阅读说明：本技术 一种垂直井管外出砂亏空剖面预测及高饱和砾石充填施工方法 (Vertical well pipe external sand production and depletion profile prediction and high-saturation gravel packing construction method ) 是由 董长银 王力智 赵益忠 梁伟 周博 李常友 宋洋 刘晨枫 李志芬 于乐香 于 2020-03-19 设计创作，主要内容包括：本发明属于油气开发与开采的技术领域,尤其疏松砂岩出砂油气藏领域,具体的涉及一种垂直井管外出砂亏空剖面预测及高饱和砾石充填施工方法。该垂直井管外砾石充填施工方法包括垂直井管外生产层位纵向出砂剖面亏空预测；出砂亏空剖面非均质模式判别；垂直井管外挤压砾石充填泵注程序设计。所述施工方法充分考虑了出砂亏空剖面及其非均质性,将出砂亏空地带充填密实,大大提高了充填程度,达到高饱和充填,提高了防砂效果。(The invention belongs to the technical field of oil and gas development and exploitation, particularly relates to the field of loose sandstone sand production oil and gas reservoirs, and particularly relates to a vertical well pipe sand production depletion profile prediction and high-saturation gravel filling construction method. The construction method for filling gravel outside the vertical well pipe comprises the steps of predicting the depletion of a longitudinal sand production profile of a production horizon outside the vertical well pipe; judging a heterogeneous mode of the sand-producing void section; and designing a pumping program for extruding gravel pack outside the vertical well pipe. The construction method fully considers the sand-producing void section and the heterogeneity thereof, and the sand-producing void zone is densely filled, so that the filling degree is greatly improved, high-saturation filling is achieved, and the sand prevention effect is improved.)

1. A vertical well pipe sand production depletion profile prediction method is characterized by comprising the following steps:

(1) calculating the vertical sand production deficit index: firstly, respectively calculating a rock density intensity index and a rock sound wave time difference intensity index according to density logging data and sound wave time difference logging data of a production layer; then calculating a longitudinal sand production and depletion index through the weighted average of the rock density intensity index and the rock sound wave time difference intensity index to obtain longitudinal sand production and depletion index distribution of a production horizon outside the vertical well pipe;

(2) calculating the average equivalent deficit radius: firstly, estimating the accumulated sand production volume of a vertical well, namely the sand production void volume according to production historical data including production age, average yield and average sand content; then calculating the average equivalent deficit radius of the whole production horizon of the vertical well according to the sand production deficit volume;

(3) drawing a longitudinal sand production depletion section view: firstly, calculating the equivalent deficit radius at the depth point i of the production horizon of the vertical well by combining the longitudinal sand production deficit index distribution obtained in the step (1) and the average equivalent deficit radius obtained in the step (2), and then drawing a distribution diagram of the sand deficit radius along the longitudinal direction according to the data obtained by calculation, namely a longitudinal sand production deficit profile diagram, wherein the equivalent deficit radius r at the depth point i of the production horizon of the vertical well_iThe calculation formula is as follows:

in the formula-mean value of longitudinal sand production deficit index of production horizon, dimensionless;

r_i-equivalent deficit radius at depth point i, m;

K_i-longitudinal sand production deficit index at depth point i;

r_s-average equivalent deficit radius of the vertical well overall production horizon.

2. The method for predicting the sand production depletion profile outside the vertical well pipe according to claim 1, wherein the formula for calculating the rock density strength index in the step (1) is as follows:

where rho_iDensity logging, g/cm, of the ith depth point of the production horizon³；

ρ_max、ρ_minProduction horizon rock density log maximum and minimum, g/cm³；

K_ρi-rock density strength index, dimensionless;

the formula for calculating the rock sound wave time difference intensity index is as follows:

in the formula,. DELTA.t_i-the longitudinal wave time difference, s/m, at the ith depth point of the production horizon;

T_iintermediate characterization variable m of ith depth point of production horizon²/s²；

T_maxIntermediate characterising variable T_iMaximum value of (1), m²/s²；

T_minIntermediate characterising variable T_iMinimum value of (1), m²/s²；

K_tiRockThe stone sound wave time difference intensity index is dimensionless;

the calculation formula of the longitudinal sand production void index is as follows:

K_i＝1-(0.5K_ρi+0.5K_ti)

in the formula K_iAnd the vertical sand production and deficit index of the ith depth point of the production horizon is dimensionless.

