阅读说明：本技术 一种基于动态指标的海上窄河道油藏调剖选井决策方法 (Offshore narrow river channel oil reservoir profile control and well selection decision method based on dynamic indexes ) 是由 王凤刚 李云鹏 张锋利 任宜伟 尹彦君 黎运秀 刘艳涛 张震 李瑞雪 赵云斌 姜 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种基于动态指标的海上窄河道油藏调剖选井决策方法,包括基于累产油、累产水进行一次筛选和基于日产液量和含水率进行二次筛选,本方法基于油井动态指标,利用产油量累计偏差和产水量累计偏差双重因素将油井生产特征分为四类,将高油高水井、低油高水井、低油低水井做为疑似井,在第二次筛选中,高日产液量、高含水率油井具有水窜特征,筛选对应井组进行调剖作业,该方法针对海上横向变化快,纵向叠置复杂的窄河道油藏,具有适用性好,筛选效率高,准确的优点。(The invention discloses a dynamic index-based offshore narrow-river oil reservoir profile control and well selection decision method, which comprises the steps of carrying out primary screening based on accumulated oil and accumulated water and carrying out secondary screening based on daily liquid yield and water content.)

1. A dynamic index-based offshore narrow river channel oil reservoir profile control well selection decision method is characterized by comprising the following steps: the method comprises the following steps:

step one, performing primary screening based on accumulative production oil and accumulative production water

Based on the heterogeneous index of the accumulated oil yield and the heterogeneous index of the accumulated water yield, a continuous change curve chart of the average value difference of the oil well and the oil field is manufactured, and the category of the oil well is determined:

the heterogeneous index of the accumulated oil yield and the heterogeneous index of the accumulated water yield can be represented by a formula 1:

in equation 1: ko (i, t) is the cumulative oil production heterogeneous index of the ith well on the t day, and Kw (i, t) is the cumulative water production heterogeneous index of the ith well on the t day; i is the well serial number (i ═ 1, 2, 3, …, n); t is the time variable, day; j is the well production time (j ═ 1, 2, 3, …, t); q. q.s_o(i，j)The j day oil production of the ith well, m³/d；q_w(i，j)The j day water yield, m, of the ith well³/d。

Projecting the coordinates (Ko (i, t), Kw (i, t)) into a rectangular coordinate system to obtain a continuous variation curve chart of the difference value of the average value of a certain oil well and the oil field; the four quadrants correspond to different oil well categories respectively, wherein the first quadrant is a high-oil high-water well with the oil yield higher than the average value of the oil well and the water yield higher than the average value of the oil well, the second quadrant is a low-oil high-water well with the oil yield lower than the average value of the oil well and the water yield higher than the average value of the oil well, the third quadrant is a low-oil low-water well with the oil yield lower than the average value of the oil well and the water yield lower than the average value of the oil well, and the fourth quadrant is a high-oil low-water well with the oil; and taking the oil wells falling in the I-th quadrant, the II-th quadrant and the III-th quadrant as suspected wells for further screening.

Step two, secondary screening is carried out based on daily liquid yield and water content

Selecting the latest daily liquid yield and water content, and performing secondary screening on the profile control suspected well by using the heterogeneous index, wherein the expression is as follows:

in equation 2: k_l(i) Is the i-th well daily fluid heterogeneity index, K_f(i) The water-containing heterogeneous index of the ith well; i is the well serial number (i ═ 1, 2, 3, …, n); q. q.s_l(i)The daily liquid production of the ith well, m³/d；f_w(i)Water content of the ith well,%.

And calculating the daily liquid yield and the water content of each current oil well by using the heterogeneous index, wherein the oil wells with the daily liquid yield higher than the average value of the oil wells and the water content higher than the average value of the oil wells have sufficient energy and low-efficiency circulation and are wells to be profile-controlled.

Technical Field

The invention belongs to the technical field of oil reservoir water injection development, and particularly relates to a dynamic index-based offshore narrow river channel oil reservoir profile control and well selection decision method.

