阅读说明：本技术 一种超高轮次吞吐后期多层系稠油油藏开发方法 (Ultrahigh-rotation huff and puff later-stage multilayer heavy oil reservoir development method ) 是由 李星 刘士梦 钟玉龙 龙卫江 刘斌 李岩 刘宁 费永涛 黎明 李长宏 于 2020-06-02 设计创作，主要内容包括：本发明涉及一种超高轮次吞吐后期多层系稠油油藏开发方法,包括如下步骤：首先根据稠油油藏各油层的剩余油分布规律进行分类,分为叠合程度好的多套油层和叠合程度不好的油层；将叠合程度好的多套油层再划分为主力层和非主力层；所述叠合程度为各油层剩余油纵向叠合程度；然后对所述主力层的井网进行加密原有井网开发,对所述非主力层进行井网完善开发；对叠合程度不好的油层进行水平井开发。本发明的方法配合开发方式和注采参数优化可以有效提高各类型油层采收率,并且尤其适用于纵向多层系的超高轮次吞吐后期的稠油油藏。(The invention relates to a method for developing a multilayer heavy oil reservoir in the later period of ultra-high rotation huff and puff, which comprises the following steps: firstly, classifying according to the distribution rule of residual oil of each oil layer of a heavy oil reservoir into a plurality of sets of oil layers with good superposition degree and oil layers with poor superposition degree; dividing a plurality of sets of oil layers with good superposition degree into a main force layer and a non-main force layer; the superposition degree is the longitudinal superposition degree of the residual oil of each oil layer; then, carrying out encryption on the well pattern of the main force layer and original well pattern development, and carrying out well pattern perfection development on the non-main force layer; and carrying out horizontal well development on the oil layer with poor superposition degree. The method provided by the invention can effectively improve the recovery ratio of each type of oil layer by matching with a development mode and injection-production parameter optimization, and is particularly suitable for heavy oil reservoirs in the later period of ultrahigh-round huff-puff of longitudinal multi-layer systems.)

1. A method for developing a multilayer heavy oil reservoir in the later period of ultra-high rotation huff and puff is characterized by comprising the following steps:

1) obtaining the residual oil distribution of each oil layer of the heavy oil reservoir according to the geological model and the production historical data;

2) classifying according to the residual oil distribution of each oil layer of the heavy oil reservoir into a plurality of sets of oil layers with good superposition degree and oil layers with poor superposition degree; dividing a plurality of sets of oil layers with good superposition degree into a main force layer and a non-main force layer; the superposition degree is the longitudinal superposition degree of the residual oil of each oil layer;

3) carrying out encryption on the well pattern of the main force layer and original well pattern development, and carrying out well pattern perfection development on the non-main force layer;

and carrying out horizontal well development on the oil layer with poor superposition degree.

2. The method for developing the multi-layer heavy oil reservoir in the ultra-high round-trip later period according to claim 1, wherein in the step 1), the distribution of the residual oil in each oil layer of the heavy oil reservoir is corrected according to the distribution rule of an underground pressure field, a temperature field, a viscosity field and an oil-containing saturation field.

3. The ultrahigh-round late-throughput multilayer heavy oil reservoir development method according to claim 2, wherein the division standard of the main force layer and the non-main force layer is one or more of the following parameters: oil layer thickness, crude oil viscosity, production level.

4. The method of claim 3, wherein the partitioning of the primary and non-primary layers is further with reference to partitioning of historically developed layer series.

5. The method for developing an ultra-high-round handling later-period multi-layer heavy oil reservoir as claimed in claim 1, 2 or 3, wherein the horizontal well development comprises a drainage pattern horizontal well development.

6. The method for developing a multi-layer heavy oil reservoir in the ultra-high round-trip late stage according to the claim 1, 2 or 3, wherein the encrypted original well pattern comprises a plane encryption form and a three-dimensional encryption form.

7. The ultrahigh-round-trip later-period multilayer heavy oil reservoir development method according to claim 1, 2 or 3, characterized in that the well pattern of the non-principal layer is perfected into a five-point well pattern in a steam trip-out period.

8. The ultrahigh-round throughput late-stage multilayer heavy oil reservoir development method according to claim 7, characterized in that the well pattern of the non-main power layer is perfected into an anti-nine-point well pattern or a vectorized well pattern in a steam flooding stage.

9. The ultra-high-round-trip late-stage multi-layer heavy oil reservoir development method of claim 7, wherein the steam-trip phase further comprises chemically assisted steam flooding or hot water flooding.

10. The method for developing the multi-layer heavy oil reservoir at the later stage of the ultrahigh round throughput, according to claim 9, is characterized in that an area steam swallowing and spitting method is adopted in the steam throughput stage.

Technical Field

The invention relates to a method for developing a multilayer system heavy oil reservoir in the later period of ultrahigh round huff and puff, and belongs to the technical field of multilayer system heavy oil exploitation.

Background

In China, crude oil with viscosity of more than 50cp under the oil layer condition is called thick oil and is divided into common thick oil, extra thick oil and super thick oil. The heavy oil is called as heavy crude oil internationally, crude oil with API degree of 10-20 is called as heavy crude oil in countries such as the United states, and crude oil with API degree of less than 10 is called as asphalt.

Huge thickened oil resources are stored in the world, are several times of conventional crude oil resources, and have very important strategic position of petroleum energy. The thickened oil resource is widely distributed and is found in almost all oil producing countries. Chinese heavy oil resources are also very abundant, and account for about 25% -30% of the total petroleum resources.