3. The method for predicting the depletion profile of sand produced outside the vertical well pipe according to claim 1, wherein the calculation formula of the cumulative sand production volume of the vertical well in the step (2) is as follows:

V_s＝t_p×365×Q×C_s/100

the average equivalent deficit radius calculation formula of the overall production horizon of the vertical well is as follows:

in the formula t_pVertical well sand production life, a;

q-average daily production of vertical well, m³/d；

C_s-vertical well volume sand content,%;

r_w-wellbore radius, m;

h-production layer position thickness, m;

V_scumulative sand volume, m, of vertical well³；

r_s-average equivalent deficit radius, m, of the vertical well overall production horizon.

4. The construction method for gravel packing outside the vertical well pipe is characterized by comprising the following steps:

(1) and (3) predicting the depletion of the vertical well pipe external production horizon longitudinal sand production profile: performing vertical sand production profile depletion prediction on a production horizon outside a vertical well pipe by adopting the prediction method of claim 1 to obtain a vertical sand production depletion profile;

(2) and (3) judging the heterogeneous mode of the sand-producing void section: analyzing a longitudinal distribution rule of the sand-producing section deficit according to the longitudinal sand-producing deficit profile diagram obtained in the step (1), and judging to obtain a sand-producing deficit profile heterogeneous mode;

(3) and (3) designing a pumping program of the vertical well pipe external extrusion gravel packing: designing a construction procedure of a multistep staged extrusion filling mode and a multi-group parameter combination pump injection according to the sand production deficit profile heterogeneous mode judged in the step (2); aiming at weak and strong deficit parts in different heterogeneous modes, a plurality of groups of pump injection parameters of variable displacement and sand ratio are designed, and a staged pump injection construction procedure combining multi-stage displacement and sand ratio is adopted.

5. The vertical wellbore external gravel pack construction method of claim 4, wherein the sand depletion profile heterogeneous mode in steps (2) and (3) comprises type A: the upper weak and lower strong type is formed by an upper weak deficit and a lower strong deficit; type B: a top strong and bottom weak type composed of a top strong deficit and a bottom weak deficit; type C: the middle-weak edge strength type is formed by a middle weak deficit and upper and lower strong deficit; type D: a middle-strong side weak type consisting of a middle strong deficit and upper and lower weak deficit; type E: substantially homogeneous.

6. The vertical wellbore external gravel pack construction method of claim 4, wherein the pump injection volume is divided into three levels in the step (3): stage I low displacement: the discharge capacity is low, the flow rate is low, and the sand carrying capacity is weak; discharge capacity in stage II: the discharge capacity is medium, the flow rate is medium, and the sand carrying capacity is medium; high displacement of the III level: the discharge capacity is large, the flow rate is high, and the sand carrying capacity is strong;

in the step (3), the sand injection ratio of the pump, namely the ratio of the volume of the quartz sand gravel or the artificial ceramsite particles in the sand carrying liquid to the volume of the sand carrying liquid is divided into three grades: i-grade low sand ratio: the sand ratio is 5-15%, the concentration of quartz sand gravel or artificial ceramsite particles is low, and deposition is not easy to occur; sand ratio in II grade: the sand ratio is 15-35%, the concentration of quartz sand gravel or artificial ceramsite particles is medium, and the deposition risk is medium; level III sand ratio: the sand ratio is 35-60%, and the quartz sand gravel or artificial ceramsite particles are high in concentration and easy to deposit.

