RU2719889C1 - Drilling method in water area - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry, in particular to drilling wells in water area with preliminary testing of possible complications in form of abnormally high formation pressure (AHFP), absorption of drilling mud and clamping of drilling tool. To implement the method drilling under the direction and drilling of the rock interval for the conductor is performed in two stages. At the first stage to detect possible complications, a drilling tool is used in the form of a casing pipe (CP) equipped with a burglar gear. At the second stage drilling under direction and drilling of the interval for the conductor is performed by CP equipped with a bit. At the first stage of the drilling for the conductor interval there used is either industrial water or sea water or drilling fluid depending on geological conditions. Drilling solution is used at the second stage of drilling the interval for conductor. Drilled interval is cased with a conductor with subsequent cementing; the next interval is drilled similarly.

EFFECT: technical result is improved efficiency and safety of drilling due to reduced time for elimination of the complication.

4 cl, 7 dwg, 8 tbl

Description

The invention relates to the oil and gas industry, in particular, to drilling wells with their preliminary investigation in the testing mode of possible complications in the form of abnormally high reservoir pressure (AAP), mud absorption and sticking of a drilling tool in case of talus and landslides.

As you know, exploration drilling complications occur, the elimination of which takes time and materials. When drilling on the Arctic shelf, in addition to the manifestations of surface gas and gas hydrates, there were cases of absorption of the drilling fluid and sticking of the tool due to talus and landslides (Fig. 1). According to foreign data, AVPD was observed during hoisting operations (STR) 44%, during drilling 41%, during circulation 9% and other operations on the drilling 6% (Anti-spontaneous safety. IWCF, AMNGR Education Center. - Murmansk: AMNGR, 1995. - 195 with.). In this regard, ensuring the safety of drilling is very important.

There is a method of opening a productive horizon in terms of AAP (Pat. RF No. 2309203, publ. 09/07/1995), including drilling at an active interval after preliminary determination of the nature of the complication during technological operations with the initial technological parameters, then change the technological parameters, determine the likelihood of complications, further deepening along the active interval is carried out with parameters that meet the condition set forth in the description of the invention.

The technical result, to which the claimed invention is directed, consists in increasing the safety of drilling, the economic efficiency of drilling by reducing the time to eliminate the complication.

To achieve a technical result in the proposed method of drilling in the water area, drilling under the direction and drilling the interval of rocks under the conductor is carried out in two stages, at the first stage, to identify possible complications, a drilling tool in the form of a casing (OT) equipped with a burgole is used, at the second stage, drilling for the direction and drilling of the interval for the conductor, an OT equipped with a bit is carried out, while in the first stage of drilling the interval for the conductor, either technical water, or sea water, or drill new solution, depending on geological conditions, at the second stage of drilling the interval under the conductor, drilling fluid is used, the drilled interval is cased with a conductor followed by cementing, drilling of the next interval is carried out similarly.

There is standard drilling and casing technology (Drilling with Casing Advances to Floating Drilling Unit with Surface BOP Employed. Edi Sutriono-Santos, Ralph Adams-Santos, Greg Galloway - Weatherford, Ken Dalrymple - Weatherford. 2003 World Oil Casing Drilling Technical Conference )

The proposed drilling method is illustrated by the drawings shown in FIG. 1-7.

In FIG. 1 presents statistics of complications, in FIG. 2 is a schematic representation of standard drilling; FIG. 3 is a schematic representation of casing drilling (OT) with a bit; FIG. 4 is a schematic illustration of the proposed drilling method, in FIG. 5 is a schematic representation of standard drilling at the time of the complication (Instructions for calculating drill strings for oil and gas wells. IRBK-97), FIG. 6 is a schematic representation of casing drilling (OT) with a bit at the time the complication manifests itself; FIG. 7 is a schematic illustration of the proposed drilling method at the time of the development of surface gas.

In the figures, the positions indicated:

1 - water area

2 - direction

3 - interval under the conductor

4 - casing (OT)

5 - burgolovka

6 - chisel

7 - seabed

8 - drilling fluid.

The essence of the proposed method of drilling in the water area is as follows.

Drilling in water area 1 under direction 2 and drilling of intervals 3 under the conductor is carried out in two stages: in the first, to identify possible complications, casing 4 (OT) equipped with a burgole head 5, in the second - OT equipped with a bit 6. Drilling in water area 1 first produced under direction 2. For this, a drilling tool is lowered into the bottom of the sea 7 in the form of a casing 4 (OT) equipped with a burgole 5, for example, of a cutting type and drilling is carried out, for example, to a depth of 90 meters, but it is preferable to drill to a greater depth, which will provide a safety margin when drilling OT with a bit 6 in the second stage. Then the drilling tool is lifted, the burgole head 5 is removed, the drilling tool is supplied with a chisel 6 and a direction of 90 m is drilled with a chisel 6, then the direction of 2 is cemented and then a cement cup is drilled. Drilling under direction 2 is carried out on sea water.

