RU2406822C1 - Surveying method of horizontal well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: pipe string with perforated section on the end surface is arranged in horizontal part of the well. Bottom-hole instruments are arranged in perforated section, namely the instruments connected to logging cable. Bottom-hole instruments are lowered and moved along the pipe string by pushing of logging cable with instruments to the well or lifting it from the well. Pipe string and logging cable is chosen from condition of ratio of diametre of inner surface of pipes to diametre of outer surface of logging cable of not more than 1.82. Before the surveys are performed, well liquid is replaced with fresh water with addition of "МЛ-81Б" surface-active substance in quantity of 0.1-0.3 vol. % and process exposure is performed till the well temperature is recovered. Pipe string is equipped with starting clutches. Well stimulation is performed by pumping of nitrogen from the mouth to tube space using compression method. Parametres are measured by means of bottom-hole instruments and measurement results are processed.

EFFECT: increasing efficiency of surveys.

Description

The invention relates to the oil industry and can be used in studies of horizontal wells.

A known method of hydrodynamic research of horizontal wells, including the placement of instrumentation at the end of the string of flexible pipes, inside which a geophysical cable is passed, pushing the flexible pipes into the horizontal wellbore, injecting fluid or gas through the flexible pipe cavity and conducting research (Osadchiy V.M. , Teleshkov V.M. State and prospects of development of technology for research of horizontal wells during testing and operation // Scientific and Technical Bulletin "Karotazhnik". 2001, p.107-19).

The disadvantage of this method is the complexity of the excitation of the well in the research process and the need to change the position of the pipes to study different intervals of the horizontal wellbore.

Closest to the proposed invention in technical essence is a method of hydrodynamic research of horizontal wells, including placing containers in the form of pipe sections with slots in the tubing string, installing deep autonomous instruments inside the containers, lowering the tubing string into the well, installing in vertical parts of the well in the tubing string of the sucker rod pump, below which a filter is placed from the perforated portion of the tubing of the pump string o-compressor pipes, through slots in containers and a perforated filter, the flow of well fluid to the pump from the tubing string and annulus, stimulation of the well with a sucker rod pump, measurement of parameters using depth instruments located in horizontal sections with different geophysical characteristics, and processing of measurement results (RF patent No. 2243372, publ. 12/27/2004 - prototype).

The known method allows you to use only stand-alone deep devices, which does not allow you to quickly make decisions on the operation of the well.

The proposed invention solves the problem of increasing the efficiency of research.

The problem is solved in that in a method for researching a horizontal well, including placing in a well a string of pipes with a perforated section plugged from the end in the horizontal part of the well, placing in the perforated section of the downhole tools, exciting the well, measuring parameters using downhole tools and processing the measurement results, according to According to the invention, as depth devices, devices connected to a geophysical cable are used, the pipe string and the geophysical cable are selected from the condition the diameter of the inner surface of the pipes and the diameter of the outer surface of the geophysical cable is not more than 1.82, the pipe string is provided with start-up couplings, the lowering and moving of downhole instruments along the pipe string is carried out by pushing the geophysical cable with instruments into the well or lifting it from the well, before carrying out the research, replace the well fluid with fresh water with the addition of the surfactant ML-81B in an amount of 0.1-0.3 vol.% and carry out technological exposure to restore the temperature in the well, and the excitation the wells are carried out by a compressor method by injection of nitrogen from the wellhead into the annulus.

SUMMARY OF THE INVENTION

The study of horizontal and multilateral wells to determine the profile of inflow and intervals of water supply (in flooded wells) is an urgent task today, especially for wells with an uncased horizontal part. In such wells, stand-alone devices do not provide operational information about the properties of the intervals of the reservoir, and devices delivered to the horizontal wellbore on a rigid cable do not reach the bottom. The proposed invention solves the problem of increasing the efficiency of research through the use of instruments on a geophysical cable. The proposed method solves the problem of delivering devices on a cable to a horizontal wellbore, which, in combination with connecting devices to a cable, solves the problem of research efficiency.

The problem is solved as follows.

When examining a horizontal well, a string of pipes is placed in the well with a perforated section muffled from the end in the horizontal part of the well. Perforate the pipe section with round or slotted holes. In the upper part, the pipe string is equipped with start-up couplings, usually located at a depth of 700 and 900 m from the wellhead. As depth instruments, devices connected to the cable are used. The pipe string, geophysical cable and instruments are selected from existing assortments for cable, instruments and pipes and from the condition of a minimum clearance between the inner surface of the pipes and the outer surface of the geophysical cable and instrument. This ensures the absence of cable bends, loops, etc. In these conditions, the rigidity, stability of the cable and the ability to push the devices deep into the well are retained as much as possible. The ratio of the inner diameter of the pipes and the diameter of the outer surface of the geophysical cable should be no more than 1.82. So, for example, with an outer cable diameter of 35 mm, the string can be made up of a maximum of pipes with an inner diameter of 63.5 mm (2.5 inches). With a larger ratio, difficulties arise in pushing the cable with the devices through the pipes due to the curvature of the cable and the loss of stiffness.