Except for common thick oil I types, most of the thick oil resources in China are developed by adopting a steam huff-puff and steam drive mode, wherein the steam huff-puff is a thick oil yield increasing measure for periodically injecting steam into an oil well and introducing a large amount of heat into an oil layer. At present, most of old oil fields enter the later stage of ultrahigh-cycle steam huff-puff, and through ultrahigh-cycle steam huff-puff exploitation, the formation pressure is greatly reduced along with the improvement of the extraction degree, the pressure maintaining level is below 30%, so that the liquid yield of an oil well is low, and the huff-puff development effect of the subsequent stage is severely restricted.

Meanwhile, steam channeling is serious, and due to the heterogeneity of an oil layer and imbalance of steam injection and oil extraction stages in steam huff and puff development, steam channeling channels or high-consumption steam strips are easy to form among huff and puff wells, so that steam is circulated inefficiently among the wells, and the production effect is seriously influenced. With the increase of the throughput rounds, the steam fleeing forms also have the initial corner fleeing and the diagonal fleeing to develop the net fleeing in the later period of the high-round throughput.

Finally, the well condition of the ultra-high-round huff-puff well is poor, and the casing damage and the fault broken well are aggravated year by year, so that the production wells with diseases and the production stop wells are increased year by year, and the reserves of partial areas are out of control. The recovery ratio of producing the oil reservoir by continuously carrying out steam huff and puff is difficult to further improve, but the effect of directly converting old well patterns into steam flooding is poor, and the steam flooding stage inherits the high steam consumption strips of the huff and puff stage, so that the injection and production well directly forms steam ineffective circulation. Therefore, it is difficult to further increase the recovery ratio in the latter period of the ultra-high rotation throughput regardless of the development mode.

Disclosure of Invention

The invention aims to provide a method for developing a multilayer heavy oil reservoir in the later stage of ultrahigh rotation huff and puff, which is used for solving the problem that the recovery ratio is difficult to improve in the later stage of ultrahigh rotation huff and puff.

In order to achieve the above object, the scheme of the invention comprises:

the invention relates to a method for developing a multilayer heavy oil reservoir in the later period of ultrahigh round huff and puff, which comprises the following steps:

1) obtaining the residual oil distribution of each oil layer of the heavy oil reservoir according to the geological model and the production historical data;

2) classifying according to the residual oil distribution of each oil layer of the heavy oil reservoir into a plurality of sets of oil layers with good superposition degree and oil layers with poor superposition degree; dividing a plurality of sets of oil layers with good superposition degree into a main force layer and a non-main force layer; the superposition degree is the longitudinal superposition degree of the residual oil of each oil layer;

3) carrying out encryption on the well pattern of the main force layer and original well pattern development, and carrying out well pattern perfection development on the non-main force layer; and carrying out horizontal well development on the oil layer with poor superposition degree.

After the heavy oil reservoir at the later stage of the super-high-turn huff and puff is mined for a long time, the oil storage of each oil layer is changed, and the recovery ratio is difficult to further improve by a single oil well form, so that the scheme classifies the changed reservoir and purposefully optimizes the well pattern form based on the characteristics of each classified reservoir, and the recovery ratio can be effectively increased.

Further, in the step 1), the residual oil distribution of each oil layer of the heavy oil reservoir is corrected according to the distribution rule of an underground pressure field, a temperature field, a viscosity field and an oil-containing saturation field.

Further, the division standard of the main force layer and the non-main force layer is one or more of the following parameters: oil layer thickness, crude oil viscosity, production level.

The main development oil layer has higher extraction degree and lower thickness, and the viscosity of the crude oil is reduced due to multiple rounds of steam huff and puff. According to the standards, the dominant developed oil layer and the non-dominant developed oil layer can be accurately distinguished.

Further, the partitioning of the principal and non-principal layers also references the partitioning of historically developed layer systems.

And comparing and compounding the historical development layer system, mainly verifying the historical upper layer system, mainly solving the exposed contradiction in the development, and correcting the prior achievement by means of geological reconsideration. Meanwhile, the accuracy of oil layer classification can be increased.

Further, the horizontal well development comprises a drainage pattern horizontal well development.

And the recovery ratio of an oil layer with poor superposition degree is increased through a horizontal well drainage pattern.

Further, the encrypted original well pattern comprises a plane encryption form and a three-dimensional encryption form.

Further, the well pattern of the non-principal layer is perfected into a five-point method well pattern in the steam throughput stage.

The proportion of the water injection wells and the oil production wells of the five-point method well pattern is 1 to 1, and each oil production well is influenced by 4 water injection wells; each water injection well is associated with 4 surrounding production wells. Therefore, the well arrangement mode is a strong-production strong-injection development well pattern, and the oil well after water injection has quick effect and high oil production speed.

Further, the well pattern of the non-principal layer is perfected into an anti-nine-point well pattern or a vectoring well pattern in a steam flooding stage.

Further, the steam throughput phase also comprises chemical auxiliary steam flooding or hot water flooding.

And performing combined steam huff and puff at the later stage of the ultrahigh rotation huff and puff, and performing chemical auxiliary steam drive or hot water drive mode optimization design according to the distribution rule of underground four fields. The "four fields" underground are pressure, temperature, viscosity and oil saturation fields.

Furthermore, the steam throughput stage adopts an area steam throughput method.

The area steam huff and puff is a preferred mode of carrying out steam huff and puff on multiple wells simultaneously, namely simultaneously injecting steam, simultaneously stewing the wells and simultaneously discharging the liquid, thereby effectively avoiding the influence of high-steam-consumption strips.

Drawings

FIG. 1 is a flow chart of a method for developing a multi-layer heavy oil reservoir in the later period of ultra-high-rotation huff and puff according to the invention;

FIG. 2 is a schematic diagram of a horizontal well pattern;

FIG. 3 is a schematic diagram of a five-point well pattern;

FIG. 4 is a schematic diagram of an inverse nine-point method well pattern.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.