The way to develop flooded oil fields with inhomogeneous zonal and rannapromenaadi layers

 

(57) Abstract:

Usage: to develop flooded oil fields with inhomogeneous zonal and rannapromenaadi layers exposed at least one injection and multiple producing wells. The method involves the injection into the injection well of the rim agent that increases the filtration resistance of the porous medium, followed by water injection and sampling of formation fluids through the production wells. The injection of water before welting agent are disabled when producing wells to the extent that the creation of resilient stock low permeability of the reservoir. Download fringe agent produce when producing wells with a cut above average.

The invention relates to the oil industry, in particular to the design of flooded oil fields with inhomogeneous zonal and rannapromenaadi layers.

Known methods of development of flooded oil fields with inhomogeneous zonal and rannapromenaadi the layers by injection of agents designed to increase the filtration resistance, high permeability, flooded areas playcomplete, already water-washed areas of the Deposit. However, along with highly permeable bridging agents partially enclosed in low-permeability, not yet covered by the impact sites, deposits, reducing or completely eliminating thus their further development.

Closest to the proposed technical essence is a way of developing heterogeneous oil reservoirs [2] the essence of which consists in the following. Via the injection well into the reservoir to inject the rim selectively gelirem composition that provides temporary blocking of surface sites with low permeability without penetration of the composition into the structure with low permeability. The composition is a solution of chromate xanthan gum, sodium hydroxide and formaldehyde in saline solution). Then via the injection well pump constituting agent that increases the filtration resistance of the porous medium (polyacryamide, polysaccharide and Monomeric acrylamide), which is deposited mainly in areas with high permeability. After that, via the injection well pump leaching agent that can destroy the gel structure previously introduced their level of initial permeability. Then via the injection well pump water, and through the production wells are selected formation fluids.

The disadvantages of this method is low efficiency and complexity: galerey composition mainly falls into the high-permeability areas and only a small part in low permeability areas. Despite the large consumption of this composition, it may not be enough for temporary isolation of low-permeability areas. Then during the subsequent injection of an agent that increases the filtration resistance of the porous medium, it will clog and low permeability areas. In addition, you need to very accurately maintain the conditions necessary for the gelatin composition, which is very difficult reservoir conditions. Other disadvantages of the method the ability of the violation of the ecological balance of the environment due to the high toxicity of chromium, and expensive reagents.

The purpose of the invention increase the efficiency of development of flooded oil fields with inhomogeneous zonal and rannapromenaadi layers.

This objective is achieved in that in the method development of flooded oil fields with inhomogeneous zonal and rannapromenaadi the formations opened as a mini the rims agent, increase of filtration resistance of the porous medium, followed by water injection and sampling of formation fluids through all producing wells, before download fringe agent that increases the filtration resistance of the porous medium, disable producing wells and injection wells pump water to the extent that the creation of resilient stock low permeability of the reservoir, defined by the formula:

VZackV.Cn(KinTOn), where VZackthe amount of water injection, m3;

V.Cnelastic supply of low-permeability reservoir, m3;

TOinand Knpermeability, respectively, of high-permeability and low-permeability reservoirs, μm2.

The next task rims agent that increases the filtration resistance of the porous medium, is produced when operating producing wells with water content above a predetermined average.

Thus, the proposed method meets the criteria of the invention of "novelty."

The essence of the proposed method lies in the fact that the injection into the injection well water when disconnected producing wells in particular is discapacity layer. After creation in low-permeability reservoirs elastic barrier have pumped agent that increases the filtration resistance of the porous medium. While off On a well with a water content below average, leaving working On a well with a water content above average. Thus at the time of injection of the agent is disconnected from the development of low-permeability layers (L wells perforated in these layers have a lower water content than D. wells perforated in high-permeability reservoirs). As a result, the agent gets only in high-permeability, water-washed layers, increasing them in filtration resistance, and then injected the water rushes in low-permeability, are not subjected to this influence.

In the known method, in order to prevent high-viscosity agent in low-permeability reservoirs, at the time of injection of this regeneca cover impermeable film selectively gelirem composition, which is then destroy special washing liquid. In addition, when the injection of an agent that increases the filtration resistance, are all producing wells regardless of their water content, which promotes the penetration of the agent and in low-permeability reservoirs. All of you who e differences".

