STUDY OF ADDITIVES FOR SELF-HEALING OF CEMENT SHEATH

Abstract

The article discusses a study of cement sheath integrity improvement in oil and gas wells. This problem has been studied for more than 40 years. Nevertheless, every year it inextricably linked with the solution of current problems that challenge drilling specialists. Therefore, the search for solutions to problems in this area has great potential and prospects for further improvement. There are three conceptual approaches to the self-healing of cement stone: self-healing systems based on capsules (granules), in a vessel (fiber) shell and without shells. There is also a definition proposed by the Union of Laboratories and Experts in Building Materials. According to this concept, self-healing can occur during autogenous (natural) process, in which the filling of cement cracks occurs due to its own fund of non-hydrated particles when contact with water. Self-healing can also be autonomous (artificial, due to the introduction of additives such as polymers, bacteria and other components capable of either expanding or producing a substance that fills the void space under certain environmental conditions). However, despite the absence of auxiliary materials, autogenous healing is limited by the size of the cracks formed. Experience also shows that autonomous recovery also has negative aspects, which are associated with the characteristics of a particular material and medium - an activator. Therefore, in each case, the approach to solving the problem should be specific and unique. becomes more and more relevant due to the constant deterioration of mining and geological conditions in the process of drilling new wells. The process of adaptation to new conditions is After a series of successful studies aimed at the effect of water-oil-swelling additives on the self-healing ability of cement stone, the focus of the study was shifted to the problem of integrity of gas and gas condensate wells. In this regard, the study provides a detailed step-by-step description of the various processes aimed at finding a solution to the problem. The process of selecting a modifying additive with an assessment of the swelling ability to obtain the effect of self-healing cement stone in difficult mining and geological conditions is considered. Tests of additives in various conditions and environments are carried out. Attempts are made to create an experimental stand that allows simulating well conditions and evaluating the effect of stone restoration when creating artificial cracks. This study makes a significant contribution to the search and understanding of the performance of various additives in the formation environment. The creation of a test equipment is the first step towards modeling formation conditions at the surface. Further modernization of the stand will allow for more accurate tests and significantly reduce the time for selecting reagents. Thus, the use of this technology will improve the quality of well casing, as well as the safety of work in environmental terms.