“A Wild Goose Chase on the Texas Gulf Coast”
The Seabreeze Field had been there a long time and had been thoroughly drilled; so everyone thought! The location of Seabreeze Field is in Southeast Texas in Chambers County (Figure 1.) Finally following a letter request to management, we had acquired a 3D data set over the area and the hunt was back on. I loved to goose hunt on the Texas Gulf Coast; some of the best goose hunting in the world, so the naming scheme for newly found prospects on the new 3D became names of different kinds of wild geese. The naming scheme was logical and so the “wild goose hunt” began. The basic trapping structure of the main field was a north- south trending four way anticlinal closure downthrown to a large north –south trending down to the east listric normal fault. One well, on top and in the middle of the structure, had already produced over 4 BCF from the Frio Nodosaria blanpedi (Seabreeze F-4 Series) and the assumption was that the sands and structure were drained. The basic Field Stratigraphy and Biostratigraphic nomenclature is outlined in Figure 2. When we received the data and loaded it on our new Geoquest workstations, Greg Bunk and I were both panning through the data volume vertically and horizontally hunting for structural and stratigraphic complexity variation and that is when the “1st big goose landed in the spread of past well decoys”. The structure was faulted by another fault, that no one had recognized in past structural interpretations, running enechelon to the large north –south trending down to the East fault. The bright spot that showed up on the upthrown side of that fault was amazing and there was no significant amplitude on the downthrown side where the older well had produced several BCF in the past. When I found out that the acreage was in jeopardy of being lost, I ran down the hall to our district manager and told him we needed to save the lease because it looked like there was a great prospect there to be drilled immediately. The company almost immediately got a dozer out there and scraped of the location and the hunt was on. We brought one of our Offshore guys into supervise the well since there was a very good chance we would find something really good. The well was spudded very soon after building location. My mud logger called in to the house early in the AM one morning as we drilled into the Frio Nodosaria Sand. The “wild goose had set it wings and landed”!! His voice was shaking. We had max gas of around 5000 units with severe mud cut to 12.5 PPG and the well was definitely talking to us. In his shaking voice he simply said “I don’t know if we can hold this one”! The Greater Canadian wild goose was literally trying to take off! I had named this prospect Nodosaria “Greater”. After a couple of days of fighting the well and slowly building mud weight the well (“the Greater Wild Goose”) was finally back under control. All the guys on location did a great job of keeping the “goose from taking off”. I had lined up the e- logging out of Liberty, Texas through Schlumberger and I met the logging crew in the Field to get a “triple combo” over the section we had encountered. Even though we had plenty of mud weight to hold the zone, the well and sand had still talked to us strongly indicating that the sand was going to be something special as far as rock properties and pressure. The recently trained e-logging engineer was a young lady from China and we communicated in broken English and sketched pictures as we prepared to log. In Figure 3 is what we encountered and what a “special wild goose” it was. As it came across the logging screen; the image was etched forever in my memory! 70’ of net gas /condensate pay with 1000 ohm- meters resistivity and an average of 30% density porosity; a magnificent Blocky Frio distributary channel full with 50 ‘ net pay and 20’ of net pay in stringers of an overbank crevasse splay. Wow, we had really bagged a trophy wild goose on that shot. Oh, and as the 3D indicated, it was a new virgin pressure fault block.
After getting the pipe set to bottom it was time to complete the well. My Company sent me to Southeast Texas to witness and observe the perforation of the high quality Frio Channel Sand. It was a very cold day on the Gulf Coastal Plain hovering just above freezing. We confirmed the perforation of the pipe by the sound conveyed up the pipe through conduction with headphones. The well was opened up and the fluid the well was loaded with began to unload and flow through the pipe going to the testing unit. The unloading fluid was warm through the pipe to my hands and then the gas condensate “hit” and made it to the surface and almost froze my hand to the pipe as the “cool down affect” occurred. In fact I called the office just as it actually started to snow in Southeast Texas and let them know that the hydrocarbons were to the surface with a really dramatic cool down affect.
The testing was accomplished and the technician generated charts and graphs and descriptions of the well’s ability to flow hydrocarbons. The technician generated a calculated absolute open flow (CAOF) value and brought me the results. He looked at it and wasn’t sure he had performed the calculation correctly and went through the process again. He brought it back and said “no this is the correct value” but also said he had never seen one this high. Most of the time onshore the CAOF values are between 2 MMCFD and say 80 MMCFD. I had seen a CAOF value for a Miocene well offshore once for 450 MMCFD. The CAOF for this well calculated at 994039 MCFD (Figure 4.). In other words if this sand could have been brought to the surface and flowed unimpeded without constraint by a certain diameter of pipe to the atmosphere it would have flowed at almost 1BCFD; almost unbelievable flow characteristics; a near perfect sandstone reservoir; an example of some of the best subsurface sand on the planet.
Yep, this was some kind of trophy goose!
As time went on, my team and I kept hunting and drilled several other wells. Most were successful; it was a good hunt. In Figure 5 and Figure 6 are 2 more special e-logs and again these prospects were named after wild geese. The Oryx Sun Fee wells were drilled on an unusual piece of real estate. The manager of our district asked if there was another immediate idea to drill like the 1st one. I said yes, and we proceeded to get ready to drill another prospect. When land check out the property, we discovered that we owned it “lock, stock, and barrel”. We owned the surface and the minerals, and our income interest was somewhere around 97%; again almost unbelievable. There was another untested fault block to be drilled. There were also some “bright spots” at the top of the FRIO in the Marginulina as well as the good looking Frio Nodosaria “bright spot”. We drilled through the upper Frio sands and stopped to set pipe right above the Nodosaria. When I logged the well there were some really nice thinner gas sands in the Marginulina, section as we had predicted. When pipe was being set, the cement flash set up inside the pipe well above the newly discovered sands; so we capped the well(the White Fronted Prospect) and skidded the rig slightly on the location pad and spudded the well again knowing that we already had pay to drill out to and perforate later. Guess you could say we had that “goose in the bag”. The hunt was back on. We drilled through the Marg sands again, logged them and set pipe. Then we drilled into our main Frio Nodosaria target and we found the “big sand” again. This time we held it better from the start. We logged the well and Figure 6 shows you what we found. We filled the Frio Distributary Channel Sand up again with 48’ of net gas/condensate pay, but the crevasse splay stringers were wet this time; apparently further down the Paleo structure of the original trapping anticline. Still a very nice wild goose! We set pipe and from the annotations on the log you can see what a great well it made. We then drilled out the other well with the flash set cement and also made another Excellent well.
All I can say is “what a wild goose chase that was but we successfully bagged our game!” Thank you Sun-Oryx for sponsoring a great and profitable hunt. Those were great times in the Oil Patch!
Dennis A. Taylor; Geologist, Owner, & President
Metate Minerals LTD
Corpus Christi, Texas