The Fishbone Technology: To Use or Not to Use?

The Fishbone Technology: To Use or Not to Use?

New technologies in the oil and gas industry enable operators to capitalize on new opportunities. Horizontal drilling, for instance, is opening up reserves in fields that were not previously economically viable, which is further helping operators to gain higher recovery from old fields. However, with every new technology comes a risk and all technologies must be tested first in order to secure a place into the future. The fishbone technology was pioneered by Shell, where it was tested in the Western Desert. But now that Shell is selling its Western Desert assets, should the fishbone technology stand the test of time and be leveraged by other operators?

What Is the Fishbone Technology?

The fishbone technology, developed by Fishbones, a well-known Norwegian well stimulation technology company, is a series of multilateral segments that fall into a horizontal well. They are called so because they look like the skeleton of a fish. A fishbone stimulation system is ideally used in onshore low permeability tight gas reservoirs to increase well productivity and access difficult geological formations and unconventional reservoirs.

The technology offers an alternative solution that is relatively safer and more cost-effective. Fishbones stimulation technologies are field proven in sandstone, carbonate and coal bed methane formations. The technology is designed to improve reservoir stimulation, delivering the accuracy of cemented and perforated technologies, the operational efficiency of open hole slotted liners, and the productivity of fracturing.

In essence, the fishbone technology is used for multi-hole wells with a fishbone trajectory so it would not be necessary to construct separate wells for each horizontal shaft. That way, it lessens the drilling costs while reaching each horizontal stratum that bears oil and increasing the injection capacity of the well as a whole. Since wells are drilled in a variety of geological formations, there are two types of fishbone operations – jetting and drilling.

Fishbones jetting operations are simple – spaced out at even intervals of the strata where tubes with small diameters (needles) jet out simultaneously to penetrate the reservoir. At full extension, achievable penetration is typically about 12 meters (m), with the number of laterals deployed tailored according to each well. Fishbones jetting can be used with acid for jetting of carbonates or non-reactive fluids for other formations.

On the other hand, fishbones drilling operations are simple and fast – completed within only a few hours. They are also spaced out at even intervals and deployed at depth. Penetration is typically 10.8 m, with three laterals drilled from each fishbones drilling sub.

Drilling Supervisor at Badr El Din Petroleum Company (Bapetco), Mamdouh Zakaria, explained to Egypt Oil &Gas that “Fishbone technology has mainly two applications; either using jetting force or using small drillbit heads. The former is the one utilized in limestone applications along with the use of acid pumping. Generally, fishbone technique has proven to be successful in terms of improved productivity of reservoir and improved ultimate recovery and reduced water production.”

Economic and Production Viability

Over the last decade, tight oil development has been powered by technological leaps, among which is horizontal well drilling. To reach wells within thin layers of formation, thousands of feet under the ground, a wide scale application of new horizontal drilling techniques is frequently tested, making the market more competitive.

In a case study by Manshad, A.K. et al. (2019) on the economic and productivity of different horizontal drilling scenarios applied in the Middle East oil fields, the fishbone structure increased production by 393%, whereas the drilling cost was only 130% more than that of a conventional horizontal well.

The case study further explored other simulation models in an attempt to find out which can have the optimum production. It was concluded that the fishbone technology is the most suitable for a fishbone well with four branches, covering the maximum contact between well and reservoir. There are several variables to identify the best scenario for optimizing the productivity of multilateral wells, which include length of main hole, length of sidetrack, space between sidetracks, number of sidetracks, and the angle between sidetracks and main hole. Using this data, the fishbone performance can be evaluated. This specific evaluation showed that there is a significant difference between horizontal wells and fishbone wells, which indicates that by increasing contact area between wellbore and reservoir formation, the total production rate of fishbone well is increased significantly compared to the conventional horizontal well.

“In the current economics of the oil and gas industry, cost efficiency comes second only to health, safety, and environment (HSE). Cost is now the driving factor in all operations and particularly in brownfields. However, that does not mean we should avoid new technologies. In more than one case, new technologies are utilized for the sake of cost saving. In Bapetco, we are open to trying new technologies and new designs, with proper cost management,” Zakaria added.

