Shale Gas Development Pacing Example

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Shale Gas Development Pacing

This page will walk you through how to build a Shale Gas Development Pacing project.

1) Developing the Network

First we are going to set up the skeleton of the network. On network tab, create a diagram that looks like the one below. In this screen capture all facilities and wells have their Asset Sub-Type indicated.

Note:

The pipelines from the Dehydrator facility have split the products, with a pipeline that carries only water going to Water Disposal, and a pipeline that carries all remaining products to the Gas Sales Facility (See Pipelines). The Gas Sales Facility has been set as a Sales Point that is constrained at 50 mmcf/d (See Specifying a Sales Point), while both Type Wells have been excluded from calculations (See Using a Type Well).

2) Entering Production

Next we are going to enter production into the 3 wells that we have in our network (See Building a Decline Set). In this instance we are going to make an Array (Time) table for gas and water for the PDP well, and multi-segment declines for the type wells.

Well - PDP Production (Economics)

You can create both simultaneously by selecting Array (Time) under Gas and Water and clicking "Create Declines".

Once the arrays are created, click on the Edit Arrays... link and enter the following values (Be sure that the table is set to monthly). Use the link below to find an excel file. You will find the array on the first tab. Follow directions inside the .xls file.

ShaleGas.xls

Well - Type Well - Hz Upper Zone

For this well, we will be creating a multi-segment decline (See Creating a Multi-Segment Decline) for the gas and a single segment decline for water. To do this we can use the same method as for the PDP Production well, the only difference being selecting Decline instead of Array(Time).

To add another segment to your Gas Decline, click the page with the green "+" sign beside the number one. Note that clicking the other identical link (the upper left corner) will create a different decline series, rather than a new segment within the current series. Set the first segment of the Gas decline to Hyperbolic, and the second segment to exponential. Set the water's method to Linear.

After you have your empty declines created, fill them in with the following information. Be sure to have the right Checkboxes flagged and unflagged, as this can change the decline forecast drastically, or simply not calculate due to an invalid combination of parameters. Only the blanks beside a checked box will be editable.

To change the Delay unit from months to days, click on the link "mo" and it will change to dy. It works the same way vice versa.

Well - Type Well 1

Create a third decline set for Type Well 1. This will be the same skeleton as PDP (Gas/water declines, 2 segments in gas), except the method for water will be exponential instead of linear. After the skeleton is created enter the following values:

To change the Delay unit from months to days, click on the link "mo" and it will change to dy. It works the same way vice versa.

3) Create Drilling Programs in Scheduler

The next step is to create the drilling programs in the scheduler. Click Drilling Program, and the following screen below will appear. The first step is to create resources that are required to complete this Drilling Program (See Creating a Drilling Program).

Creating Resources

In the resource tab, indicated in the above picture, select [Add Resource] and a resource will be created (See Scheduler Resources). For this project, we will have one Named 'Precision Rig A' , one named 'Precision Rig B' and one called 'Frac Spread 1'. Copy the information about the 3 resources below.

Precision Rig A - Drilling Rig, Available forever (default)

Precision Rig B - Drilling Rig, Available from Jan 2010 to June 2010, repeating 100 times.

Frac Spread 1 - Changing one of the default work types to be called 'Frac Spread' is possible through UserData. For the sake of simplicity, we will categorize this under Work Type 3. Available forever.

Now that the resources are set up, we can begin inputting information into our drilling program.

Data Entry - Drilling Program

First, change the program name to 'HBP Drilling Program'. Then go to the Well List Tab and you will see this:

ShaleGas.xls

Use the link above to go to an excel file, and find on the second tab (Labeled HBP Drilling Program Well List) a well list. This list was created by copying a blank table from WellSpring to Excel, filling in the values, and then pasting it back from Excel to WellSpring. After you paste it in, your Well List populates.

All of these wells are now imported into WellSpring, but will only appear in calculations and the network if you have a Well Task that indicates how many wells are being created, and of which type well. In the picture below, I have specified the name of a Well, the Template Name, and the # of copies.

Next we are going to add a few steps to the drilling program, to make it more realistic. Step 1 will be Drilling, will require a drilling rig, and will last 20 days.

Step 2 will be the Completion phase, and will require the Frac Spread resource we created earlier.

Step 3 has no resources or duration, but the 'Can Produce when finished' box is checked, so as soon as the program hits that step it will start producing.

Drilling the Pad Wells

Our last step is drilling the majority of the wells, after the HBP wells are created. To do this you follow the same process as you did with the HBP Drilling Program, but the Well List is different, as is the Well Task. Also, we will be adding a condition to make sure this program takes place after the HBP Drilling Program.

ShaleGas.xls
Using the link above, find the Well List for the 'Drilling Pad Wells' program. It is located on the third tab of the excel file. After renameing the new drilling program and inserting the new Well List, it should appear like this:

The next step is to create the Well Task that corresponds to the well list we just entered. Follow the same procedure as before, only with a different type well and different name. Your well task general tab should look like this:

The steps 1, 2, and 3 will all be the same as the first program (Drilling, Frac Spread, On Production).

Condition
Our final step is to condition 'Drilling Pad Wells' to start after the first program, 'HBP Drilling Program' finishes. To do this, you go into your Drilling Pad Wells program's conditions tab (See Scheduler Conditions).

Set it so that this program is conditioned to FinishStart with the HBP Drilling Program.

After it is conditioned, the Task List will show the conditioned program shifted to the right underneath the program before it. It is possible to have multiple conditions across multiple programs, so this hierarchy could be a useful visual aid.
Your final network will look like this (Note i have many of the wells minimized into their downstream asset, to avoid clutter. This is indicated by a [+] beside the asset.)