Fiber Optic Installation at the Sand Face Enables Real-Time Flow Monitoring and Compaction mitigation in Openhole Applications

Abstract

Subsurface stresses can cause formation faults, slippage, and reservoir compaction, which can damage or permanently shut in a well. Traditional means of detecting these failures are limited and usually require moving a costly rig onto locations, and then interrupting production to re-enter the well. This results in late detection of issues and allows limited counteractive options. A new system has been developed to actively monitor strain and temperature of wells. The system consists of three key enabling technologies: A fiber optic support device deployed at the sand face, a cost effective high-flow liner system that protects the instrumentation in openhole applications, and two optical wet connects for up to 12 channels. The fiber optic support device provides a means of holding a helically wrapped optic fiber rigidly in place at the sand face. This new technology can be installed over traditional sand screens in gravel pack or frac pack applications, with no negative impact on the sand control functionality of the screens, or the quality of the pack. The installed fiber optic provides the equivalent of a strain gauge positioned every centimeter along the length of the producing zone. For openhole applications, a high-flow liner system was developed to protect the fiber optic support device, and the control lines. This system includes a special quick connect that simplifies the on-rig assembly and allows torque transmission in an openhole deployment. The final key to this system is the two 6-channel optical wet connects, allowing a total of 12 connected channels. This game changing technology provides an information conduit between the fiber optic at the sand face and operators at the surface. The same wet connect can also be used to connect more traditional means of measurements such as pressure temperature gauges, or distributive temperature sensing (DTS). The information relayed through this system allows the operator to infer flow and detect subsidence or compaction of the sand face before the well is compromised, allowing time to plan and execute mitigative actions. This paper will discuss the design, testing, and potential applications of this new system. Introduction The production of hydrocarbons can often cause a decrease in porosity of the rock formation containing them. This phenomenon is known as compaction. Wells can sustain significant damage as the formation layers shift or move along formation boundaries as a result of compaction. Fig. 1 illustrates this type of shift caused by compaction. The wellbore on the left of Fig. 1 illustrates the original location of the well, and the wellbore on the right illustrates the same well post compaction (Earles 2010).