Then, an interval of 3 rocks is drilled under the conductor; for this, a drilling tool is lowered into the well in the form of an OT, for example, with a diameter of 444.5 mm. OT is equipped with a burglar head 5, for example, a cutting type. Next, drilling is carried out at the design depth of the conductor descent, for example, at 612 meters. At the same time, depending on the geological conditions that are indicated in the plan of the geological and technological order (GTN) for the construction of the well, either technical water, or sea water, or drilling mud are used 8. Eliminate complications if they occur.

Then they raise the drilling tool, remove the burgole 5, supply the drilling tool with a bit 6, lower it into the well and drill an interval of 612 meters, using drilling mud 8. A drilled interval of 612 meters is cased with a conductor, followed by cementing. The next interval is drilled again with OT with a burgole head 5, for example, at a design depth of 1600 meters and all operations are repeated. Drilling the proposed method is presented schematically in figure 4.

The proposed method of drilling in the water area in the event of a complication in the form of ARPD or absorption, or tool sticking, or ejection of a drilling tool has advantages.

When AVPD prepare weighted drilling mud (BR) design density depending on the pore pressure of the reservoir. At the same time, the volume of the weighted drilling fluid and, accordingly, the time for its preparation are significantly less compared to standard drilling (Tables 1, 4) and casing drilling (hereinafter referred to as OT) with a bit, i.e. time to eliminate complications in the form of AVPD is significantly reduced.

During the absorption, which is detected by a decrease in the level of technical water in the well, a clogging substance (nutshell, wood shavings, etc.) is pumped into the well to stabilize the water level. At the same time, during standard drilling and drilling at OT with a chisel, there is a loss of toxic drilling fluid, in the proposed method of drilling in the waters, the loss of the same volume of technical water in the case of using technical or marine water, which significantly affects the efficiency of the process, as well as the environmental friendliness of the process in winning plan (table. 5).

In the event of a tool sticking (scree, collapse, differential sticking, narrowing of the borehole walls in the case of plastic rocks), the drill string is rotated (Pustovoitenko IP Prevention and methods for eliminating drilling complications. - M: Nedra, 1987, 234 p .; A collection of instructions for drilling wells with PBU PO “Arktikmorneftegazrazvedka.” - Murmansk, 1992, 532 pp.).

To confirm the above advantages of the proposed method of drilling in the water area, below are the calculations in comparison with the standard method of drilling and drilling at the OT with a bit.

Calculation of the required volume of drilling mud (hereinafter referred to as BR) of killing during drilling using standard technology. The calculation will be from the bottom up. The following layout is given: BHA - 444.5 mm drill bit, UBT 241.5 mm 135 m, UBT 203 mm 6 m, UBT 165 mm 9 m, BT 127 mm 677 m.The direction was lowered with a diameter of 762 mm to a depth of 90 m from the sea bottom. Depth of manifestation is 612 m. Depth of water area is 193 m. Altitude of the rotor table is 22.5 m. Marine riser (riser MS-610) [Pogiev V.E., Galaburda V.K., Urmanchev V.I., Korostin V.Ya. A collection of instructions for drilling wells with a software control unit at Artikmorneftegazrazvedka III part. M: Murmansk 1992, with 535.].

The first complication under consideration is abnormally high reservoir pressure (hereinafter AVPD). Let the complication occur when drilling under the conductor at a current well depth of 612 m. To eliminate this complication, it is necessary to prepare a weighted drilling mud (KMW) with the volume of the entire well taking into account the metal of the drill string assembly.

We calculate the volume of metal in the range of location of the UBT 241.3 mm:

The volume of drilling fluid in the interval UBT 241.3:

We calculate the volume of metal in the range of location of the UBT 203 mm:

The volume of drilling fluid in the interval UBT 203 mm:

We calculate the volume of metal in the range of location of UBT 165 mm:

The volume of drilling fluid in the range of UBT 165 mm:

We calculate the volume of metal in the range of BT 127 mm - an open barrel

The volume of drilling fluid in the interval BT 127 mm - open hole:

We calculate the metal volume in the range of BT 127 mm - the direction

The volume of drilling fluid in the interval BT 127 mm - direction:

We calculate the metal volume in the range of BT 127 mm - riser

MS-610 riser volume

The volume of drilling fluid in the interval BT 127 mm - riser:

Vbrr = Vrise-VmBTR = 62.3 m ³

Total solution in the well:

Vp241 + Vp203 + Vp165 + Vp127oc + Vp127n + Vbrr = 195.2 m ³

Here is a drawing of the well during drilling in the testing mode of the complication:

Let us start drilling under the conductor from under the direction of the burgole head.

