Geosteering process should not be seen as a process solely designated for the most expensive or highest profile horizontal wells. It can be regarded as another tool for improving the odds of success by remaining for longer periods of drilling in the productive zone. Also it can be used to optimize the positioning of a horizontal well bore in the sweet spots within the reservoir.
Exploration and Production (E&P) companies are continuously being driven to reduce the cost per BOE. Convergence of E&P needs and technologies related to advanced and accurate directional drilling, communication of vital data in real-time through the internet, as well as reduced cycle time associated with advanced forward-looking 3D geomodelling and visualization technologies (Figure 1) are currently aligned. These have been advancing the horizontal well geo-steering process using Measurement While Drilling(MWD) into mainstream drilling practices.
Convergence of Technologies for Geo-steering Figure 1 (Available in full paper). The universal economic benefits gained can be found in all resource play types (conventional oil and gas, heavy oil, tight gas and coal bed methane).
It is important to note that the process described here is essentially collaborative. For best results, there must becooperation between the E&P operational staff, wellsite geologist, directional driller and geo-modeling staff as well as the consultants involved in the project (i.e. the team as a whole).
Reducing Costs and Increasing Performance for Optimal Well Results Whether drilling a long reach horizontal in heavy oil or a tight gas play, the basic requirements for a successful well are:
Planning the optimal path based on the current knowledge of integrated geological/geophysical models.
Monitoring the progress of the well through real-time updates.
Continuously remapping to identify the true stratigraphic position (TSP) of the bit relative to the reservoir. This information is used to provide advice to the drilling team for staying in the zone of interest while drilling.
Timely reporting on the updated road map for the horizontal well to provide the information necessary for drilling ahead of the bit.
Depending on the depth and/or rock type the speed of drilling can range from very fast (200 m/hr in shallow heavy oil horizontals) to very slow (3–10 m/hr in tight formations). For fast or slower drilling, the geo-steering process is used as a planning and monitoring tool. This reduces guesswork in the drilling process which translates into less drilling time for a given well ultimately decreasing the total cost and increasing profits. The 3D geo-models can be updated every few minutes for structural changes and periodically for characterization of the gamma ray (GR) and other reservoir attributes.
Another benefit for operators working in reservoirs that have multiple rigs drilling is that the information gathered and processed will influence and change the 3D mapping window (or highway) for current or subsequent wells. ‘Just in time’ modelling reduces re-drill costs associated with sidetracks. Geo-steering a horizontal well while drilling is not only important, it is also profitable.
