随着油藏老化，运营商需要有关岩石中剩余石油、天然气和水的最新信息，以便更好地提取储量。

当存在较大钻孔时，许多随钻测井和电缆工具可用于评估裸眼环境中的初始储量。一旦油井下套管并完井，获取该信息通常需要具有小外径 (OD) 的工具，可以穿过 2 3/8 英寸的完井。这通常意味着组件的小型化，有时甚至使更小的工具变得更强大。

最新的答案是哈里伯顿的 IntelliSat 脉冲中子测井服务，预计将在今年年底前投入商业使用。到目前为止，它已部署在阿拉斯加、Lower 48 和墨西哥湾，温度范围为 90 F 至 240 F，压力范围为 1,800 psi 至 14,300 psi，深度为 1,500 英尺至 6,450 英尺的砂岩和碳酸盐岩中。

在这些部署中，它采用了传统的 RMT-i 工具，两种工具的结果“非常匹配”，哈里伯顿公司的电缆和射孔团队的油井干预产品冠军约翰·萨维奇 (John Savage) 表示。

当哈里伯顿开始为较小的套管井环境创建工具时，设计清单上有一些必须满足的条件：外径不能超过 1 11/16 英寸，以便可以在 2 3/8 英寸完井中工作。它需要能够在 350 F 和 15,000 psi 的环境中工作。它必须收集与传统 RMT-i 工具相同水平的“更好”细节，后者可以在 2 7/8 英寸环境中运行。它需要能够比传统工具多产生 50% 的中子，以减少统计不确定性并实现更快的测井速度。

哈里伯顿认为 IntelliSat 满足了这些要求。

“我们在硬件设计方面做得很好，现在我们只是对分析软件进行一些调整，”萨维奇说。“我们减少了工具包的尺寸，现在我们的探测器不再依赖于温度，并且具有更好的光谱分辨率。”

该工具可以帮助操作员了解油-水或气-水接触发生的位置。其他应用包括记录套管外的水流和评估砾石充填的位置。它还可以计算元素产量，用于了解岩性并确定总有机碳 (TOC)。

“他们正在寻找总有机碳，”萨维奇说。传统上，这些信息可以在油井下套管之前获得，而 IntelliSat 服务“为我们提供了一种在油井下套管后获取信息的方法。”

该工具使用中子发生器来产生中子，进而产生伽马射线。

“我们测量的是那些伽马射线”，因为它们与储层中的分子相互作用，为了获得最佳结果，他说，“我们需要尽可能多的中子。”

伽马射线的能量水平表明储层中存在不同的元素，包括碳、氧、钙和硅。

创建 IntelliSat 工具的第一个挑战是开发一种中子发生器，能够比其前身产生更多的中子。管制造工艺的改进和电源的进步使得发电机的输出更高，现在更可靠，寿命更长。

“我们的目标是将中子发生器的输出增加 50%。我们实际上已经超越了这个目标，”萨维奇说。

但产生中子来产生伽马射线只是该过程的一部分。必须探测伽马射线，哈里伯顿新工具上的探测器能够获取伽马射线信息，以生成高分辨率能谱和衰变阵列。他说，这些探测器也足够灵敏，可以在发生器关闭的情况下收集自然背景辐射，计算用于粘土分型的钾-铀-钍 (KUTh) 测井并增强 TOC 计算。

一旦获得结果，就必须对其进行分析。

“保持非常稳健的表征至关重要，”他说，并补充说该工具的建模软件基于蒙特卡罗 N 粒子代码。他说，核模型通过轨道实验室在各种钻孔配置以及岩石和流体类型下进行的数千次实验进行了验证和优化。

IntelliSat 工具可以在具有表面读数的标准电子线路单元上运行，也可以在钢丝或连续油管上使用内存包运行，或者在数字钢丝上使用质量控制表面读数数据运行。通过添加套筒，将外径增加到 2 1/4 英寸，该工具可以在高达 20,000 psi 和 425 F 的环境中运行。对于 30,000 psi 环境，可以使用 2.48 英寸外径外壳。

预计该工具将于今年晚些时候推出，因为在表征软件的矿物方面仍有一些工作要做。

“我们对我们的饱和模型非常有信心，”萨维奇说。“我们正在努力研究矿物学[和]元素产量”，以便能够向运营商提供岩性和 TOC 信息。

As reservoirs age, operators need updated information about the oil, gas and water remaining in rock so reserves can be better extracted.