7. The vertical well pipe external gravel pack construction method according to claim 6, wherein when the bottom of the sand-producing depletion profile in the heterogeneous mode determined in the step (2) is strong depletion, the bottom strong depletion region is subjected to the following operation in the step (3): filling, using the middle discharge capacity of the II level and the low sand ratio of the I level for construction; stopping adding sand, stopping sand squeezing, increasing the discharge capacity to a level III, and continuing construction; and thirdly, reducing the discharge capacity to the middle discharge capacity of the II level, increasing the sand ratio to the middle sand ratio of the II level or the high sand ratio of the III level, performing sand filling and squeezing, continuing construction, and filling the top of the strong deficit area.

8. The vertical well pipe external gravel pack construction method according to claim 6, wherein when the upper portion of the sand-producing depletion profile in the heterogeneous mode discriminated in the step (2) is a strong depletion, the upper strong depletion region is subjected to the following operation in the step (3): firstly, carrying out reinforced squeeze injection by using a grade III high discharge capacity, a grade II medium sand ratio or a grade I low sand ratio, and filling most of the bottom of a strong deficit area at the upper part in construction; secondly, reinforced squeezing is continuously carried out by using a III-level high discharge capacity, a II-level medium sand ratio or a III-level high sand ratio, and the top space of the upper part strong depletion area is filled until the filling is finished.

9. The vertical well pipe external gravel pack construction method according to claim 6, wherein when the middle part of the sand-producing depletion profile in the heterogeneous mode determined in the step (2) is a strong depletion mode, the middle strong depletion region is subjected to the following operation in the step (3): firstly, carrying out reinforced squeezing by using a grade III high discharge capacity, a grade II medium sand ratio or a grade I low sand ratio, and filling most of the bottom of a middle strong deficit area; and secondly, reducing the discharge capacity to the middle discharge capacity of II level, increasing the sand ratio to the middle sand ratio of II level or the high sand ratio of III level, performing sand supplement and squeeze injection, and continuing construction.

10. The vertical well pipe external gravel packing construction method according to claim 6, wherein when the upper part of the sand producing deficit profile in the heterogeneous mode distinguished in the step (2) is weak deficit, II-level medium displacement, II-level medium sand ratio or III-level high sand ratio construction is performed on the upper weak deficit area in the step (3) until the packing is finished; when the middle part of the sand production deficit section in the heterogeneous mode distinguished in the step (2) is weak deficit, construction filling is carried out on the middle weak deficit region in the step (3) by using the II-level medium discharge volume, the II-level medium sand ratio or the III-level high sand ratio; and (3) when the bottom of the sand production deficit section in the heterogeneous mode judged in the step (2) is weak deficit, performing construction filling on the bottom weak deficit region by using the II-level medium discharge volume, the II-level medium sand ratio or the III-level high sand ratio.

Technical Field

The invention belongs to the technical field of oil and gas development and exploitation, particularly relates to the field of loose sandstone sand production oil and gas reservoirs, and particularly relates to a vertical well pipe sand production depletion profile prediction and high-saturation gravel filling construction method.

Background

In the process of producing the loose sandstone oil and gas reservoir, because the rock cementation of the loose sandstone oil and gas reservoir is weak, some fine sand grains can be peeled off under the action of the ground stress and the scouring of fluids such as oil, gas and water and the like, and enter a shaft or flow to the ground along with the production of the fluids, and the process is called as the sand production of an oil and gas well. During the production process, the oil and gas reservoir continuously produces stratum sand grains which tend to leave pores in the stratum; when the sand production of the stratum is serious or after long-term sand production, a deficit can be formed in the near wellbore area.

Due to factors of geological deposition, formation sand grains, cementing strength, acoustic wave time difference, rock density and the like of an actual oil and gas reservoir are not uniformly distributed, but have large difference in the longitudinal direction, so that the reservoir has heterogeneity in the longitudinal direction. Longitudinal heterogeneity of the reservoir, however, results in severe sand production and a vertical heterogeneity of the sand void profile, as shown in figure 1.

For sand production oil and gas wells, gravel filling is a common and dominant sand control process technology, wherein in the step of gravel filling and sand control by extrusion, quartz sand or artificial ceramsite particles are mixed into a sand carrying liquid in a certain proportion, the sand carrying liquid is used for carrying and extruding to fill a sand production void zone of a casing outer stratum at a high pressure and high flow rate, and the solid particles can fill a sand production void zone to form a gravel filling layer, so that the effect of blocking formation sand production is achieved, and meanwhile, the liquidity and the productivity are kept.

