CN106056252A - Shale gas field well group division three-level optimization method - Google Patents

Abstract

The invention discloses a shale gas field well group division three-level optimization method. The technical scheme adopts a hierarchical optimization and integration strategy and converts a well group optimization division issue into a three-level optimization issue, and is characterized by, with minimum construction cost of gas-collection pipe network systems in various development years of a shale gas field being an objective function, establishing gas-gathering station site optimization models in different development years; dividing the optimum gas-gathering station site in each development year into a plurality of cluster groups through a hierarchical clustering method, the cluster center of each group serving as a global optimum gas gathering station site; and with the minimum sum of the distance between global optimum gas gathering stations and well fields being an objective function, establishing an optimization model of membership relation between the shale gas field global optimum gas gathering stations and the well fields. With unconventional features of fast production decline of the shale gas wells and continuous new well operation being taken into consideration, the invention provides a new method for determining the well group division scheme, where the construction cost of the gas-collection pipe network of the shale gas filed in a full life circle is minimum, and the method is of great importance in reducing the construction cost of the shale gas ground engineering.

Description

A kind of shale gas field three grades of optimization methods of well group division

Technical field

The present invention relates to a kind of shale gas field well group division optimization method, belong to shale gas field collection transmission pipe network system layout excellent Change technical field.

Background technology

Shale gas is as the unconventional gas resource of a kind of great Development volue, institute in world's natural gas resource total amount Accounting example rises the most year by year, is paid high attention to by countries in the world.But owing to shale gas well has production declines speed product fast, upper Time length, using the unconventional features such as extensive rolling development, cause development cost high, investment risk is big, it is necessary to implement low one-tenth This strategy could realize profit.Shale gas ground transportation network system is optimized design, is to reduce shale gas development cost One of important channel.

Shale gas stratum permeability is poor, needs on stream to bore a large amount of producing well.For saving development cost and minimizing Impact on environment, often bore in same well site 4～20 mouthfuls not etc. from formula well.Well group division refers to determine that shale gas field is big Amount well site point group a scheme, i.e. determine the quantity of gas gathering station, position and and well site between membership.At present, shale gas Field well group division typically uses the mode of scheme comparison or overall merit.Its basic thought is according to engineering experience, sets up several Relatively reasonable well group division scheme, then it is carried out mutually ratio choosing, therefrom select more excellent scheme as final scheme.This side Formula is simple, but closely related with the experience of engineering staff, and optimum results is difficult to global optimum.At present, learn both at home and abroad Person there has been lot of research on the well group optimization method of conventional gas field, has obtained relatively broad answering in engineering practice With, the well group optimization of shale gas gas field is divided and has certain reference.It generally uses the method for founding mathematical models, the most logical Cross the object function of relation between structure reflection optimization aim and variable, under constraints, solve the extreme value of object function, with The well group obtaining correspondence optimizes splitting scheme.Common mathematical model is roughly divided into three classes, the most respectively with pipe-line construction expense Save, length of pipeline is the shortest, pipeline yield distance is the shortest as object function, selects gas gathering station site, well site to be subordinate to gas gathering station Relation, as decision variable, under the constraintss such as gas gathering station administrative well site number and the defeated radius of collection, sets up corresponding well group optimization Partitioning model.But these models be based on it is assumed hereinafter that: go into operation in each well site simultaneously；Each well site yield is constant, time not with exploitation Between change and change.Therefore, model above is only used for the conventional gas field of construction cycle length and stable yield, is not suitable for having product Amount rate of decay product time fast, upper length, use the shale gas field well group optimization of the essentially very rule features such as extensive rolling development Divide.

Summary of the invention

The purpose of the present invention is aiming at the defect that existing optimization method exists, it is provided that a kind of shale gas well production that adapts to declines Subtract fast, constantly to have unconventional characteristics such as bringing in a well well group and optimize division methods, for obtaining in the Life cycle of shale gas field The well group division scheme that gas gathering network construction cost saves most provides foundation, to reduce shale gas ground engineering construction cost.