Hitting the Egyptian Market

As Shell continues to embrace new technologies, the international oil company (IOC) has pioneered the use of fishbone technology in the Western Desert last February. The Bed 9-G well was successfully drilled and completed using the state-of-the-art technology, yielding significantly higher rates than previously expected.

Senior Geologist and Geo-Modeler at Bapetco, Sherif Shafik, who was a part of the team that worked with and implemented the fishbone technology with Shell, told Egypt Oil & Gas (EOG) that it all started out as a way to open new doors and opportunities for operations in Egypt, in regards to applying the best operational and cost-effective methods in the industry. If the technology is proven successful, that would mean the entire supply chain in the oil and gas industry would be altered.

Zakaria, who was also a part of the team to run this application in a horizontal limestone reservoir, said that Bapetco has applied the fishbone technology in one well so far. “Despite all operational difficulties, I think [fishbones] should be used more in Egypt. The well production jumped to 150% of estimated production with little to 0% of water production compared to offset wells which had high water oil ratio of around 40-50%.”

According to Shafik, there is no direct contact in Egypt with the mother company. Instead, on behalf of Fishbone company, O&G Quest does seminars and workshops to showcase the latest stimulation techniques. O&G Quest approached Shell to apply this technology in Egypt as Shell had previously applied it with Petroleum Development Oman (PDO).

O&G Quest’s Chairman, Osama Kamel, explained to EOG that his company is the local arm of Fishbones. The mutual relations extended since 2015. “The technology has been introduced to the market with combined technical marketing efforts to both IOC’s operating in Egypt as well as the joint ventures (JVs) who have challenges that Fishbones can solve. One successful job was performed for Bapetco/Shell in 2018,” Kamel said.

It was planned that Shell would start drilling the Obaiyed H18 well – the first endeavor in Egypt to unlock tight gas in deep hard rock, proving that the fishbone stimulation is feasible. Without the need to frac the tight reservoirs, the long reach horizontal well should increase productivity by enhancing well contact area to reservoir. This promises to unlock the tight gas potential of Obaiyed field that contains a significant volume of gas in tight clastic (sandstone) reservoirs through deploying long-reach horizontal completion at lower cost.

According to Shafik, the fishbone entails very expensive resources. However, when it comes to cost efficiency there are many variables to consider. Both frac and fishbone are relatively expensive, although in comparison to frac, fishbone remains more cost efficient. For instance, when Apache used frac, the cost was estimated at EGP 5 million; however, Shell’s total cost of fishbone drilling in the Western Desert came close to EGP 3 million, Shafik added.

“But it is still too early to judge whether fishbone is economical or not. We do not have the full picture of the technology yet, as this takes time,” the geologist claimed.

“It is always nice to apply a new technology. New technologies benefit the whole oil and gas sector because they affect production and costs,” Shafik said, explaining that “new technologies are always expensive in the beginning, but when it becomes more widespread and received by more suppliers, this technology becomes more accessible. Thus, prices become bound to decrease.”

In addition, Shafik clarified that any new technology is a risk, and as an industry leader, Shell takes those risks and always welcomes new technologies. According to Shafik, the Ministry of Petroleum and Mineral Resources (MoP) was keen to learn the technology’s results to base their decision on whether it should start applying fishbone as well or not.

Fleeing the Egyptian Market?

On October 20, Shell Egypt revealed its plan to sell its onshore upstream assets in the Western Desert to focus on offshore gas growth. It became unclear whether the fishbone technology would still be applied by new potential buyers or not.

Shell’s portfolio in the Western Desert includes stakes in 19 oil and gas assets including the Badr El Din and Obaiyed areas, as well as the North East Abu El Gharadig, West Sitra, Bed 1 gas, and West Alam El Shawish concessions

Khaled Kacem, Shell Egypt Country Chairman, said in a press statement, “Any sale is contingent on finding an appropriate buyer, commercial negotiations, and required approvals. We anticipate the start of active engagement with potential buyers in Q4 2019. During the divestment process we remain committed to ensure continued safe and reliable operations and will keep our stakeholders regularly informed.”