Because the limited validity period of sand control measure, the scene needs many rounds of gravel packing sand control, and along with the layer frame of sand control round, the reservoir deficit can expand to the stratum outside gradually, because the deficit scope is great and vertical deficit heterogeneity, leads to the filling of deficit position more difficult.

At present, the concrete operation of extrusion gravel packing sand prevention construction outside a vertical well pipe of a loose sandstone sand production oil-gas reservoir is as follows: firstly, squeezing and injecting a pre-treatment fluid (a pretreatment fluid), then continuously pumping and carrying quartz sand gravel or artificial ceramsite particles with a basically fixed sand ratio, squeezing and filling the quartz sand gravel or artificial ceramsite particles to an external stratum of a pipe, and finally squeezing and injecting a displacement fluid to displace gravel particles in a shaft to the stratum. The pumping procedure during construction includes squeezing pretreatment liquid, fixing sand ratio, continuous pumping gravel grains and pumping displacing liquid.

The pumping procedure of the existing external extrusion filling construction has the following defects:

(1) when the existing construction pump injection program is designed, the sand production depletion section and the longitudinal distribution rule of the underground reservoir are not known, a prediction means is lacked, and further, a design basis is lacked, so that a reasonable design method cannot be obtained;

(2) because the existing construction pump injection program design lacks basis, the existing extrusion filling construction belongs to general extrusion filling, lacks purpose, can not accurately master which depth parts should be filled more, and which depth parts can be filled less due to small vacancy; the filling of the void part is not full, and the sand prevention effect is poor;

(3) when the longitudinal heterogeneity of the sand-producing void section is strong, the existing general extrusion filling construction has large void space and is difficult to fill a gravel layer, so that the sand prevention effect is poor.

However, the current technology for increasing the gravel packing degree (rate) in the oilfield field is mainly aimed at the circulating packing of a horizontal well casing space (inside a casing or a borehole), namely, increasing the packing compactness degree in the borehole. And the improvement of the gravel filling degree of the vertical well casing external stratum which is completely different from the horizontal well in the aspects of filling objects, technical principles, technical processes and the like without the complete research of a specific system.

Disclosure of Invention

The invention aims to provide a vertical well pipe sand-out vacancy profile prediction and high-saturation gravel filling construction method aiming at the problems of lack of basis, general construction, poor comprehensive effect and the like of the existing extrusion filling construction, particularly aiming at a vertical well which has serious sand production, obvious sand production vacancy and needs to be subjected to high-saturation filling of an outer stratum of the vertical well pipe, wherein the sand production vacancy profile prediction method can clearly understand and master the sand production vacancy profile outside the vertical well pipe to obtain the longitudinal distribution rule of the sand production vacancy profile, so that scientific and sufficient basis is provided for the subsequent extrusion gravel filling construction; the construction method fully considers the sand-producing void section and the heterogeneity thereof, and the sand-producing void zone is densely filled, so that the filling degree is greatly improved, high saturation filling is achieved, and the sand prevention effect is improved.

The technical scheme of the invention is as follows: a vertical well pipe sand production depletion profile prediction method comprises the following steps:

(1) calculating the vertical sand production deficit index: firstly, respectively calculating a rock density intensity index and a rock sound wave time difference intensity index according to density logging data and sound wave time difference logging data of a production layer; then calculating a longitudinal sand production void index through the weighted average of the rock density intensity index and the rock sound wave time difference intensity index to obtain longitudinal sand production void index distribution of a vertical well pipe outer production layer position;

(2) calculating the average equivalent deficit radius: firstly, estimating the accumulated sand production volume of a vertical well, namely the sand production void volume according to production historical data including production age, average yield and average sand content; then calculating the average equivalent deficit radius of the whole production horizon of the vertical well according to the sand production deficit volume;

