The World's First Real Time Logging with Tractor in an Extended Reach Horizontal Well with Proof of True Stimulation

Abstract

Although engineers have employed tractor interventions relatively extensively in well stimulation of extended reach wells in this field, an outstanding challenge in the field and even in the industry has been to conduct real-time acquisition of inflow or production profiles and to evaluate treatment effectiveness in extended reach open hole horizontal wells. This challenge was overcome from real-time electrical to optical (EtO) water injection profile measurements simultaneously with running a tractor. The motorhead assembly (MHA) of coiled tubing (CT) was successfully wired through a tractor to allow the world's first successful real-time acquisition of an inflow profile in an extended reach open hole horizontal power water injector in one of the current largest field development projects in the world. The well, located on one of two finger islands, was completed to a total depth of nearly 30,000 ft (over 9.10 km) MD; making it the deepest open hole section logged in the field development outside the normal reach of tapered CT for well intervention. The intervention on the well was successfully carried out through the application of a 2-in. tapered CT and well tractor. The well's treatment involved 3,850 barrels of emulsified acid recipe in 14 stages. A comparison of the pre-and poststimulation injectivity indices showed an eightfold injectivity index improvement from 53 bpd/psi to 400 bpd/psi. The resulting marked improvement in injectivity from acid stimulation also revealed the benefit of informed decisions from the real-time fiber optic distributed temperature sensing (DTS) in fluid placement. TX 75083-3836, U.S.A., fax +1-972-952-9435 IPTC 16665The well used to test real-time logging with a tractor is one of several wells for peripheral water injection in the pressure maintenance strategy for the field development of one of the largest increments in Saudi Arabia's history. The PWI wells are typically open hole completed extended reach wells with more than 65% of the wells beyond 17,000 ft in length and outside the reach of coiled tubing (CT). A caliper log obtained from the well in Fig. 2 shows an uneven borehole. Indeed, the well is typical of other wells in the field that follow relatively complicated trajectories with length. Such undulations and azimuth changes could have been the result of the need for drilling control or the need to take advantage of anisotropy for optimum (radial and linear) flow or injection contribution. Figures 3 and 4 are cross section plots of the subject well. Objectives of the InterventionThe objectives for the well intervention were threefold; namely to stimulate the well with CT using a hydraulic tractor to enhance the CT reach, run a real-time production logging tool (PLT) to evaluate the injectivity of the open hole zone after the stimulation, and to evaluate the injectivity index (II) of the well. Obtaining the injection profiles of the water injectors is a vital step in understanding the conformance or non-conformance of the injected water, including channeling or well-t...