Patent ID: 8026198
Filing Date: 2011-09-27
Classification: C09K

Abstract:
1. A water-based drilling fluid for use in drilling wells through a formation containing a shale which swells in the presence of water, the drilling fluid comprising: an aqueous based continuous phase; a weighting material; and a shale hydration inhibition agent (SHIA) selected from the group consisting of (a) propylamine derivatives having the formula: (b) hydrogenated poly(propyleneimine) dendrimers (HPPID) having a core with the formula N(-A-N*)3 and branches with the formula —H wherein A=(CH (c) polyamine twin dendrimers (PTD) having a core with the formula wherein 2≦x≦6, and branches B with the formula —(CH wherein n is the dendrimer growth generation number and n<10; wherein the SHIA is present in a sufficient amount to reduce shale swelling.