How to develop a heterogeneous multilayer oil deposits

 

(57) Abstract:

The invention relates to the oil industry and can find application in the development of heterogeneous multilayer oil deposits. Provides increased oil recovery from reservoirs due to more complete coverage of the formation impact of involvement in the development of broken seams. The essence of the invention: lead-inject working agent through the injection wells and oil extraction through production wells from the reservoir. Stop at least one borehole, cement previously perforated intervals set in the well cement bridge with the formation of new artificial face above the perforation intervals. From a depth above the top of the perforated interval of the Buryats new inclined wellbore with the transition to a horizontal shaft bypassed in the reservoir. Have a new face at a distance of not less than 50 m from bottom hole previously drilled wells. A drilled well is used as an injection. The horizontal length of the well performing according to the required capacity of the well. The pressure and volume of injection in a drilled well to reduce exceptions breakthrough working agent in the adjacent layers through the casing, the issue is Ah increase the bottomhole pressure at a value of reduction of the pressure of injection of the working agent in injection wells.

The invention relates to the oil industry and can find application in the development of heterogeneous multilayer oil deposits.

There is a method of secondary opening productive reservoirs of oil and gas wells, comprising cutting a window in the production string above the roof of the reservoir, through the drilling of radially directed inclined holes of small diameter for clogging area and behind-the-casing flows of fluid at all productive interlayers of productive layers. In this case, applying the composite solutions are petroleum-based. The formulation of solutions to pick based on the analysis of a core from a nearby vertical wells in this area. In the operation of the window in the production string block slot filter (Patent RF №2087671, CL E 21 In 29/06, publ. 1997.08.20).

The known method does not allow to develop oil reservoir with high oil recovery.

Closest to the invention to the technical essence is a way to develop heterogeneous multilayer oil deposits, including the injection of working agent through the injection wells, oil extraction through production wells from the reservoir, stopping at least one well, the goal is the education of the new artificial face above the perforation intervals, from a depth above the top of the perforated interval the inclined drilling a new borehole with the transition to a horizontal shaft bypassed in the formation, arrangement of new faces at a distance of not less than 50 m from the faces of previously drilled wells, the purpose of the perforation density of trunks bypassed layers according reservoir properties reservoir (RF Patent No. 2097536, CL E 21 In 43/20, publ. 1997 - prototype).

There is a method allows the extraction of oil deposits are the main deposits, but deposits remain significant bypassed reserves.

In the proposed invention solves the problem of increasing oil deposits due to more complete sweep impact, involvement in the development were not engaged in productive layers.

The task is solved in that in the method of developing an inhomogeneous multilayer oil deposits, including the injection of working agent through the injection wells, oil extraction through production wells from the reservoir, stopping at least one well, the cementing pressure previously perforated intervals, setting the downhole cement bridge with the formation of new artificial face above the perforation intervals, with opertion is hydrated trunk bypassed in the reservoir, the location of the new face at a distance of not less than 50 m from bottom hole previously drilled wells, according to the invention a drilled well is used as an injection, the horizontal length of the well performing according to the required capacity of the well, the pressure and volume of injection in a drilled well to reduce exceptions breakthrough working agent in the adjacent layers through the inter-layer jumper, pumping the working agent are cyclically, and in producing wells reduce the bottomhole pressure at a value of reduction of the pressure of injection of the working agent in the injection well.

The essential features of the invention are:

1. download working agent through the injection well;

2. the selection of oil through the production wells from the reservoir;

3. stop at least one well;

4. cementing under pressure previously perforated intervals;

5. the installation stopped in the well cement bridge with the formation of new artificial face above the perforation intervals;

6. in the stopped borehole from a depth above the top of the perforated interval the inclined drilling a new borehole with the transition to horizontal the AI is not less than 50 m from bottom hole previously drilled well;

8. the use of drilled wells as injection wells;

9. the choice of the length of the horizontal section of the well based on the required capacity of the well;

10. reducing the pressure and volume of injection in hole to eliminate breakout working agent in the adjacent layers through the annulus of the main wellbore;

11. download working agent in cyclic mode;

12. in producing wells increased downhole pressure on the value of reducing the pressure of injection of the working agent in the injection well and the increase in oil extraction.

Signs 1-7 are shared with the prototype, signs 8-12 are the salient features of the invention.

The invention

When designing heterogeneous multilayer oil deposits of part of the reserves of the Deposit is not covered by the impact. In practice, the reservoir may consist of 20 or more layers. Because the layers have different permeability, porosity, etc., i.e., the reservoir is heterogeneous, production of reserves from reservoirs is uneven. All layers reveal a common filter and are under development. However, in the development involves, typically, 40-60% of net pay thickness. Ohw water along the wellbore of the stocks remains as if buried in deposits. The elimination of such flows by known means is temporary and largely ineffective. Because of the proximity of oil-water and gas-oil contacts are not opened whole areas of low productivity, which can not be involved in the development of conventional methods. For these reasons, the rate of heterogeneous multilayer oil deposits is 10-20 points lower than normal deposits. In the proposed invention solves the problem of increasing oil recovery from an inhomogeneous multilayer deposits due to more complete sweep impact, involvement in the development hasn't worked bypassed reservoirs in idle, idle, inefficient, unprofitable, high water-cut wells. The problem is solved by the following set of operations.

