After a wellbore has been drilled, the wellbore typically is cased by inserting lengths of steel pipe (“casing sections”) connected end-to-end into the wellbore. Threaded exterior rings called couplings are typically used to connect adjacent ends of the casing sections at casing joints. The result is a “casing string” including casing sections and couplers that extends from the surface to a bottom of the wellbore. The casing string is then cemented in place to complete the casing operation. After a wellbore is cased, the casing is often perforated to provide access to one or more desired formations, e.g., to enable fluid from the formation(s) to enter the wellbore.
Treatments may be applied to a formation to increase or inhibit flow. However, proper application of treatments is difficult. As an example, when acid is injected in a formation, most of the acid goes to the zone nearest to the injection point and leaves most of the formation untreated. Thus, high permeability zones that are treated become over-stimulated. In particular, the problem arises for long horizontal wells, where the heel of the well becomes over-stimulated while the toe of the well is under-stimulated.
Distributed temperature sensing (DTS) technology has been employed to monitor fluid injection since the formation and the injected fluids are at different temperatures. However, formation characteristics such as thief zones, cross-flow across producing zones, depth of investigation, geothermal gradient, and presence of water zones decrease the level of confidence in DTS interpretation. There exists a need for improved systems or methods for treatment monitoring.
It should be understood, however, that the specific embodiments given in the drawings and detailed description thereof do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed in the scope of the appended claims.