Oil and Gas Linked for Study Groups


 Mississippi Play in Anadarko Basin- OK (data from www.ihsenergy.com)

 Mississippi Production in Anadarko Basin (CfD- Click for Details) – OK

The areas of studying is between 29N-20w to 24N-4E which include Mississippi wells in CHAUTAUQUA PLATFORM.  During this 5 years, operators drilled  593 wells,  195 wells are Horizontal wells in the direction of N/S. 


  During Jan1, 2007 to Mar 31, 2012; Operators produced Cum Oil = 8,062,047 bbl and Cum Gas = 61, 376,072 Mcf.  SANDRIDGE drilled 98 wells in these areas, and Chesapeake drilled 60 wells, from 182 wells in Anadarko Basin.  Majority of these wells were drilled closed by Oklahoma/Kansas State line in Woods and Alfalfa Counties. 

  September 2011, Eagle Energy completed the Longhurst #3H-34 (CfD) with the highest initial rate at 2225 bopd of 32 API gravity of Oil, 4767 Mcf and 2,789 bwd.

  Mississippi Overview by Eagle Energy:- 

The Mississippian Limestone of northern Oklahoma and southern Kansas is comprised of four basic depositional environments. These are the Mississippi “Chat”, Chester, Meramec and Osage.

The Mississippi “Chat” is the uppermost member at the unconformity between the Pennsylvanian and Mississippian aged rocks and is considered to be a very good hydrocarbon reservoir. These “Chat” reservoirs are very wide spread, vary in gross thickness from a few feet to 80’ thick and are heterogeneous in nature. Net porosity thicknesses greater than 5% range from a few feet to greater than 40 feet. This is caused in part through uplift, alteration, erosion and deposition of the original limestone commonly referred to as Mississippi Lime. The “Chat” is comprised of varying amounts of weathered chert, limestone and dolomite. Porosities range from 3 to 35%. The resistivities are generally low due to the amount of weathered chert and appear to be wet on logs by conventional petrophysical analysis. These reservoirs are in fact not wet but do produce some water associated with the production of hydrocarbons. Water rates vary between wells depending on the actual mineral composition of the formation being completed. 

The Mississippi Lime underlies the “Chat” and is comprised of the Mississippi Chester, Manning, Meramec and Osage. It is a deep water to shallow marine limestone sequence with interbedded dolomite facies enhancing porosity and permeability. This zone is also productive in the prospect area in addition to the Chat. Porosities range from 5 to 15% with water saturations ranging from 25 to 60%. Net porosity thickness greater than 5% range from 10 to 100’ with an average of 30 to 50’. 

Due to the heterogenic porosity development within the Mississippian formations it is advantageous to drill horizontal wells to interconnect a larger percentage of porosity with one well bore. Fracture treatment of the formation during completion in addition to the horizontal placement of the well bore will add significant conduits for production of hydrocarbons adding significant recoverable reserves. These reserves would not be recovered with a conventional vertical well.  

Mississippian Play in Oklahoma.

    Mississippian Play in Oklahoma: 


 On March 19, 2011, one of the wells that Eagle operates caught fire as drill pipe was being tripped into the wellbore. The following provides some background and status.

While the lateral was being drilled in the Mississippi formation, the drilling rig was tripping out of the hole to replace the drilling bit when the first gas kick occurred. This kick was controlled and Eagle was tripping back into the hole when a second gas kick was experienced. Drilling personnel attempted to shut in the well on this second kick and the blow out prevention valves failed, and as a result gas and oil flow came to the surface. The rig subsequently caught fire. Two employees of the drilling contractor were injured and one is still hospitalized. 

The well was the Buckles IH-3 in Woods County, Oklahoma. The well was flowing oil and gas for approximately 36 hours before it was controlled using heavy drilling mud and cement. It is anticipated that clean up and remediation efforts will last about three weeks. It does not appear that the hole was lost or that the incident will impact reserves. The Company is investigating the cause of the incident. While also the subject of review by the Company, it is anticipated that the financial impact will be mitigated by insurance carried by the Company and the drilling contractor. 

The Company will update this information as there are changes.

Chesapeake led the industry into the Mississippian oil resource play in early 2007. With a land position of 230,000 net acres, Chesapeake produces approximately 3,000 boe/day (September 2010) from 30 wells.

