Flow Diagnosis in an Extended Reach Well at the Wytch Farm Oilfield Using a New Toolstring Combination Incorporating Novel Production Technology

Abstract

Tfws papaf was sebcted for preaentatmn by an SPE Prcgram Canmmae following rewew of mfamahon Con! aineal In an abstract s.ulmm tad by the authcf (s) Ccmlcnw of ma papar as pfe8entad, have nof been revmwad by lha Society of Petrolaum Engmaers and ale subject to cm'rMon by the author(s) The ma!enal as pmsemed, does not necessary reflect any pomt$m of the SOmaty of Petrolmm Ewmemrs, is offcars, or mambars Pap-am presanted at SPE meslmgs are subpct to pubhcatum rewew by EdNortal Commt!ees of the Somety of Petroleum EngIn%ers Perm!swon to copy !s restricted to an abstracl of not more than 300 wofds Illustralons may not be cOpted The abstract shoulo conlam conspicuous &5muwk@tnenl of where and by whcm the paper was presented V/me L,braflan, SPE P O BOXS33S3S, Richwdscm TX TSCW-2836. U S A lax 01-21 4-952-W35Abstract A joint initiative between BP and Schlumberger began in mid-1994 to develop techniques for the diagnosis and treatment of unwanted fluid entries in high angle and horizontal wells. The first full scale test of the flow diagnosis technology to occur in a BP asset took place in an extended reach well at the Wytch Farm oilfield in November 1995.In order to measure oil and water flow rates it is necessary to measure both the hold-up and velocity of each phase. A novel toolstring combination was developed which incorporated new sensors especially targeted at the stratitied flow regimes encountered in horizontal wells and featured the capability of measuring flow parameters by several independent methods, enhancing confidence in interpretation.The new sensors could independently measure the velocity of the oil and water phases by measuring the time of flight of iniected Dassive fluid markers as well as bv the well . . established oxygen activation method. Fluid holdup was obtained from a nuclear carbon-oxygen ratio method and an imaging tool. Additionally the imaging tool, based on an array of local electrical probes, could give a real time representation of the distribution of hydrocarbons and water in the borehole. Conventional production logging measurements such as the spinner, pressure and temperature were also made.The primary objectives of the logging were to determine the oil and water flow profile along the cemented and perforated liner and monitor the movement of the reservoir oil-water contact. Entry points for oil and water as well as zonal contributions were confirmed by excellent correlation between the various logging sensors.

Multiphase Well Surveillance with a Permanent Downhole Flowmeter

“…B/D = barrels/day RB/D = reservoir barrels/day STB/D = stock tank barrels/day α = phase volume fraction ("holdup"), L 3 /L 3 ρ = density, m/L 3 …”

“…Slip between phases creates very complicated flow patterns in high-angle and horizontal wells and is the reason for the complexity in production logging tools designed to operate in this environment. 3 Empirical slip models can help fill the gap in two-phase oil and water flows, but are of limited use in three-phase flow. One reason is that gas density downhole can be orders of magnitude higher than at surface conditions and the slip laws are defined, in general, on the basis of data taken at surface conditions.…”

Advanced Production Logging Technology For More Accurate Flow Profiling - Case Studies from the Gulf of Suez

“…In either mode (telemetry or recorder) the sensors remain identical, providing the same high quality data in both configurations. (1,2,6,7) The PBMS* Platform Basic Measurement Sonde module regroups in a single highly compact device the measurements that are traditionally taken in producing wells. That is Gamma ray, Casing Collar Locator, Pressure and Temperature.…”

“…(1,2,6,7) Sigma/porosity and carbon-oxygen measurements can be readily combined with the PS PLATFORM. When run on electric line, the production profile and the reservoir behind the casing can be evaluated on a single trip into the well.…”

Well Surveillance with a Permanent Downhole Multiphase Flowmeter

“…However, both the simple hydrostatic-density measurement and the fiber-sensor technique are affected by slip between the phases, which must be taken into account to give the correct flow fractions. Slip between phases creates very complicated flow patterns in high-angle and horizontal wells and is the reason for the complexity in production-logging tools designed to operate in this environment (Lenn et al 1996). Empirical slip models can help fill the gap in two-phase oil and water flows, but are of limited use in three-phase flow.…”