Patent ID: 9506330
Filing Date: 2016-11-29
CPC Classification: E21B

Claim Text:
1. A method of sequentially performing a plurality of perforations along a predetermined interval of a wellbore in a tight reservoir rock formation in order to deeply penetrate into the rock, the method comprising: a. securing a latch coupling to the downhole end of a length of casing, lowering the casing and latch coupling from the wellhead and securing them in the wellbore with the latch coupling at a predetermined position above and proximate to the interval to be perforated; b. lowering a gun that is secured to the downhole end of a latching tool into position adjacent the interval to be perforated; c. releasably engaging the latching tool with the latch coupling; d. firing a first series of charges from the gun to penetrate the reservoir rock along the interval with a first series of openings; e. pulling the latching tool upwardly in the wellbore to disengage the tool from the latch coupling; f. retrieving the gun from the wellbore, reloading the gun with fresh charges and returning the gun and latching tool to an engaged position with the latch coupling; and g. firing a second series of charges from the gun into the formation at the same locations as the first series to provide openings penetrating deeper into the formation than the first series of openings.