ABOUT SKIN EFFECTS OF OBLITERATION AND COMPRESSION
Authors: Qafar Ismayılov Qafar Ismayılov , Shahin Ismayılov Shahin Ismayılov , Arzu Sultanova Arzu Sultanova 
Published: March 2022

There should be factual information on the skin-effect on each well that reduces oil and gas production for operational work, as well as for the calculation of oil and gas deposits or for the design of field development.
Well development and operation experience shows that contamination of the bottomhole zone and deterioration of leakage properties may be associated not only with collution, but also with events such as obliteration and rock compaction. Thus, during the operation of wells, events such as shrinkage and retention of microcatches and capillaries in fractured-porous formations over time are inevitable. The impact of this factor must also be taken into account, as the method of impact on the bottomhole zone and the compression of formations under the influence of overburden pressure. Such events should be attributed to the factors that increase the resistance of the bottomhole zone and should be studied as an object of research.
The discovery of deep hydrocarbon deposits and their development experience show that failure to take into account the deformation of the porous medium as a result of a drop in formation pressure during development reduces the reliability of development parameters. The commissioning of deeper oil, gas and gas condensate fields requires the interpretation of mining data and the development of methods for hydrodynamic research of wells, taking into account the density of layers. Compression of stratified formations with significant deformation during development and the impact of this effect on the development process significantly improves the theory of filtration, taking into account the compression of formations in gas-hydrodynamic modeling, interpretation of mining data and other issues.
In order to study and assess the skin effect associated with obliteration and compression, it is necessary to analyze real well data during the operation of productive oil layers. Three of them used the concepts of "normal" production, productivity, as well as the lowest production and productivity of the oil well in operation, and analyzed the performance of the well for several years.
This analysis is based on the fact that production changes from depression to exponential law. The article puts forward a version of the existence of obliteration and compression skin effects along with colmatation in a practical example, and a methodology has been developed and tested to determine them. It has been found that during real depressions for collectors, these skin effects (So-c) may be greater than the colmatation skin effect (Scol). However, in practice, the value of the Scol is not accurately determined by one measurement based on the pressure build-up curve. The skin effect of obliteration and compression (So-c) is simply often negligible.
In order to assess the skin-effect of colmotion and obliteration-compression in the reduction of well production, calculations were made at the values of the contour radius Rk = 150 m and well radius rq = 0.1 m. As a result, it was determined that the production of wells can be reduced by 64% due to the obliteration-compression effect. This is about 10 times more than skin effect of colmotation.
It was determined that the skin-effect of obliteration and compression had a greater effect on productivity should be taken into consideration when forecasting well production.
Keywords: obliteration, skin effect, collector, productivity, production, pressure