Background

The offshore oilfield river channel type sand body has the characteristics of narrow river channel width and quick change of deposition thickness, peripheral oil well water injection effects are uneven, the swept volume of injected water can be effectively improved through reasonable profile control, the water content of an affected well is reduced, and the oil yield is improved.

At present, in the process of profile control and well selection of a medium-high permeability reservoir, a pressure index decision method is a common method, but the relevance of a decision factor in the pressure index decision method and the cumulative oil increase and the cumulative precipitation of an effective well group is not strong, and the profile control effect prediction effect of the effective well group is weak. At present, no profile control well selection method matched with the offshore narrow river channel oil reservoir which has rapid transverse change and complex longitudinal superposition exists.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a dynamic index-based offshore narrow river channel oil reservoir profile control and well selection decision method.

The invention is realized by the following technical scheme:

a dynamic index-based offshore narrow river channel oil reservoir profile control and well selection decision method comprises the following steps:

step one, performing primary screening based on accumulative production oil and accumulative production water

Based on the heterogeneous index of the accumulated oil yield and the heterogeneous index of the accumulated water yield, a continuous change curve chart of the average value difference of the oil well and the oil field is manufactured, and the category of the oil well is determined:

the heterogeneous index of the accumulated oil yield and the heterogeneous index of the accumulated water yield can be represented by a formula 1:

in equation 1: ko (i, t) is the cumulative oil production heterogeneous index of the ith well on the t day, and Kw (i, t) is the cumulative water production heterogeneous index of the ith well on the t day; i is an oil well serial number (i ═ 1, 2, 3, ·, n); t is the time variable, day; j is the well production time (j ═ 1, 2, 3, ·, t); q. q.s_o(i,j)The j day oil production of the ith well, m³/d；q_w(i,j)The j day water yield, m, of the ith well³/d。

Projecting the coordinates (Ko (i, t), Kw (i, t)) into a rectangular coordinate system to obtain a continuous variation curve chart of the difference value of the average value of a certain oil well and the oil field; the four quadrants correspond to different oil well categories respectively, wherein the first quadrant is a high-oil high-water well with the oil yield higher than the average value of the oil well and the water yield higher than the average value of the oil well, the second quadrant is a low-oil high-water well with the oil yield lower than the average value of the oil well and the water yield higher than the average value of the oil well, the third quadrant is a low-oil low-water well with the oil yield lower than the average value of the oil well and the water yield lower than the average value of the oil well, and the fourth quadrant is a high-oil low-water well with the oil; and taking the oil wells in the I, II and III quadrants as suspected wells for further screening.

Step two, secondary screening is carried out based on daily liquid and water content

Selecting the latest daily liquid yield and water content, and performing secondary screening on the profile control suspected well by using the heterogeneous index, wherein the expression is as follows:

in equation 2: k_l(i) Is the i-th well daily fluid heterogeneity index, K_f(i) The water-containing heterogeneous index of the ith well; i is an oil well serial number (i ═ 1, 2, 3, ·, n); q. q.s_l(i)The daily liquid production of the ith well, m³/d；f_w(i)Water content of the ith well,%.

And calculating the daily liquid yield and the water content of each current oil well by using the heterogeneous index, wherein the oil wells with the daily liquid yield higher than the average value of the oil wells and the water content higher than the average value of the oil wells have sufficient energy and low-efficiency circulation and are wells to be profile-controlled.

The method has the advantages that based on the dynamic indexes of the oil wells, the production characteristics of the oil wells are divided into four categories by utilizing dual factors of oil yield accumulative deviation and water yield accumulative deviation, high-oil high-water wells, low-oil high-water wells and low-oil low-water wells are screened as suspected wells, in the second screening, the high-daily-production-capacity and high-water-content oil wells have water channeling characteristics, and corresponding well groups are screened for profile control operation. The method aims at the narrow river channel oil reservoir which is fast in horizontal change on the sea and complex in longitudinal superposition, and has the advantages of being good in applicability, high in screening efficiency and accurate.

