Analysis of the Possibilities of Using an Organic Bridging Material for Sealing the Borehole Wall

The process of exploiting hydrocarbon deposits is subject to many complications, some of which can make exploitation very difficult or impossible. These factors include damage to the wellbore zone by drilling fluid, which impedes the flow of reservoir fluid from the production zone to the well. This article presents the results of research conducted to develop drilling fluid compositions with the best possible ability to form a tight sealing sediment on the borehole wall. In addition to traditional carbonate blockers, modern organic agents were used as bridging agents. Research was conducted on the selection of the drilling fluid composition, the rheological parameters of which would ensure the suspension of the solid phase in the form of various types of blockers. After preparing the base drilling fluid, its composition was modified by adding different configurations of blockers. The sets of blockers added to the fluid varied in both chemical structure and particle size. Such modified fluids were then subjected to tests of technological properties, such as rheological parameters, API filtration, and pH. In the next stage, sealing tests of the filter cake formed by the tested fluids were carried out on the surface of the rock core using the PPT—Pore Pressure Transmission Test. Based on the obtained results, it can be concluded that the new type of organic blockers used allows the rapid formation of a tight filter cake on the borehole wall, and thus significantly reduces drilling fluid filtration. During PPT, the sediment formation time (tpmax) for OB2 was 45 min; for the combination of OB1 and the carbonate inhibitor, it was 8 min; and for the carbonate inhibitor alone, it was 150 min.