Pinpointing Water Entries in Dead Horizontal Wells

Abstract

Abstract Increased water production is often the cause of reduced well performance, decreased hydrocarbon production, and/or killing the well. Water entry must be pinpointed before the remedial work to shutoff the water and to increase well productivity. A standard practice for shutting off the water is by running an integrated multiphase production logging tool, which is challenging in horizontal wells due to the high deviation, wellbore conditions, and multiple flow regimes. The diagnosis of this type of well becomes complicated when the horizontal well is dead. In this paper, three field examples are presented on data acquisition (logging) in dead horizontal wells, with subsequent interpretation to pinpoint the water entry interval(s). The first well was completed with an inflow control device (ICD). An integrated production logging run during shut-in identified a leak with crossflow from the blank pipe to the open hole. The water source was determined to be a zone above the completed intervals. The second example is an open hole completion. The well flowed after nitrogen (N2) gas kickoff and the water entry was pinpointed from the toe section along with the oil profile. The third example is also a horizontal open hole completion. This well did not flow naturally, despite N2 lifting for 8 hours. Logging was conducted while injecting N2. Repeated passes yielded consistent results in pinpointing the water entry interval, and the water entry was identified also from the toe section. These field examples demonstrated that integrated job planning and integrated interpretation are essential to opening new opportunities for diagnosing dead wells and providing solutions. Guidelines and recommendations for logging dead wells are now available for these types of logging conditions. Introduction The objectives of running integrated horizontal multiphase production logging (MPL) tools are mainly to obtain fluid-flow profiles, determine the relative contribution of the reservoir intervals, and identify water/gas breakthrough intervals to provide data for water/gas shutoff operations. Integrated horizontal MPLs are also used to evaluate the performance of open hole horizontal producers (Al-Muthana, et al. 2008), the effectiveness of a well completion (such as smart completions) or workover operations (such as water/gas shutoffs). Multiphase production logging is challenging in horizontal wells due to high deviation, wellbore conditions, and/or multiple flow regimes. In addition, there are many different scenarios that could lead to high-water production sources such as:· Tubing, casing, or packer leak· Flow behind the casing and problems in or near the wellbore such as poor cement· Water coning· Rapid breakthrough of water through fissures