We calculate how much we need to prepare a weighted drilling fluid in the case of the occurrence of surface gas. We conduct drilling with a burgole head on casing pipes with the same diameter. The gap between the walls of the burgolovka let it be 15 mm.

We calculate how much rock is inside the casing when drilling with a burgole head. We calculate the inner diameter of the rock, DGP:

Dgp = 444.5-2 × 15 = 414.5 mm

The volume of rock Vgp inside casing and burgolovki:

Metal volume of casing pipes in an open borehole, wall thickness FROM 10 mm.

The diameter of the open hole when drilling under the conductor - burgolovka

Doc = 444.5 + 2 × 15 = 474.5 mm

Open hole drilling fluid volume

Riser metal volume in riser

The volume of solution in the riser

Vbrotr = Vrise-Vview = 60 m ³

Metal volume of casing in direction

Solution volume in the direction

The total volume of drilling fluid in the riser, direction and conductor when drilling with a burgole head

Vbrbg = Vbrotr + Vbrotn + Vprot = 114.6 m ³

We calculate the volume of drilling fluid needed to shut the hole when drilling with casing and bit technology, fig. 2.

Calculate the volume of drilling fluid in the open hole:

Vbros = Voc-Vmot = 85.2 m ³

Since the layout of the drill string in the riser and direction is identical to the drill string, the calculation of the total volume of drilling fluid in the well will be:

Vbrskv = Vbrr + Vbrnapr + Vbrisk = 185.1 m ³

Calculation of time for weighting the drilling fluid.

Let it be necessary to prepare a solution from a solution with a density of 1.12 g / cm ³ (for example, for killing a well) with a density of 1.2 g / cm ³ .

Determine the amount of clay for the preparation of 1 m ^{3 of} drilling fluid with a given density of 1.12 and 1.2 g / cm ³ . We also determine the time required to weight the entire volume of drilling fluid when applying the drilling technologies under consideration.

The density ρ mud powder _Ch = 2.6 g / cm ³ _in the density of water ρ = 1 g / cm ^3, n = 0.1 - clay humidity.

We calculate the clay mass necessary for the preparation of 1 m ^{3 of} drilling fluid of a given density, according to the formula:

Then the clay mass required to weight 1 m ^{3 of the} drilling fluid to 1.2 g / cm ³ will be equal to ΔS = S _1.2 -S _1.12 = 0.106 t.

We will find the clay mass and volume necessary to weight the entire drilling fluid volume to the required density for all the drilling technologies under consideration and summarize all the calculations in tables.

The clay mass is determined by the formula:

M _hl = V _r-ra * ΔS

Clay volume:

V _hl = M _hl / ρ _hl

We calculate the time spent on weighting the drilling fluid to the required density using a clay mixer GKL-2MA with a capacity of q = 2 m ³ / h:

T = V _rd / q

Conclusion: Since the volume of the required killing drilling fluid is reduced by 80.6 m ³ when compared with the standard drilling technology, compared to the standard casing drilling technology using a 70.5 m ³ bit, the time required to increase the required drilling fluid volume is in comparison with standard drilling and drilling at OT with a bit, it is reduced by 1 hour 39 minutes and 1 hour 26 minutes, respectively. Thus, the time to eliminate complications is carried out in a shorter period of time.

The second complication manifests itself in the form of absorption of drilling fluid with a volume of V _lost equal to 6 m ³ at a depth of 612 m. When drilling with standard technology and casing drilling technology when this type of complication is manifested, measures are taken to eliminate it (Sharubin A.S., Drilling wells absorbing horizons, M: Nedra, 1980, pp. 76–12.; Eliyashevsky IV, Sideskiy MN, Orsulyak Y. M. Typical tasks and calculations in drilling, M .: Nedra, 1982, from 178-179). To determine the coefficient of absorption capacity of the formation, you can use [Eliyashevsky I.V., Party, MN, Orsulyak Ya.M. Typical tasks and calculations in drilling, M: Nedra, 1982, p. 178]. When drilling an interval for a conductor by the proposed method, at the first stage, when using a burgole head, drilling can be carried out either on industrial water or on sea water, if geological conditions permit.

