A. V. Patutin

Sealing of coal bed methane drainage holes by barrier screening method

The authors have developed the barrier screening method to seal coal bed methane drainage holes. The method reduces air leakage from enclosing rocks to evacuation holes. The compositions of screens with external seal preventing from fluid leakage to ambient medium are offered and analyzed.

Procedure and equipment for sealing coal bed methane drainage holes by barrier shielding

The article presents guidelines, test model design and barrier shield design model aimed to improve the quality of sealing coal bed methane drainage holes by the barrier shielding method.

Froth gel for gas-bearing coal bed hydrofracturing in mine conditions

For the purposes of coal bed hydrofracturing and enhancement of coal methane recovery, frothed gel with small fluid volume residual has been developed. The article describes tests of the frothed gel composed of mixed methyl cellulose and aluminosilicate proppant.

Prospects for directional drilling in hard rocks

The study is focused on the existing methods of long directional borehole drilling in hard rocks in high-viscous oil and natural bitumen field development. The authors suggest improving the hard rock mass drilling process by combining percussion–rotary drilling and positioning systems.

Mathematical modeling of stress state of surrounding rocks around the well subjected to shearing and normal load in hydraulic fracturing zone

The authors report the numerical modeling data on stress state of a rock mass in the vicinity of hydraulic fracturing when two closely-spaced intervals of the well are subjected to shearing and normal load. The article shows applicability of such coupled loading in creation of a fracture across an uncased well.

Open-hole multistage hydraulic fracturing system

The presented system is intended for multistage hydraulic fracturing in long open holes of any orientation to create transversal fractures with a radius to 5 m in soft and medium-hard rocks. The downhole system has an inbuilt transport unit. This fracking equipment uses chemically active fluids generated in the fractured interval by mixture of two components injected in individual high-pressure hoses.

Precision dilatometer with built-in system of advance along the borehole

The article describes engineering designs of dilatometer to measure transverse deformation in borehole subjected to internal pressure exerted through impermeable shell. The device is equipped with the robotized system for advance along the borehole without special sectional barrels. Functionality and capacities of the dilatometer are optimized for surveying in long directional drill holes in mines.

Experimental test of directional hydraulic fracturing technique

The article reports the data of a lab test of directional hydraulic fracturing carried out on a block made of organic glass. A fracture across a hole is created by means of additional shearing stress applied to the hole walls within the interval of the fracture. It is found that seismic emission under hydraulic fracturing appears after the fracture completion.

Stimulation of Underground Degassing in Coal Seams by Hydraulic Fracturing Method

The problems preventing the use of mine hydraulic fracturing for stimulating the preliminary degassing in coal seams are considered. The solutions are presented for sealing the borehole interval by solidifying composition with initiator for transverse fracture of rocks. An original system for transportation of equipment along the holes and a robotized device for hydraulic fracturing of roof-and-floor selfsustaining rocks of coal seam are designed. The working fluid with a low-density proppant is proposed, which ensures creation of fractures with a high rate of methane migration.

Assessment of deformation properties of rocks by pressuremeter testing in hydrofractured interval

The authors propose the method to estimate deformation properties of rocks by the data on pressuremeter test in hydrofractured interval, allowing in situ values of Young’s modulus and Poisson’s ratio of rocks. It is shown that combination of pressuremeter tests and hydraulic fracturing expands the scope of deformation measurements and improves efficiency of stress assessment in rocks using hydrofracturing method.