• Proved reserves of 21 MMboe with 400 MMboe of estimated unrisked resource potential
Finding & Development cost estimated at less than $10/boe

• Type curve EUR of 360 Mboe/well (67% oil and NGL’s), short of both Eagle and SandRidge

• Drilled 30 wells in the play and currently operating three rigs; given it’s recent successes 
  Chesapeake plans to drill 40 net wells with four rigs in 2011

Chesapeake’s horizontal D&C costs of ~$2.8 million/well including SWD capital allocation source


A much more scattered horizontal play is targeting what is identified by operators as the Mississippi Lime and/or Chat. These are different reservoirs but are combined on Figure 9 due to inconsistent naming. The Chat produces horizontally mostly in Osage and Kay Counties and appears to have had relatively little drilling activity in 2010.

Most of the horizontal drilling activity seemed to be targeting the Lime and was more spread out.

The Mississippi Lime is a regional carbonate found across most of the State. It has produced from what are often marginally economic vertical wells for decades. Horizontal drilling has made this reservoir economic over a much wider area. Although it can develop minor porosity and permeability, reservoir quality tends to be poor. It is often fractured, and horizontal drilling affords the opportunity to enhance natural fractures with multi-stage acid-fracture stimulations. The Mississippi Lime is thick and oil-prone across much of the northern half of the State, giving it the potential to become the areally largest and perhaps the most productive horizontal oil play in Oklahoma (Figure 9).

The horizontal Mississippian wells completed in 2010 were clustered mostly around the main area of production in Woods and Alfalfa Counties. This part of the play is dominated by Chesapeake and SandRidge, who have each leased several hundred thousand net acres in the last 18 months.

Production statistics are preliminary - only 17 wells have any records. To date, wells in this area have average cumulative recoveries of 18 MBO + 51 MMCF and a daily production in August 2010 of 37 BOPD + 131 MCF. Clearly, one of its attractions is the fact that this is a true oil play, with oil representing about two thirds of BOE production.

The Mississippi Chat is a thin, siliceous zone of variable reservoir quality that intermittently develops on top of the Mississippi Lime. Like the Mississippi Lime it has produced for decades from vertical wells. It can now be identified seismically, and horizontal wells drilled on seismic anomalies have allowed operators to maximize reservoir exposure. Because it is permeable these wells are often untreated.

The Oklahoma oil and gas industry has applied horizontal-drilling technology to dozens of other reservoirs across the State and will continue to test the limits of where it can be applied. Many of the horizontal wells drilled thus far are clearly sub-economic, but this may be as much due to the manner in which the wells were drilled and completed as any inherent geological factors. The learning curve from first (often marginal) production to efficient, consistent, moneymaking development is a process measured in years. There are a number of reservoirs that were not discussed that, based

on initial potentials, show promise. These wells, which are classified as ‘Other’ in Figure 8 and shown as black dots in Figure 9, may develop into larger horizontal-drilling plays in the future.

Significant Missippian Wells in 2010

1) Sec. 19-29N-9W (Alfalfa County): In a major eastward extension of horizontal Mississippi Lime production on the Anadarko Shelf, SandRidge completed the 1-19H Victor. Completed in September 2010, this well does not yet have reported production. However, the initial potential is 421 BO + 3.1 MMCF + 3,957 BWPD. The productive lateral extends from 4,961 – 9,315 ft (TVD 4,855 ft) and was treated with about 800,000 pounds of sand. In this part of the horizontal Mississippi Lime play there are 21 wells with some reported production. These have produced 500 MBO and 2 BCF and about 60 BOPD per well.

2) Sec. 31-22N-4E (Pawnee County): Pablo Energy quietly pushed the Mississippi Lime horizontal play on to the Cherokee Platform with the drilling of their Ripley 1H-31 in 2008. With a completion that was registered in 2010, the well now shows a September 2008 initial potential of 94 BO + 1 MCF + 1009 BWPD and a retest one year later of 295 BO + 100 MCF + 785 BWPD. With still no reported production it is difficult to determine how good this well is, but it definitely set off a land rush in this part of the State.

Pablo has since drilled additional wells: the Bruce 1H-32 one mile east (269 BO + 45 MCF + 1,238BWPD), and the Turkey Creek 1H-30 one mile north (145 BO + 167 MCF + 1,947 BWPD). Five miles west they are drilling the Gilbert 1H-32, which was spudded in November of last year, and one mile south the Larry 1H-6 has been permitted. Clearly the Ripley well gave Pablo a lot of encouragement. Produc ing 35 degree API crude, the Ripley was completed in a 4150-7054 ft lateral (TVD 3908 ft) and was treated with 1.4 million pounds of sand.

The above articles are the partial report from  http://www.ogs.ou.edu/OilGas/pdf/2010DrillingHighlights.pdf


and www.occeweb.com