Its technical scheme comprises the steps of

Step a, the prospect pit Production development curve obtained according to the guiding development experiments in shale gas field, use power law index to pass Subtraction or hyperbolic decline method obtain the production declines characteristic curve of respective block individual well；According to each individual well go into operation plan arrange and Production declines characteristic curve, determines each well site production decrement curve；

Step b, haul oneself willingly into product with shale gas field since each exploitation time gas gathering network system Construction expense save as target letter most Number, using gas gathering station site, the membership of well site and gas gathering station is as decision variable；When the constraint of well site membership, exploitation Between retrain, the constraint of gas gathering station treating capacity, gas gathering station administrative well site number constraint, collect defeated Radius Constraint, gas gathering station site constraint etc. Under constraints, set up the shale gas field gas gathering station site Optimized model in the difference exploitation time；

Step c, employing hierarchical clustering method, the optimum gas gathering station site that shale gas field is respectively developed the time is divided into several Clustering cluster, the cluster centre of each bunch is as the gas gathering station site of shale gas field global optimum；

It is step d, the shortest as object function with shale gas field gas gathering station of global optimum site to the distance sum between well site, Using the membership of well site and gas gathering station as decision variable；At the constraint of well site membership, gas gathering station treating capacity constraint, gas collection Administrative well site number of standing retrains, collects under the constraintss such as defeated Radius Constraint, sets up shale gas field gas gathering station of global optimum and well site Between the Optimized model of membership.

According to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step Shale gas field gas gathering network system Construction expense described in b includes the construction cost of gas gathering line and gas gathering station.

According to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step Constraints described in b and step d: membership constraint in well site refers to for arbitrary well site, has and only one of which gas gathering station Coupled；Development time constraint refers to all bring the well site of shale gas field difference exploitation operation in period into corresponding Optimized model In；Gas gathering station treating capacity constraint refers to the treating capacity upper and lower bound of arbitrary gas gathering station, should meet the administrative well site of process and respectively open Send out whole yield in time；Gas gathering station administrative well site number constraint refers to that the maximum quantity in well site can be administered by single gas gathering station；Collection Defeated Radius Constraint refers to that collecting pipe length should be less than economic gas collection radius；Gas gathering station site constraint refers to that gas gathering station is located at The yield center of administrative well group.

According to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step Hierarchical clustering method described in c uses single-linkage clustering method.

The invention has the beneficial effects as follows: consider the characteristic that the decay of shale gas well production has new well site to go into operation soon and constantly, Use Interest frequency and integrated strategy, shale gas well group division problem is converted into three grades of optimization problems.Corresponding by setting up Optimized model, determine respectively shale gas field difference develop the optimum gas gathering station site in time, shale gas field global optimum collection Site, gas station and and well site between optimal membership.The present invention is for determining shale gas field global set gas pipe network construction cost The well group division scheme saved most provides new approaches, and to reducing, shale gas field ground engineering construction cost is significant.

Accompanying drawing explanation

Fig. 1 is the production decrement curve in certain two typical well site of different blocks, shale gas field

Fig. 2 is certain shale gas field development optimum well group division scheme of the 6th year

Fig. 3 is certain shale gas field 2014～optimum gas gathering station of all of year site between the year two thousand thirty

Fig. 4 is the gas gathering station site of certain shale gas field global optimum

Fig. 5 is the optimum well group division scheme in certain shale gas field Life cycle

Fig. 6 is the flow chart of shale gas field three grades of optimization methods of well group division

Detailed description of the invention

Specific embodiment: as a example by certain shale gas field domestic, and combine accompanying drawing present disclosure to be described and realizes former Reason:

The technical scheme is that employing Interest frequency and Integrated Strategy, well group is optimized partition problem and is converted into three grades Optimization problem: respectively develop time gas gathering network system Construction expense with shale gas field and save as object function most, sets up difference exploitation The gas gathering station site Optimized model in time；Hierarchical clustering method is used to be divided into some by the optimum gas gathering station site in each exploitation time Individual clustering cluster, using the cluster centre of each bunch as gas gathering station of global optimum site；With gas gathering station of each global optimum and well site Distance sum is the shortest for object function, sets up the membership between shale gas field gas gathering station of global optimum and well site and optimizes mould Type.Detailed process is as follows:

1, well site basic situation and production declines law forecasting

Certain shale gas field has completed early stage pilot production assessment the most, it was demonstrated that this block reservoir thickness is big, stock number is enriched.Plan Amount between 2014-2030 and dispose drilling well more than 1050 mouth, 86, well site, stable yields stage design production capacity 1500 × 10⁴m³/d。 According to shale gas ground engineering construction scheme, shale gas field development and building time arrangement, as shown in table 1.Well site is distributed such as Fig. 5 Shown in.

