Print
As discussed earlier, the exploration geologist and geophysicist (amongst others) generate locations for future exploration prospects. Once exploration prospects are generated, drilling engineers work with the exploration geologists to develop the drilling proposal(s) for any Exploration Wells. Exploration wells are wells which are drilled with an objective of proving or disproving the presence of commercial hydrocarbon accumulations. A popular slang term for the first Exploration Well drilled in a geologic basin or region is a “Wildcat Well”.
The drilling proposal is a plan for the well. Normally, an exploration geologist and the drilling engineer take the joint lead role in the development of the well proposal. This proposal typically includes:
- the objectives of the well (the reasons for drilling the well)
- the proposed drilling rig to be used for the well
- the surface location of the rig site (latitude and longitude)
- the well target:
- the bottom-hole location (latitude and longitude) of the well
- the target depth(s) of the well
- directional drilling information
- the wellbore diameter and depth of the wellbore (wellbore diameters will change during drilling operations due to changes in drill bits)
- the specifications for all bits required during drilling operations
- the anticipated geologic cross-section and stratigraphic column during drilling operations
- the pore-pressure profile anticipated during drilling operations (pore pressures versus depth)
- the fracture pressure profile anticipated during drilling operations (formation fracture pressures are the pressures at which the rock will mechanically fail – fracture)
- the casing design and specifications for the well
- the drilling fluid (mud) design for the well
- the well control and safety procedures for the well
- the required data acquisition that is essential for the exploration geologist to appraise the well
- the anticipated time required to drill the well (depth versus time forecast)
- cost estimates for the well:
- one estimate for an unsuccessful well (no hydrocarbons discovered)
- one estimate for a successful well (hydrocarbons discovered) which may include completion costs and additional data acquisition cost (well logs, core data, etc.)
Once a drilling proposal is generated and approved, the drilling engineer coordinates with the drilling companies, service companies, suppliers, and manufactures for all of the equipment required by the well. Some of this equipment may can be purchased “off the shelf” and can be delivered in a relatively short time; while other equipment (Long Lead Time Equipment) may need to be manufactured to specifications developed specifically for the well. This long lead time equipment may take over a year for delivery. The logistics of coordinating the on-time delivery of the equipment for the well is the responsibility of the drilling engineer.
Drilling engineers also interact and coordinate with the company’s Health, Safety, and Environment (HSE) Departments and government permitting agencies to ensure that the well meets the company’s and the government’s HSE guidelines and that all of the government permits are properly obtained.
Only after the required equipment is onsite (or guaranteed to be delivered on time) and all permits are in hand can drilling operations begin. Again, a drilling engineer takes the lead role in all drilling operations. Whenever a drilling rig is required for some operation (drilling, cementing, Major Rig Workover (MRWO)), a drilling engineer will take the lead. Depending on the organization of the company, the drilling engineer who designed the well may not necessarily be the drilling engineer in charge of drilling the well. A company may be organized in a manner where Staff Drilling Engineers are working with the exploration geologists developing drilling proposals and developing the plans and logistics for the wells, while Field Drilling Engineers are drilling the wells.