Persistence can pay off: Discovery for Morgans Bluff Field Orange County, Texas

Morgans Bluff Field began its journey to discovery as Nibletts Bluff Prospect; conceived from interpretation of residual gravity data in 1979. A strong gravity maximum was noted in the area, which was dip (south) directed. More importantly the anomaly was atypical of the maxima-minima geometry relationship observed in the trend area. A fault was interpreted across the widest point of the maxima (E-W) and a target area was identified covering approximately 1,200 acres on the downthrown (southern) side of the fault. The lead area was in equal parts east and west of the Sabine River. Widely spaced Hackberry trend production was known from the area at Rose City, Starks, and N E Edgerly Fields. The elusive updip Hackberry sands just below intermediate pipe around 8,000 feet were the prospect objectives. With great enthusiasm my geophysical coworker, Gil Eppich and I set about checking for available seismic data in an attempt to apply some science to the concept. The available "big oil company" data in the area was virtually uninterpretable. As you might suspect we bought it anyway because it just needed "reprocessing". In fact an alternate version of deconvolution processing did a great job of cleaning up the data. With a great deal of effort a leasable prospect was born.
After much discussion it was determined that the initial test would be drilled on the Powell Lumber Company lease west of the Sabine. In 1981 the final log run of the Sandefer # 1 Powell Lumber Company well indicated a dry hole with no Hackberry sand. After the initial disappointment we started thinking about what to do next. A major company seismic crew was shooting 2-D data in the area. Gil Eppich contacted the crew chief and ask if he could borrow the crew long enough to shoot a north-south line through the well. The crew chief responded "no problem we were going to shoot it anyway". We only had to grant a permit and pay half the cost of the line to get the data. This was great! We now had new data and a chance to figure out where we went wrong. It appeared we had drilled the high side of a buried fault. We now knew the sands were further south and most likely developed half way between the initial test and the Mobil # 1 St.Ls. 6089 well in Louisiana which cut about 600 feet of the target sands.
With a substantial lease position remaining and a new interpretation we went to the street to sell an interest in a second test as our available joint venture funding would not be used to fund all the well cost. A second dry hole on the same prospect would be hard to explain to the same set of partners. If some third party felt the well was drillable we would all feel better about the risk (i.e." misery loves company "). Reducing the well cost through promotion would also allow the spreading of available drilling dollars into other prospects. This time the drill site was to be east of the Sabine on a Louisiana State lease. The location could be reached by drilling barge up the river. Only one railroad bridge (not opened in about forty years) would have to be rotated to gain access. After numerous presentations it was clear no one wanted to participate in the drilling of a Hackberry wildcat in this area. We began to suspect no one wanted to drill a Hackberry well - ever, anywhere! Without a new partner the probability of causing a second well to be drilled looked bleak. Due to eminent lease expirations it became clear that the project could not be salvaged. A new strategy was conceived "if we can''t sell this thing maybe we can give it away for a call on half the deal in a later joint venture program"? Contact was made with one of my earlier major company mentors. He had formed a company and was making a play in the area, some leasehold had already been acquired. His play was based on a major Yegua nose with a related low relief Vicksburg closure; in addition a Frio age Hackberry channel was interpreted crossing the area with a northeast to southwest trend. We presented our Nibletts Bluff Prospect data and he agreed that if he reconstructed the prospect he would offer half to Sandefer Oil & Gas upon completion of additional technical work and leasing. He completed his portion of the deal and offered participation. The prospect as presented was not considered competitive with others in inventory or being considered at the time. Participation (much to my later regret) was declined.
Morgans Bluff Prospect was placed with Celeron. The history from rejection of participation by Sandefer Oil & Gas and acquisition by Celeron is sketchy due to my lack of involvement. I understand their reason was to round out their budget and use a rig which would be used to drill another prospect in the area. The discovery well, Celeron # 1 Powell Lumber Co. was drilled during September 1985 and found 13 feet of net Hackberry gas condensate pay (by log) which later tested as an oil well. The well was drilled using a drilling barge, which reached the location, by transport up the Sabine River. At March 1, 1999 the field contains 14 productive wells with an average of 100 feet of pay and has produced 11 MMBO with 18.6 BCF of associated gas. The reservoirs( at least two based on different pressure regimes) are interperted as deepwater deposits with high porosities and permeabilities. The field which covers about 600 acres is being produced under pressure maintainance by salt water injection. At this point in the letter the basic story of discovery of Morgans Bluff Field is completed. Recent history, however, and its relationship to past events,will demonstrate why one should never give up while they still have an undiscovered field in their head.
As mentioned earlier it appeared the prospective area would extend into Louisiana. Prior to discovery of Morgans Bluff Field and subsequent to the failed effort to cause a second wildcat to be drilled on Nibletts Bluff Prospect a Houston company (one of many who viewed the proposal) leased a portion of the expired Louisiana lease block. There was some personal satisfaction taken from the fact that someone thought enough of the idea to drill a well. It may be presumptuous to assume that exposure of the prospect had anything to do with the test. Their location was staked and drilled within 1,500 feet of the second test proposed for Nibletts Bluff Prospect. Their effort resulted in a dry hole.
In 1995 efforts to cause a well to be drilled to extend Morgans Bluff''s productive area across the Sabine into Louisiana were renewed. By this time new 2-D data was available which clearly defined the extension of the originally proposed fault into Louisiana. Morgans Bluff Field (now ten years old) was also indicative of what might be expected across the river. This time the renamed Heritage Prospect was shown as an open acreage idea and therefore had limited exposure. These efforts did not yield results. The most common reason for rejection was sand risk, which is of course a generic reason for avoiding the Hackberry.
In the winter of 1996-''97 a proprietary 3-D survey was acquired over the area. A recently drilled well (Neuman # 1 S. L. 15155) had its surface location on the Texas side of the Sabine and was directionally drilled into Louisiana (about a one-mile kick). The well encountered about 250 feet of Hackberry sand and has about 90 feet of pay.The accumulation is seperated from Morgans Bluff Field by a structural saddle. This wells bottom hole location is 500 feet south of the old proposed location for the second wildcat test of Nibletts Bluff Prospect.
It is now clear that the original target area interpreted from residual gravity data was a fairly accurate geographic description of the two productive areas. Gravity data, in my opinion, is an underutilized tool in exploration lead generation. Perhaps this topic will be the subject of another "letter" for the HGS Bulletin or web site.
The observations and recollections presented