In field conditions the method is as follows.

The area of oil field is represented by two layers of n and with the following characteristics:

Vn80 thousand m3Vin120 thousand m3,

mamin0,25

Vnthen20 thousand m3Vinthen30 thousand m3< / BR>
TOn200 μm2TOin600 μm2< / BR>
W710-10PA-1,p510-10PA-1where Vnand Vinthe amount of layers n and;

mnand minthe porosity of the layers n and;

Vnthenand Vinthenthe pore volume of the reservoir h and V;

TOnand Kinthe permeability of layers n and;

Wandpthe coefficient of elasticity of the fluid and rock.

The site opened one injection (H) and three mining (D) wells and developed by injection into N well water and sampling of formation fluids through all D. wells. By the time of the proposed method watercut D wells was: 1 44% 2 65% 3 99% the average water content 69,3 (44 + 65 + 99)/3.

As an agent that increases the filtration resistance of the porous medium, the use of 0.05% aqueous solution of the polymer in an amount of 10% of the pop layer create an elastic barrier (pillow), prevents the penetration of there agent. When disabled (closed) D. wells Mr. wells pumped water volume (VZack) compute as follows.

Set pressure value of the elastic supply of reservoir Rnthat depends on the time of creation of the rims and the ratio of appointest high - and low-permeability reservoirs.

In this case, it is enough to create elastic pressure reserve value 25 bar (2.5 MPa). Based on this pressure calculated elastic supply (V.Cn) by the formula:

V.Cn(mW+p) VnPn= (0,25 7 10-101/ a+ 5 10-101/a) 80 thousand m32.5 MPa 135 m3. Despite the fact that the elastic barrier created in low-permeability reservoir, the injected water enters the high permeability layer, therefore, is calculated according to the formula above, the volume should increase in proportion to the ratio of permeability of high - and low-permeability reservoirs. Then the volume of water injection when disabled D. wells will be VZackV.Cn(KinTOn). For this oil deposits this amount equals 135 600/200 405 m3. When the injection bore 20 which are On a well with a water content higher than average, i.e. exploiting high-permeability layer (for the considered deposits-hole cut 99%). However due to the high permeability of the formation by the elastic pressure of the stock drops to the reservoir, and in the low-permeability layer N. this pressure is maintained for a long period and serves as a barrier that prevents the penetration of injected agent in this layer.

Download agent solution of polymer are in is included On the borehole and disabled D. wells. It also promotes penetration and promotion of the polymer solution on the high-permeability layer of the century as soon As you downloaded the entire volume of the polymer, i.e., be isolated highly permeable water reservoir to include all remaining D well, N well pumped water, and from D. wells selected formation fluids. Coming through the N well water, sreca in highly irrigated barrier layer of polymer, will rush in are not covered by the influence of low-permeability areas, crowding out of them oil.

Feasibility advantage of the proposed method is that it allows, without the use of expensive reagents reliably protect the low permeability, not the basement is made water areas of the porous medium, and thus to increase the coverage of the reservoir effect.

The WAY to DEVELOP FLOODED OIL fields WITH INHOMOGENEOUS ZONAL AND RANNAPROMENAADI LAYERS, including the opening of at least one injection and multiple producing wells, injection into the injection well of the rim agent that increases the filtration resistance of the porous medium, followed by water injection and sampling of formation fluids through the production wells, wherein before download fringe agent disable producing wells and injection wells inject water into the volume VCandtofor creating elastic stock low permeability of the reservoir, defined by the formula

VZack= Vny.C(KinKn)

where Vyy.Celastic supply of low-permeability reservoir, m3;

Kinand Knpermeability respectively high - and low-permeability reservoirs, μm2,

determine the average water cut wells and the subsequent injection of rims agent produced when operating producing wells with water content above a predetermined medium until

 

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FIELD: oil and gas production.

SUBSTANCE: groups of high intake- and low intake-capacity injecting wells are chosen in a single hydrodynamic system and, for each well, oil reservoir properties and permissible degree of pollution of fluid received by high intake-capacity wells are determined. When fluid from low-permeable oil reservoir flows off through high intake-capacity wells, this fluid is cleaned to permissible degree of pollution.

EFFECT: reduced losses in intake capacity of formations and increased time between treatments of wells.

1 dwg

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