Drawings

FIG. 1 is a typical cumulative heterogeneous index change diagram of well water production and oil production according to step 1 of the present invention

FIG. 2 is a heterogeneous index change diagram of the accumulated water and the accumulated oil of the reservoir oil well in example 1 of the present invention

FIG. 3 is a diagram of the daily fluid production and water content heterogeneous index of the suspected profile control well of the oil reservoir in example 1 of the present invention

FIG. 4 is a production curve before and after the profile control of the E05 well group of example 1 of the present invention

For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the present invention is further described below with reference to specific examples.

Example 1:

a dynamic index-based offshore narrow river channel oil reservoir profile control and well selection decision method comprises the following steps:

step 1) carrying out primary screening based on the accumulative oil and water. Selecting two production indexes of the accumulated oil yield and the accumulated water yield and carrying out primary screening by using the heterogeneous index.

The heterogeneous index can be reflected by the variation of production index, HI is the average value of a certain production index M and the production index of a block of the oil wellDifference of (d) and average value of the production indexThe expression is:

by using the heterogeneous index, the difference and the good of the single well production condition compared with the average production condition of the oil well of the oil field can be reflected. Taking the daily oil production index as an example, when the daily oil production of the oil well is higher than the average daily oil production, HI is more than 0; equal to the average, HI is 0; less than average, HI < 0.

The heterogeneous index of the accumulated oil yield and the heterogeneous index of the accumulated water yield can be expressed by a formula 1.

In equation 1: ko (i, t) is the cumulative oil production heterogeneous index of the ith well on the t day, and Kw (i, t) is the cumulative water production heterogeneous index of the ith well on the t day; i is an oil well serial number (i ═ 1, 2, 3, ·, n); t is the time variable, day; j is the well production time (j ═ 1, 2, 3, ·, t); q. q.s_o(i,j)The j day oil production of the ith well, m³/d；q_w(i,j)The j day water yield, m, of the ith well³And d. By means of the non-homogeneity index,

the accumulated oil yield and the accumulated water yield of each oil well along with the change of time can be calculated, the coordinates (Ko (i, t) and Kw (i, t)) are projected into a rectangular coordinate system, a continuous change curve chart of the difference value of a certain oil well and the average value of the oil field is obtained, and the process that multiple factors deviate from the average value of the oil field is reflected.

The variation curve diagram of the deviation index of the accumulated water and the accumulated oil of the oil well is shown in the attached figure 1, four quadrants correspond to different oil well categories respectively, the first quadrant is a high-oil high-water well with the oil yield higher than the average value of the oil well and the water yield higher than the average value of the oil well, the second quadrant is a low-oil high-water well with the oil yield lower than the average value of the oil well and the water yield higher than the average value of the oil well, the third quadrant is a low-oil low-water well with the oil yield lower than the average value of the oil well and the water yield lower than the average value of the oil well, and the fourth quadrant is a high-.

In the first screening process, the high-oil low-water well in the fourth quadrant has good production condition without adjustment, and the low-oil high-water well in the second quadrant has the characteristics of a low-efficiency well, but cannot determine whether the injected water of the well forms a cross flow along a large channel. The high oil-high water well and the low oil-low water well in the I-th quadrant and the III-th quadrant have the characteristics of high daily water yield and low daily oil yield at the same time or low daily oil yield at the same time, and clear judgment can not be given to the two types of wells. And taking the oil wells in the second quadrant, the first quadrant and the third quadrant as suspected wells for further screening.

And 2) carrying out secondary screening based on the daily liquid yield and the water content. And selecting the latest daily liquid yield and water content, and performing secondary screening on the profile control suspected well by using the heterogeneous index. The expression is as follows:

in equation 2: k_l(i) Is the i-th well daily fluid heterogeneity index, K_f(i) The water-containing heterogeneous index of the ith well; i is an oil well serial number (i ═ 1, 2, 3, ·, n); q. q.s_l(i)The daily liquid production of the ith well, m³/d；f_w(i)Water content of the ith well,%.

. The daily liquid yield and the water content of each current oil well can be calculated by utilizing the heterogeneous index, and the deviation of the average value of the daily liquid yield and the water content can be calculated.