Many logging-while-drilling and wireline tools exist to assess initial reserves in place in an open-hole environment when there is a larger borehole. Once the well is cased and completed, getting that information typically requires a tool with a small outside diameter (OD) that can fit through a 2 3/8-inch completion. That often means miniaturizing components and sometimes making the smaller tools more powerful.

The latest answer is Halliburton’s IntelliSat pulsed-neutron logging service, expected to launch commercially before the end of the year. So far, it has been deployed in Alaska, the Lower 48 and the Gulf of Mexico, in temperatures ranging from 90 F to 240 F, in pressures of 1,800 psi to 14,300 psi and to depths of 1,500 ft to 6,450 ft in sandstones and carbonates.

In those deployments, it followed use of the legacy RMT-i tool, and the results of both tools matched “excellently,” said John Savage, Halliburton’s well intervention product champion for its wireline and perforating group.

When Halliburton set about creating a tool for the smaller cased-hole environment, there were a few musts on the design list: The OD couldn’t exceed 1 11/16 inch so that it could work in the 2 3/8-inch completion. It needed to be able to work in 350 F and 15,000 psi environments. It had to collect the same level of –or better– detail than the legacy RMT-i tool, which could operate in a 2 7/8-inch environment. And it needed to have the ability to generate 50% more neutrons than the legacy tool to reduce statistical uncertainty and enable faster logging speeds.

Halliburton contends IntelliSat checks those boxes.

“We're pretty well there on the hardware design, and now we’re just doing some tweaks on the analysis software,” Savage said. “We've reduced the tool package size, and we've got detectors now that aren't temperature-dependent anymore and that have much better spectral resolution.”

The tool can help operators understand where the oil-water or gas-water contact is occurring. Other applications include logging the flow of water outside the casing and evaluating placement of gravel packs. It also can calculate elemental yields, which is used to understand lithology and determine total organic carbons (TOCs).

“Total organic carbon is what they're looking for,” Savage said. Traditionally, that information can be obtained before the well is cased, and the IntelliSat service “allows us a way to do that after there's been casing put in the well.”

The tool uses a neutron generator to create neutrons, which in turn create gamma rays.

“What we’re measuring is those gamma rays” as they interact with the molecules in the reservoir, and for the best results, he said, “we want as many neutrons as possible.”

The energy level of the gamma rays indicates the different elements present in the reservoir, including carbon, oxygen, calcium and silicon.

The first challenge in creating the IntelliSat tool was developing a neutron generator that would create more neutrons than its predecessor. Improvements in the tube-manufacturing process and advancements in the power supplies have enabled a much higher output from the generator that is now more reliable, and with longer life.

“Our objective was a 50% increase in neutron generator output. We've actually exceeded that objective,” Savage said.

But generating the neutrons to create the gamma rays is only part of the process. The gamma rays have to be detected, and the detectors on Halliburton’s new tool are able to acquire the gamma ray information to generate high-resolution energy spectra and decay arrays. These same detectors are also sensitive enough to collect natural background radiation with the generator off, to calculate a potassium-uranium-thorium (KUTh) log for clay typing and to enhance the TOC calculation, he said.

Once the results are acquired, they must be analyzed.

“Having a very robust characterization is critical,” he said, adding that the tool’s modeling software is based on the Monte Carlo N-Particle code. The nuclear model is validated and optimized through thousands of experiments in the track lab under various borehole configurations and rock and fluid types, he said.

The IntelliSat tool can be run on a standard e-line unit with surface readout or run with a memory package on slickline or coiled tubing, or with quality-control surface readout data on digital slickline. With the addition of a sleeve, which increases the OD to 2 1/4 inches, the tool can operate in environments up to 20,000 psi and 425 F. For 30,000 psi environments, a 2.48-inch OD housing is available.

The expectation is the tool will launch later this year, as there is still some work to be done on the mineral side of the characterization software.

“We’re quite confident in our saturation models,” Savage said. “We're working hard on mineralogy [and] elemental yields” to be able to deliver lithology and TOC information to operators.