RU2344273C1 - Method of well hole operation and making - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil industry and may find application in operation and making of well horizontal hole in oil beds, where areas of drilling agent absorption are available. Substance of invention: when isolating area of complete drain, at first mixture of oil, cement and calcium chloride is pumped in the following ratio: oil:cement:calcium chloride as 1:(1-4):(0.002-0.24) by volume - accordingly in volume of 6-12 m³. Mixture is held for 12-14 hours. Then cement mortar is pumped in, containing 2-6% of calcium chloride in volume of 6-18 m³ and held for up to 2 days. Well operation in the first 10 days in done at minimum flows and pressures, at which well operation is possible.

EFFECT: better reliability of complete drilling agent drain area isolation, increase of well debit and reduction of time required for oil resources workout.

1 ex

Description

The invention relates to the oil industry and may find application in the operation and wiring of a horizontal wellbore in oil reservoirs in which mud absorption zones are encountered.

A known method of constructing a well of a multilayer oil field, including drilling a well to the design depth, lowering the production casing and cementing it. After opening the first oil reservoir by drilling, the well is fixed. Further, the drilling of the well continues with a bit of smaller diameter, revealing the remaining productive formations with subsequent cementing of the drilled part of the well. The last tubing shank pipes extending opposite the first oil reservoir are selected from easily drilled material, for example fiberglass. In this case, before the cementing of the well, a disconnector is installed opposite the reservoir, which is lowered into the well as a part of the casing, followed by cementing of the separated part of the well below and above the disconnector (RF Patent No. 2161239, publ. 2000.12.27).

The disadvantage of this method is that when an open absorption zone with extremely high permeability, called the zone of complete drilling mud withdrawal, the drilling process becomes uncontrollable due to the difficulty of monitoring the drilling fluid withdrawal. Drilling fluid penetrates into the formation to a considerable depth, worsens reservoir properties. As a result, after completion of drilling, the well is put into operation with a low oil production rate. Its operation is delayed for a long time, due to the increased cost of its maintenance

Closest to the proposed invention in technical essence is a method of operating and wiring a horizontal wellbore, including wiring the well with opening the complete drilling mud care zone, stopping the wiring, operating the well until profitability or flooding of the produced products is achieved, isolating the complete mud drilling zone, descent from using the coiled tubing installation of long flexible pipes with a downhole motor and an eccentric bit and continuing wiring to the next full zone ode mud or design point with flushing oil by its closed-loop circulation wellbore operation (RF Patent № 2234597, published 2004.08.20 -. prototype).

The known method involves the isolation of the zone of complete care of the drilling fluid after the development of the productive interval, which reduces the flow rate of the well, because at the same time, other productive intervals remain uncovered, and the time for developing reserves of the deposit is delayed. The invention solves the problem of improving the reliability of isolation of the complete drilling mud care zone, increasing the well production rate and shortening the oil production time.

The problem is solved in that in the method of operating and conducting the well, including conducting the well with opening the complete drilling mud zone, stopping the wiring, isolating the full drilling mud zone, continuing the wiring to the next full drilling mud zone and isolating it or the design point and operating wells, according to the invention, when isolating the complete care zone, first a mixture of oil, cement and calcium chloride is pumped in the ratio oil: cement: calcium chloride as 1: (1-4) :( 0.002-0.24) by volume, respectively a volume of 6-12 m ³ , carry out technological exposure for 12-14 hours, pump a cement solution containing 2-6% calcium chloride in a volume of 6-18 m ³ , carry out technological exposure for up to 2 days., and well operation in the first 10 day lead at minimum costs and pressures at which well operation is possible.

