University of Kansas Petroleum Technology News Second Quarter 2000

Mull Completes Horizontal Well Energy Researchers Receive Grant TORP Developing Coalbed Manual Workshop Summary Coiled Tubing Appeals to Kansas PTTC's Director Rowell Resigns Duttlinger Takes Position Higher Oil Prices Boost Drilling Biggs Honored with Stewardship   KIOGA Annual Meeting  Top 25 Oil Producers in Kansas  Upcoming Events

Mull Drilling Completes Successful Horizontal Well In Ness County In April, Mull Drilling Co., Inc. completed the Ummel #4-H, a horizontal drilling effort involving the combined resources of Mull, the Kansas Geological Survey, and the Department of Energy. The drilling contractor was Norseman Drilling, Sperry-Sun provided the guidance and surveys, Weatherford and Scientific Drilling the specialty tools, Dunbar Mud the drilling fluids, and LogTech the setting tools. The well was completed in the Warsaw (Mississippian) formation in the Ness City North Field in Ness County, Kansas. The project involved detailed reservoir characterization and simulation, performed by KGS personnel as part of the DOE Class 2 project, to describe and evaluate the reservoir. Geologic, pressure and production data from the vertical wells in the field were utilized in formulating the simulation of the horizontal well. The old Ummel #4, a plugged and abandoned vertical well, was reentered and the 5 ½" casing was cleaned out. The kick-off portion of the curve began at a depth of 4115', using a radius of approximately 180' the horizontal portion of the lateral was at a true vertical depth of 4298'. The lateral length, within the Mississippian, is 533 feet. A 3 ½" liner was run to 4400', leaving the last 428' open. The well was completed natural. A 2" rod-pump was set at 4003' in the vertical section about 300 feet above TVD. Mark Shreve, president and CEO of Mull, stated that Mull would not have been able to drill the well "at this time" without the benefit of the DOE grant. Their company, as well as the rest of the industry in Kansas, is still basically learning about horizontal drilling and the DOE assistance was instrumental in providing enough additional capital to offset the expense of developing the "learning curve". Due to problems experienced in this well, Mull probably will drill new wells rather than utilize the reentry method in the future. Problems were encountered drilling cement out of the old casing, orienting the tools to cut the casing window, handling sloughing shale in the build section of the new hole and difficulty running the liner. Shreve further stated that the most critical aspect of drilling the horizontal well is drilling the curve and emphasized the necessity of expert navigation - in this case, Sperry-Sun. In future wells, the company will case the build section prior to drilling the lateral. The process of drilling out the old hole, setting the whipstock, milling the casing window, and drilling the build section took twelve days, while only three days were required to drill the lateral and run the liner. Desiring to keep total fluid withdrawal within the 100-150 BPD range, the operator has limited the pumping rate. Initial producing rate was 69 BOPD and 62 BWPD. Now, nearly two months later, the rate is relatively stable at 48 BOPD and 48 BWPD. Adding data obtained from the horizontal well to that which was previously gained from the old wells, KGS personnel performed a post-drilling simulation of the Ummel #4-H. The results of this simulation indicate the well should ultimately produce 80,000 to 100,000 barrels of oil, much better than could be anticipated from a vertical infill well drilled into the same reservoir. A technical workshop on horizontal drilling that will be cosponsored by North Midcontinent PTTC will be conducted in conjunction with the annual KIOGA meeting. Additional details on the drilling of this horizontal well will be presented at the workshop, which will include photographs taken during the drilling process by Richard Pancake. Richard is a petroleum engineer with TORP who was responsible for the observation and documentation of the drilling of this well.

Structure map on top of Mississippian reservoir unit showing field outline, leases and wells in the Ness City North Field. The Ummel lease and Mull Ummel #4-H well are highlighted. The Ummel #4 was reentered and a horizontal lateral drilled toward the center of the field (well path is shown schematically). Numerous other Mississippian reservoirs surround the immediate vicinity of the site.

Pre-drill simulation output for Mull Ummel #4H showing production rates for oil and water. Simulation was for a horizontal well with an effective horizontal well length of 400 feet, a uniform skin of 4.5 across the producing length, and a Pwf of 675 psi. Fluid production rates are plotted for the expected (Qo, Qw) and the best-case (Qo-best, Qw-best) simulations. Average production rates observed in the first month are shown (Qo-recorded, Qw-recorded).