A composition for treating a subterranean formation is formed from water, a water-soluble polymer and a crosslinking system. The crosslinking system utilizes 1) primary crosslinking agent of at least one of a dialdehyde benzene source, a dioxane, and a trioxane, 2) a secondary low temperature organic crosslinking agent that generates aldehyde, and 3) a phenol source. The crosslinking system provides the composition a delayed gel time of about 2 to about 20 hours at temperatures of about 250° F. (121° C.) or higher. A method of treating a subterranean formation penetrated by a wellbore is also accomplished by forming a treatment fluid from the composition and introducing the treatment fluid into the formation through the wellbore.

A variety of methods, compositions, and systems are disclosed, including, a method comprising: introducing a treatment fluid into a wellbore penetrating a subterranean formation wherein the treatment fluid comprises: a base fluid; and multi-grade diverting particulates, wherein the multi-grade diverting particulates comprise a degradable polymer, wherein the degradable polymer comprises a first portion of the degradable polymer and a second portion of the degradable polymer of different grades, wherein the multi-grade diverting particulate at least partially plugs a zone in the subterranean formation; and diverting at least a portion of the treatment fluid and/or a subsequently introduced fluid away from the zone.

The present invention relates to the well drilling field in petrochemical industry, and discloses a drilling fluid additive composition and water-based drilling fluid suitable for horizontal shale gas wells. The composition comprises a nano-plugging agent, a bionic wall bracing agent, a bionic shale inhibitor, an emulsifier, and an amphiphobic wettability reversal agent, wherein, the nano-plugging agent is modified silicon dioxide nano-particles, and its modifying group includes an acrylic copolymer chain; the bionic wall bracing agent is carboxymethyl chitosan with a dopamine-derived group grafted on its main chain; the bionic shale inhibitor is composed of structural units of arginine and structural units of lysine; and the amphiphobic wettability reversal agent is a dual-cation fluorocarbon surfactant. The drilling fluid containing the additive composition provided in the present invention has high temperature-resistance, high plugging and high inhibition performance, is environment friendly, especially has high density, and is applicable to shale gas mining.

An ultralow-permeability agent contains a structural unit provided by styryl hydrophobic monomer, maleic anhydride and acrylamide; the drilling fluid contains two or more of water, sodium bentonite, Pac-Lv, the ultralow-permeability agent, calcium carbonate, one-way plugging agent, white asphalt and barite which are stored in a mixed manner or independently stored. When the amphiphilic block polymer provided by the invention is used as the ultralow-permeability agent of the intelligent temporary plugging type water-based drilling fluid, the self-adaptive characteristic is realized; according to the amphiphilic block polymer, temporary plugging layer gaps formed in pore and throats by plugging materials in drilling fluid can be fully filled under the condition that the sizes and the distribution of the pore and throats of reservoirs are not required to be clear, so that the permeability of temporary plugging layer is greatly reduced, ultralow-permeability is realized.

Electro-responsive hydrogel particles are flowed into a first wellbore formed in a subterranean formation. An electric circuit is established between the first wellbore and a second wellbore formed in the subterranean formation. An electric current is applied through the electric circuit, thereby exposing the electro-responsive hydrogel particles to an electric field and causing at least one of swelling or aggregation of the electro-responsive hydrogel particles to form a flow-diverting plug within the subterranean formation. Water is flowed into the first wellbore to increase hydrocarbon production from the second wellbore.

Method of treating a portion of a subterranean formation comprising the injection of an aqueous fluid containing a modified polysaccharide bearing ethylenically unsaturated double bonds and an initiator of radical polymerization.

The present invention relates to the use of a sequenced polymer as an agent for monitoring the filtrate in a fluid injected under pressure into an oil rock, wherein the fluid comprises solid particles and/or is brought into contact with solid particles within the oil rock after being injected, the polymer comprising at least three blocks, including: at least one first block which is adsorbed, preferably irreversibly, onto at least some of the particles (p); a second block (B) having a composition other than that of the first and a mean molecular weight of more than 10,000 g/mol, and which is soluble in the fluid (F); and at least one third block of type (A) or type (B).

Compositions that swell on contact with water contain a non-swellable thermoplastic or thermoset polymer and a swellable inorganic compound. In particular, the compositions are suitable for use in subterranean wells such as those used in the oil and gas industry. The polymer may be polypropylene and the inorganic compound may be magnesium oxide.

Described herein are methods of enhancing the rheological properties of a colloidal mineral suspension in a liquid with high-intensity acoustical energy. In some examples, the colloidal mineral suspension may be dehydrated after treatment with high-intensity acoustical energy.

The current method comprises producing a loss control blend by selecting blend ingredients that contribute to thixotropy of the blend, density of the blend, and compressive strength of the set blend, wherein at least one of the blend ingredients contributes positively to all three of these attributes.