; the formula can be derived by using polynomial regression.

It seems that the non-linearity of temperature profile in Mahakam is mainly caused by lithology (Net to Gross ratio) rather than porosity (and fluid). Sands are having a very high thermal conductivity value. The effect of overpressure is look like less to temperature which probably due to well consolidated rocks close to and along overpressure interval.

This paper details the non-linear temperature profile in Mahakam fields, East Kalimantan, and further provides a technique to derive proper formation temperature profile formula which can be applied in other areas outside Mahakam.