Certain shale gas field development of table 1 and building time arrangement

The part individual well Production development curve obtained based on the guiding development experiments in shale gas field, is respectively adopted power law index The average product curve of diminishing method and hyperbolic decline method well all to each block is fitted, and chooses the song that fitting degree is higher Line is as the well yield attenuation curve of this block.In conjunction with the operation plan arrangement of each well site, obtain each well site by stacking method Production decrement curve, as shown in Figure 2.

2, the foundation of the gas gathering station site Optimized model in shale gas field difference exploitation time

Since hauling oneself willingly into product with shale gas field, each exploitation time gas gathering network system Construction expense saves as object function most, chooses The membership of gas gathering station site, well site and gas gathering station is as decision variable.Well site membership constraint, the development time about Bundle, gas gathering station treating capacity constraint, gas gathering station administrative well site number retrain, collect defeated Radius Constraint and gas gathering station site constraint etc. about Under the conditions of bundle, set up the shale gas field gas gathering station site Optimized model in the difference exploitation time.Its concrete steps include:

(1) object function is set up

Shale gas field gas gathering network system Construction expense includes the construction cost of gas gathering line and gas gathering station.Wherein, gas collection The construction cost of pipeline is main and the relating to parameters such as its length, caliber and wall thickness.But the internal gathering line in shale gas field typically belongs to In same pressure rating, pipeline wall thickness is more or less the same.Additionally, in the case of collecting pipe length is certain, pipeline flow is main Relevant with caliber.Owing to each well site can only be connected with a gas gathering station, between well site and gas gathering station, collecting pipe flow is The real-time gas production in well site.Therefore, the construction cost of gas gathering line can be expressed as length and the function of well site gas production.With Time, gas gathering station construction cost is the most relevant with its disposal ability.Least square regression etc. can be used according to conventional design data Method obtains the functional relationship between gas gathering station construction cost and its treating capacity.Each exploitation time gas gathering network system Construction expense Minimum scheme is the well group optimal dividing scheme in this time.Wherein, the well group division object function of t is:

$\min F(\mathrm{\δ},U,t)=\underset{i=1}{\overset{m_t}{\Σ}}\underset{j=1}{\overset{n_t}{\Σ}}\[C_{ij}+C_j\]=\underset{i=1}{\overset{m_t}{\Σ}}\underset{j=1}{\overset{n_t}{\Σ}}\[{\mathrm{\δ}}_{ij}{\mathrm{KL}}_{ij}{q_{i,t}}^{\mathrm{\γ}}+f\left(Q_j\right)\]---\left(1\right)$

In formula: m_t、n_tIt is respectively well site number and the gas gathering station number of shale gas field development t；C_ijFor well site i to collection Gas gathering line construction cost between the j of gas station, unit；C_jFor gas gathering station j construction cost, unit；L_ijBetween well site i to gas gathering station j Collecting pipe length,km；K, γ are coefficient, can adopt according to conventional design data Obtain by methods such as least square regressions；Q_jFor the day output of gas gathering station j, 10⁴m³/d。

(2) constraints is set up

Well site membership constraint: for arbitrary well site, have and only one of which gas gathering station is coupled；Development time is about Bundle: the value in shale gas field development time should go into operation in first well site time and all well sites enter stable production period time it Between；Gas gathering station treating capacity constraint: the treating capacity upper and lower bound of arbitrary gas gathering station should meet the administrative well site of process in each exploitation year Whole yield of part；Gas gathering station administrative well site number constraint: the maximum quantity in the administrative well site of single gas gathering station；Collect defeated radius about Bundle: collecting pipe length should be less than economic gas collection radius；Gas gathering station site constraint: gas gathering station is located in the yield of administrative well group The heart, is represented by:

