阅读说明：本技术 一种沉积末端水下分流河道的储层预测描述方法 (Reservoir prediction description method for sediment end underwater diversion river channel ) 是由 郭威 贾宗玉 李维 伍永亮 李小芳 邓卫东 刘瑞环 吴红霞 程晓翠 何丽娟 于 2021-05-25 设计创作，主要内容包括：本发明提供一种沉积末端水下分流河道的储层预测描述方法,通过测井相特征和生产特征,在测井相对单井纵向钻遇的各小层中,获取不同区域的已知河道,得到已知河道的展布图；已知河道以外的其它区域为未知河道；运用沉积相的继承性原理,通过复制已知河道到其它小层对应的未知河道,来预测在其它小层的未知河道的展布图；运用沉积相的差异性原理,每个沉积时期的物源供给是变化的,结合井区已钻井情况,对得到的未知河道的展布图,修正未知河道的宽度和长度；将所有未知河道进行修正后,得到各小层各河道的展布图,进行平面和纵向河道对照修正异常井点,得到整体河道空间立体展布情况。(The invention provides a reservoir prediction description method of a sediment end underwater diversion river channel, which comprises the steps of obtaining known river channels in different areas in each small layer drilled and encountered by a logging well relative to a single well longitudinally through logging phase characteristics and production characteristics to obtain a spread chart of the known river channels; other regions outside the known river are unknown river channels; by applying the inheritance principle of sedimentary facies, the spreading diagram of the unknown river channels in other small layers is predicted by copying the known river channels to the unknown river channels corresponding to other small layers; by using the difference principle of a sedimentary facies, the source supply of each sedimentary period is changed, and the width and the length of an unknown river channel are corrected for an obtained spreading diagram of the unknown river channel by combining the drilled well condition of a well region; and correcting all unknown river channels to obtain the layout of each river channel of each small layer, and correcting abnormal well points by comparing a plane river channel with a longitudinal river channel to obtain the space three-dimensional layout condition of the whole river channel.)

1. A reservoir prediction description method for a sediment tail end underwater diversion river channel is characterized by comprising the following steps: the method comprises the following steps:

s1, determining the known river channel:

respectively acquiring known riverways in different areas in single layers longitudinally drilled and encountered by logging relative to a single well through the logging phase characteristics and the production characteristics of the underwater diversion riverway at the deposition tail end to obtain a spreading diagram of the known riverway; other regions outside the known river are unknown river channels;

s2, predicting unknown river channels:

by applying the inheritance principle of sedimentary facies, the riverways of the upper and lower monolayers in the longitudinal direction of the monolayer where the known riverway is located have inheritance, and the spreading diagram of the unknown riverway of other monolayers is predicted by copying the known riverway to the unknown riverway corresponding to other monolayers;

s3, correcting unknown river channels:

by using the difference principle of the sedimentary facies, the source supply of each sedimentary period is changed, and the width and the length of the unknown river channel are corrected for the spreading diagram of the unknown river channel obtained by S2 by combining the drilled well condition of a well region;

s4, summarizing river course spreading:

and correcting all unknown river channels to obtain the spread pattern of each single-layer river channel, and correcting abnormal well points by comparing a plane river channel with a longitudinal river channel to obtain the space three-dimensional spread condition of the whole river channel.

2. The method of claim 1, wherein: the S1 includes:

and (4) carrying out deposition microfacies division according to the single-layer longitudinal drilling of the logging relative to the single well, and determining the classification of each single-layer deposition microfacies of the single well.

3. The method of claim 2, wherein: the S1 further includes: in combination with the production dynamics, the most developed region of each monolayer was obtained as the known river.

4. The method of claim 1, wherein: said S3 includes: the actual drilling condition of the single layer of the unknown river channel is marked by combining the actual drilling condition, the material source supply condition and the logging display condition, so that the river channel spreading is corrected on the single layer of the unknown river channel, and the river channel is corrected left and right according to the logging phase characteristics.

5. The method of claim 4, wherein: the S3 further includes: and judging the supply of the single-layer material source according to the actual drilling condition of the single layer where the unknown river channel is positioned, and correcting the extending length of the river channel by combining the actual logging display condition.

6. The method of claim 1, wherein: the other monolayer is an adjacent monolayer.

7. The method of claim 1, wherein: and when the logging facies are characterized by box type or bell type, the corresponding known river channel is obtained as the central area of the river channel or the edge area of the river channel.

8. The method of claim 1, wherein: in S1, the current production situation shows that the single well of the river channel central well is high in initial stage and accumulated production, the side edge of the river channel is inferior, and the production well at the edge of the river channel is worst.

Technical Field

The invention belongs to the field of reservoir distribution description of a sedimentary tail end, and particularly relates to a reservoir prediction description method of an underwater diversion river channel of a sedimentary tail end.