Findings. Thus, when absorbing according to the technology of drilling at an OT with a burgole, 6 m ^{3 of} industrial water or sea water is lost if they are used, and if other technologies are used, the same volume of toxic drilling mud will be absorbed.

на 5000 PSI марки Хайдрилл, плашечный превентор U типа диаметром

на 7500 PSI марки Кэмерон, режущий плашечный превентор марки Шаффен диаметром

на 5000 PSI (Противофонтанная безопасмность.IWCF, AMNGR Education Centre. - Мурманск: АМНГР, 1995 г, с 113-125).The third type of complication is a seizure of a drilling tool in case of talus-landslides in the wellbore. When drilling on casing, this complication is not a problematic complication, because seized drilling tools are cemented (Drilling with Casing Advances to Floating Drilling Unit with Surface BOP Employed. Edi Sutriono-Santos, Ralph Adams-Santos, Greg Galloway - Weatherford, Ken Dalrymple - Weatherford. 2003 World Oil Casing Drilling Technical Conference). Drilling can also be done at 508 mm under the conductor. When using standard drilling technology, the complication may result in the loss of part of the tool. The purpose of all technologies is that it is necessary to drill an interval under the conductor with a diameter of 508 mm. When using the MS-610 riser, it is necessary to use a preventer of the type: universal preventer

5000 PSI of Hydril brand, U type die-type preventer with diameter

on a Cameron 7500 PSI, Schaffen diameter cutting die preventer

at 5000 PSI (Uncontrolled Security. IWCF, AMNGR Education Center. - Murmansk: AMNGR, 1995, 113-125).

Conclusion: To achieve this goal, it is necessary to drill on casing pipes with a diameter of 508 mm. We also offer drilling by the method in test mode for OT with a burgole head, it is also necessary to conduct a diameter of 508 mm.

We compile a table of well deepening by source (Pat. RF No. 2309203, publ. 09/07/1995) and the proposed method of drilling in the water.

Based on the data table. 6 according to the source (Pat. RF №2309203) it follows that the a priori information on which the probability is based is known in advance. In the proposed method of drilling in the water area, a priori information on possible complications is missing. Summarize the data in table 7.

When using OT drilling using a burgole head, cementing a well is performed in the same way as when drilling OT with a bit.

Conclusions: For this type of complication of the problem, only standard (traditional) drilling technology will have problems.

The fourth type of complication is the ejection of a drilling tool. In the proposed method of drilling in the water area, the ejection force due to reservoir pressure, in the case of using an OT with a burgole head 5, is significantly less than the force acting on the bit, because the cutting surface area of the burgole head 5 is significantly less than the area of the bit 6 of the same denomination. The calculations below show that this force is less than 3 times less.

We calculate the buoyancy force for bit 6 and burgole 5:

For chisel:

F _D = S _D × R _pl = 1.28 × 10 ⁶ N

For burgolovki:

F _bg = S _bg × P _pl = 0.36 × 10 ⁶ N

Conclusion: since the buoyancy when drilling with a burgole head is lower than the weight of the drill string, the tool will not be ejected, and when the bit is used, the tool can be ejected, because buoyancy is almost 2 times the weight of the drill string.

Conclusion: Naturally, in the general case, the full amount of weighted drilling fluid will be required, but at the time of elimination of the complication, time is reduced. Part of the interval, if geological conditions permit, can be drilled on technical or sea water, which is a saving in drilling mud and less environmental damage. Thus, the proposed method of drilling in the water area is intended for drilling in difficult mining and geological conditions in the first place.

Claims (4)

1. The method of drilling in the water area, characterized in that the drilling for direction and drilling the interval of rocks under the conductor is carried out in two stages, at the first stage to identify possible complications using a drilling tool in the form of a casing (OT), equipped with a burgole, at the second stage drilling under the direction and drilling the interval under the conductor is carried out by an OT equipped with a bit, while at the first stage of drilling the interval under the conductor either technical water, or sea water, or drilling mud are used, depending from geological conditions, at the second stage of drilling the interval under the conductor, drilling fluid is used, the drilled interval is cased with a conductor followed by cementing, drilling of the next interval is carried out similarly. 2. The method according to p. 1, characterized in that they use, for example, a cutting type burgolovka. 3. The method according to p. 1, characterized in that the drilling under the direction at both stages are conducted in sea water. 4. The method according to p. 1, characterized in that the geological conditions are taken from the plan of the geological and technological order for the construction of the corresponding well.

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