nice reply slippery wing. here are techologies and a bit of the history and the importance they have played regarding drilling.
edited
Acid Treatments (1950's). Acid treatment of wells caused considerable development during the 1950's in Pearsall Field of Frio County, Texas and several other smaller, shallower fields. Unfortunately, activity greatly subsided because of rapid declining production rates. Acid treatments are usually not required for wells drilled horizontally.
Large Fracture Treatments (1973). Small scale fracture treatments occurred before 1973. Large amounts of treating fluid and sand injected into wells at high rates. From this apparent success, large amounts of drilling dollars were spent in Pearsall field. A few other small fields were active for a period such as Mag Field in Gonzales. With time, results were only marginally successful. Drilling declined significantly during late 1976 in the Pearsall area. However, activity in Giddings field increased in 1976 and has continued to this date. Many of these wells in Giddings were placed onto production without fracture treatment. However, many wells with little indication of production (except being near a fault) were fracture treated and produced large quantities of oil and gas. Fracture treatments of wells are usually not required for horizontal wells.
Seismic (1976). A true revolution in the development of oil ands gas reserves in site locations using both 3-D and 2-D.
Horizontal Drilling (1985). In the United States, horizontal drilling dates back to the 1920s-1930s, with the first technically successful applications attempted in the 1940s. It was not until successful horizontal wells were drilled in Rospo Mare in Italy, and the first horizontal well was designed and drilled on the North Slope of Alaska before the oil industry began to give horizontal drilling a chance. In 1986, there were only 39 wells drilled worldwide. Horizontal drilling has been attempted for over fifty years but the technology was not economic until medium radius horizontal drilling commenced.
Medium Radius Horizontal Drilling (1985). Testing of equipment in actual field conditions began in 1985 in Giddings field. Initially, “under the river” drilling tools were modified in 1985 by Maurer Engineering with a $1,700,000 research project funded by Bechtel Investments, Inc. The first reentry medium radius horizontal well drilled in an oil field anywhere in the world occurred in the Giddings field in Fayette County, in a well operated by J&G Operating Company, a small Houston operator in 1986. The well was drilled as a reentry of a 5-1/2 inch cased oil well. Before 1991, horizontal wells were usually being drilled with one lateral for short distances in Pearsall and Giddings fields which opened only a small part of the total reservoir rock. Since then, wells with multiply and long laterals have greatly increased oil and gas recovery. By 1997, reentry of existing vertical wells became the preferred technique. Frequently two or more lateral are being drilled.
Short Radius Horizontal Drilling (1999-Present). This technology is successful in certain faulted areas. For example, many wells located in Lee County are perfect candidates. However, un-faulted areas such as Burleson County may not be very successful. This technology will become a standard technique for certain situations.
Multilateral Wells (1992). Multilateral well refer to any well where more than one branch is made into a reservoir from the main trunk or wellbore in order to maintain or increase productivity of the well. The first dual horizontal well completion was accomplished by Torch Energy Advisors in 1992. Maersk also drilled the first multilateral horizontal in the North Sea in 1992. Simple uncased and cased “branches became technically feasible in 1994-1995. The uncased well advancement by industry was propelled by companies drilling opposing and stacked laterals out of the parent wellbore. The leading operator in the 1990s advancing the drilling of these type wells was Union Pacific Resources. This more complex architecture allowed for crossing more fractures and provided greater reservoir exposure for Austin Chalk wells, and allowed for draining more than one horizon. In Texas, there are many irregular shaped leases, and this technique allows for better exploitation of the resource.
Underbalanced or Controlled Pressure Drilling (1964). While the first documented approach to drilling with underpressure occurred in design in the 1960s, commercial application occurred largely because of development of this technology in the Austin Chalk Trend, principally in the late 1980s-early 1990s. By using a simple low pressure flow diverter while drilling, Chalk drillers learned to flowdrill with pressures approaching 600 pounds to 800 pounds at the wellhead. This allowed for much more efficient and economic horizontal drilling of the critical zones. This type drilling was important to apply because of the nature of crossing depleted and un-depleted fractures in the Austin Chalk Formation. Later a company by the name of Williams Tool Company developed a more powerful diverter which could take much higher underbalanced pressures, causing a step change in making many more wells economically feasible to successfully drill and complete.
