A method of actuating a downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") in a wellbore (410, 500, 650), the wellbore (410, 500, 650) having casing collars (254, 354, 654) that form a physical signature for the wellbore (410, 500, 650), comprising: acquiring a CCL data set from the wellbore (410, 500, 650), the CCL data set correlating recorded magnetic signals with measured depth, thereby forming a first CCL log for the wellbore (410, 500, 650); selecting a location within the wellbore (410, 500, 650) for actuation of a wellbore device; downloading the first CCL log into a processor (216, 616) on-board the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600"); deploying the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") into the wellbore (410, 500, 650) such that the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") traverses casing collars (254, 354, 654), the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") comprising the processor (216, 616), a casing collar locator (214, 614), and an actuatable wellbore device; wherein the processor (216, 616) is programmed to: continuously record magnetic signals as the downhole tool traverses the casing collars (254, 354, 654), forming a second CCL log; incrementally compare the second CCL log with the first CCL log during deployment of the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") to correlate values indicative of casing collar locations; recognize the selected location in the wellbore (410, 500, 650); and send an actuation signal to the actuatable wellbore device when the processor (216, 616) has recognized the selected location; and sending the actuation signal to actuate the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600"): CHARACTERISED IN THAT: the processor is programmed to transform the recorded magnetic signals of the second CCL log by applying a moving windowed statistical analysis; and the incremental comparison is of the transformed second CCL log with the first CCL log; and wherein applying a moving windowed statistical analysis comprises defining a pattern window size for sets of magnetic signal values, and then computing a moving mean m( t +1) for the magnetic signal values over time. acquiring a CCL data set from the wellbore (410, 500, 650), the CCL data set correlating recorded magnetic signals with measured depth, thereby forming a first CCL log for the wellbore (410, 500, 650); selecting a location within the wellbore (410, 500, 650) for actuation of a wellbore device; downloading the first CCL log into a processor (216, 616) on-board the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600"); deploying the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") into the wellbore (410, 500, 650) such that the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") traverses casing collars (254, 354, 654), the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") comprising the processor (216, 616), a casing collar locator (214, 614), and an actuatable wellbore device; wherein the processor (216, 616) is programmed to: continuously record magnetic signals as the downhole tool traverses the casing collars (254, 354, 654), forming a second CCL log; incrementally compare the second CCL log with the first CCL log during deployment of the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") to correlate values indicative of casing collar locations; recognize the selected location in the wellbore (410, 500, 650); and send an actuation signal to the actuatable wellbore device when the processor (216, 616) has recognized the selected location; and sending the actuation signal to actuate the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600"): continuously record magnetic signals as the downhole tool traverses the casing collars (254, 354, 654), forming a second CCL log; incrementally compare the second CCL log with the first CCL log during deployment of the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600") to correlate values indicative of casing collar locations; recognize the selected location in the wellbore (410, 500, 650); and send an actuation signal to the actuatable wellbore device when the processor (216, 616) has recognized the selected location; and sending the actuation signal to actuate the downhole tool (200', 200", 300', 401, 402, 406, 501, 502, 600', 600"): CHARACTERISED IN THAT: the processor is programmed to transform the recorded magnetic signals of the second CCL log by applying a moving windowed statistical analysis; and the incremental comparison is of the transformed second CCL log with the first CCL log; and wherein applying a moving windowed statistical analysis comprises defining a pattern window size for sets of magnetic signal values, and then computing a moving mean m( t +1) for the magnetic signal values over time. the processor is programmed to transform the recorded magnetic signals of the second CCL log by applying a moving windowed statistical analysis; and the incremental comparison is of the transformed second CCL log with the first CCL log; and wherein applying a moving windowed statistical analysis comprises defining a pattern window size for sets of magnetic signal values, and then computing a moving mean m( t +1) for the magnetic signal values over time.