Analytics require a standard for well location integrity

The oil and gas industry has as its principle goal, finding and producing hydrocarbons. To do this a massive amount of information must be interpreted, analyzed, and decisions made as to drillable prospects. This process has been ongoing since the middle of the 19th century.

The most fundamental piece of knowledge starts with the location of the well. It defines the relationship of location with everything relative to drilling, completion, development, and ultimately the termination of the drilled site.

 Wells have a coordinate integrity issue. This situation becomes increasingly evident as we observe the intersection of new well information being merged with historical information.  However; the uncertainty that exists is solvable with a plan and method.

 The purpose of this paper is to point out the significance of knowing well location by developing and defining an industry standard. The key criteria for this process are; classification, verification, and validation.

 Well location changes create uncertainty…

 First there is the physical part of selecting, planning, permitting, constructing and finally drilling.  Next comes the monitoring and production of the well during its life cycle. Finally there is the process of terminating and shutting in the well. Throughout these steps, a well location may be defined in the same place or for various reasons it may be changed.  It is those changes that often contribute to confusion about well location.

 The well’s location may be exchanged between hundreds of people and entities to correctly place the information accompanying it. Those exchanges can and do occur throughout the entire life cycle of a well. This often creates multiple and differing versions of the well location.

 Ultimately each well’s location is added to other locations to form a cohesive set of well location information which combined with other spatial data provides critical sub-surface understanding.  

 It is for these reasons that any deviation from the actual well location should be fully understood. The spatial relationship between observations is a fundamental aspect of scientific evaluation.

 We have reached a point where there needs to be a way to validate the usability and trustworthiness of all well locations. For purposes of this paper I will use the term “standard” to define criteria necessary for understanding, creating and ultimately retaining well location integrity.

 This standard provides an independent means with which to validate the coordinates used to describe a well’s location and is independent of the coordinates themselves.

A new standard and criteria…

We all understand it would be practically impossible to physically go back to the field and re-survey every well, so we have to choose a means which accomplishes this for the greatest percentage of wells without prohibitive time and expense. The best way to determine if a well location is correct is to see if it is visible in imagery. 

 Well locations need Classification in order to define the reliability of the location through visible physical evidence and the quality of that evidence.  Classification becomes a simple designation of visibility. For purposes of establishing these criteria we have chosen “Excellent”, “Good” and “Poor”. Excellent infers that there is physical evidence of the actual drilling location. Good infers that there is physical evidence of a well-site or pad and Poor indicates that the location cannot be verified.

 The existing well location requires Verification to confirm it matches what was observed in imagery. Imagery offers a reference that is both geodetically consistent, covers a significant period of time and has measurable accuracy and resolution. By observing the location against a visible feature, we can observe the differences; which allows us the ability to verify the coordinates and if necessary adjust them to the visible feature.

 Finally the standard must include Validation which retains verification by capturing the well location and the observed physical evidence in imagery. This provides permanence and integrity. With classification and verification, any future doubt that a change has or may occur can be quickly compared to the retained validation.

 Applying the standard…

 We apply the standard’s criteria to data and through the effort are able to indicate the levels of uncertainty.  Through application we can classify all wells; validate 25% of the wells; correct and validate 61% of the wells and finally highlight 14% of the wells which retain continued uncertainty.

 Figure 1 is the base data set before applying the standard and the only knowledge about the well locations is the coordinate identity assigned to each within this data set.

Figure 2 indicates which well locations have been validated through the application of the standard.

Figure 3 shows which wells were moved to a visible feature and result in being verified and validated through application of the standard.

 Figure 4 is wells which cannot be verified through imagery but have been classified and would require special effort to validate.

A standard highlights something about data that is unknown…

 The standard once applied provides absolute knowledge about the coordinates used to locate the well. The process of applying the standard may also bring forward wells to a point of verification. The classification however defines all wells and that knowledge allows the well locations to be judged as to their true fit for purpose usage.

 A standard prevents something becoming unknown…

 In capturing the visualization associated with the well that is verified, those wells retain integrity from that point forward and the standard is easily applied to all new wells.