Abstract: A circulating sub apparatus including a substantially tubular outer body member having a throughbore formed therein and a substantially tubular inner body member. The outer body member having at least one hole formed therein and a displacement mechanism for producing movement of the inner body member relative to the outer body member such that the inner body member is moveable between an open configuration and an obturated configuration. The inner body member includes a seat member adapted to catch a dropped object, the seat member is located upstream of the hole(s) of the outer body member in both the open and obturated configurations, and wherein the seat member is adapted to permit at least a proportion of fluid to flow past the dropped object when it is seated thereon.

Abstract: An activation device for use in a downhole well for activation of a downhole tool in the well. The downhole tool has a seat adapted to engage the activation device. The activation device can travel through a borehole of the downhole well to reach the seat. The activation device has an outer layer and a core. The material of the outer layer resists erosion by drilling fluid when the activation device is in the borehole. The material of the core is eroded by drilling fluid when the activation device is engaged in the seat. The activation device is then able to pass through the seat. There is also described a method of operating a downhole tool having a seat for engaging an activation device. The method includes the step of eroding at least a portion of the activation device with drilling fluid until it can pass through the seat.

Abstract: A selectively operable downhole valve for use with core sampling apparatus, the valve comprising a throughbore through which a first body may pass, and an obstructing member which is capable of selectively obturating the throughbore, the obstructing member being arranged to open or close the throughbore by movement of the first body with respect to the valve. A core sample of the formation may then be obtained and retrieved from the bore under pressure since the valve seals the bore downhole. Retrieving the sample under pressure maintains the integrity of the core sample so that subsequent analysis of the sample will more closely reflect the true characteristics of the formation.

Abstract: A circulating sub apparatus comprising: a substantially tubular outer body member having a throughbore formed therein; a substantially tubular inner body member; wherein both the inner and outer bodies normally have holes formed therein; and a displacement mechanism for producing movement of the inner body member relative to the outer body member between: an open configuration, in which the hole(s) on the outer body member are open such that fluid is passable between a throughbore and the outside of the circulating sub apparatus via the one or more holes; and, an obturated configuration, in which the hole(s) on the outer body member are obturated; wherein the inner body member comprises a seat member adapted to catch a dropped object, and wherein the seat member is adapted to permit at least a proportion of fluid to flow past the dropped object when it is seated thereon. Normally the seat member is located upstream of the hole(s) of the outer body member in both the open and obturated configurations.

Abstract: A method of stabilizing a core sample is described, and an agent for use in the stabilising method. The method involves injecting a foam around a core sample in a cylindrical liner. The foam comprises mixture of a first pressurized polymerisable-based fluid and a second pressurized fluid, which are simultaneously injected as a foam into an annulus between the core sample and liner. The foam preserves the sample and cushions it for transportation. The foam can include a dye or colorant to distinguish the foam from other materials in the core sample.

Abstract: A selectively operable downhole valve for use with core sampling apparatus, the valve comprising a throughbore through which a first body may pass, and an obstructing member which is capable of selectively obturating the throughbore, the obstructing member being arranged to open or close the throughbore by movement of the first body with respect to the valve. A core sample of the formation may then be obtained and retrieved from the bore under pressure since the valve seals the bore downhole. Retrieving the sample under pressure maintains the integrity of the core sample so that subsequent analysis of the sample will more closely reflect the true characteristics of the formation.

Abstract: The present invention relates to an apparatus and method for recovering a sample from a subterranean formation. The apparatus comprises a receptacle for receiving a sample and at least two seal assemblies disposed on an inner surface of the receptacle. The seal assemblies can be arranged to allow a portion of the sample therethrough during the sampling process and to retain fluids within the receptacle during recovery of the sample. The seal assemblies can comprise at least one seal. The at least one seal can be provided with at least one fluid pocket configured to change shape as the volume of fluid therein alters in response to a pressure differential. A plurality of pairs of seal assemblies can be spaced along the length of the inner surface of the receptacle.

Abstract: A method for determining the flow characteristics of a geological formation; in a particular embodiment the method comprising the steps of: providing a container such as a core barrel within the formation; adding a portion of the formation, such as a core sample, into the container; and whilst the container remains in the formation, injecting fluid into the container such that a portion of the fluid flows through said portion of the formation and measuring the flow of the injected fluid to give information on the nature, such as permeability, of the core sample. In preferred embodiments fluid is received from the portion of the formation in the container to give more information on the core sample. Certain embodiments include packers to direct the flow of the fluids within the container. Such in situ measurements provide more accurate data on the reservoir characteristics, such as reservoir permeability.

Abstract: A method of stabilizing a core sample is described, and an agent for use in the stabilising method. The method involves injecting a foam around a core sample in a cylindrical liner. The foam comprises mixture of a first pressurized polymerisable-based fluid and a second pressurized fluid, which are simultaneously injected as a foam into an annulus between the core sample and liner. The foam preserves the sample and cushions it for transportation. The foam can include a dye or colorant to distinguish the foam from other materials in the core sample.

Abstract: A container for receiving and retaining a sample from a subterranean formation, wherein the container is arranged to be removably accommodated within a coring assembly. The container comprises a receptacle, formed from at least two receptacle portions and a connector for connecting each receptacle portion to the adjacent receptacle portion, such that the receptacle portions are separable on disconnection of the connector. The receptacle portions can be complementary to form a receptacle in the shape of a substantially hollow cylinder. A cylinder axis can be defined by the long axis extending through the cylinder. The receptacle portions can be connectable along a line parallel to the cylinder axis of the receptacle such that at least one of the receptacle portions is movable radially away from the sample on disconnection of the connector.

Abstract: The present invention relates to an apparatus and method for recovering a sample from a subterranean formation. The apparatus comprises a receptacle for receiving a sample and at least two seal assemblies disposed on an inner surface of the receptacle. The seal assemblies can be arranged to allow a portion of the sample therethrough during the sampling process and to retain fluids within the receptacle during recovery of the sample. The seal assemblies can comprise at least one seal. The at least one seal can be provided with at least one fluid pocket configured to change shape as the volume of fluid therein alters in response to a pressure differential. A plurality of pairs of seal assemblies can be spaced along the length of the inner surface of the receptacle.

Abstract: A double-tube core drill wherein the inner tube (2) is connected to the outer tube (1) by a multi-element needle and/or ball bearing (11), allows for the inner tube (2) to be made rigid and prevents it from rotating along with the outer tube (1). The extraction device (9) and the inner wall (38) of the tube are preferably covered with an antifriction coating. A set of stabilizing elements (67) are spread along the outer tube to stabilize the inner tube (2). Said inner tube has a tapered shoe (32) provided with a lower bevelled lip (14). The drill also comprises a device for indicating that the core has jammed in the inner tube (2) and a sealing device (19) designed to receive a ball (46) provided for sealing the inner tube (2) of said core drill.