The main objective of surveying accumulations and wells is obtaining information about them to calculate oil and gas reserves, designing, analyzing, regulating the development of accumulations and operating wells. The survey starts immediately after the discovery of accumulations and continues throughout the lifetime of the field, i.e., is carried out during well drilling and operating that provide direct access to the accumulation.
The composition of various measures aimed at measuring certain parameters (pressure, temperature, liquid level, flow rate, etc.) and sampling of formation fluids (oil, water, gas and gas condensate) in flowing or shut-in wells and their recording in time.
Interpretation of well hydrodynamic surveys enables to evaluate the productive and filtration characteristics of formations and wells (reservoir pressure, production flow rate or filtration coefficients, water cut, gas factor, hydroconductivity, permeability, piezoelectricity, skin factor, etc.), as well as features of the near-wellbore and remote formation zones. These surveys are a direct method for determining the rocks filtration properties under modes of occurrence, the nature of formation saturation (gas/oil/water), and the physical properties of formation fluids (density, viscosity, volumetric coefficient, compressibility, saturation pressure, etc).
Types of Surveys:
- Surveys using steady sampling method (indicator diagram);
- Surveys using unsteady sampling method (pressure build-up curve – pressure falloff curve);
- Bottomhole pressure measurement;
- Reservoir pressure measurement;
- Bottomhole temperature measurement;
- Well interaction surveys – pressure interference testing;
- Subsurface and wellhead sampling;
- Static level marking;
- Dynamic level marking;
- Recording of level build-up curve;
- Bottomhole pressure;
- Reservoir pressure;
- Reservoir temperature;
- Bottomhole zone skin factor;
- Formation productive flow rate;
- Formation fluid mobility;
- Formation permeability;
- Formation hydroconductivity;
- Formation piezoelectric conductivity;
- Potential liquid flow rate (oil, gas, water);
- Average daily flow rate of liquid and gas with determination of the oil-water content in percents;
- Density of formation fluid;
- Recommendations on the optimal exploitation regime for the reservoir during its further operation.