Background

At present, reservoir prediction description technologies mainly utilize information provided by seismic data to perform three major categories of seismic inversion methods, seismic attribute analysis technologies, AVO technologies and the like. But reservoir thickness typically needs to be over 10 meters to be identifiable and traceable. For the prediction of the thin sand layer, because the single-layer thickness of the thin sand layer is generally far lower than the resolution capability of seismic resolution, the sedimentary characteristics and the like of the reservoir layer cannot be well described by using the seismic related reservoir layer description technology, so that the reservoir layer with thin sand body and small area has larger depicting difficulty, and no better method exists at present.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a reservoir prediction description method of an underwater diversion river channel at a sediment tail end is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows: a reservoir prediction description method for a sediment terminal underwater diversion river channel comprises the following steps:

s1, determining the known river channel:

respectively acquiring known riverways in different areas in single layers longitudinally drilled and encountered by logging relative to a single well through the logging phase characteristics and the production characteristics of the underwater diversion riverway at the deposition tail end to obtain a spreading diagram of the known riverway; other regions outside the known river are unknown river channels;

s2, predicting unknown river channels:

by applying the inheritance principle of sedimentary facies, the riverways of the upper and lower monolayers in the longitudinal direction of the monolayer where the known riverway is located have inheritance, and the spreading diagram of the unknown riverway of other monolayers is predicted by copying the known riverway to the unknown riverway corresponding to other monolayers;

s3, correcting unknown river channels:

by using the difference principle of the sedimentary facies, the source supply of each sedimentary period is changed, and the width and the length of the unknown river channel are corrected for the spreading diagram of the unknown river channel obtained by S2 by combining the drilled well condition of a well region;

s4, summarizing river course spreading:

and correcting all unknown river channels to obtain the spread pattern of each single-layer river channel, and correcting abnormal well points by comparing a plane river channel with a longitudinal river channel to obtain the space three-dimensional spread condition of the whole river channel.

In the above method, said S1 includes: and (4) carrying out deposition microfacies division according to the single-layer longitudinal drilling of the logging relative to the single well, and determining the classification of each single-layer deposition microfacies of the single well.

According to the above method, said S1 further comprises: and (4) selecting the most developed area in each monolayer as a known river channel by combining the dynamic condition of production.

In the above method, said S3 includes: the actual drilling condition of the single layer of the unknown river channel is marked by combining the actual drilling condition, the material source supply condition and the logging display condition, so that the river channel spreading is corrected on the single layer of the unknown river channel, and the river channel is corrected left and right according to the logging phase characteristics.

According to the above method, said S3 further comprises: and judging the supply of the single-layer material source according to the actual drilling condition of the single layer where the unknown river channel is positioned, and correcting the extending length of the river channel by combining the actual logging display condition.

The other monolayers are adjacent monolayers as described above.

The invention has the beneficial effects that: for the reservoir stratum of the underwater diversion river channel with thin sand body and small area, a clear prediction method is provided, the depicting difficulty is reduced, a new searching idea is provided for some hidden traps at the sediment end of the river channel, and the method has important guiding significance for making a reasonable policy for the next development of the reservoir stratum.

Drawings

FIG. 1 is a flowchart of a method according to an embodiment of the present invention.

Fig. 2 is a graph of LX field 1 oil monolayers defining a known river course layout.

Fig. 3 is a flow chart of replicating a predicted river.

Fig. 4 is a drilling plot of the thickness of each single sandstone layer of LX oil field 1 oil group.

Fig. 5 is a display diagram of the oil gas encountered by each single layer of the LX oilfield 1 oil group.

Fig. 6 is a diagram for predicting the spreading of individual single-layer riverways in the LX oilfield 1 oil group.

Detailed Description

The invention is further illustrated by the following specific examples and figures.

The invention provides a reservoir prediction description method for a sediment end underwater diversion river channel, which comprises the following steps of:

s1, determining the known river channel:

respectively acquiring known riverways in different areas in single layers longitudinally encountered by logging relative to a single well through the logging phase characteristics and the production characteristics of the underwater diversion riverway at the sediment tail end, and obtaining a spreading diagram of the known riverway; other areas outside the known river are unknown river channels. The method specifically comprises the following steps: and (3) carrying out deposition microfacies division according to the logging relative to the single-well longitudinal drilling encountering each monolayer, determining the classification of each monolayer deposition microfacies of the single well, and selecting the most developed area in each monolayer as a known river channel by combining the dynamic production condition.

The water line divides the river channel sand body, the center of the river channel is mostly box-shaped or bell-shaped, and according to the characteristics, the center area and the edge area of the river channel are judged; according to the current production situation, the single well of the river channel central well is high in initial stage and accumulated yield, the side edge of the river channel is inferior, and the production well at the edge of the river channel is worst. And summarizing the characteristics of the riverway sand at the tail end of the sediment through statistical summary, and depicting the known riverway.