(3) drawing a longitudinal sand production depletion section view: firstly, combining the longitudinal sand production and deficit index distribution obtained in the step (1) and the step(2) Calculating the equivalent deficit radius at the depth point i of the production horizon of the vertical well according to the obtained average equivalent deficit radius, and then drawing a distribution diagram of the sand deficit radius along the longitudinal direction according to the calculated data, namely a longitudinal sand deficit profile, wherein the equivalent deficit radius r at the depth point i of the production horizon of the vertical well_iThe calculation formula is as follows:

in the formula-mean value of longitudinal sand production deficit index of production horizon, dimensionless;

r_i-equivalent deficit radius at depth point i, m;

K_i-longitudinal sand production deficit index at depth point i;

r_s-average equivalent deficit radius of the vertical well overall production horizon.

The calculation formula of the rock density strength index in the step (1) is as follows:

where rho_iDensity logging, g/cm, of the ith depth point of the production horizon³；

ρ_max、ρ_minProduction horizon rock density log maximum and minimum, g/cm³；

K_ρi-rock density strength index, dimensionless;

the formula for calculating the rock sound wave time difference intensity index is as follows:

in the formula,. DELTA.t_i-the longitudinal wave time difference, s/m, at the ith depth point of the production horizon;

T_iintermediate characterization variable m of ith depth point of production horizon²/s²；

T_maxIntermediate characterising variable T_iMaximum value of (1), m²/s²；

T_minIntermediate characterising variable T_iMinimum value of (1), m²/s²；

K_ti-rock acoustic time difference intensity index, dimensionless;

the calculation formula of the longitudinal sand production void index is as follows:

K_i＝1-(0.5K_ρi+0.5K_ti)

in the formula K_iAnd the vertical sand production and deficit index of the ith depth point of the production horizon is dimensionless.

The calculation formula of the accumulated sand production volume of the vertical well in the step (2) is as follows:

V_s＝t_p×365×Q×C_s/100

the average equivalent deficit radius calculation formula of the overall production horizon of the vertical well is as follows:

in the formula t_pVertical well sand production life, a;

q-average daily production of vertical well, m³/d；

C_s-vertical well volume sand content,%;

r_w-wellbore radius, m;

h-production layer position thickness, m;

V_scumulative sand volume, m, of vertical well³；

r_s-average equivalent deficit radius, m, of the vertical well overall production horizon.

A construction method for gravel packing outside a vertical well pipe comprises the following steps:

(1) and (3) predicting the depletion of the vertical well pipe external production horizon longitudinal sand production profile: performing longitudinal sand production profile vacancy prediction on a production stratum outside a vertical well pipe by adopting the prediction method of claim 1 to obtain a longitudinal sand production vacancy profile;

(2) and (3) judging the heterogeneous mode of the sand-producing void section: analyzing a longitudinal distribution rule of the sand-producing profile vacancy according to the longitudinal sand-producing vacancy-deficient profile diagram obtained in the step (1), and judging to obtain a sand-producing vacancy-deficient profile heterogeneous mode;

(3) and (3) designing a pumping program of the vertical well pipe external extrusion gravel packing: designing a construction procedure of a multistep staged extrusion filling mode and a multi-group parameter combination pump injection according to the sand production deficit profile heterogeneous mode judged in the step (2); aiming at weak deficit parts and strong deficit parts in different heterogeneous modes, a plurality of groups of pump injection parameters of variable displacement and sand ratio are designed, and a staged pump injection construction procedure combining multi-stage displacement and sand ratio is adopted.

The heterogeneous mode of the sand production deficit profile in the steps (2) and (3) comprises an A type: the upper weak and lower strong type is formed by an upper weak deficit and a lower strong deficit; type B: a top strong and bottom weak type composed of a top strong deficit and a bottom weak deficit; type C: the middle-weak edge strength type is formed by a middle weak deficit and upper and lower strong deficit; type D: a middle-strong side weak type consisting of a middle strong deficit and upper and lower weak deficit; type E: substantially homogeneous. The heterogeneous mode of the sand production void profile of the 5 vertical well production layers can be used for conveniently judging the heterogeneous characteristics of the actual sand production profile of the oil well. The sand production mode has the characteristics of simplicity, convenience and intuition, is very favorable for on-site sand control operation engineers to quickly design and formulate a simple pump injection procedure, and improves the sand control construction efficiency.

