Abstract: An aryl-substituted saccharide or glycoside or a mixture of a plurality of aryl-substituted saccharides or glycosides have at least good resistance to high temperatures and salt, and lower filtration loss. These aryl-substituted saccharide or glycoside are used in making a drilling fluid composition. The aryl-substituted saccharide or glycoside or the mixture of a plurality of aryl-substituted saccharides or glycosides each or in combination bears a substituent A and a substituent B, wherein the substituent A contains a unit —O—R6— in its structure and the substituent B contains a unit in its structure, and the substituents and the numbers are defined in the description.

Abstract: A flow splitting device for gas reverse circulation drilling, including: an upper joint for connecting with a double-wall drill pipe; an inner tube which is arranged in the upper joint and defines a first passageway in communication with an inner chamber of the double-wall drill pipe, a second passageway in communication with an annular space in the double-wall drill pipe formed between the inner tube and the upper joint; a lower joint, having an upper end fixedly connected with the upper joint and a lower end for connecting with a drill tool; and a flow guiding member provided between the upper joint and the lower joint. A flexible sealing mechanism is provided outside the upper joint. The flexible sealing mechanism extends radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall.

Abstract: The present invention relates to substituted saccharides or glycosides and their use in drilling fluid compositions. The substituted saccharide or glycoside bears a substituent A, a substituent B and a substituent C, wherein the substituent A comprises in its structure a group the substituent B comprises in its structure a group and the substituent C comprises in its structure a unit —NH—R7—. The definition of each group is described in the description. The drilling fluid composition can show good temperature resistance, filtration loss reducing reduction property, pollution resistance, inhibition property, lubricating property or reservoir protection property, and has no biotoxicity.

Abstract: A flow splitting device for gas reverse circulation drilling, including: an upper joint for connecting with a double-wall drill pipe; an inner tube which is arranged in the upper joint and defines a first passageway in communication with an inner chamber of the double-wall drill pipe, a second passageway in communication with an annular space in the double-wall drill pipe formed between the inner tube and the upper joint; a lower joint, having an upper end fixedly connected with the upper joint and a lower end for connecting with a drill tool; and a flow guiding member provided between the upper joint and the lower joint. A flexible sealing mechanism is provided outside the upper joint. The flexible sealing mechanism extends radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall.

Abstract: A double-channel fluid injection apparatus includes a main shaft, a bearing box, and a sealing box. The main shaft includes an outer tube and an inner tube. An internal channel of the inner tube and a vertical through channel constitute a first fluid passageway. The inner tube and the outer tube form an annular gap, and a channel D is radially formed at a lower part of the outer tube and is in communication with the annular gap, thus constituting a second fluid passageway. The bearing box is mounted on a boss of the outer tube. The sealing box includes a sealing cylinder fixedly connected to a lower end of a lower end cap of the bearing box. A channel E in communication with the second fluid passageway is radially formed at a position of the sealing cylinder corresponding to the channel of the outer tube.