SUMMARY OF THE INVENTION

When a well is drilled in an inhomogeneous reservoir, zones with extremely high absorption of fluids are found — complete care zones, characterized in that even with a slight excess pressure, the zones absorb the supplied fluid in unlimited volumes, for example, drilling mud. The isolation of such zones is extremely complex and ineffective by known methods. In the presence of such zones, the well is unstable, there are drops in production rates or an excessive increase in injectivity without a clear increase in reservoir pressure. The proposed method solves the problem of increasing the reliability of isolation of the zone of complete drilling mud care, increasing the flow rate of the well and reducing the time for the development of oil reserves. The problem is solved as follows.

They conduct the wellbore with the opening of the complete drilling mud care zone. This zone is characterized by the fact that it completely absorbs drilling fluid under a pressure higher than hydrostatic. Stop wiring. Isolate the complete drilling mud care zone. For this, a mixture of oil, cement and calcium chloride in the ratio of oil: cement: calcium chloride as 1: (1-4) :( 0.002-0.24) by volume, respectively, is pumped into the zone of complete drilling mud care. The volume of the injected mixture is 6-12 m ³ . Close the well and conduct technological exposure for 12-14 hours. Then a cement solution containing 2-6% calcium chloride in the amount of 6-18 m ^{3 is} pumped in, the well is closed and technological exposure is carried out for up to 2 days. The duration of technological exposure is determined by the amount of calcium chloride, which is an accelerator of setting cement. As a rule, technological exposure is prescribed from 0.5 to 2 days. Continue wiring to the next complete drilling mud care zone and its isolation or design point. Well operation in the first 10 days. lead at minimum costs and pressures at which well operation is possible, i.e. at minimum flow rates of the order of 0.5-2 t / day. This allows you to save the installed insulation material in the reservoir and extend its hardening period.

The use of oil cement contributes to filling the complete care zone with a viscous inactive mass, which slowly sets as oil is replaced by water in reservoir conditions. The presence of calcium chloride in oil cement contributes to the rapid setting and hardening of cement at the first contact with formation water. Due to this, a strong and dense plugging layer is created in the complete care zone. Subsequent injection of a cement solution with calcium chloride allows you to quickly create a strong layer of durable cement stone behind a layer of oil cement. However, even with such isolation, well development is carried out in gentle conditions that do not allow sharp technological loads on the isolation of the complete care zone.

Concrete example

The wiring of the trunk of the oil producing well is conducted with the opening of the zone of complete drilling mud leaving in the range of 825-827 m. The wiring is stopped. Isolate the complete drilling mud care zone. To do this, pump a mixture of oil, cement and calcium chloride in the ratio of oil: cement: calcium chloride as 1: 2: 0.1 in volume, respectively, in a volume of 7 m ³ . Close the well and spend technological exposure for 12 hours. A cement solution containing 4% calcium chloride is pumped in a volume of 12 m ³ , the well is closed and technological exposure is carried out for 1.5 days. They continue drilling to the next complete care zone at 830-832 m, similarly to the above, isolate this zone and continue drilling to the design point at 840 m. The wells are operated at the minimum production rate of 1 t / day for the first 10 days.

As a result, it is possible to completely isolate the complete care zone, put the well into operation and produce oil from the entire productive interval, and thereby increase the flow rate of the well and shorten the life of oil reserves.

The application of the proposed method will allow to solve the problem of improving the reliability of isolation of the zone of complete drilling mud care, increasing the flow rate of the well and reducing the time for the development of oil reserves.

Claims (1)

A method of operating and wiring a well, including wiring a well with opening the complete drilling mud zone, stopping the wiring, isolating the full mud zone, continuing the wiring to the next full mud zone and isolating it or the design point and operating the well, characterized in that when isolating the complete care zone, first a mixture of oil, cement and calcium chloride is pumped in the ratio oil: cement: calcium chloride as 1: (1-4) :( 0.002-0.24) by volume, respectively, in a volume of 6 -12 m ³ those restraint technologically for 12-14 h, is pumped cement slurry containing 2-6% calcium chloride in the amount of 6-18 m ^{3, the} process carried out exposure to 2 days, and wells operation in the first 10 days are at minimum costs and pressures at which may well be exploited.