$(x_j,y_j)=(\frac{\underset{i=1}{\overset{m_t}{\Σ}}{\mathrm{\δ}}_{ij}{x}_i{q}_{i,t}}{\underset{i=1}{\overset{m_t}{\Σ}}{\mathrm{\δ}}_{ij}{q}_{i,t}},\frac{\underset{i=1}{\overset{m_t}{\Σ}}{\mathrm{\δ}}_{ij}{x}_i{q}_{i,t}}{\underset{i=1}{\overset{m_t}{\Σ}}{\mathrm{\δ}}_{ij}{q}_{i,t}}),i=1,2,\mathrm{...},m_t---\left(2\right)$

In formula: (x_i,y_i), (x_j,y_j) it is respectively well site i and the position coordinates of gas gathering station j；q_i,tRepresent at exploitation time t Time, the gas production of well site i；m_tFor well site quantity during exploitation time t；δ_ijFor 0-1 variable, represent the person in servitude of well site i and gas gathering station j Genus relation, i.e. works as δ_ijValue when taking 1, represent that the two is connected；Work as δ_ijValue when taking 0, represent that the two is not attached to.

By model is solved, available shale gas field respectively develop gas gathering station quantity corresponding to time, site and with Membership between well site.Needed for each exploitation time, the quantity of gas gathering station is as shown in table 2, and shale gas field is developing the 6th year Optimum gas gathering station site and and well site between membership as shown in Figure 3.Between the 2014-2030 that will obtain, each year is Excellent gas gathering station collects, as shown in Figure 4 site.Can be obtained by Fig. 4 and Biao 2, maximum gas gathering station number needed for the overall situation of shale gas field It is 8,99 year optimum gas gathering station sites altogether.

The quantity of gas gathering station needed for the time is respectively developed in table 2 shale gas field

3, the determination of shale gas field gas gathering station of global optimum site

According to gas gathering station number maximum needed for the shale gas field overall situation obtained and 99 year optimum gas gathering station sites, use 99 year optimum gas gathering station sites are divided into 8 clustering cluster, using the cluster centre of each bunch as shale by hierarchical clustering method The gas gathering station site of gas field global optimum.It specifically comprises the following steps that

(1) analysis sample set is set up

Shale gas field is respectively developed the optimum gas gathering station site in time as analyzing sample set.

(2) distance matrix is set up

First, each gas gathering station is seen as a clustering cluster.Now, the distance between two bunches be Liang Ge gas gathering station it Between distance, the distance between any two bunches is represented by:

$d_{kl}=\left|\right|X_k-X_l\left|\right|=\sqrt{{(x_k-x_l)}^2+{(y_k-y_l)}^2},k=1,2,\mathrm{...},N;l=1,2,\mathrm{...},N---\left(3\right)$

In formula, d_klFor the distance before kth gas gathering station and l gas gathering station；(x_k,y_k)、(x_l,y_l) it is respectively X_k、Y_k Coordinate, be kth number and l gas gathering station site；K, l are respectively the numbering of sample；N is the quantity of sample.Each gas gathering station Between distance matrix be:

(3) the gas gathering station site of shale gas field global optimum is determined

Use single-linkage clustering method that shale gas field is respectively developed the optimum gas gathering station site in time and be divided into 8 Individual clustering cluster, and using the cluster centre of each bunch as the gas gathering station site of shale gas field global optimum, be represented by:

$(\stackrel{\‾}{x_j},\stackrel{\‾}{y_j})=\left(\frac{\underset{k=1}{\overset{N}{\Σ}}{\mathrm{\μ}}_{jk}{x}_k}{\underset{k=1}{\overset{N}{\Σ}}{\mathrm{\μ}}_{jk}},\frac{\underset{k=1}{\overset{N}{\Σ}}{\mathrm{\μ}}_{jk}{y}_k}{\underset{k=1}{\overset{N}{\Σ}}{\mathrm{\μ}}_{jk}}\right)---\left(5\right)$

In formula:For the coordinate of the cluster centre of jth bunch, it is gas gathering station of the global optimum site of jth bunch； μ_kjFor 0-1 variable, represent the membership between kth gas gathering station and jth clustering cluster, i.e. work as μ_kjValue when taking 1, represent Kth gas gathering station is under the jurisdiction of jth clustering cluster；Work as δ_ijValue when taking 0, otherwise.Accordingly, it is determined that the gas gathering station of 8 global optimums Site, as shown in Figure 5.