In the step (3), the pump injection displacement is divided into three levels: stage I low displacement: the discharge capacity is low, the flow rate is low, and the sand carrying capacity is weak; discharge capacity in stage II: the discharge capacity is medium, the flow rate is medium, and the sand carrying capacity is medium; high displacement of the III level: the discharge capacity is large, the flow rate is high, and the sand carrying capacity is strong; during actual extrusion filling operation, the specific selection of the construction displacement of pump injection is related to the thickness of a reservoir, the type of a carried filling material, the type of a sand carrying liquid and the viscosity, the absolute value of the pump injection is changed to a certain extent according to well conditions, and the absolute value is difficult to adopt a unified standard. The displacement class is therefore used in the method to indicate the relative size of the displacement of the construction pump.

In the step (3), the sand injection ratio of the pump, namely the ratio of the volume of the quartz sand gravel or the artificial ceramsite particles in the sand carrying liquid to the volume of the sand carrying liquid is divided into three grades: i-grade low sand ratio: the sand ratio is 5-15%, the concentration of quartz sand gravel or artificial ceramsite particles is low, and deposition is not easy to occur; sand ratio in II grade: the sand ratio is 15-35%, the concentration of quartz sand gravel or artificial ceramsite particles is medium, and the deposition risk is medium; level III sand ratio: the sand ratio is 35-60%, and the quartz sand gravel or artificial ceramsite particles are high in concentration and easy to deposit.

When the bottom of the sand-producing deficit profile in the heterogeneous mode distinguished in the step (2) is a strong deficit, performing the following operation on the bottom strong deficit region in the step (3): filling, using the middle discharge capacity of the II level and the low sand ratio of the I level for construction; stopping adding sand, stopping sand squeezing, increasing the discharge capacity to a level III, and continuing construction; and thirdly, reducing the discharge capacity to the middle discharge capacity of the II level, increasing the sand ratio to the middle sand ratio of the II level or the high sand ratio of the III level, performing sand filling and squeezing, continuing construction, and finishing filling the top of the strong deficit area.

When the upper part of the sand-producing deficit profile in the heterogeneous mode determined in the step (2) is a strong deficit, performing the following operation on the upper part strong deficit region in the step (3): firstly, carrying out reinforced extrusion and injection by using a grade III high discharge capacity, a grade II medium sand ratio or a grade I low sand ratio, and filling most of the bottom of a strong deficit region at the upper part in construction; secondly, reinforced squeezing is continuously carried out by using a III-level high discharge capacity, a II-level medium sand ratio or a III-level high sand ratio, and the top space of the upper part strong depletion area is filled until the filling is finished.

When the middle part of the sand-producing deficit profile in the heterogeneous mode distinguished in the step (2) is a strong deficit, performing the following operations on the middle strong deficit region in the step (3): firstly, carrying out reinforced extrusion injection by using a grade III high discharge capacity, a grade II medium sand ratio or a grade I low sand ratio, and filling most of the bottom of a middle strong deficit area; and secondly, reducing the discharge capacity to the middle discharge capacity of II level, increasing the sand ratio to the middle sand ratio of II level or the high sand ratio of III level, performing sand supplement and squeeze injection, and continuing construction.

When the upper part of the sand production deficit section in the heterogeneous mode distinguished in the step (2) is weak deficit, constructing the upper weak deficit area by using the II-level medium discharge volume, the II-level medium sand ratio or the III-level high sand ratio in the step (3) until the filling is finished; when the middle part of the sand production deficit section in the heterogeneous mode distinguished in the step (2) is weak deficit, construction filling is carried out on the middle weak deficit region in the step (3) by using the II-level medium discharge volume, the II-level medium sand ratio or the III-level high sand ratio; and (3) when the bottom of the sand production deficit section in the non-homogeneous mode judged in the step (2) is a weak deficit, performing construction filling on the bottom weak deficit region by using the II-level medium discharge volume, the II-level medium sand ratio or the III-level high sand ratio.

