Disclosed herein are compositions and methods for increasing the viscosity of a calcium-containing fluid by addition of a modifying agent. The resulting enhanced viscosity fluid may be used in a variety of applications including drilling, to create an enhanced-viscosity fluid, and demolition/mining to create an expansive putty for use in underwater and overhead applications.

Fast-setting Portland cement compositions for filling voids, such as mine shafts and excavated utility trenches, are described. The Portland cement compositions set quickly and are useful when traditional slow setting compositions are less desirable. The acceleration of the set time results from the addition of dry calcium chloride to the Portland cement composition. The compositions consist of Portland cement, dry calcium chloride, water and sometimes preformed cellular foam. Some compositions can include also include fly ash. The compositions may have a compressive strength of between 0 psi and 30 psi after 4 hours, a compressive strength of between 30 psi and 120 psi after 24 hours, a compressive strength of between 200 psi and 500 psi after 28 days, a penetration resistance of between 0.1 tsf and 5 tsf after 10 hours, a penetration resistance of between 0.8 tsf and 10 tsf after 24 hours, and a removability modulus of between 0.2 and 1.0 after 28 days. Also disclosed are methods of filling a void with fast-setting Portland cement.

Fast-setting Portland cement compositions for filling voids, such as mine shafts and excavated utility trenches, are described. The Portland cement compositions set quickly and are useful when traditional slow setting compositions are less desirable. The acceleration of the set time results from the addition of dry calcium chloride to the Portland cement composition. The compositions consist of Portland cement, dry calcium chloride, water and sometimes preformed cellular foam. Some compositions can include also include fly ash. The compositions may have a compressive strength of between 0 psi and 30 psi after 4 hours, a compressive strength of between 30 psi and 120 psi after 24 hours, a compressive strength of between 200 psi and 500 psi after 28 days, a penetration resistance of between 0.1 tsf and 5 tsf after 10 hours, a penetration resistance of between 0.8 tsf and 10 tsf after 24 hours, and a removability modulus of between 0.2 and 1.0 after 28 days. Also disclosed are methods of filling a void with fast-setting Portland cement.

Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof; introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof; introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

Methods for producing construction material utilizing loose pieces of aggregate (30), enzyme producing bacteria, an amount of urea and an amount of calcium ions. A first solution is prepared which includes urease which is formed by enzyme producing bacteria. A second solution is prepared which includes urea and calcium ions. The first and second solutions are added to the loose aggregate (30). The calcium ions contribute to the formation of calcium carbonate wherein the calcium carbonate fills and bonds between at least some of the gaps between the loose pieces of aggregate forming a solid construction material (92).

Methods for producing construction material utilizing loose pieces of aggregate (30), enzyme producing bacteria, an amount of urea and an amount of calcium ions. A first solution is prepared which includes urease which is formed by enzyme producing bacteria. A second solution is prepared which includes urea and calcium ions. The first and second solutions are added to the loose aggregate (30). The calcium ions contribute to the formation of calcium carbonate wherein the calcium carbonate fills and bonds between at least some of the gaps between the loose pieces of aggregate forming a solid construction material (92).

This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

Calcium silicate-based cements and concretes are disclosed, which result in concrete compositions that have an improved strength development. A cement product includes a plurality of particles of a carbonatable calcium silicate cement and a first additive; wherein, the first additive is an organic molecule with at least one primary, secondary or tertiary amine group.