When emergency situations in environmentally sensitive areas occur, drilling a relief well to intercept and kill the blowout well often requires various types of magnetic ranging technologies to navigate into the problematic well. Outside this scenario, we do not commonly hear about magnetic ranging. The main objective of this paper is to raise awareness among operators about magnetic ranging-while-drilling technology as wellbore placement service to make planned wellbore intersections to boost production. Reactivation of mature fields is often an economically viable option when demand for energy pushes oil prices upwards. In order to boost production from an existing mature field, an operator provided a service company with an interesting challenge: utilize proven directional drilling expertise in conjunction with alternative wellbore positioning techniques to drill two high-angle deviated wells from opposing directions and intercept a common vertical producer well for a gravity drainage concept. During the pre-planning phase, one of the major challenges was MWD survey accuracy for the horizontal wells. The 2-sigma major-axis uncertainty of the MWD surveys after applied corrections at the point of planned contact with the vertical producer was over 106 ft while the size of the target to intercept was only 1 ft in the lateral dimension. Implementation of magnetic ranging while drilling technology combined with north-seeking gyroscopic sensor allowed optimal positioning of all three wells relative to each other. Bottom hole assembly equipped with a smart mud motor, MWD, and magnetic bit-sub avoided collisions and steered successfully between other producing wells in the mature field. This challenging project from two opposite surface locations took several weeks of directional drilling and resulted in precise positioning both horizontal drainage sections within close proximity of vertical producer. Hydraulic communication with the vertical producer was successfully established from both horizontal wells after completion of the drilling operations.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn the PEMEX Southern Drilling and Producing Region, which includes all land wells drilled in the southeastern states of Mexico, directional drilling has gradually increased to 75% of wells drilled. Producing zones in the region are also deep with difficult targets under high pressure and temperature. These factors have led PEMEX to seek out new technology in an effort to optimize drilling and producing operations.One of the special projects defined for the year 2001 was to evaluate the application of running a high-accuracy gyroscopic directional survey instrument in tandem with PEMEX logging systems. In the process, the Southern Region engineering group and the PEMEX wireline logging division worked with a local survey company to build a special housing to run the gyro probe on top of several different logging instruments. This paper describes the development of the tandem gyrologging combination tool and tests in three wells. System performance is analyzed and comparisons are made between gyro survey results and other survey instrumentation. Conclusions indicate that the success of running two services in one run in the well saves substantial rigtime and eliminates the costs of additional wireline runs. Furthermore, the application of high-accuracy survey information may prove valuable in more accurate wellbore placement and reservoir mapping-leading to enhanced production. In the future, the combination run may also have value in detecting the orientation of imaging logs in both cased and open hole to determine fracture orientation and formation dip angle.