INCREASING WELL FASTENING BY APPLICATION OF CURING FOAMS

Abstract

Increasing the support of the well is the creation of an artificial bridge in the borehole space of the well, filling voids in rocks (pores, cracks, cavities), fastening the structures of loosely bonded rocks and thereby contributing to the blockage of the channels of the drilling mud into the formation and preventing scree and collapses of unstable rocks. Composite materials of cured grouting foams, technology and conditions of their application are considered. In the proposed technology, it is supposed to drill on foams and transfer them to a solid state (foams) in complicated intervals of rocks, thereby clogging the channels of the drilling mud exit. Relevance. The development of the domestic geological exploration industry makes it very relevant to develop scientific approaches to the compositions of drilling fluids that allow drilling cycles with high mechanical speed and simultaneous padding of absorption zones in areas of low reservoir pressure. From these positions, the use of gas–liquid mixtures as a cleaning agent and grouting material is most relevant. The loss of drilling fluid in the well occurs due to the excess of the bottom-hole pressure over the reservoir. The absorption intensity is determined by the presence of open porosity of rocks, intense fracturing and cavities. The development of technologies to improve the integrity of the well walls and the borehole space, allowing the drilling process to be carried out on foams and in complicated intervals of rocks to transfer them to a solid state, while significantly increasing the well support, is a very significant task. The purpose of this article is to show the effectiveness of the use of foams in the well construction cycle when drilling on permafrost rocks, in circulation loss zones, in unstable and weakly cemented rocks (clay, sand, silt, soft clay shales). Curable foams with adjustable setting times allow you to increase the adhesion and strength of the grouting stone, create an impenetrable barrier when eliminating drilling mud losses. Methods. To solve the tasks set, a methodology was used, including a review of literary and patent information sources, their scientific analysis; empirical studies of the functional properties of gas–liquid mixtures; laboratory and bench tests; approbation of the obtained dependencies in production conditions. The study uses foams based on urea resins, curing catalysts and their compositions, methods of delivery to the complication zone under excessive pressure while reducing the injection energy intensity. Results. The author has developed the technology of drilling on foam compositions (of any multiplicity) and their transfer in the case of opening the absorbing horizon into foam, which will allow without stopping the drilling process passing the complicating horizon without an accident. The author developed and recommended a composition of the cured mixture with polymerization terms: 12–22 min and s after 24 hours – 100 kg/cm2, a composition of increased hydrophobicity and strength of urea foam with a modification of the cubic residue of the antioxidant FCH-16 TU 3830257-76. The technology of tamponing of complication zones is recommended, taking into account the temperature increase from adiabatic compression of the air phase at the pressure of injection and pushing. Conclusions. The developed compositions of foams based on carbamide resins meet the basic requirements for tampon mixtures.

Keywords

• elimination of drilling mud absorption
• well wall anchoring
• foams and curable foams (foams)
• grouting mixtures
• carbamide resins