4, the foundation of the membership Optimized model between shale gas field gas gathering station of global optimum and well site

The shortest as object function with shale gas field gas gathering station of global optimum site to the distance sum between well site, choose well With the membership of gas gathering station as decision variable.In the constraint of well site membership, gas gathering station treating capacity constraint, institute of gas gathering station Linchpin well site number constraint and collect under the constraintss such as defeated Radius Constraint, set up shale gas field Life cycle optimum gas gathering station with Membership Optimized model between well site.It specifically comprises the following steps that

(1) object function is set up

Gas gathering station sites based on fixed 8 global optimums, in conjunction with position, each well site, arrive with optimum gas gathering station site Distance sum between well site is the shortest for object function, can be expressed as follows:

$\min F\left(\mathrm{\δ}\right)=\underset{i=1}{\overset{m}{\Σ}}\underset{j=1}{\overset{n}{\Σ}}{\mathrm{\δ}}_{ij}{L}_{ij}---\left(6\right)$

In formula: m is the number of overall situation gas gathering station, n is well site, shale gas field sum.

(2) constraints is set up

Well site membership constraint: for arbitrary well site, have and only one of which gas gathering station is coupled；Gas gathering station treating capacity Constraint: the treating capacity upper and lower bound of arbitrary gas gathering station should meet the whole yield processing administrative well site in the shale gas overall situation；Collection Administrative well site, gas station number constraint: the maximum quantity in the administrative well site of single gas gathering station；Collect defeated Radius Constraint: collecting pipe length should Less than economic gas collection radius.

By model is solved, obtain the optimal membership between shale gas field gas gathering station of global optimum and well site, As shown in Figure 5.The flow process of shale gas field provided by the present invention three grades of optimization methods of well group division is as shown in Figure 6.

Claims (4)

1. three grades of optimization methods of shale gas field well group division, is characterized in that comprising the steps of

Step a, the prospect pit Production development curve obtained according to the guiding development experiments in shale gas field, use power law index diminishing method Or hyperbolic decline method obtains the production declines characteristic curve of respective block individual well；Arrange and yield according to the plan of going into operation of each individual well Attenuation characteristic curve, determines each well site production decrement curve；

Step b, haul oneself willingly into product with shale gas field since each exploitation time gas gathering network system Construction expense save as object function most, with The membership of gas gathering station site, well site and gas gathering station is as decision variable；Well site membership constraint, the development time about Bundle, gas gathering station treating capacity constraint, gas gathering station administrative well site number retrain, collect the constraint such as defeated Radius Constraint, gas gathering station site constraint Under the conditions of, set up the shale gas field gas gathering station site Optimized model in the difference exploitation time；

Step c, employing hierarchical clustering method, the optimum gas gathering station site that shale gas field is respectively developed the time is divided into several clusters Bunch, the cluster centre of each bunch is as the gas gathering station site of shale gas field global optimum；

Step d, the shortest as object function, with well with shale gas field gas gathering station of global optimum site to the distance sum between well site With the membership of gas gathering station as decision variable；In the constraint of well site membership, gas gathering station treating capacity constraint, institute of gas gathering station Linchpin well site number retrains, collects under the constraintss such as defeated Radius Constraint, sets up between shale gas field gas gathering station of global optimum and well site The Optimized model of membership.

2. according to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step b Described in shale gas field gas gathering network system Construction expense include the construction cost of gas gathering line and gas gathering station.

3. according to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step b With the constraints described in step d: well site membership constraint refer to for arbitrary well site, have and only one of which gas gathering station with It is connected；Development time constraint refers to all bring the well site of shale gas field difference exploitation operation in period into corresponding Optimized model In；Gas gathering station treating capacity constraint refers to the treating capacity upper and lower bound of arbitrary gas gathering station, should meet the administrative well site of process and respectively open Send out whole yield in time；Gas gathering station administrative well site number constraint refers to that the maximum quantity in well site can be administered by single gas gathering station；Collection Defeated Radius Constraint refers to that collecting pipe length should be less than economic gas collection radius；Gas gathering station site constraint refers to that gas gathering station is located at The yield center of administrative well group.

4. according to a kind of shale gas field three grades of optimization methods of well group division described in claims 1, it is characterised in that step c Described in hierarchical clustering method use single-linkage clustering method.