Education of the republic of uzbekistan tashkent state technical university named after islam karimov

 
Keywords:
gas, gas recovery, reservoir, terrigenous rocks, filtration - capacitive properties, 
Jurassic, deposits.

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108 
INTRODUCTION. 
Currently, none of the researchers denies the fact that it is not possible to 
achieve 100% recovery of the volume of gas contained in the pore space of productive reservoirs 
during the development of gas and gas condensate deposits in a natural mode [1, 4, 5, 7, 9 , 10, 12, 
13]. 
For a long time [12], not fully extraction of gas was related to economic factors, since the use 
of secondary methods made the production of residual gas unprofitable. 
In addition, deposits were brought into development, confined to high-capacity, highly 
permeable non-clay reservoirs with a homogeneous granular structure, with a large reserve of 
reservoir energy, in which the proportion of residual gas did not exceed 5-10 % of the total volume. 
Therefore, this amount of unrecovered gas could be neglected. It should also be pointed out that 
under the conditions of the gas regime, the pressure of the "overflow", when the reservoir energy is 
no longer sufficient for the flowing of wells, was empirically found to be of the order of 0.1 MPa. 
Therefore, in the formula for calculating reserves by the volumetric method, the gas recovery 
factor (К
ex.g
) was taken equal to 1 [1]. 
However, the involvement in the development of reservoirs of which are characterized by 
relatively low reservoir properties and a small reserve of reservoir energy, as well as reservoirs in 
which the reservoir pressure is either below hydrostatic or close to it, has led to the fact that the 
share of not extracted from the reservoir gas in the gas development mode has become very 
significant. 
In the Republic of Uzbekistan, such a problem arose in connection with the development of 
gas condensate deposits confined to the terrigenous reservoirs of the Jurassic deposits of the Ustyurt 
oil and gas region. 
Lerner U [7] studied in detail the structure of reservoirs, filtration-volumetric and productive 
characteristics of reservoirs, the structure of their pore space, granulometric composition, degree of 
clay content and the effect of these indicators on the degree of gas recovery from reservoirs. The 
characteristics of deposits and reservoirs were established for the calculated gas recovery factor, 
which was determined by the equation: 
(1), 
where: 
Q
g. 
produced - the total volume of produced gas before the completion of 
development, million m
3
; 
Q
g. 
geological. - gas reserves listed by deposits calculated by the volumetric method, the 
material balance method or any other method provided for by the current regulatory framework. 
The amount of gas recovery of productive terrigenous reservoirs developed in the natural 
(gas) mode essentially depends on: 
- the reliability of determining the initial hydrocarbon (HC) reserves; 
- the effectiveness of the selected development system, allowing the drainage processes to 
cover the entire reservoir; 
- lithological features of the structure of reservoirs (grain size, degree of sorted, clay content, 
etc.); 
- uniformity of the structure of the pore space of reservoirs over the area of the deposit and the 
section (uniformity in porosity and permeability); 

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109 
- Consistency of reservoir layers in terms of thickness and uniformity of their interlayers in 
terms of reservoir properties. 
According to these factors, an analysis of the change in the final gas recovery (h
г
) of the 
deposits was carried out.