Production log tests

Determination of leakage spots in the production column, tubing, bottomhole, second bore cutting-in interval is used in all categories of wells with different survey technologies: injection from the water conduit, unit, flowing, invoking the inflow by compression or swabbing, injection of short-lived radioactive isotopes

TASKS HANDLED:

• Determining places of leakages of the production column and downhole equipment;
• Determining the type of leaks: casing or tubing couplings, fractures along the body of the pipe, column rupture, tubing breakage;
• Monitoring well structure technical members;
• Defining flow rate (injectivity) of leaks;
• Determining the leaked interval inflow composition;
• Detecting behind casing leaks.

Defining the Inflow Profile

Defining the inflow profile is based upon recording the physical fields determined by the presence and structure of fluid flows in the wellbore and near-wellbore space. The measurements are carried out with steady (long-term operating wells), unsteady (wells with changing flow conditions), and transient thermodynamic fields. Unsteady conditions occur after a well is started or shut-in. The combination of a short-time start and a subsequent stop leads to the appearance of transient fields. To solve the problems of determining the inflow profiles and sources of water troubles, surveys under various conditions are used: in the shut-in and flowing wells, as well as in the process of invoking the influx through swabbing, ejector unit, flowing wells and compression. Measurements are carried out within a separate interval of detailed studies. When working in wells with low reservoir pressures (non-flowing), additional measurements along the wellbore in the variation intervals of the static and dynamic levels of the media interfaces are performed. SOVA, KSAT and PLT series integrated geophysical equipment is used.

Methods used:

• Gamma ray logging;
• Magnetic collar locator;
• Barometry, manometry;
• High-sensitivity temperature logging;
• Dielkometric moisture logging;
• Inductive resistance logging;
• Thermoconductive flow indicator;
• Mechanical flow measurement.
• Acoustic noise logging

TASKS HANDLED:

• Marking oil, water and gas inflow intervals;
• Defining the inflow profile, sources of water troubles;
• Estimating flow rate and inflow composition, determining water cut percentage;
• Marking intervals of radiogeochemical anomalies;
• Determining the position of static and dynamic levels of wellbore phase separation.

Determining the Injectivity Profile

In determining the injectivity profile, injectivity profile and intervals, behind the casing leaks intervals are marked, total and interval volume of well-injected water is determined, injection pressure and overburden on formation are determined. Geophysical surveys are carried out whilst injection, outflow and in a shut-in well. Water is injected from the water conduit or the unit. SOVA, KSAT and PLT series integrated geophysical equipment is used for surves

Methods used:

• Gamma ray logging;
• Magnetic collar locator;
• Barometry, manometry;
• High-sensitivity temperature logging;
• Thermoconductive flow indicator;
• Mechanical flow measurement

TASKS HANDLED:

• Determining well injectivity.
• Recording injected fluid discharge profile.
• Determining the column integrity below the tubing shoe and packer.
• Determining the tubing integrity against the set of measurements: high-sensitivity thermometer, indication downhole flowmeter, manometer

Swabbing

Swabbing involves reducing the well fluid level by step-by-step carry over of the over-the-piston (swab) fluid volumes to the surface. Standard equipment for well workovers and geophysical lifts equipped with a regular logging cable are used for the work. On the X-mas tree, a tee and quick-release valve and a geophysical lubricator equipped with a hydraulic stuffing box are mounted. The tee and quick-release valve is hooked up with a measuring tank.

TASKS HANDLED:

• Lowering of the liquid level before perforation to ensure formation fracturing at the underburden on formation;
• Well developing;
• Bottomhole formation zone cleaning;
• Increasing production well flow;
• Invoking formation inflow whilst geophysical surveys: hydrodynamic, determining inflow profile, source of water troubles, diagnostics of well integrity.

Well Development Using UEOS Type Ejector Pump (Jet Pump)

To develop wells by ejector surveys, UEOS jet pump is used to invoke inflow from the formation to survey wells and influence on the subsurface formation zone, in particular for fields with abnormally low reservoir pressures and high (up to one Darcy) reservoir permeability. Designed for developing and intensifying inflow, long-term oil production in complicated downhole conditions – sand ingress, high gas factor, water cut, temperature, with deteriorated reservoir filtration properties, in directional and curved wells

TASKS HANDLED:

• Lowering the bottomhole pressure and invoking formation inflow;
• Wireline cable eophysical surveys in the mode of preset values of underburdens on formation by geophysical instruments not exceeding 43 millimeters in diameter;
• Formation hydroimpact;
• Multi-cycle hydrodynamic studies from smaller underburdens on formation to larger ones with recording of bottomhole pressure by autonomous manometers;
• Conducting hydrodynamic surveys in wells under steady or unsteady conditions;
• Formation influence by hydrodynamic methods, physical fields using small-sized devices run into the borehole on a cable in modes of underburden on formation;
• Retrieving reaction products out of the near-wellbore formation zone under various chemical treatments.

Determining Current and Residual Oil and Gas Saturation

Determination of the current and residual oil and gas saturation by pulsed spectrometric neutron gamma-ray logging (PSNGR) is based upon recording the gamma radiation of inelastic scattering (GRIS) and radiation capture (GRRC) of neutrons generated by a high-frequency fast neutron emitter. In the modification of carbon-oxygen logging, the generator used emits 14 MeV neutron pulses at a certain fixed frequency (~ 10 kHz). Analysis of the spectra of GRIS and GRRC, due to their individual features for the elements composing the rock, makes it possible to determine the mass contents of carbon, oxygen, calcium, silicon and a number of other elements in the rock, thus ensuring the solution of problems of evaluation of porosity, lithology, and oil saturation.

TASKS HANDLED:

• Estimating current and residual oil saturation;
• Defining intervals of water cut of reservoirs irrespective of mineralization of formation waters;
• Section lithologic dismemberment;
• Supporting the process of reservoir oil recovery intensification.

Gyroscopic Directional Survey

Gyroscopic directional survey is performed to determine the wellbore spatial position, to adjust the well path during drilling of directional wells and to verify matching of the actual wellbore path and the design data

TASKS HANDLED:

• Monitoring the specified direction of the borehole axis in space;
• Marking borehole axis bend segments that can cause complications during drilling and operation;
• Determining true depths of productive formations.