Flowing gels for loss circulation prevention

Loss circulation is a common problem in drilling operations. It is a problem in which not only the valuable drilling fluid is lost, but also time and money accompany those losses. In order to mitigate this problem various loss circulation materials (LCMs) are being used all over the world. Among those LCMs are crosslinked polymer gel systems. In this work, a polymeric LCM system was studied for its potential use as a loss prevention material. The system studied is composed of polyacrylamide (PAM), phenol and formaldehyde as the main components. Under certain temperature and mixing conditions, their interaction constitutes a strong flowing gel. To study the effectiveness of the system, the gel was tested into a self-fabricated see through flow apparatus to study the effectiveness of the gel system in preventing mud losses under different permeability conditions. The crosslinked polymeric gel system was tested under three different permeability conditions. It was observed that the gel system was effectively able to prevent losses in two of those porous media at room temperature and moderately high-pressure conditions. Of these, the least permeable thief zone had a porosity of 36% and a permeability of 300 D. The same porous media was selected to study the behavior of the gel with respect to time. For this experiment a bulk volume of the gel was prepared and left static in the LCM displacement vessel. The flow experiment was conducted at three different timelines. It was observed that with the passage of time the gel system gets denatured but still remains relatively effective. This paper will highlight and add to the usage of crosslinked organic polymer gelants as LCMs. It will present the findings of an in-house see through flow setup that was used to study the effectiveness of the LCM in relation to the differential pressure across the loss zone.