In this example, 1 oil group of the LX oilfield is selected, the oil group is divided into 5 individual layers, and a known river channel is carved in each individual layer. The riverways are numbered from north to south in sequence, and 6 riverways are totally numbered, wherein the river way 1 is developed most when drilling in a reservoir stratum at a layer III, so that the planar distribution of the river way 1 which is developed most at the deposition period of the layer III is determined. In the same way, the single layers in other areas find out that the river course is relatively developed and confirmed to be known river course reservoir spreading, and the river course No. 2 is relatively developed in the layers III and IV; the No. 3 river channel develops in the No. III and No. IV layers; the No. 4 river channel develops in the No. I, II and IV layers; the No. 5 river channel is relatively developed in the No. IV layer; river course 6 develops in layers I, II, III and V, as shown in FIG. 2.

S2, predicting unknown river channels:

by applying the inheritance principle of sedimentary facies, the reservoir river channel has inheritance in the longitudinal direction of the monolayer where the known river channel is located, and the spreading diagram of the unknown river channel in other monolayers is predicted by copying the known river channel to the unknown river channel corresponding to other monolayers. To improve accuracy, the other monolayers are typically adjacent monolayers.

The knowledge of the longitudinal deposition of the reservoir is changed, and through deposition research, the region is found to belong to a very stable river-lake basin deposition system, the variation of the tail end of the source supply is small, and river sand in different deposition periods has inheritance. For example, as shown in fig. 3, the planar distribution area of the river channel No. 1 in the layer iii is copied to the adjacent layer ii and layer iv, so as to obtain the predicted river channel planar distribution map of the river channel No. 1 in the layer ii and layer iv, and other river channels can be obtained in the same manner.

S3, correcting unknown river channels:

and (3) applying a deposition phase difference principle, wherein the source supply of each deposition period is changed, and the width and the length of the unknown river channel are corrected according to the well drilling condition of the well region and the spread diagram of the unknown river channel obtained in the S2. The method specifically comprises the following steps: marking the actual drilling situation of the single layer of the unknown river channel by combining the actual drilling situation, the material source supply situation and the logging display situation, so as to correct the river channel spreading on the single layer of the unknown river channel, and then correcting the left and right of the river channel according to the logging phase characteristics; and judging the supply of the single-layer material source according to the actual drilling condition of the single layer where the unknown river channel is positioned, and correcting the extending length of the river channel by combining the actual logging display condition.

According to the theory of variability of the dephasing: the development degree of the riverways with different single-layer sand bodies is different, and the spreading area is different. And correcting the migration position and the extension length of the river channel by combining the actual drilling situation, the source supply situation, the logging display situation and the like. Firstly, the river channel migration position and the spreading area are confirmed. Marking the actual drilling conditions of the predicted riverway plane spread single layer, correcting riverway spread on the single layer, and correcting the riverway left and right according to the riverway logging phase characteristics, as shown in fig. 4. And (3) judging the supply of the single-layer material source according to the single-layer drilling condition, and correcting the extended length of the river channel by combining the actual logging display condition, as shown in fig. 5.

In this embodiment, drilling conditions of reservoirs drilled in each single layer are combined to distinguish that the reservoirs are roughly located in the center of a river channel, the side edge of the center of the river channel or the boundary of the river channel, and then, the conditions of well logging display are integrated to perform distribution of a plurality of river channels on the whole plane, river channel left-right migration rules and river channel extension distances.

S4, summarizing river course spreading:

and correcting all unknown river channels to obtain the spread pattern of each single-layer river channel, and correcting abnormal well points by comparing a plane river channel with a longitudinal river channel to obtain the space three-dimensional spread condition of the whole river channel.

After the positions of the river channels in different areas are copied and corrected through the known river channels of the single layers, the single layers form a reservoir plane spreading condition by a plurality of unconnected river channel sands, so that a new trap is formed in an unknown area, as shown in fig. 6.

In the embodiment, the test is carried out in the LX oilfield, so that the good effect is achieved, four storage potential increasing layers of 2, 3, 5 and 6 of the newly-added 3 oil groups are implemented in total, and the newly-added oil-containing area is estimated to be 4.5km²Newly increased predicted reserves of 49.8X 10⁴t. Wherein the No. 2 single layer of the next 3, L1-8-5 drilling meets 5m oil layer, and the initial stage of production12t of high daily oil production, and the estimated new oil-containing area is 0.26 km²Newly increased reserve of 20.34X 10⁴t. No. 5 monolayer of new lower 3, L1-9-3 drilled oil layer 4.5m, highest daily oil production 9.5t at initial production stage, newly increased oil-containing area 0.1 km²Newly increased reserve of 7.4X 10⁴t。

The above embodiments are only used for illustrating the design idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes and modifications made in accordance with the principles and concepts disclosed herein are intended to be included within the scope of the present invention.