Stop at least one borehole, cement under pressure previously perforated intervals and set in the well cement bridge with the formation of new artificial face above the perforation intervals. Cementing pressure leads to a complete blockage of the perforations and areas around the wells and the almost complete cessation of all inflow of reservoir fluids into the well and vdol is Horatii upper reservoir cut out a window in the production string and drill new directional directional wellbore with the transition to a horizontal shaft bypassed in the reservoir. Drilling of the new wellbore and the actual liquidation of the previous stem leads to the elimination of previously formed water flows. In subsequent rule out the insulation work. Horizontal or inclined shaft Buryats only deverbative layer. Previously formed cone water and cross flows are from the new trunk at a distance of at least 20-50 m, which is enough to exclude their influence on the flooding of products produced or injected care working agent.

The location of the new faces at a distance of not less than 30 m from the faces of previously drilled wells contributes to a more complete sweep impact and development not previously produced reserves deposits.

A drilled well is used as an injection. Although in the main wellbore been cementing previously perforated intervals and the establishment of well cement bridge, behind-the-casing flows can take place. Their ability and intensity are determined by the pressure in the reservoir and the pressure differential between the layers. Therefore, the pressure and volume of injection in a drilled well choose exclusive breakthrough working agent in the MCA is in adjacent layers. This increases the uniformity of receipt of the working agent in thickness and square bypassed reservoir, increases coverage of reservoir pressure and increase oil recovery reservoir.

As is known, with increasing length of the horizontal section of the well is increased injection capacity of the well while maintaining the pressure of injection. Therefore, the horizontal length of the well performing according to the required capacity of the well. The pressure and volume of injection in a drilled well to reduce exceptions breakthrough working agent in the adjacent layers through the annulus of the main wellbore, typically on the magnitude of 2-5 MPa. The same considerations in producing wells to increase the bottomhole pressure at a value of reduction of the pressure of injection of the working agent in the injection well, i.e. the same value 2-5 MPa. Download desktop agent are in cyclic mode, basically, sut 5-16 loading, sut 5-16 stop.

The use of an existing wellbore for drilling new shafts eliminates the drilling of the main stem and reduce the cost of production works. Increasing the sweep effect and uniformity reserves allow to increase nettet is with the following characteristics: the depth of deposits 1147,5 m, the oil-water contact depth of 1000 m, the reservoir pressure of 12.5 MPa, reservoir temperature 28C, porosity 16, permeability 0,171 μm2the saturation of 0.8, the viscosity of the oil at reservoir conditions 180,2 MPas, density of oil at surface conditions 0,916 g/cm3the saturation pressure of 5 MPa, the gas factor 3,557 m3/t collector - pore. Deposit multilayer. The number of layers varies on deposits from 2 to 7. The layers are separated from each other clay layers with a thickness of 0.8-10 m Permeability of the layers varies from 0,176 to 0,083 μm2. Balance reserves fluctuate layers 17,000 to 100,000 thousand tons

Download the working agent through 180 injection wells, take away oil after 600 producing wells. Choose a production well having the maximum number of surrounding wells with broken seam passing through 2-6 layers, of which 5 subansiri oil or vodonayeva. Cement under pressure of 15 MPa at the mouth of the previously perforated intervals. From a depth of 150 m above the target horizon, i.e. from a depth above the top of the perforated interval, cut out a "window" in the production string of the required length. The inclined drilling a new borehole is produced through oketani 30 meters or more from the previous barrel. Drilled horizontal wellbore perform the necessary length of 10 meters or more in the productive interval of the formation and grow in a column (or a slit filter), perforined. If bypassed reservoir is divided thin clay bridges thickness of 4 m or less, beyond repair without destroying the cement sheath and the clogging of the source layer, a drilled well is used as an injection. The horizontal length of the well perform a length of 10 meters or more, based on the required capacity of the well. The pressure and volume of injection in a drilled well is reduced to prevent breakthrough of the working agent in the adjacent layers through the annulus of the main wellbore to the amount of 10-40% of the original. Thus, the injection pressure at the wellhead set equal to 10.2 MPa at a flow rate of the working agent 200 m3/day. As a working agent use of waste water. In the surrounding producing wells, water-saturated layers disable selective materials or cement and lead the selection of oil only from the planned reservoir. Over the next few producing wells where the reservoir newrabota, lead the selection of oil. In producing wells increases Zabrze value of 4 MPa. The bottomhole pressure is set to 3 MPa. Download desktop agent are cyclically, 15 days. download, 15 days. stop.

On the site of the Deposit, the water content of the produced oil has decreased to 20%, oil recovery deposits increased by 10% and amounted to 43%.

Application of the proposed method will increase the recovery of oil deposits.

How to develop a heterogeneous multilayer oil deposits, including the injection of working agent through the injection wells, oil extraction through production wells from the reservoir, stopping at least one well, the cementing previously perforated intervals, the installation in the borehole cement bridge with the formation of new artificial face above the perforation intervals, from a depth above the top of the perforated interval the inclined drilling a new borehole with the transition to a horizontal shaft bypassed in the reservoir, the location of the new pit at least 30 m from the bottom hole previously drilled borehole, characterized in that the drilled hole is used as an injection, the horizontal length of the well performing according to the required capacity of the well, the pressure and volume of the injection hole of Umanskaya, download desktop agent are cyclically, and in producing wells to increase the bottomhole pressure at a value of reduction of the pressure of injection of the working agent in the injection well.

 

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