Table 1 shows the results of selecting and screening heterogeneous index parameters of the oil well, and the oil well having a daily liquid yield higher than the average value of the oil well and a water content higher than the average value of the oil well has sufficient energy and inefficient cycle, and needs to be profile-controlled.

TABLE 1 oil well heterogeneous index parameter selection and screening results

Example 2: offshore E reservoir profile control well selection decision

E, the oil reservoir is a lithologic-tectonic oil reservoir, the width of a single-phase river channel is 180-200m, the thickness of the single-phase river channel is 4-10m, and the regional deposition background is lake-receding type birdfoot-shaped shallow water delta deposition formed by three-lifting and three-lowering of sea level; average porosity of 31%, average permeability of 2715mD, and reservoir depth of 1700 m. The viscosity of the crude oil in the stratum is 120 mPa.s on average, the oil is produced in multiple layers and in irregular well patterns, 29 oil wells and 12 water injection wells are shared in the middle of 2019, the comprehensive water content is 80%, and the production degree is 13.9%. The oil reservoir has a large amount of residual oil enrichment and has a profile control material base.

According to the requirements of the step 1), on the basis of current production parameters, taking accumulated oil and accumulated water to make a heterogeneous exponential graph on all oil wells of an oil reservoir E, and summarizing 29 oil well classifications (shown in a graph 2) of the oil field, wherein a high-oil low-water well in a fourth quadrant is a high-efficiency well, accounts for 41 percent of the total number of oil wells, is mainly distributed in a sand main river channel, has large oil reservoir thickness, is complete in a water-drive well pattern, and is communicated with injection and production; the oil wells in the I, II and III quadrants are suspected profile control wells.

According to the requirements of the step 2), carrying out statistical analysis on the current daily fluid yield and water content of the suspected profile control well, and carrying out secondary screening by using a heterogeneous index method (figure 3), wherein the daily fluid yield and the water content of 9 oil wells (E01, E02, E06, E38H, E28H1, E10, E04, E17 and E12) in the first quadrant are high, and the well is screened as the well to be profiled because the reservoir permeability is large in change, the water channeling is serious, the fluid production capacity of the oil well is relatively strong, but the water content is fast in rising, and the well has the characteristic of an inefficient circulating well, and the well with the water content screened in the second quadrant, the well in the third quadrant or the daily fluid yield does not have the characteristic of inefficient circulating completely, so the non-profiled well is obtained.

And comprehensively analyzing each well group of the E oil reservoir, and selecting the E05 well group to perform a profile control experiment. The water injection well E05 is peripheral to be beneficial to the oil production well from the first line of 6 ports E01, E02, E04, E08, E09 and E38H, the water content difference of the oil well is large, the water content is 50-90%, E01, E02, E04 and E38H are all screened profile control wells, the residual recoverable reserve of a well group is 40% of geological reserve, the potential of large potential for excavation is high, the injection pressure of the E05 well head is 6.5MPa, the fracture pressure is 18.5MPa, the space is adjusted upwards by 12MPa, the injection pressure of the well head is increased after the profile control, the injection allocation can be completed, and the cementing quality of the peripheral oil well is qualified.

According to the research result, polymer microspheres are injected into the E05 well group from 12 months and 25 days in 2018 to 6 months and 30 days in 2019 to perform profile control operation. After the profile control is implemented on the E05 well group, the development effect is obviously improved, the oil yield of the well group is steadily and moderately increased, and the average daily oil production increase is 44m³The water content of the well group slowly decreases, and the average decreasing amplitude of the water content4% (fig. 4). Cumulative oil increase of 1.3 multiplied by 10 for 11 month bottom well group in 2019⁴m³Wherein, the cumulative oil increment of the E01 well is 0.13 multiplied by 10⁴m³Cumulative oil gain of 0.1X 10 for E02 well⁴m³Cumulative oil gain of 0.37X 10 for E04 well⁴m³Cumulative oil gain of 0.24X 10 for E38H well⁴m³。

The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.