S. V. Serdyukov

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.

Protection of operating degassing holes from air inflow from underground excavations

The article considers the method of recovering structural integrity of operating degassing holes without outage and the scheme of cross-wise hydraulic fracturing in the hole-bottom zone using mechanical anchor. Advantages of the scheme with anchor are discussed as against directional fracturing with a slot initiator. The technical solutions on protection of methane drainage zone from air leaks from underground excavations are presented.

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.

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.

Assessment of stress state in rocks by deformation characteristic of borehole zone with hydrofracture

The authors propose the method of stress state assessment in permeable rocks. The method is numerically studied as the relationship between cross-section area of borehole length interval with a hydrofracture and the loading pressure on the borehole walls. The test data processing algorithm and the practical application of the method are considered.

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.

Wave tomography of methane pockets in coal bed

The wave tomography method is a finite difference analog of the classical seismic ray tomography. The computational investigation is reported in the article. The proposed approach allows identification of velocity anomalies in jointed rock zones of methane accumulations if the sizes of these zones are comparable with the dominant wave length of seismic sounding.

Near-field range of the direct-impact seismic source

The authors have developed and numerically analyzed a model of near-field range of the percussion-type well seismic source emission. The obtained estimates of attack energy on productive strata at underspeed seismic waves and varied position of the source relative to the stratum are presented in the article.