The invention has the beneficial effects that: the method for predicting the sand production and depletion profile outside the vertical well pipe can clearly understand and palm hold the sand production and depletion profile of the vertical well, obtain the distribution rule and the heterogeneous mode of the sand production and depletion profile, understand the positions of the strong depletion region and the weak depletion region in the longitudinal direction of the production horizon, and provide sufficient basis for the subsequent pump injection construction of the extrusion gravel filling.

The prediction method adopts a mode of combining density logging information and time-difference logging information to predict the sand production profile of the reservoir, and then judges a sand depletion mode. The two logging data are integrated and cooperated, and the one-sidedness and the limitation of a single logging data index are made up. Because density logs reflect the degree of rock cementation and compaction, rock strength is reflected from a certain side; the acoustic logging reflects the rock strength and pore size through the propagation speed of porous medium materials with different strengths and porosities to sound. The testing principle and the explaining method of the two have different side difficulties for reflecting the physical properties of the rock. The invention innovatively provides the integration of the two data, and the sand depletion index is calculated by combining the two data, so that the prediction accuracy can be greatly improved, and the two logging data are easy to obtain on site.

The construction method for gravel packing outside the vertical well pipe is a high-saturation extrusion gravel packing pump injection construction method aiming at improving the packing degree. Has the following advantages:

1. the construction method comprises the steps of firstly adopting the prediction method to carry out longitudinal sand production profile depletion prediction on a production position outside a vertical well pipe, clearly knowing and mastering the distribution rule and the heterogeneous mode of the sand production depletion profile outside the vertical well pipe, knowing the specific positions of a strong depletion area and a weak depletion area along the longitudinal direction of the production position, accurately mastering which depth parts are required to be filled more, and which depth parts can be filled less due to small depletion, defining the construction key target of high-saturation extrusion filling, and providing a sufficient basis for the reasonable design of a subsequent construction pumping program. The construction purpose and the sand control effect are improved totally, and compared with the traditional general filling without knowing the characteristics of the sand-producing and depletion profile of the production stratum, the total construction efficiency is improved by 25-40%.

2. The construction method adopts a multi-step segmented extrusion filling mode and a construction procedure of multi-group parameter combination pump injection, so that advanced sand blocking and filling of the deficit region can be effectively avoided, the deficit region existing at any position can be effectively and completely filled, and poor sand prevention effect caused by instability of a filled gravel layer due to the existence of deficit is avoided; meanwhile, the formation fine sand is prevented from filling the deficit area to form a low permeable layer, so that the oil well yield is seriously reduced. Therefore, the construction method improves the stability and sand blocking effect of the sand blocking layer, improves the circulation and keeps the high yield of the oil and gas well. Compared with the traditional cage filling, the construction method has the advantages that the effective sand prevention rate is improved by 15-25%, the comprehensive sand prevention effect is improved by 20-30%, and finally the exploitation benefit of the sand production oil and gas reservoir is improved.

3. The construction method is characterized in that multiple groups of pump injection parameters of variable displacement and sand ratio are designed for weak and strong deficit parts in different heterogeneous modes, a segmented pump injection construction procedure combining multi-stage displacement and sand ratio is adopted, high-saturation and high-density filling of the whole deficit part is achieved, and the problem of incomplete filling of a conventional construction procedure is avoided. Meanwhile, the total construction time is favorably shortened, the liquid consumption of the sand-carrying liquid is reduced, the sand prevention cost is saved, the pollution of the sand-carrying liquid to a reservoir is reduced, and the comprehensive sand prevention effect is improved. Compared with the whole well section filling sand control system, the average cost is saved by about 15-25%.

Drawings

FIG. 1 is a schematic diagram of the comparison before and after sand production and sand production depletion of a production reservoir.

Fig. 2 is a schematic diagram of the heterogeneous model of five reservoir sand-depletion profiles according to examples 1 to 5.

