In the geological and field analysis of an oil field, the principal goal is to evaluate the effectiveness of the development system by analysing its technological indicators. Improvements in technological indicators can be achieved by making changes to the current development system or by improving it while regulating field operations. But to a greater extent, the technological development indicators depend on the geological and physical characteristics of the oil reservoir. The determining factors are the type, size, and shape of the oil deposit, the heterogeneity of the structure of the productive object, the oil reserves in it, and the relative mobility of the oil.

As a first step, databases of geological and field characteristics of the development object must be built, replenished, or acquired. In addition, it is necessary to have a package of processing programs that correspond to the formats of the available databases.

Geological and field analyses determine the type and size of the deposit and its structural and tectonic characteristics (erosion, tectonic disturbances, unconformity surfaces, etc.). Data from drilling new wells and the positions of current water oil contact (WOC) and gas oil contact (GOC) marks of developed deposits can be used to specify the initial position of COC and GOC.

In order to determine the reservoir's lithological variability, reservoir distribution maps may construct, which should contain the following basic information: reservoir presence zones, reservoir absence zones, zones of distribution of various reservoir lithotypes and zones of reservoir confluence with overlying and underlying productive layers.

The directed geological models should be built based on databases, using the appropriate software. These models are used to represent both a three-dimensional image of a productive reservoir as well as various planar images (geological profiles, horizontal sections, mapping schemes, etc.).

It is mandatory that all geological maps, profiles, and any image of a productive reservoir contain information on the development of the reservoir.

The main lithological and physical characteristics of the development object need to be specified according to the core data, well logging, and hydrodynamic studies. Depending on the purpose, these studies can either be standard or special. The difference between them is determined only by the set of studied properties of reservoir rocks and the tasks that need to be solved for a particular development object.

Specification of heterogeneity of productive layers is mainly related to the detailed reservoirs of the development object. Along with the standard methods of the manual version, automated methods of well-section correlation can be used. However, correlation itself should always be preferred in the traditional geological plan, since the geologist uses much more information and his own experience in this operation than the automatic correlation algorithm. Correlation methods that combine traditional and automated methods give the best and fastest results in these studies.

Summary-statistical sections, which can be used to characterize development object heterogeneity, take into account only reservoir presence or absence in vertical sections. This widely used method should be supplemented with data on the quantitative values of the main lithological and physical parameters of the development object (porosity, permeability, oil saturation, etc.), which increases the information content of such summary statistical sections.

A geological and field analysis provides information about the heterogeneity of the development object by specifying average values and variations of parameters, net-to-gross ratios, compartmentalization, and constructing maps of these parameters for selected reservoir objects (packs, layers, etc.). It is not difficult to perform these operations with the appropriate databases.

The physicochemical properties and composition of formation fluids should be specified with particular care. A sufficient number of analyses is required to examine the distribution of properties over the area and section of the development object. It is important to compare new data with initial estimates since oil properties (such as density and conversion factor) can vary depending on how long the object has been under development.

The purpose of laboratory studies of the core and the properties of formation liquids and gases over sections and areas of oil deposits is to clarify the variability of geological and physical characteristics.

The development of a field (or hydrocarbon deposit) is a continuous process involving geophysical and field analysis, the intermediate results of which are summarized when any development project document is prepared (a development flow chart, a development project, or additional development. It is, therefore, necessary and desirable to present materials uniformly for the analysis of the development of oil and gas-oil fields so that it is possible to objectively compare the efficiency at which oil reserves are extracted from various deposits and fields.

During geological and field analyses of the development process, the most important task is determining whether design solutions are adequate for specific geological and mining conditions of deposits and fields and whether they have been implemented completely. To accomplish this two-pronged task, in essence, the following tasks should be performed:

• assessment of the energy state of the deposits;
• the dynamics of changes in the water cut of the products produced;
• assessment of the nature and extent of the development of oil reserves;
• evaluation of the effectiveness of methods to improve well productivity and increase oil recovery.

Providing complete information about the development process is vital to the quality of work on the analysis of it because the frequency and volume of the field studies of wells and formations are determined by the current instructions and guidance documents. In order to control the development of productive formations, it is essential to implement research programs to the fullest extent possible.