Abstract: A shock sensing tool for use with well perforating can include a generally tubular structure which is fluid pressure balanced, at least one strain sensor which senses strain in the structure, and a pressure sensor which senses pressure external to the structure. A well system can include a perforating string including multiple perforating guns and at least one shock sensing tool, with the shock sensing tool being interconnected in the perforating string between one of the perforating guns and at least one of: a) another of the perforating guns, and b) a firing head.

Abstract: A method for performing a downhole perforating and fracturing operation from a wellbore (12) positioned within a subterranean formation (18). The method includes locating a perforating gun string (24) within the wellbore (12), detonating a first perforating gun (28) to create a first discrete fracture initiation site (42) in the formation (18), repositioning the perforating gun string (24) within the wellbore (12) and detonating a second perforating gun (30) to create a second discrete fracture initiation site (44) in the formation (18). Thereafter, the method also includes pumping a fracture fluid into the wellbore (12) and propagating a single dominant planar fracture (56, 58) from each of the discrete fracture initiation sites (42, 44).

Abstract: A formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, the pressure sensors being longitudinally spaced apart along the perforating string, firing the perforating guns and the pressure sensors measuring pressure variations in a wellbore after firing the perforating guns. Another formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, firing the perforating guns, thereby perforating a wellbore at multiple formation intervals, each of the pressure sensors being positioned proximate a corresponding one of the formation intervals, and each pressure sensor measuring pressure variations in the wellbore proximate the corresponding interval after firing the perforating guns.

Abstract: A method of adjusting a pressure reduction to occur in a wellbore following firing of at least one perforating gun can include determining a desired free gun volume which corresponds to a desired pressure reduction in the wellbore resulting from firing of the perforating gun, and varying a free gun volume of the perforating gun until the free gun volume is substantially the same as the desired free gun volume. A well system can include at least one perforating gun positioned in a wellbore, the perforating gun comprising multiple perforating charges and a free gun volume, and the free gun volume being reduced by presence of a flowable material about the multiple perforating charges.

Abstract: A method for performing a downhole perforating and fracturing operation from a wellbore (12) positioned within a subterranean formation (18). The method includes locating a perforating gun string (24) within the wellbore (12), detonating a first perforating gun (28) to create a first discrete fracture initiation site (42) in the formation (18), repositioning the perforating gun string (24) within the wellbore (12) and detonating a second perforating gun (30) to create a second discrete fracture initiation site (44) in the formation (18). Thereafter, the method also includes pumping a fracture fluid into the wellbore (12) and propagating a single dominant planar fracture (56, 58) from each of the discrete fracture initiation sites (42, 44).

Abstract: A method of enhancing communication between a wellbore and an earth formation intersected by the wellbore can include forming a fracture in the formation, and permitting communication between the wellbore and a low pressure volume in response to a desired characteristic of the fracture being maximized. Another method of enhancing communication between a wellbore and an earth formation can include forming a fracture in the formation, and then, while pressure in the formation proximate the wellbore is at least about a closure pressure of the fracture, decreasing pressure in the wellbore by exposing the wellbore to a low pressure volume.

Abstract: A method of adjusting a pressure reduction to occur in a wellbore following firing of at least one perforating gun can include determining a desired free gun volume which corresponds to a desired pressure reduction in the wellbore resulting from firing of the perforating gun, and varying a free gun volume of the perforating gun until the free gun volume is substantially the same as the desired free gun volume. A well system can include at least one perforating gun positioned in a wellbore, the perforating gun comprising multiple perforating charges and a free gun volume, and the free gun volume being reduced by presence of a flowable material about the multiple perforating charges.

Abstract: A formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, the pressure sensors being longitudinally spaced apart along the perforating string, firing the perforating guns and the pressure sensors measuring pressure variations in a wellbore after firing the perforating guns. Another formation testing method can include interconnecting multiple pressure sensors and multiple perforating guns in a perforating string, firing the perforating guns, thereby perforating a wellbore at multiple formation intervals, each of the pressure sensors being positioned proximate a corresponding one of the formation intervals, and each pressure sensor measuring pressure variations in the wellbore proximate the corresponding interval after firing the perforating guns.

Abstract: A shock sensing tool for use with well perforating can include a generally tubular structure which is fluid pressure balanced, at least one strain sensor which senses strain in the structure, and a pressure sensor which senses pressure external to the structure. A well system can include a perforating string including multiple perforating guns and at least one shock sensing tool, with the shock sensing tool being interconnected in the perforating string between one of the perforating guns and at least one of: a) another of the perforating guns, and b) a firing head.

Abstract: A method and system for performing data integrity process is provided. The method includes selecting a cyclic redundancy code (“CRC”) mode from amongst append, validate and keep, and validate and remove mode. If the append mode is selected, then CRC is appended after each data block boundary. A CRC seed value is incremented for each data block providing a unique CRC value for each data block. If validate and keep mode is selected, then CRC accompanying any data is compared to CRC that may have been accumulated. If validate and remove mode is selected, then CRC is first validated and then CRC is removed before data is sent out. The system includes CRC logic that allows firmware running on an adapter to select one of plural CRC modes including append, validate and keep, and validate and remove mode.