Fig. 3 is a schematic view of a construction process in a heterogeneous mode of an a-type (upper weak and lower strong type) sand-producing void section in example 1.

Fig. 4 is a schematic view of a deficit caused by advanced sand plugging in an existing conventional construction process in an a-type (upper weak and lower strong type) sand-producing deficit profile heterogeneous mode in example 1.

Fig. 5 is a longitudinal sand production and depletion index distribution calculated at a certain position of a well in the eastern solitary oil field in case 1.

Fig. 6 is a simulated image of a deficit radius profile of a certain layer of a well of an eastern solitary oil field calculated by the method of the present invention in case 1.

Fig. 7 is a simulated filling image of a certain position of a well in an eastern solitary oil field, which is obtained by utilizing the method of the present invention to design a pumping program for construction in case 1.

Fig. 8 is a simulated filling image of a certain position of a well in an eastern solitary oil field, which is obtained by using the conventional pump injection construction method.

Detailed Description

The present invention will be described in detail below by way of examples.

The method for predicting the sand production depletion profile outside the vertical well pipe specifically comprises the following steps:

(1) calculating the vertical sand production deficit index: firstly, respectively calculating a rock density intensity index and a rock sound wave time difference intensity index according to density logging data and sound wave time difference logging data of a production layer; then calculating a longitudinal sand production and depletion index through the weighted average of the rock density intensity index and the rock sound wave time difference intensity index to obtain longitudinal sand production and depletion index distribution of a production horizon outside the vertical well pipe; the calculation formula of the rock density strength index is as follows:

where rho_iDensity logging, g/cm, of the ith depth point of the production horizon³；

ρ_max、ρ_minProduction horizon rock density log maximum and minimum, g/cm³；

K_ρi-rock density strength index, dimensionless;

the formula for calculating the rock sound wave time difference intensity index is as follows:

in the formula,. DELTA.t_i-the longitudinal wave time difference, s/m, at the ith depth point of the production horizon;

T_iintermediate characterization variable m of ith depth point of production horizon²/s²；

T_maxIntermediate characterising variable T_iMaximum value of (1), m²/s²；

T_minIntermediate characterising variable T_iMinimum value of (1), m²/s²；

K_ti-rock acoustic time difference intensity index, dimensionless;

the calculation formula of the longitudinal sand production void index is as follows:

K_i＝1-(0.5K_ρi+0.5K_ti)

in the formula K_i-longitudinal sand production deficit index, dimensionless, of the ith depth point of the production horizon;

(2) calculating the average equivalent deficit radius: firstly, estimating the accumulated sand production volume of a vertical well, namely the sand production void volume according to production historical data including production age, average yield and average sand content; then calculating the average equivalent deficit radius of the whole production horizon of the vertical well according to the sand production deficit volume; the calculation formula of the accumulated sand production volume of the vertical well is as follows:

V_s＝t_p×365×Q×c_s/100

the average equivalent deficit radius calculation formula of the overall production horizon of the vertical well is as follows:

in the formula t_pVertical well sand production life, a;

q-average daily production of vertical well, m³/d；

C_s-vertical well volume sand content,%;

r_w-wellbore radius, m;

h-production layer position thickness, m;

V_scumulative sand volume, m, of vertical well³；

r_s-average equivalent deficit radius, m, of the vertical well overall production horizon.

(3) Drawing a longitudinal sand production depletion section view: firstly, calculating the equivalent deficit radius at the depth point i of the production horizon of the vertical well by combining the longitudinal sand production deficit index distribution obtained in the step (1) and the average equivalent deficit radius obtained in the step (2), and then drawing a distribution diagram of the sand deficit radius along the longitudinal direction according to the data obtained by calculation, namely a longitudinal sand production deficit profile diagram, wherein the equivalent deficit radius r at the depth point i of the production horizon of the vertical well_iThe calculation formula is as follows:

in the formula-mean value of longitudinal sand production deficit index of production horizon, dimensionless;

r_i-equivalent deficit radius at depth point i, m;

K_i-longitudinal sand production deficit index at depth point i;

r_s-average equivalent deficit radius of the vertical well overall production horizon.