Geophysical studies are carried out by the methods of thermometry, thermoconductive debitometry, moisture metering, resistivity measurements, gamma-ray logging, pulsed neutron logging, etc. The lowering and moving of downhole tools along the pipe string is carried out by pushing a geophysical cable with instruments into the well or lifting from the well. As a string of pipes in the horizontal bore interval, a string of metal or non-metallic pipes, for example, polyethylene, polypropylene, vinyl plastic, fiberglass, and the like, is used. Such pipes allow not only determining the parameters of the reservoir fluid, but also the parameters of the rock in the near-wellbore zone. So, when using metal pipes for these purposes, you can use a small-sized pulsed neutron generator, and with non-metal pipes, an induction logging tool. Before conducting the research, the well fluid is replaced with fresh water with the addition of the ML-81B surfactant in an amount of 0.1-0.3 vol.% And technological exposure is carried out until the temperature in the well is restored. MP-81B exhibits properties similar to soap or good lubricant, i.e. reduces friction and helps slip the cable through the pipes. Due to this, the ability of the cable to push devices deep into the well increases. After placement in the horizontal section of the pipes of the downhole instruments, the wells are excited, the parameters are measured using the downhole instruments located in horizontal sections, and the measurement results are processed. Well excitation is carried out by injecting nitrogen into the annulus and reducing the pressure when nitrogen reaches the start-up clutch.

The preparation ML-81B is produced by industry in accordance with TU 2481-007-48482528-99 and is a multicomponent mixture of anionic and nonionic synthetic surfactants of various chemical structures, taken in a strictly defined ratio. ML-81B has a liquid consistency, a density of 1070-1090 kg / m ³ , has an average viscosity, dark brown color, a weak specific smell. Non-toxic, explosion-proof and fireproof, does not contain biologically rigid components. It is well soluble in fresh, sea and produced water, forming colloidal solutions. The hydrogen index of a 1% solution of ML-81B in distilled water is 7–9.

Concrete example

Perform hydrodynamic studies of a horizontal oil well. The well has a vertical section 1160 m long and a horizontal section 160 m long. The horizontal section of the well is made without a casing string. A tubing string with an inner diameter of 63.5 mm was lowered into the well. The lower part of the column 160 m long is made of perforated fiberglass pipes. The pipe end is drowned. As depth devices, devices connected to the cable are used, in particular KSAT-7 (device diameter 38 mm), SOVA-3-28 (device diameter 28 mm), IK-42K (device diameter 42 mm), IGN-30 (diameter instrument 30 mm). Geophysical studies are performed by the methods of thermometry, thermoconductive debitometry, moisture measurement, resistivimetry, gamma-ray logging and pulsed neutron logging. The pipe string, geophysical cable and instruments are selected from the condition of the minimum clearance between the inner surface of the pipes and the outer surface of the geophysical cable and instrument, in particular the KG3-300-90-Oa geophysical cable with an outer diameter of 35 mm and a pipe with an inner diameter of 63.5 mm . Replace the well fluid with fresh water with the addition of the surfactant ML-81B in an amount of 0.2 vol.%. (The use of fresh water with the addition of the ML-81B surfactant in an amount of 0.1 to 0.3 vol.% Leads to a similar result.) Lowering and moving downhole tools along the pipe string is carried out by pushing the geophysical cable into the well and lifting from the well with appliances. After placing the devices, technological exposure is carried out for 24 hours, i.e. to restore the temperature in the well. Excitation of the well is carried out by the injection of nitrogen into the annulus before it enters the pipe string through the starting couplings. Measure the parameters of the reservoir fluid and the reservoir using deep instruments located on a horizontal section of the well. The processing of measurement results is carried out.

As a result, it is possible to solve the problem of increasing research efficiency through the use of instruments on a geophysical cable and to solve the problem of delivering instruments on a cable to a horizontal wellbore.

The application of the proposed method will improve the efficiency of research of horizontal wellbores.

Claims (1)

A method for examining a horizontal well, including placing in a well a string of pipes with a perforated section muffled from the end in the horizontal part of the well, placing deep instruments in the perforated section, exciting the well, measuring parameters with the help of deep instruments and processing the measurement results, characterized in that as deep instruments use instruments connected to the geophysical cable, the pipe string and the geophysical cable are selected from the condition of the ratio of the diameter of the inner surface the pipe diameter and the diameter of the outer surface of the geophysical cable is not more than 1.82, the pipe string is provided with start-up couplings, the lowering devices are lowered and moved along the pipe string by pushing into the well or lifting the geophysical cable from the well with instruments, before carrying out the research, replace the well fluid with fresh water with the addition of the surfactant ML-81B in an amount of 0.1-0.3 vol.% and carry out technological exposure until the temperature in the well is restored, and the well is excited by compress by injection into the annulus from the mouth of nitrogen.