As a geographer and geospatial professional, I am always seeking the answers to questions such as:
- Where are things?
- How did things came to be where they are?
- Why are things arranged in space a specific way or in a particular location?
- Where is the optimal location or placement for things to be?
I know it may sound a little crazy, but the topic of multi-well pads in the STACK (and elsewhere) is an interesting geospatial topic. In this continuation of our look at Pilot Well programs in the STACK we’ll look at multi-well pad drilling using my geospatial/philosophical construct above.
Where are multi-well pads being used in the STACK?
A quick glance at the STACK map above effectively communicates the preponderance of wells with 2 key characteristics in common: 1) the wells are associated with horizontal laterals; 2) in many instances there is more than one lateral originating from a well.
How did multi-well pads come to be predominant in the STACK as well as within the U.S. oil and gas industry?
Ten or fifteen years ago, the map above would have looked dramatically different as most wells in the core STACK counties of today were drilled vertically with one well per pad. While this design was surface area and resource intensive, it was also slower to drill multi-well projects in a given area due to the constant need to disassemble and reassemble (“rig-up” and “rig-down”) drilling rigs as they relocated to drill the next well.
In the early 2000’s drilling activity was growing and horizontal drilling for shale oil and gas in the U.S. became dominant. Operators were under increasing pressure to ramp up production while keeping costs down. Midway through the new century’s 2nd decade, pressures dramatically increased as supply versus demand for oil and gas fell precipitously out of balance resulting in steep declines in commodity prices. During this period operators began drilling more horizontal wells per pad to increase efficiency and decrease costs for drilling, completing, and servicing wells. By 2013, less than 10% of the wells drilled in Oklahoma were drilled vertically. Today, according to the Oklahoma Energy Resources Board (OERB) a typical deep horizontal well in our state can replace as many as 6 vertical wells.
Why are multiple horizontal wells arranged on single well pads in the STACK and throughout other North American Plays?
The simple answer is that multi-well pad drilling provides the mechanism by which operators can strike a balance between operational efficiency and cost. The benefits listed below are some of the primary drivers my research has uncovered.
Where is the optimal location or placement for things to be?
In the first “Trakin’ the STACK” article, I mentioned some of the determinations operators are seeking to make through their pilot well programs. As it turns out, these same considerations usually apply to all multi-well pad drilling. For example, operators are still concerned with optimizing well spacing and the number of wells on a pad while keeping costs low and providing ample space for equipment on the pad. The map below depicts Continental’s Ludwig and Verona pilot well projects. Notice the shared water impoundment and pad spacing. Pad sizes average between 3-5 acres regardless of time period and contain 1-3 wells as is the case for most STACK wells.
The ideal number of wells per pad is also a financial decision as cash flow can be affected by the timing and order of drilling, completing, and producing wells. The use of “walking rigs” can offset any negative impacts of drilling order because the rig can be repositioned on the pad without disassembly. In the map below, Continental has varied the number of pilot wells from two to as many as five suggesting their continuing efforts to determine optimal number and spacing of their 10,000’ lateral wells.
Finally, as we saw with Pilot Well projects, minimizing the amount of interference between multiple wells during stimulation is key to optimizing production of all wells on the pad.
Bottom line, although conditions may vary from location to location, the priority remains to strike a balance between operational efficiency and cost.
In Part 4 of “Trakin’ the STACK” we’ll look at how geospatial data and technology improve the well planning process. Until then, I’m always here to help. Email me at firstname.lastname@example.org.
Julie Parker has a decade of experience serving the Energy industry where she became an expert in the integration and application of geospatial technologies to exploration and production projects and workflows. Ms. Parker entered the industry in 2006 when she became the first GIS Director for Chesapeake Energy, a large independent producer of natural gas headquartered in Oklahoma City, Oklahoma with operations throughout the U.S. During her tenure at Chesapeake, Ms. Parker built and lead a robust, cross-functional GIS department that gained a reputation for developing and deploying leading edge solutions for nearly all areas of the company.