Kacem announced that the company is looking for a capable buyer that will bring new investment and growth into the Western Desert and build on the company’s successful partnership with the Egyptian General Petroleum Corporation (EGPC).

Since the company’s key strategy is “More Upstream, Profitable Downstream”, it is common that Shell defers some of projects, notably in unconventional oil. However, the IOC supports growth potential that sustains strong operational performance and continued investment, while continuing to unlock unconventional oil and gas resources. The company seeks portfolio opportunities that offer more potential through either increased oil price exposure or through securing additional scope for recovery from appraisal or the application of new technology.

Thus, the future of fishbone is still ambiguous, especially that these negotiations with buyers are still confidential during this time. However, Egypt has many potential areas with reservoirs that can definitely benefit from the fishbone stimulation model.

Potential Areas

It is worth noting that Shell’s horizontal well at the Obaiyed concession development well OBA D-41 ST was previously drilled and completed with a result of 26.2 million standard cubic feet per day (mmscf/d).

“It is well known that in the Western Desert as well as in other areas in Egypt, there are tight formations and thin layers that requires careful controlled stimulation to avoid getting in contact with unwanted elements such as water. So, the future of the technology is secured and bright since it is so far the most effective solution in the industry for the mentioned challenges,” O&G Quest’s Chairman ensured.

A multidisciplinary approach to help understand productivity enhancement of low permeability reservoirs in the Western Desert of Egypt was explained in a paper titled Multistage Horizontal Well Hydraulic Fracturing Stimulation Using Coiled Tubing to Produce Marginal Reserves from Brownfield: Case Histories and Lessons Learned by Hassan A. et al (2019). According to the paper, primary well production from the horizontal well was enhanced from 37 to 70% of recoverable reserve and the recovery factor was doubled.

It was clear that a single horizontal well with approximately 3,000 feet (ft) lateral could replace three vertical wells in terms of production and ultimate recovery. The productivity of the horizontal is better than that of the vertical because of the large productive area and the dense development represented in multistage fracturing treatments. The chances of missing the sand were also low compared to the vertical wells (two vertical wells are necessary to develop the same area).

Khalda and Umbarka fields are two mature fields located in the Egyptian Western Desert that can leverage the fishbone technology. They are characterized by their low, depleted reservoir pressure and laminated shaley sands (Upper Bahariya formation), in addition to their significant hydrocarbon reserves. However, because of their relatively low permeability and thin layers, it is very difficult to produce economically from this formation. Single-stage hydraulic fracturing treatments in vertically drilled wells resulted in a production of 25 to 40 barrels per day (b/d) per well, which is uneconomic for field developments.

The Baharyia formation is another common reservoir in the Western Desert of Egypt. It is characterized as a heterogeneous reservoir with low sand quality. It is comprised of fine-grained sandstone, thin, laminated, sand-poor parasequences with shale interbeds. The heterogeneity and low permeability of the Upper Baharyia reservoirs are the primary challenges to maintaining economic well productivity.

O&G Quest’s Chairman declared that other than their work with Shell, they are expecting another job in the near future. “We have been recently in a dialogue with two to three IOCs and JVs regarding the application of the fishbones technology, to stimulate challenging formations that couldn’t be stimulated by the traditional hydraulic frac method,” he said.

“O&G Quest is keen on introducing strategic niche technologies that can increase production. [These technologies] are more environmentally friendly, more efficient, and more accurate than traditional technologies. Such technologies are related to reservoir stimulation, completion, subsea, and drilling,” Kamal said.

In conclusion, there are many mature fields in Egypt that are yet to be tapped into. Meanwhile, Shafik concluded that “in recent years, drilling has been revolutionized. Instead of drilling a well in two to three months, we now drill in 20 to 30 days maximum. Thus, anything that speeds up the production is always welcomed.”


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