A wellhead choke controls the surface pressure and production rate from a well. Chokes usually are selected so that fluctuations in the line pressure downstream of the choke have no effect on the production rate. This requires that flow through the choke be at critical flow conditions. Under critical flow conditions, the flow rate is a function of the upstream or tubing pressure only. For this condition to occur, the downstream pressure must be approximately 0.55 or less of the tubing pressure.

Although conformance-improvement gel treatments have existed for a number of decades, their widespread use has only begun to emerge. Early oilfield gels tended to be stable and function well during testing and evaluation in the laboratory, but failed to be stable and to function downhole as intended because they lacked robust chemistries. Also, because of a lack of modern technology, many reservoir and flooding conformance problems were not understood, correctly depicted, or properly diagnosed. In addition, numerous individuals and organizations tended to make excessive claims about what early oilfield gel technologies could and would do. The success rate of these gel treatments was low and conducting such treatments was considered high risk. As a result, conformance-improvement gel technologies developed a somewhat bad reputation in the industry. Only recently has this reputation begun to improve. The information presented in this chapter can help petroleum engineers evaluate oilfield conformance gels and their field application on the basis of well-founded-scientific, sound-engineering, and field-performance merits.

Horizontal wells are being employed in innovative ways in steam injection operations to permit commercial exploitation of reservoirs that are considered unfavorable for steam, such as very viscous oils and bitumen and heavy oil formations with bottomwater. This page discusses some of the ways in which horizontal wells have been used to enhance steamflooding. Numerous papers have explored steam injection using horizontal- vertical-well combinations by use of scaled physical models or numerical simulators. For example, Chang, Farouq Ali, and George[1] used scaled models to study five-spot steamfloods, finding that for their experimental conditions, a horizontal steam injector and a horizontal producer yielded the highest recovery. Figure 1 shows a comparison of oil recoveries for various combinations of horizontal and vertical wells and for four different cases: homogeneous formation, 10% bottomwater (% of oil zone thickness), 50% bottomwater, and homogeneous formation with 10% pore volume solvent injection before steam.

In a very brief amount of time (geologically speaking), the exploration and production energy business has dramatically shifted to an unconventional universe where geologic risk is low, completion technology is arguably as important as the geology, and where favorable economics are the well-honed byproduct of cost reduction, sweet spot definition, drilling and completion efficiency, and midstream transmission. Having spent our entire careers (more than 40 years each) in the upstream business, it is important to step back and look at the big picture every once in a while. We have seen many exploration paradigms broken--resulting in the birth of deepwater exploration, subsalt development and, most recently, unconventional shale development. We have also seen the demise of some false saviors along the way such as the Atlantic Tethyan reef play, Destin Dome off the Gulf Coast, Mukluk in the Beaufort Sea, the lowly Lodgepole play in North Dakota, and post-sanction exploration in Libya, to name a few. Whether successful or otherwise, all of these exploration concepts required creative thought and a willingness to invest capital into what could ultimately become a commercial venture.

Millennials, loosely defined as individuals born between the 1980s and 2000s, now make up the SPE young professional demographic. We are known for many things, both good and bad, but perhaps most notably, we are not satisfied with putting our heads down and waiting our turn to climb the corporate ladder. We have come to expect exceptional reward for exceptional work. As a result, we are rarely satisfied staying in one role or at one company for too long. So, the question is, how do we keep our careers exciting and dynamic? Kim McHugh, general manager of drilling and completions for Chevron Services Company, and Jake Howard, operations supervisor for Chevron, weigh in on how to manage these transitions gracefully and strategically.

Ask a group of university engineering students to name the most technology-driven companies in the US today, and the odds are against any oil and gas businesses turning up on the list. But while the energy industry is certainly a mature business compared with, say, the electronics industry, there is no reason to believe that the evolution of the underlying technological basis of our business has somehow come to a halt. In fact, a close examination of current projects and future trends in global energy markets paints a far different picture. While some doomsday critics insist the world is running out of oil and gas, many energy analysts believe that we have produced only about one-fifth of our known resource base. That leaves 80% of our global oil and gas resources yet to be developed.

Ask a group of university engineering students to name the most technology-driven companies in the US today, and the odds are against any oil and gas businesses turning up on the list. But while the energy industry is certainly a mature business compared with, say, the electronics industry, there is no reason to believe that the evolution of the underlying technological basis of our business has somehow come to a halt. In fact, a close examination of current projects and future trends in global energy markets paints a far different picture. While some doomsday critics insist the world is running out of oil and gas, many energy analysts believe that we have produced only about one-fifth of our known resource base. That leaves 80% of our global oil and gas resources yet to be developed.

Clay Neff is president of Chevron Africa and Latin America Exploration and Production Company, a position he has held since January 2017. He is responsible for Chevron's oil and gas exploration and production (E&P) activities in both regions. Before his current position, Neff was managing director of Chevron's Nigeria/Mid-Africa business unit. Previously, Neff was part of Chevron's Southern Africa strategic business unit, initially as Production Operations manager, and later as Asset Development general manager. He has also held a number of management roles with Chevron in North America.

This past year witnessed significant activity and growth related to heavy-oilfield developments worldwide, and this was accompanied by a record number of SPE paper submissions on related topics. This feature article highlights several technical focus areas identified in this new literature set. Several papers describe the development, testing, and field piloting of completions that incorporate various types of inflow-control devices (ICDs). While most of these consider passive or autonomous control devices, one paper describes the installation and early performance of an intelligent-well-completion system with full surface activation and control of the ICDs in an SAGD well. Technical challenges associated with sand control, erosion, scaling, and plugging also must be addressed as these various systems evolve and their use continues to grow.

The operator has initiated a cyclic-steam-stimulation (CSS) project in the Opal A diatomite of the Sisquoc formation on the Careaga lease in the Orcutt oil field in Santa Barbara County, California. The operator has received entitlement to proceed with an expansion consisting of 110 additional new wells. The target zone contains high oil content ranging from 1,800 to 3,000 bbl/acre-ft in massive intervals with 200- to 700‑ft thickness at depths of 600 to 1,000 ft and with a permeability of 5 to 15 md. The pilot currently consists of 19 cyclic-steam-injection wells configured in a 4 5 matrix spaced approximately 120 ft apart, producing from an average depth of 925 ft. A supervisory control and data-acquisition system is used to control and monitor various aspects of field operations, especially the steam-injection-process protocols.