Table 1. Statistical Table of Lost Circulation in the Hasan Area.

well number	well depth where lost circulation occurred, m	layers where lost circulation occurs	leakage velocity, m3/h	leakage amount, m3
Hasan 2	671.27	Carboniferous system		71
	1227.71		26	158.3
	2434.66		6	27.7
Hasan 201	3322.64	Carboniferous system andesite	loss of return	173.1